The California Watershed Assessment Manual
California Watershed Assessment Manual Executive Summary August 2004
Authors
Fraser Shilling Sari Sommarstrom Rick Kattelmann Department of Environmental Science and Policy University of California Davis, CA 95616
Joan Florsheim Department of Geology University of California Davis, CA 95616
Russ Henly Fire and Resource Assessment Program Department of Forestry and Fire Protection Sacramento, CA 94244-2460
Barbara Washburn Ecotoxicology Unit Office of Environmental Health Hazard Assessment Sacramento, CA 95812-4010
Technical Editor
Kathryn Ankrum
Funding
California Department of Forestry and Fire Protection The Bay Delta Authority (through CDF)
Cover Photographs
Rick Kattelmann Fraser Shilling Irrigated fields east-side Sierra Nevada Downtown Los Angeles Muir Woods, Iron Mountain
Reference/Citation
Shilling, F., S. Sommarstrom, R. Kattelmann, B. Washburn, J. Florsheim, and R. Henly. California Watershed Assessment Manual. August, 2004. Prepared for the California Resources Agency (http://cwam.ucdavis.edu).
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Acknowledgements
Thanks to our Steering Committee, who assisted us in developing the project, reviewed and edited drafts of the Manual, and continue to provide guidance for this challenging project. We also would like to extend gratitude to the dozens of groups, agencies, and individuals who provided input during the information collection phase of writing the Manual. Finally, we would like to thank the members of the California Biodiversity Council’s Watershed Workgroup and attendees at the Watershed Management Forums who helped get this project off the ground.
Steering Committee
Cathy Bleier (Resources Agency) Sungnome Madrone/Ruth Blyther Dennis Bowker (CALFED) (alternates, For Sake of the Salmon), Ken Coulter (State Water Resources Julia McIver (Coastal Conservancy) Control Board), Liza Prunuske (For Sake of the Salmon), Steve Greco (University of California, Ann Riley (San Francisco Regional Water Davis), Quality Control Board), Dennis Heiman (Central Valley Regional Kevin Shaffer (Department of Fish and Water Quality Control Board), Game) Stefan Lorenzato (Department of Water Brian Staab (United States Forest Resources), Service) Luana Kiger/Vern Finney (Natural Resources Conservation Service)
Contributing Groups/Organizations (In addition to the agencies/organizations represented in our Steering Committee, representatives from these groups, agencies, organizations, and businesses provided feedback in the initial stages of the Manual’s development) o California Departments of Parks & o San Francisco Public Utilities Recreation, Water Resources Commission o East Bay Watershed Center (Merritt o Santa Clara Basin Watershed College) Management Initiative o Friends of Five Creeks o Santa Cruz Blue Circle o Los Angeles San Gabriel Rivers o Sonoma Ecology Center Watershed Council o Southern California Wetlands o Mattole Restoration Council Recovery Project o MUSCI-Natural Resource Assessment o US Army Corps of Engineers (Los o Orange County (Michael Wellborn) Angeles office) o Pacific Lumber Company o US Forest Service (Redwood o Pit River Watershed Alliance Sciences Laboratory) o Regional Water Quality Control Board o Western Shasta Resource (Central Valley, North Coast) Conservation District o Roseburg Forest Products
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Executive Summary
Watersheds by their nature are fluid and team, determining the assessment’s complex, making it difficult to fully purpose, planning and conducting the understand their processes and conditions. assessment work, and completing the Understanding watersheds in California is assessment report. The Manual also all the more challenging, due to the state’s describes the basics of watershed exceptionally diverse array of geographic functioning, thus laying a foundation for and hydrologic conditions, which is overlain understanding the rest of the Manual and by an equally diverse set of social and watersheds generally. It lays out methods economic conditions. The amount of data for defining the assessment’s boundaries, available about these conditions also varies for determining how complex the analysis greatly from watershed to watershed which should be, and for identifying gaps in data, adds to difficulty in understanding knowledge, or analysis. It provides methods watershed condition. All of these factors for gathering, managing, analyzing, and contribute to watershed assessment in the presenting data, and it suggests state being a challenging undertaking. approaches for integrating information in order to better understand watershed “Watershed assessment” is one method conditions. The Manual describes ways to used to understand a watershed. It is a present the assessment and use it to process for evaluating how well a watershed support decision-making and adaptive is functioning. Watershed assessment may management. include identifying important issues, examining historic conditions, evaluating This is the first version of the Manual. It is present conditions and processes, and intended to provide guidance for planning determining the effects of human activities. and conducting watershed assessments for It can mean describing the parts and wildland and rural areas of northern and processes of the whole watershed and central California. However, many aspects analyzing their functioning in general, or of it will be useful for other areas in the state relative to some standard (such as a water and country. Future editions of the Manual quality standard or historic condition). It also will focus on the remainder of California and can mean focusing on particular concerns issues relating to particularly agricultural about human activities, conditions, or and urban areas, pending additional processes in the watershed. funding. We welcome your feedback and contributions, which will make future The California Watershed Assessment versions of the Manual even more Manual provides a series of approaches responsive to the needs of California’s that will assist watershed assessors, and watershed assessors. those guiding assessments, in planning and carrying out watershed assessments. These Manual Structure approaches are appropriate for a variety of watershed stakeholders, including members The Manual currently contains 8 chapters. of watershed groups, agency These flow from the introductory chapter representatives, landowners, scientists, (1), through chapters describing the details members of the academic community, of assessment planning (2), fundamentals business representatives, and consultants. of watershed functioning (3), data collection While the Manual is not prescriptive, it is (4), data analysis (5), and data integration thorough. It presents a comprehensive view (6). Chapter 7 gives details on how to of the watershed assessment process, with structure an assessment report; and chapter specific guidance on starting the process, 8 describes connecting the assessment with putting together an integrated assessment decision-making. An additional chapter (9)
Page 4 California Watershed Assessment Manual Executive Summary August 2004 will talk about using the assessment to assessment and give a rough sketch of the support a continuing assessment (or assessment itself. We also take on the monitoring) program. The Appendix will be a topics of scale, uncertainty, and data and compendium of tools for use in specific knowledge gaps. circumstances and with specific natural or human processes or conditions. The Chapter 3 chapters are described in slightly more detail below. To provide a baseline for understanding the watershed processes that are usually the Chapter 1 subject of watershed assessments, we devote this chapter to describing many of We describe the Manual’s purpose, these processes within the general intended audience, regional focus, identified categories of geography, hydrology, climate, need, development process, format, and geology, sediment, water quality, aquatic next steps in evolution. and terrestrial ecosystems, land and water use and management, and socio- Chapter 2 economics. Readers with substantial background in particular topics can skip We describe some of the decisions that around to areas where they want more need to be made before beginning the information. assessment, after first defining what a watershed assessment is and is not. Chapter 4 Planning topics include deciding the purpose, focusing on questions about This chapter marks the beginning of the watershed condition, developing the data-intensive part of the assessment – the assessment team, working with the collection and organization of information watershed communities, and deciding the about the watershed. We suggest sources boundaries of the analyses and the of information about watershed conditions in assessment area. We talk about steps that California. We also talk about the how to should be taken to prepare for the organize collected data appropriately
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“Ideal” Adaptive Watershed Management relationships between activities in the Sequence watershed and impacts and condition. We also “demystify” modeling, talk about the role of change over time, and provide guidance for conducting scenario Assessment development.
Chapter 7
This chapter describes the basic Monitoring Plan components of a watershed assessment report, including the minimum information to include, how to present different kinds of data, and tailoring the assessment report to match the decision-making process.
Evaluation Implementation Chapter 8
This chapter focuses on the different relative to the questions developed earlier in decision-making processes that a the planning process. watershed assessment can support, since the product is not an endpoint. These Chapter 5 processes range from designing a monitoring program, responding to Data analysis is at the heart of figuring out regulatory requirements for land use or the conditions in the watershed in response nonpoint source pollution discharge, and to questions about these conditions. This local land use planning to developing a chapter provides tools for preparing the data watershed restoration or protection plan. analysis, resources for conducting data analysis and applying statistics, information Chapter 9 (to be constructed) on space and time considerations, and ways to evaluate and present data. Once a watershed assessment is done, it becomes a point in the continuum of Chapter 6 knowledge about a watershed. We will discuss how to make a watershed Information integration is the focus of this assessment a continuing process through chapter. We define information integration periodic assessment and monitoring as the process of synthesizing data on programs. social, physical, chemical, and biological conditions in the watershed, and the Appendix (to be constructed) watershed processes that mediate them, into a single analysis. The integration The Appendix will offer a variety of tools for product is intended to be used for decision- analyzing natural and human processes and support. Data integration is not easily done conditions, organized by topic. For example, and is not commonly done in today’s we will describe how channel processes are watershed assessment. We discuss ways measured, how surface erosion process can that watershed assessors can take be described and quantified, how benthic information collection and knowledge macroinvertebrate data can be collected development, described in earlier chapters, and used in watershed assessment, and and draw conclusions about potential how spatial modeling is conducted.
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Glossary of Terms acid mine drainage (AMD)--water draining out of operating or abandoned mines that has very low pH and may contain high concentrations of various metals and/or sulfur. adaptive management--monitoring or assessing the progress toward meeting management objectives and incorporating what is learned into future conceptual models, management plans and actions, and monitoring. anadromous--a type of life cycle where fish return from the ocean to freshwater to spawn aqueduct--a pipe, conduit, or channel designed to transport water from a remote source, usually by gravity. aquifer--a geologic formation(s) that is water bearing. A geological formation or structure that stores and/or transmits water, such as to wells and springs. Use of the term is usually restricted to those water-bearing formations capable of yielding water in sufficient quantity to constitute a usable supply for people's uses. aquifer (confined)--soil or rock below the land surface that is saturated with water. There are layers of impermeable material both above and below it and it is under pressure so that when the aquifer is penetrated by a well, the water will rise above the top of the aquifer. aquifer (unconfined)--an aquifer whose upper water surface (water table) is at atmospheric pressure, and thus is able to rise and fall. artificial recharge--an process where water is put back into ground-water storage from surface-water supplies such as irrigation, or induced infiltration from streams or wells. base flow--streamflow coming from ground-water seepage into a stream. benthic--referring to the bottom of a waterway benthic macroinvertebrates--invertebrates (e.g., snails, worms, aquatic larvae of insects) living in or on the benthos (bottom) of waterways. bioengineering--usually plant-based structural approaches to controlling geomorphological responses to land-uses and disturbance. biota--living things, such as plants, animals, and microorganisms. capillary action--the means by which liquid moves through the porous spaces in a solid, such as soil, plant roots, and the capillary blood vessels in our bodies due to the forces of adhesion, cohesion, and surface tension. Capillary action is essential in carrying substances and nutrients from one place to another in plants and animals.
Central Valley Project (CVP) - Federally operated water management and conveyance system that provides water to agricultural, urban, and industrial users in California
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Central Valley Project Improvement Act (CVPIA) - This federal legislation, signed into law on October 30, 1992, mandates major changes in the management of the federal Central Valley Project. The CVPIA puts fish and wildlife on an equal footing with agricultural, municipal, industrial, and hydropower users commercial water use--water used for motels, hotels, restaurants, office buildings, other commercial facilities, and institutions. Water for commercial uses comes both from public-supplied sources, such as a county water department, and self-supplied sources, such as local wells. conceptual model--a descriptive picture or diagram of the relationships among key factors within the watershed. Explicit statements of the hypothesized functional relationships underlying management decisions regarding environmental resources." conjunctive use - Integrated management of surface water and groundwater supplies to meet overall water supply and resource management objectives consumptive use--that part of water withdrawn that is evaporated, transpired by plants, incorporated into products or crops, consumed by humans or livestock, or otherwise removed from the immediate water environment. Also referred to as water consumed. conveyance loss--water that is lost in transit from a pipe, canal, or ditch by leakage or evaporation. Generally, the water is not available for further use; however, leakage from an irrigation ditch, for example, may percolate to a ground-water source and be available for further use. cubic feet per second (cfs)--a rate of the flow, in streams and rivers, for example. It is equal to a volume of water one foot high and one foot wide flowing a distance of one foot in one second. One "cfs" is equal to 7.48 gallons of water flowing each second. As an example, if your car's gas tank is 2 feet by 1 foot by 1 foot (2 cubic feet), then gas flowing at a rate of 1 cubic foot/second would fill the tank in two seconds. cumulative watershed effects (CWE)—the combined impact on watershed processes from multiple sources of natural and human disturbance in a watershed. decompose--to rot or decay discharge--the volume of water that passes a given location within a given period of time. Usually expressed in cubic feet per second. disturbance--a change or cause of change in an ecosystem originating from natural or human sources. A natural disturbance could be fire or flood, a human-caused disturbance could be land development or logging. diversion - The action of taking water out of a river system or changing the flow of water in a system for use in another location domestic water use--water used for household purposes, such as drinking, food preparation, bathing, washing clothes, dishes, and dogs, flushing toilets, and watering lawns and gardens. About 85% of domestic water is delivered to homes by a public-
2 California Watershed Assessment Manual -- Glossary January 2005 supply facility, such as a county water department. About 15% of the Nation's population supply their own water, mainly from wells. drainage basin--land area where precipitation runs off into streams, rivers, lakes, and reservoirs. Large drainage basins, like the area that drains into the Mississippi River contain thousands of smaller drainage basins. Usually considered larger than a "watershed." drawdown--a lowering of the ground-water surface caused by pumping. ecological processes—processes that act directly, indirectly, or in combination, to shape and form the ecosystem. These include streamflow, watershed (closely linked to streamflow; includes fire and erosion), stream channel (includes stream meander, gravel recruitment and transport, water temperature, and hydraulic conditions), and floodplain processes (include overbank flooding and sediment retention and deposition). [ ecosystem--a biological community together with the physical and chemical environment with which it interacts ecosystem function--1) any performance attribute or rate function at some level of biological organization (e.g., energy flow, detritus processing, nutrient spiraling; 2) Ecosystem productivity and functions of hydrology, feeding, and transport ecosystem management-- management that integrates ecological relationships with sociopolitical values toward the general goal of protecting or returning ecosystem integrity over the long term effluent--material flowing from a source, such as wastewater from a treatment plant enhancement-- in the context of restoration ecology, any improvement of a structural or functional attribute.
EPT index--the relative abundance of three pollution-sensitive orders of benthic macroinvertebrates to the abundance of a tolerant species of benthic macroinvertebrate. (the sum of the number of Ephemeroptera, Plecoptera, and Trichoptera divided by the total number of midges, Diptera: Chironomid) erosion--the process in which a material is worn away by a stream of liquid (water) or air, often due to the presence of abrasive particles in the stream. eutrophication—the gradual increase in nutrient concentrations of nutrients in a water- body from cycles of plant growth and decomposition, where the plant growth exceeds the consumption by grazing animals. This can result in low oxygen concentrations in the water due to microbial activity in the decomposing plant material. evaporation--the process of liquid water becoming water vapor, including vaporization from water surfaces, land surfaces, and snow fields, but not from leaf surfaces. evapotranspiration--the sum of evaporation and transpiration.
3 California Watershed Assessment Manual -- Glossary January 2005 flood-- flow that exceeds the capacity of the channel. Floods have two essential characteristics: The inundation of land is temporary; and the land is adjacent to and inundated by overflow from a river, stream, lake, or ocean. flood, 100-year--A 100-year flood does not refer to a flood that occurs once every 100 years, but to a flood level with a 1 percent chance of being equaled or exceeded in any given year. flood plain--a strip of relatively flat and normally dry land alongside a stream, river, or lake that is covered by water during a flood. fluvial--to do with streams and rivers gaging station--a site on a stream, lake, reservoir or other body of water where observations and hydrologic data are obtained. geographic information system (GIS)--a tool used to collect, store, combine, analyze and present geographic data (e.g., computer software such as ArcView, ESRI Inc.). geomorphology--the study of earth surface processes and landforms, including landslides on hillslopes or erosion and sedimentation in rivers. ground water--(1) water that flows or seeps downward and saturates soil or rock, supplying springs and wells. The upper surface of the saturate zone is called the water table. (2) Water stored underground in rock crevices and in the pores of geologic materials that make up the Earth's crust. habitats--areas that provide specific conditions necessary to support plant, fish, and wildlife communities. headwater streams--the small streams in the upper parts of the watershed that feed into larger streams below hydrologic cycle--the cyclic transfer of water vapor from the Earth's surface via evapotranspiration into the atmosphere, from the atmosphere via precipitation back to earth, and through runoff into streams, rivers, and lakes, and ultimately into the oceans. impermeable layer--a layer of solid material, such as rock or clay, which does not allow water to pass through. impervious surface--usually a human-manufactured surface that water cannot penetrate (e.g., asphalt-covered street). indicators--features or attributes of the system that are expected to change over time in response to implementation of management actions. Indicators are selected to provide measurable evaluations of important ecological processes, habitats, and species whose status individually and cumulatively provide an assessment of ecological health. Indicators of ecosystem health are the gauges we will use to measure progress toward the goal. infiltration--flow of water from the land surface into the subsurface.
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integrated resource management-- resource management that seeks to restore the structure and function of whole ecosystems by striving to understand and respond holistically to cumulative ecological impacts. integrated water management--a way to maximize water quality and quantity to meet water needs for consumptive use and aquatic ecosystems by integrating water and land- use decision-making by local and regional agencies. irrigation--the controlled application of water for agricultural purposes through manmade systems to supply water requirements not satisfied by rainfall. monitoring--the periodic collection of information about a process (e.g., change in vegetation in response to disturbance) or attribute (e.g., water temperature) that may be an indicator of condition or management actions. municipal water system--a water system that has at least five service connections or which regularly serves 25 individuals for 60 days; also called a public water system non-point source (NPS) pollution--pollution discharged over a wide land area, not from one specific location. These are forms of diffuse pollution caused by sediment, nutrients, organic and toxic substances originating from land-use activities, which are carried to lakes and streams by surface runoff. Non-point source pollution is contamination that occurs when rainwater, snowmelt, or irrigation washes off plowed fields, city streets, or suburban backyards. As this runoff moves across the land surface, it picks up soil particles and pollutants, such as nutrients and pesticides. nutrient an element or compound required by a living organism for growth. pH--a measure of the relative acidity or alkalinity of water. Water with a pH of 7 is neutral; lower pH levels indicate increasing acidity (high concentration of hydrogen ions), while pH levels higher than 7 indicate increasingly basic solutions (low concentration of hydrogen ions). parameter--measured or observed property pathogen--a disease-producing agent; usually applied to a living organism. Generally, any viruses, bacteria, or fungi that cause disease. peak flow--the maximum instantaneous discharge of a stream or river at a given location. percolation--the movement of water through the openings in rock or soil. permeability--the ability of a material to allow the passage of a liquid, such as water through rocks. Permeable materials, such as gravel and sand, allow water to move quickly through them, whereas impermeable materials, such as clay, don't allow water to flow freely. point-source pollution--water pollution coming from a single point, such as a sewage- outflow pipe.
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porosity--a measure of the water-bearing capacity of subsurface rock. With respect to water movement, it is not just the total magnitude of porosity that is important, but the size of the voids and the extent to which they are interconnected, as the pores in a formation may be open, or interconnected, or closed and isolated. For example, clay may have a very high porosity with respect to potential water content, but it constitutes a poor medium as an aquifer because the pores are usually so small. potable water--water of a quality suitable for drinking. precipitation--rain, snow, hail, sleet, dew, and frost. public supply--water withdrawn by public governments and agencies, such as a county water department, and by private companies that is then delivered to users. Public suppliers provide water for domestic, commercial, thermoelectric power, industrial, and public water users. public water use--water supplied from a public-water supply and used for such purposes as firefighting, street washing, and municipal parks and swimming pools. rating curve--A drawn curve showing the relation between gage height and discharge of a stream at a given gaging station. recharge--water added to an aquifer. For instance, rainfall that seeps into the ground. regime--a natural pattern in at least two time scales: for example, the daily-to-seasonal variation in water and sediment loads, and the annual-to-decadal patterns of floods and droughts. rehabilitation-- used primarily to indicate improvements of a visual nature to a natural resource; putting back into good condition or working order remediation--a process by which something is fixed or repaired remote sensing--the detection of conditions (e.g., types of plants) on the landscape through the use of satellite and aerial photography/imagery. reservoir--a pond, lake, or basin, either natural or artificial, for the storage, regulation, and control of water. restoration--1) return of an ecosystem, or ecosystem process to a close approximation of its condition prior to human disturbance; 2) the renewal of a natural process (e.g., natural fire regimes) or feature (e.g., native fish species) through human actions restoration, ecological-- involves replacing lost or damaged biological elements (populations, species) and reestablishing ecological processes (dispersal, succession) at historical rates. restoration, stream-- various techniques used to replicate the hydrological, morphological, and ecological features that have been lost in a stream due to urbanization, farming, or other disturbance.
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return flow--(1) that part of a diverted flow that is not consumptively used and returned to its original source or another body of water. (2) (Irrigation) Drainage water from irrigated farmlands that re-enters the water system to be used further downstream. riffle--the part of a stream with shallow, fast-moving water flowing over cobbles or rocks. riparian—the region of the landscape immediately adjacent to and influenced by a waterway with moving water. risk assessment--analysis, characterization, and possible quantification of the risks to health or the environment from disturbing agents or stressors river--a natural stream of water of considerable volume, larger than a brook or creek. runoff --that part of the precipitation, snow melt, or irrigation water that appears in uncontrolled surface streams, rivers, drains or sewers. Runoff may be classified according to speed of appearance after rainfall or melting snow as direct runoff or base runoff, and according to source as surface runoff, storm interflow, or ground-water runoff. sediment--usually applied to material in suspension in water or recently deposited from suspension. In the plural the word is applied to all kinds of deposits from the waters of streams, lakes, or seas. sediment budget--a mass balance of sediment supply, storage, and yield over time seepage--(1) The slow movement of water through small cracks, pores, Interstices, etc., of a material into or out of a body of surface or subsurface water. (2) The loss of water by infiltration into the soil from a canal, ditches, laterals, watercourse, reservoir, storage facilities, or other body of water, or from a field. solute--a substance that is dissolved in another substance, thus forming a solution. species diversity--the relative density of an individual or group of species compared to the density of all species stakeholder--someone who will be impacted socially, culturally, financially, physically, or in some other manner by a decision or decision process
State Water Project (SWP)--a state-operated water management and conveyance system that provides water to agricultural, urban, and industrial users in California. storm sewer--a sewer that carries only surface runoff, street wash, and snow melt from the land. In a separate sewer system, storm sewers are completely separate from those that carry domestic and commercial wastewater (sanitary sewers). stream--a general term for a body of flowing water; natural water course containing water at least part of the year. In hydrology, it is generally applied to the water flowing in a natural channel as distinct from a canal.
7 California Watershed Assessment Manual -- Glossary January 2005 streamflow--the water discharge that occurs in a natural channel. A more general term than runoff, streamflow may be applied to discharge whether or not it is affected by diversion or regulation. stream order--the relative size of a stream compared to other streams in the watershed; first-order streams are the smallest and twelfth order the largest. stressor--natural or unnatural sources of stress to a system or component of a system (usually called the “receptor” for the stressor). substrate--the sediment material that makes up the benthos of a waterway surface water--water that is on the Earth's surface, such as in a stream, river, lake, or reservoir. suspended sediment--very fine soil particles that remain in suspension in water for a considerable period of time without contact with the bottom. Such material remains in suspension due to the upward components of turbulence and currents and/or by suspension. thermal pollution--a reduction in water quality caused by increasing its temperature, often due to disposal of waste heat from industrial or power generation processes. Thermally polluted water can harm the environment because plants and animals can have a hard time adapting to it.
Total Maximum Daily Loads (TMDLs)—the maximum amounts of individual pollutants contributing to impairment of the “beneficial uses” of the waterbody allowed to enter a waterbody from watershed sources transpiration--process by which water that is absorbed by plants, usually through the roots, is evaporated into the atmosphere from the plant surface, such as leaf pores. tributary--a smaller river or stream that flows into a larger river or stream. Usually, a number of smaller tributaries merge to form a river. turbidity--the amount of solid particles that are suspended in water and that cause light rays shining through the water to scatter. Thus, turbidity makes the water cloudy or even opaque in extreme cases. unsaturated zone--the zone immediately below the land surface where the pores contain both water and air, but are not totally saturated with water. These zones differ from an aquifer, where the pores are saturated with water. water cycle -- the circuit of water movement from the oceans to the atmosphere and to the Earth and return to the atmosphere through various stages or processes such as precipitation, interception, runoff, infiltration, percolation, storage, evaporation, and transportation. water quality--a term used to describe the chemical, physical, and biological characteristics of water, usually in respect to its suitability for a particular purpose.
8 California Watershed Assessment Manual -- Glossary January 2005 water table--the top of the water surface in the saturated part of an aquifer. water use--water that is used for a specific purpose, such as for domestic use, irrigation, or industrial processing. Water use pertains to human's interaction with and influence on the hydrologic cycle, and includes elements, such as water withdrawal from surface- and ground-water sources, water delivery to homes and businesses, consumptive use of water, water released from wastewater-treatment plants, water returned to the environment, and instream uses, such as using water to produce hydroelectric power. watershed--the region draining into a river, river system, or other body of water above a particular point. watershed assessment--a process for analyzing a watershed's current condition and the likely causes of these conditions, usually resulting in a report documenting findings of the process. watershed health-- 1) an index or estimate of the degree to which the generation and transport of water and its constituents within a watershed function in a relatively natural manner; 2) an index or estimate of the natural functioning of the watershed relative to a reference or historic condition. watershed management--1) a multiple-step, iterative process consisting of watershed monitoring, assessment, planning, implementation, and evaluation; 2) a process for making decisions about activities that will affect the health of a watershed. watershed plan--the product of a planning process a the watershed scale considering natural and human processes relevant at the scale (e.g., natural and artificial flows). Sometimes used synonymously with “watershed management plan”. A watershed plan consists of an overall vision or set of goals for the watershed, a series of steps needed to achieve those goals, and detailed consideration of how to implement those steps. watershed restoration-- reestablishing the structure and function of an ecosystem, including its natural diversity; a comprehensive, long-term program to return watershed health, riparian ecosystems, and fish habitats to a close approximation of their condition prior to human disturbance. well (water)--an artificial excavation put down by any method for the purposes of withdrawing water from the underground aquifers. A bored, drilled, or driven shaft, or a dug hole whose purpose is to reach underground water supplies or oil, or to store or bury fluids below ground. wetland--an area of the landscape that is periodically or frequently inundated and containing vegetation and animals adapted to that condition. withdrawal--water removed from a ground- or surface-water source for use.
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Compiled from online and other sources http://ga.water.usgs.gov/edu/dictionary.html http://water.nv.gov/Water%20planning/dict-1/wwords-a.pdf
Comprehensive Monitoring and Research Program; http://www.iep.water.ca.gov/cmarp/groups/toc.html)
Classroom of the Future/Center for Educational Technology (Water Quality Module); http://www.cotf.edu/ete/modules/waterq3/WQglossary.html
National Research Council. 1992. Restoration of Aquatic Ecosystems: Science, Technology, and Public Policy. National Academy Press, Washington, D.C., 552 p.
The California Agency Watershed Management Strategic Plan (CalEPA and Resources Agency 2003)
U.S. Environmental Protection Agency. 2003. Framework for Cumulative Risk Assessment. USEPA EPA/600/P-02/001F. 01 Jan 2003. U.S. Environmental Protection Agency, Office of Research and Development, National Center for Environmental Assessment, Washington, D.C. 129 pp. http://cfpub.epa.gov/ncea/raf/recordisplay.cfm?deid=54944
Williams, J.E., Wood, C.A., and M.P. Dombeck, editors. 1997. Watershed Restoration: Principles and Practices. American Fisheries Society, Bethesda, Maryland. 561 p. 1997
Additional Online Watershed Glossaries
Hubbard Brook Ecosystem Study (USDA Forest Service); http://www.hubbardbrook.org/education/Glossary/Glossary.htm
Know Your Watershed (Conservation Technology Information Center – National Association of Conservation Districts) http://www.ctic.purdue.edu/KYW/glossary/glossary.html
Science in Your Watershed (USGS online glossary); http://water.usgs.gov/wsc/glossary.html
Terms of the Environment (USEPA); http://www.epa.gov/OCEPAterms/
Water on the Web (University of Minnesota Duluth and Lake Superior College); http://waterontheweb.org/resources/glossary.html
Watershed Education for Communities and Local Officials (North Carolina Cooperative Extension Service); http://www.ces.ncsu.edu/depts/agecon/WECO/pdfs/Watershed%20Glossary.pdf
10 California Watershed Assessment Manual, Chapter 1 August, 2004
1 Introduction
Californians are responsible for protecting provide a range of ways to approach a and managing their natural environment. problem. Watersheds, also known as catchment or drainage basins, provide a useful, natural The Manual includes guidance on planning unit for better understanding and achieving and operational principles and steps that this responsibility (California Resources are useful for assessment processes Agency & State Water Resources Control anywhere in the state. The topics addressed Board 2002). Assessing a watershed to in the Manual cover the primary natural and understand its current condition, and how it human processes in rural watersheds of got there, is usually the first step taken in northern and central California. Many of the developing a strategy toward improving and approaches for assessing urban and protecting the watershed’s condition. agricultural areas are still being developed for inclusion in a future update of the Chapter Outline Manual. The optimal organizational and geographic scale for use of the Manual is 1.1 Audience and Purpose of the for watershed groups conducting Manual assessments in 10,000-acre to 1 million- 1.2 What are Watersheds and acre watersheds. Watershed Assessments? 1.3 Approach Taken in this Manual The key reasons for developing this Manual 1.4 How Complex Should Your are: Assessment Be? 1.6 Manual Development 1. Citizen organizations and agencies 1.7 Next Steps in Manual’s Evolution requested a manual 1.8 References ______The “12 Steps to Watershed Recovery in California,” an action plan developed in May 1.1 Audience and Purpose of the Manual 2000 at the California Watershed Management Forums (Watershed The California Watershed Assessment Management Council 2000), included a Manual (CWAM or Manual) provides recommendation for developing a state guidance for conducting a watershed manual to help provide consistency and assessment in California. It is intended to clear expectations to watershed groups, support the planning and technical needs managers, and restoration specialists about primarily of watershed groups but also local recommended methods for: watershed and state agencies, academic scientists, assessments, water quality and habitat consultants, and individuals involved in monitoring, data reporting, and watershed developing and conducting a watershed plans. Further, Assembly Bill 2117 Report assessment. In doing so, the Manual to the Legislature (CRA & SWRCB 2002) includes the recognition that not all identified the following need: “Develop assessments have the same level of manuals that define the minimum level of complexity of questions or analysis. It is science needed for acceptable watershed intended to reduce the reinventing of assessments, watershed plans, and planning, data collection, and analysis monitoring activities. These manuals should approaches each time an assessment is provide technical assistance to newly done. This will result in less time spent by formed watershed partnerships and to those the assessor getting up to speed and choosing to upgrade their existing assessments and plans. The manuals
- 1 - California Watershed Assessment Manual, Chapter 1 August, 2004 should build on existing manuals and hydrological, geological, and biological provide a menu-driven approach that can be diversity. Further, most do not discuss tailored to the unique conditions of each methods for synthesizing data that links watershed in California.” human activities to alterations in watershed processes. The Oregon Watershed CWAM is a response to these requests. Assessment Manual (WPN 1999) probably is the closest to meeting the needs of 2. State watershed grant programs want California practitioners. Its target audience assessments is quite similar, the format is user-friendly, and the content is scientifically sound. CWAM seeks to provide useful information However, it focuses only on salmon- to fulfill the requirement of many grant producing watersheds, the local examples programs for watershed assessments (see are all from Oregon, and the state technical text box below). Although the Manual and information sources are not applicable includes assessment approaches and to California. Its low-tech, low-cost methods that are compatible with these approach offers some advantages, but state-agency funding programs, anyone because of this approach, the manual does conducting a state-funded watershed not include computer-modeling methods. In assessment should clarify proposed addition, it does not address a variety of methodology with the appropriate state important assessment issues related to funding agencies. scale, data analysis, complexity of analysis, and information integration.
State Watershed Grant Programs
State Agency Watershed Grant Program California Bay-Delta Authority Watershed Program (CALFED) Watershed Restoration Program, Resource Enhancement Coastal Conservancy Program, Southern California Wetland Recovery Program California Department of Resource Conservation District Grants / Watershed Conservation Coordinator Grants California Department of Fish & Fisheries Restoration Grants Program (CCSRP, Prop. 40) Game California Department of Water Urban Streams Restoration Program Grants Resources State Water Resources Control Nonpoint Source Program (NPS), Prop. 13, Prop. 204, CWA Board 205(j), CWA 319(h), Prop. 40, Prop. 50
3. Other manuals do not necessarily meet California’s needs Watershed conditions related to forest This Manual is intended to complement and practices are the emphasis of several other extend the information in other manuals. state manuals: the Washington manual Whereas other states, such as Oregon and (Washington Department of Natural Washington, have prepared very useful Resources, 1997), California’s North Coast manuals, no single existing manual meets Watershed Assessment Program Manual the unique and current needs of local (North Coast Watershed Assessment watershed practitioners in California, mainly Program, 2002), and the watershed analysis because of the State’s incredible manual for Jackson Demonstration State
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Attributes of Successful and Failed Watershed Analysis: Live or Dead? (from: Furniss 2001)
Live Watershed Analysis Dead Watershed Analysis - As It Should Be - - As It Sometimes Is - Science-based Truth by assertion Multiple scales, scale integrative Single scale, not scale integrative Interdisciplinary Mono-disciplinary Needed and effective inquiry Doing what I like to do Place-based Actions-, proposals-, recommendations-based Genuine learning Shoring up one’s position Syn-ecological Aut-ecological Rates States Open, readily updated and revised Onto the shelf. “Done” Clean communication Jargon-encrusted Finds the holes, the critical uncertainties Data bulking, nothing but knowns and givens Seeking truth Same old advocacy, spin, and worn-out, unexamined conclusions Embracing complexity Oversimplified Active doubt Dogma Distilled meaning Gobs of data Multiple hypotheses Single hypothesis, tightly held Parallel, iterative Strictly linear Questions oriented Methods oriented Seeking results Process obsessed Teaching each other Strutting our stuff Adaptive, seeks to learn from failures Static, ignores failures Discerns patterns Obsessed with details Discovers that it’s an elephant “This is a fire hose, a brief case, a hat, a…” Integrative Reductionist GIS is a tool Obsessed with GIS Welcomes and encourages critique Critique is unwelcome and polarizes Findings based on logic and backed by Data bulking with no logic trail data between data and conclusions
Forest in Mendocino County (Stillwater (USDA Forest Service, 2000). In addition, Sciences 1999). The assessment methods the issues that these forest and wildland described in these three manuals require guides address are not always applicable to professional knowledge and extensive the rest of California, their focus on public experience with physical and biological lands means they may differ appreciably in analyses. Other limitations pertain to the purpose (e.g., urban and agricultural issues federal land managers’ equivalents of are not addressed at all), users, scale, data watershed assessment manuals, such as collection, management options etc. For the guides for “Ecosystem Analysis at the these reasons, to name a few, there is a Watershed Scale” (U.S. Department of need for a California-specific manual. Agriculture 1995), “Hydrologic Condition However, the manuals from other states Assessment” (U.S. Department of Interior & and agencies can provide very useful U.S. Department of Agriculture, 1998), or information. Links to many other manuals “Reconnaissance Level Assessment”
- 3 - California Watershed Assessment Manual, Chapter 1 August, 2004 are posted on the CWAM website A “watershed” is defined as “the region (http://cwam.ucdavis.edu). draining into a river, river system, or other body of water above a particular 4. A manual will improve assessment point.” Geologists commonly refer to quality and lower costs watersheds as drainage basins. In Australia, New Zealand, and Great Britain, Common shortcomings seen in many watersheds may also be called catchments. assessments include data cataloging with It is not uncommon for people to use the little attempt at analysis, little integration of term ‘watershed’ to refer to a stream or different parts of the assessment, weak riparian corridor. In fact, a stream is just application of science, and few links to one part of the watershed. Common zones decision-making processes. within a watershed, often used for management purposes, are: 1) the upland By clearly identifying a variety of accepted area, the land above the zone inundated by assessment methods, and presenting floods or the transition between riparian and various data integration and analysis terrestrial vegetation, 2) the riparian zone, techniques, this Manual can be used as a the vegetated area between the waterbody tool to help improve the quality of watershed edge and the upland area, and 3) the assessments being performed and increase waterbody itself, any stream, river, the effectiveness of state-supported abandoned channel, pond, lake, wetlands, watershed projects. Assessment estuary, or ocean (U.S. Environmental preparation costs can also be reduced. Protection Agency, 2002). Ecologists also Groups often spend time and money distinguish between headwaters, where (through consultants or staff time) to identify water, sediment, and nutrients originate and available assessment options, a process hillslope is important (Meyer et al. 2003), that can be redundant and inefficient. The and lowlands, where channel and floodplain Manual helps individuals and organizations interactions are important (Vannote et al., narrow options at the outset. As a result, it 1980). saves time and money by reducing the spinning of wheels so common at the start Most of California’s river systems eventually of the process, and it gets the assessment drain into the ocean. On the east side of the process underway more quickly. Sierra and in arid regions like the Mojave Desert, water may drain into a water body 1.2 What are Watersheds and Watershed that has no outlet to the ocean. A Assessments? watershed’s physical features may include valleys, floodplains, ridges, plateaus, A common saying holds that “we all live in a foothills, mountains, stream and river watershed,” yet watersheds and their needs channels, riparian environments, estuaries, for assessment can be quite diverse. A and wetlands. watershed assessment for San Jose’s watershed (Santa Clara Basin), for example, The size of watersheds in California varies will be different from one for Honeydew’s from very small such as the one-square-mile (Mattole River watershed) or for Porterville’s Codornices Creek watershed in Berkeley to (Tule River watershed). There are still very large such as the 26,000-square-mile common features, however, for defining Sacramento River Basin. “watershed” and “watershed assessment” for the purposes of this Manual. Despite The term “watershed assessment” has their diversity, watershed practitioners agree been described in a variety of ways: to common definitions. It is useful to know these definitions when conducting an 1. The analysis of watershed information to assessment. draw conclusions concerning the
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conditions in the watershed. (Nehalem • A description of how the analysis can River Watershed Assessment, assist with decision making in the Washington) watershed; 2. A process for evaluating how well a • A design for the collection of future watershed is working. (Oregon monitoring data; and Watershed Assessment Manual, • A strategy to evaluate future data and Watershed Professionals Network, communicate that information via a 1999) status and trends analysis. 3. A process that characterizes current watershed conditions at a coarse scale An assessment moves beyond a simple using an interdisciplinary approach to description of what a watershed looks like, collect and analyze information. (North or what historical activities took place in the Coast Watershed Assessment Program watershed. While these are some of the 2001) building blocks, an assessment should try to 4. The translation of scientific data into connect past and current human activities policy-relevant information that is with current conditions and processes. To suitable for supporting decision making the degree that hypotheses can be and action at the watershed level. developed about these relationships or (Watershed Academy, U.S. actual cause and effect relationships can be Environmental Protection Agency). identified, the watershed practitioners can propose solutions to problems and identify Despite their differences, what is common to ways to achieve common goals. Without this each definition is a process composed of understanding, proposed solutions may actions—analysis, process, translation—that address only the symptoms. Frequently, leads to the interpretation of information watershed assessments stop short of about the watershed’s current condition. making critical connections, yet are What is most critical is that the watershed considered complete. A successful assessment effort lead to a better watershed assessment leads to the understanding of watershed condition and implementation of actions that benefit why the watershed is in a certain condition. watershed processes and conditions—the In this way, the assessment becomes a ultimate “performance measure”. useful tool to help direct further actions. A watershed assessment is ideally part of an A watershed assessment is usually overall watershed management package composed of: consisting of: • A question or set of questions about • Problem or needs identification watershed condition that sets • Assessment and analysis boundaries on the assessment; • Planning • A collection of relevant information about • Implementation human and natural processes at the • Monitoring and evaluation watershed scale; • Adaptive management • The identification of gaps in knowledge; • The combination of information about What an Assessment Is various natural processes to reflect the • An objective problem-solving tool that integrated nature of watersheds; identifies the potential causes of • Analysis and synthesis of the information problems regarding the watershed’s condition • The scientific interpretation of watershed drawn from data collections, often at information and data, leading to various geographic scales; conclusions about watershed condition
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• A tool to help identify data and information gaps Decision making, however, is part of the • Analysis and findings that can be used planning process that follows an to develop appropriate actions assessment. The assessment report itself is • A component of a watershed not the place to make management or policy management package that leads to recommendations. The appropriate planning, implementation, evaluation, decision-makers should deal with the and additional monitoring assessment’s findings under the necessarily • A product that is useful for its audience subjective next step, which begins the planning process. What to do—such as What an Assessment Is Not identifying and recommending specific • Monitoring and data collection only projects, policies, and priorities—is not • A list of data only necessarily obvious or easy. Political and • A consolidation or summary of existing economic choices come into play during the information only planning stage, which includes deciding the what, where, when, and how to be • Historical conditions or “baseline” only accomplished in the implementation phase • An identification of symptoms of (see Chapter 8). As a result, it is best to problems only clearly separate the “apolitical” assessment • A plan product from those decisions, which may • An endpoint have political, economic, or social implications. The sequence in the diagram below describes an ideal process, involving a In practice, watershed assessments and cycle of data collection, analysis, strategy, plans are sometimes combined into one decisions, actions, evaluation, and more document in order to fulfill a grant data collection. Feedback loops that assess requirement or to show the transition from whether the watershed’s problems are assessment to plan. In these cases, the improving – at the project or action level and assessment product should be distinct from at the watershed level – are important for the planning product so the reader can first gauging success. understand the findings and then see what choices were made. “Ideal” Adaptive Watershed Management Sequence A federal watershed analysis usually suggests “management recommendations responsive to watershed processes Assessment identified in the analysis,” but these suggestions are only for federal lands, which represent a different situation than a mixed- ownership watershed with various management expectations (Regional Monitoring Plan Interagency Executive Committee 1995).
1.3 Approach Taken in This Manual
The Manual provides a toolbox of appropriate approaches and methods designed to help those developing and Evaluation Implementation conducting watershed assessments. These approaches and methods address:
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A watershed assessment is: “a process for analyzing a watershed's current condition and the likely causes of these conditions”.
A watershed assessment report is: “a report documenting the findings of the watershed assessment process.”
involving an array of mathematical models. • Developing questions and strategies for The team contributing to this Manual conducting a watershed assessment; discussed various approaches to levels of • Determining the necessary complexity analysis over several months. Eventually, of an assessment (e.g., from the team decided that there wasn’t much reconnaissance to thorough) value to dividing the continuum of detail into • Collecting appropriate data; several discrete groups. The spectrum of • Analyzing data while taking appropriate progressive detail and analysis does not account of time and space scale issues naturally break into clean categories. and uncertainty about data and results; Different parts of an assessment will • Integrating the data to assess inevitably receive different degrees of watershed condition; and attention and analysis depending on the • Ensuring that the assessment can be personal interests of the people developing integrated with future watershed the assessment, the expertise and monitoring, planning, implementation, availability of those people, the principal and evaluation. issues and driving questions of the watershed assessment, data availability, The approaches and methods described in financial resources, and time constraints. In the Manual are guidance for watershed most cases, the level of effort will simply assessment and are not the State’s depend on how thorough an assessment prescription of how watershed assessments you desire balanced against your constraints must be done. While the Manual presents of time, money, and data. Another way to various existing tools and techniques, other evaluate the appropriate level of detail for a valid tools and techniques are also possible. particular part of your watershed In keeping with comments received during assessment is to consider the following the Manual’s development, it is neither a question: How much confidence in your “one-size-fits-all” guide nor a “cookbook”. conclusions can you afford? Alternatively, Given California’s diverse landscapes and how much uncertainty can you live with? watersheds, there is a need for creative and flexible approaches to performing In practice, most watershed assessments watershed assessments. At the same time, that lie in between a simple reconnaissance however, watershed assessments and other and a multi-decade, thoroughly components of watershed management interdisciplinary watershed research project should be founded in credible, science- vary in their level of detail in different based approaches like those described in aspects of the assessment. Some rely only this Manual. on existing data, but use that data in some complex mathematical models to arrive at 1.4 How Complex Should Your some carefully considered conclusions. Assessment Be? Others compile a mass of existing data and just tabulate it without any real analysis. Still Watershed assessments can be conducted other assessments acquire a lot of new data at a wide range of levels of detail and that present a thorough snapshot of current complexity – from simple reconnaissance- conditions, but largely ignore historical level overviews to very thorough studies information and are thus unable to say
- 7 - California Watershed Assessment Manual, Chapter 1 August, 2004 anything about how the current condition expertise, interest, and money will limit what developed. Some assessments are strong you can do at any stage. At almost every on hydrology and geomorphology, but pay possible level of detail, there is something to little attention to biology. Conversely, some be learned from an assessment—something assessments are all about biology and give that will contribute to dealing with the issues scant attention to the physical environment. and questions you have identified. Very few assessments adequately consider the social aspects of the watershed or of the In an effort to give you a better assessment process itself. Because most understanding of the diversity of types of assessments are a mix of complexity in watershed assessments and the various various parts, ranking one as “more levels of complexity associated with them, advanced” than another usually requires the following assessments and URLs are focusing on just a single aspect of the provided for your review. assessments. 1. Basic watershed assessments Some of the factors that contribute to the complexity of an assessment are: • Aliso Creek (USACE/OC) • Data Quantity http://www.ocwatersheds.com/watersheds/A • Data Quality liso_reports_studies.asp. • Data Analysis • Tomales Bay Watershed Stewardship • Data Synthesis & Integration Plan • Professional Understanding and www.tomalesbaywatershed.org/stewardship. Acceptance html • Social Understanding and • Cottonwood Creek Watershed Acceptance Assessment/Analysis Estimating where along the continuum of http://wim.shastacollege.edu/watersheds.as LOW HIGH various aspects of the px?ws=5 assessment fall provides an indication of the complexity of the analysis. For example, 2. Intermediate level of complexity one assessment might reflect very high data quality but low data analysis. Watershed • Arroyo Seco Watershed Restoration assessments that have most marks near the Feasibility Study higher end of the scale will be more complex www.arroyoseco.org/WatershedSlides.htm and have a lower degree of uncertainty • Upper Clear Creek Watershed Analysis associated with the conclusions than those www.shastalink.k12.ca.us/clearcreek/WA%2 that fall toward the lower end of the scale. 0Final.htm Valuable assessments can and have been • Aptos and Gazos Creeks performed at all points along the continuum. www.coastal-watershed.org Perhaps the important thing to remember is that you can approach your assessment in 3. More complex watershed assessments many different ways at many different levels of detail and still end up with a useful • Lake Tahoe Watershed Assessment product IF your approach fits your issues www.fs.fed.us/sw/publications/documents/gt and problems. The only real way to know r-175/. whether your approach has potential is to • North Coast Watershed Assessment leap in and do a reconnaissance-level Program (Gualala and Mattole Rivers) assessment, get a lot of feedback from a www.ncwatershed.ca.gov/all_watersheds.ht broad audience, refine your approach, and ml. focus on the important lessons learned from • Newport Bay/San Diego Creek Baseline the first iteration. The availability of time, Condition Report (USACE/OC)
- 8 - California Watershed Assessment Manual, Chapter 1 August, 2004 www.ocwatersheds.com/watersheds/pdfs/N levels of detail. Each increasing level ewportBay_Baseline_Conditions_Report(F3) represents progressively greater data .pdf. amounts and precision, intensity of analysis, • Napa River Basin Limiting Factors time, and (usually) cost. Each tier is Analysis designed to increase understanding and http://www.coastalconservancy.ca.gov/Progr reduce uncertainty. However, the less ams/EXECUTIVE%20SUMMARY.pdf complex levels of analysis can still produce very valuable information and should 4. Research watersheds (sites where long- contribute to the more complex levels, and term, continuous, in-depth studies of the more detailed approaches should build watershed processes and experimental on the fundamentals of the broad overviews. alterations are occurring) To get an idea of how people in other states and provinces have approached the issue of In California complexity in watershed assessments, information from British Columbia and the • Caspar Creek Experimental Watershed State of Washington is provided below. www.fs.fed.us/psw/rsl/projects/water/caspar. html. British Columbia’s Coastal / Interior • Castle Lake Watershed Assessment Procedure http://outreach.ucdavis.edu/programs/castel Guidebooks (1995 & 1999) for forested 2.htm. watersheds divides its assessment protocols • Kings River and Teakettle Creek into three levels: Experimental Watersheds • BC Level 1: A reconnaissance-level http://zimmer.csufresno.edu/~sblumens?KR analysis intended as a coarse filter to EW_INFO/KREW%20USFS1c.pdf. identify watersheds that may have impacts from the cumulative effects of Outside California: past logging or planned future logging. • BC Level 2: An overview stream • H.J. Andrews Experimental Forest (OR) channel assessment performed by www.fsl.orst.edu/lter. someone with basic experience in • Fraser Experimental Forest (CO) hydrology and/or geomorphology www.fs.fed.us/rm/fraser. • BC Level 3: A very detailed analysis • Walnut Gulch Experimental Watershed performed by a watershed specialist, (AZ) involving mostly field work. The work is www.tucson.ars.ag.gov/unit/Watersheds/W guided by the results of the level 1 and GEW.htm. level 2 analyses.
Finally, some useful insight can be gained The State of Washington distinguishes detail from the experiences of British Columbia into two levels: and Washington. Earlier watershed assessment approaches (e.g., British • WA Level 1: A reconnaissance Columbia Ministry of Environment 1995 assessment, relying predominantly on http://www.for.gov.bc.ca/tasb/legsregs/fpc/fp maps and remotely sensed information cguide/iwap/iwap-toc.htm and Ministry of with some field checking. The Forests, 1999 assessment is designed to take one to http://www.for.gov.bc.ca/tasb/legsregs/fpc/F two weeks of effort by the team, but PCGUIDE/wap/WAPGdbk-Web.pdf; could take longer depending on the time Washington State Department of Natural needed for data acquisition. Resources, 1997) recognized the need to conduct watershed assessments at different
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• WA Level 2: This level may be assessed and the social and environmental similar to Level 1, but results in a more issues facing California watershed groups detailed assessment of the overall and analysts. This document represents the watershed, or it may be focused on first version of the Manual. A revised specific resource issues identified in Manual will be released in December, 2004 Level 1. More experience and education with edits based on public comment on the are required for Level 2 specialists, and first draft. more time may be needed. The Manual is available in two formats: CD- 1.5 Manual Development ROM and online http://cwam.ucdavis.edu. The Web-site also provides relevant The concept for this Manual came from the technical and spatial information. California Watershed Management Forum (see section 1.5.1). The California In the Manual, there is an emphasis on Department of Forestry and Fire Protection narrative explanations for why particular (CDF) and CALFED provided funding to the approaches are important, short University of California, Davis, to develop explanations for how to do various tasks, the Manual, with the project coordinator and references and links to outside selected from within the Department of resources for specific protocols. Look for the Environmental Science and Policy. The text boxes inserted throughout the text and Manual was developed by an the action steps following certain sections. interdisciplinary team of watershed scientists affiliated with U.C. Davis and the 1.6 Next Steps in Manual’s Evolution Office of Environmental Health Hazard Assessment (California EPA) with The Manual focuses on watersheds of assistance from staff at CDF. A technical northern and central California. It also steering committee was established to focuses primarily on the processes of advise the team in development of the planning and conducting assessments and Manual. The committee was composed of secondarily on the specific tools associated practitioners, agency representatives, and with investigating particular watershed researchers involved in watershed processes. Future Manual sections will assessment in California. include protocols for assessing specific A critical part of the process involved watershed conditions (e.g., land-use collecting ideas and advice from diverse analysis) and functions (e.g., ground-water interests and experts from the larger supply). The process may eventually watershed community. Various include testing in real-world situations and announcements about the project were further revision of the Manual. A training distributed and team members made program may be developed to assist presentations at regional and statewide Manual users. conferences and to local, regional, and state groups, (e.g., the Bay-Delta Public Advisory 1.7 References Committee Watershed Workgroup). The team solicited comments about the types of British Columbia Environment. 1995. Forest problems encountered in conducting practices code of British Columbia: Coastal watershed assessments and suggested watershed assessment procedure tools for conducting assessments. guidebook (CWAP). Victoria, BC: Province The team assembled various watershed of British Columbia, Forest Service. assessment approaches from a wide range of sources. The team determined which British Columbia Ministry of Forests. 1999. tools best address the variety of watersheds Watershed assessment procedure and watershed factors that need to be guidebook. 2nd ed., Version 2.1. Forest
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Practices Board, Ministry of Forests, Victoria, B.C. Forest Practices Code USDA Forest Service. 2000. Rating of British Columbia Guidebook. Watershed Condition: Reconnaissance Level Assessment for the National Forests California Resources Agency and State of the Pacific Southwest Region. Region 5. Water Resources Control Board. 2002. Process Paper. Vallejo, California. Addressing the Need to Protect California’s Watersheds: Working with Local U.S. Department of Interior and USDA. Partnerships. Report to the Legislature (as 1998. A Framework for Analyzing the required by AB 2117, Chapter 735, Statutes Hydrologic Condition of Watersheds. BLM of 2000). Sacramento, California. Tech Note 405. Denver, Colorado. http://resources.ca.gov/watershedtaskforce/ http://www.stream.fs.fed.us/news/streamnt/ apr99/apr99a3.htm Furniss, M. 2001. Some lessons learned in the Pacific Northwest from federal U.S. Environmental Protection Agency (U.S. watershed analysis: ideals and pitfalls. pp. EPA). 2002. Watershed Academy. Office of 161-163 in: Proceedings of the Eighth Wetlands, Oceans, and Watersheds Biennial Watershed Management (OWOW). Conference, U.C. Water Resources Center http://www.epa.gov/owow/watershed/wacad Report No. 101, Riverside, Calif. emy/wsamap.htm
Meyer, J.L., et al. 2003. Where Rivers are Vannote, R. L., G.W. Minshall, K.W. Born: American Rivers White Paper. 24 pp. Cummins, J.R. Sedell, and C.E. Cushing. 1980. The river continuum concept. North Coast Watershed Assessment Canadian Journal of Fisheries & Aquatic Program. 2001. North Coast Watershed Science, 37(1), 130-137. Assessment Program Methods Manual. Draft. State of California. Sacramento, Washington State Department of Natural California. www.ncwatershed.ca.gov/ Resources. 1997. Standard Methodology for Conducting Watershed Analysis. Regional Interagency Executive Committee. Washington Forest Practices Board. 1995. Ecosystem Analysis at the Watershed Version 4.0. Olympia, Washington. Scale – Federal Guide for Watershed www.dnr.wa.gov/forestpractices/watersheda Analysis. Version 2.2. Regional Ecosystem nalysis/index.html Office, Portland, Ore. 26 pp. Watershed Management Council. 2000. “12 Stillwater Sciences. 1999. Watershed Steps to California’s Watershed Recovery.” Analysis Methods Manual for Jackson California Watershed Management Forums. Demonstration State Forest. Prepared for Davis California. California Department of Forestry and Fire www.watershed.org/forums Protection. Berkeley, California. Watershed Professionals Network. 1999. U.S. Department of Agriculture USDA. Oregon Watershed Assessment Manual. 1995. Ecosystem Analysis at the Watershed Governor’s Watershed Enhancement Scale—A Federal Guide for Watershed Board. Salem, Ore. Analysis. Regional Interagency Executive www.oweb.state.or.us/publications/wa_man Committee. Version 2.2. Portland, Ore. ual99.shtml
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2 Planning Your Watershed Assessment
This chapter address the typical process for plan should contain information on what data beginning your watershed assessment: a) will be collected, how it will be analyzed, and pulling together the assessment team and b) finally, how information will be synthesized developing a statement of purpose and a into a single analysis to inform decision- plan for the assessment. Assessing making. watersheds involves “art” as well as “science”. The first part of this chapter 2.1 Organize the Assessment Team: reviews the art of working with people and Assessment Planning as a Group and their decisions. The remainder of the chapter With the Community reviews the process for developing a statement of purpose and the factors you If a group functions well and builds successful should consider when laying out the plan for community relations, it is more likely to your watershed assessment. produce a successful watershed assessment. Conversely, a dysfunctional group with Chapter Outline inadequate public participation has a poor likelihood of producing an assessment with 2.1 Organize the Assessment Team: broad acceptance, as shown by evaluations Assessment Planning as a Group and of watershed groups and collaborative with the Community processes (Wondolleck et al., 2000, 2.2 Define the Purpose and Scope of the Huntington & Sommarstrom 2000). This Assessment and Develop a Plan for section of Chapter 2 will provide some Conducting the Assessment suggestions on how to successfully organize 2.3 Basic Watershed Assessment Process your assessment team. 2.4 Important Issues in Conducting a Watershed Assessment It is beyond the scope of this Manual to 2.5 References describe ways to structure and manage your ______group’s organizational abilities. There is no single method that will work in every Introduction watershed. Useful books, manuals, and other tools to help your group include: Kaner 1996; This chapter addresses the question of how Moote 1997; Sierra Nevada Alliance 1999; to plan a watershed assessment. To For Sake of the Salmon Web site summarize the process: the first step involves (http://www.4sos.org); River Network Web site organizing the assessment team. Once the (http://www.rivernetwork.org); and Know Your group is assembled, you need to define the Watershed (KYW) Web site issues of concern and develop a plan for the (http://ctic.purdue.edu/KYW/KYW.html). assessment. Some of the key parts of this plan include defining the purpose and the One increasingly popular approach to audience, defining the watershed processes improving community and agency relations is or parts of the system which will be the focus the use of collaborative, multi-stakeholder of the assessment, identifying the scope of watershed groups, also referred to as the assessment, developing a conceptual watershed partnerships. model of the watershed, and developing a plan for the actual analysis of the issues. The
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According to Know Your Watershed, common alternative approaches (such as agency characteristics of a watershed partnership advisory committees, or a single stakeholder include: group) (Moote 1997; Huntington & • Broad range of stakeholders who make Sommarstrom 2000; Wondolleck et al., 2000). decisions • Neutral coordinator respected by all with a 2.1.1 Assemble the Team and stake Committees • Actions are voluntary; benefits are personal No one has all the expertise required to do an • Strategies are specific to a watershed assessment, not consultants, agencies, academics, or watershed groups. As a result, This Manual does not assume that your your assessment effort will need to draw on watershed assessment group is such a an assessment team. partnership, but this approach may make your community involvement and ultimate Mixing Disciplines: Taking an interdisciplinary acceptance of your product easier than approach is a hallmark of the watershed assessment process. Accordingly, a good Sample Assessment Team and Committee watershed assessment team should include Structure members with a variety of disciplines or (adapted from: California Coastal Conservancy specialties. Because of the many physical, 2001; Coastal Watershed Council 2003) biological, and social connections that exist at a watershed scale, discussions, analyses, and interpretations across different Project Team specialties are often required to understand the cause and effect of a watershed + problem. A specialist in fluvial Project Inter-disciplinary geomorphology (the geologic study of the
Manager/Coordinator team (preparers) stream channel shape and evolution), for (and associates) instance, may be able to perform a sediment budget, but collaboration with a fisheries biologist may be required in order to interpret the sediment’s effect on fish Public Advisory Technical Advisory habitat, with a civil engineer to interpret the Group Committee effect on flooding, and with an long-time - for peer review of -for expertise and peer local resident to describe historical land socio-economic issues, review of assessment local knowledge, input methods, technical uses that may have triggered increased on proposed work, issues, and findings sediment production. review findings -representatives or - stakeholder scientists from each Group Size: Keeping the assessment team representatives: component discipline, and committees relatively small allows the agencies, landowners, regulatory agencies, advocacy groups, special issue experts group to make decisions in a timely fashion. business, etc. Small for a group means from three to 12 members. The team can bring on additional support people for short-term efforts on an Potential Subcommittees as-needed basis. In rural areas, finding sufficient qualified and interested people • Public Outreach (agency, academic, or public) who are • Specific Issues • Sub-watersheds available to travel potentially long distances • Other and attend many meetings will likely limit the number involved. In urban areas, the opposite may be true. In this case, having
- 2 - California Watershed Assessment Manual, Chapter 2 August, 2004 multiple, small committees may allow for your group’s staff, private consultants, agency increased participation by the higher number staff, community volunteers, scientists, of interested and available people. The Santa college students, or a combination of such Clara Basin Watershed Management Initiative people. Each person’s responsibilities may (http://www.scbwmi.org) used this approach, include one or more of the following: for example. • Helping focus the assessment on the important questions and issues; Project Manager/Coordinator: This person • Deciding upon appropriate assessment provides administrative leadership and methods; coordination for the process. Responsibilities • Compiling and evaluating existing data may include: and information; • Assigning tasks; • Collecting and analyzing new data; using • Contacting stakeholders; appropriate statistical design; • Coordinating the assessment components • Developing new maps, graphs, and other and team; visual aids; • Compiling and sharing existing data and • Preparing a written draft section or sub- information; section of the assessment; • Integrating results from individuals with • Attending team meetings, working different expertise; sessions, and public meetings; • Setting the schedule and managing the • Reviewing and commenting on sections or team against it; sub-sections prepared by others; and • Ensuring that the project stays within • Revising draft sections and completing the budget; and final product. • Achieving a satisfactory, completed product. Assessment Team members should possess skills relevant to the technical requirements of At a minimum, the Project their roles. Manager/Coordinator should possess good organizational and communication skills, Technical Committee: Members of the project management experience, and training Technical Committee may prepare and/or and experience in facilitation. A background in review the assessment, depending on how a natural resources-related field is very the committee is used. If committee members desirable. The Project Manager/Coordinator serve as peer reviewers of technical material could be a staff person from the agency or prepared by the Assessment Team, then it organization conducting the assessment, or a may be appropriate to include experts from consultant. In either case, before selecting the each relevant discipline, as well as Project Manager/Coordinator, you should representatives of regulatory or other contact references provided by the potential agencies, funding sources, and special issue hire/contractor, review the candidate’s past experts. Responsibilities for peer reviewers of work, and make expectations for the technical issues may include: assessment job clear. If the Project • Attending committee meetings; Manager/Coordinator is an outside • Advising Assessment Team members, consultant, you must address several critical • Advising on appropriate assessment issues before developing a contract with that approaches; person (see 2.1.3). • Recommending and evaluating statistical methods; and Assessment Team: The Assessment Team • Reviewing and commenting on specialty includes the Project Manager/Coordinator, areas of the draft assessment. plus the people who will actually be developing the product. These may include
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Technical Team members should possess • Attending committee meetings; identifiable and respected expertise in the • Learning about assessment topics to be covered in the assessment. methodologies; Public Advisory Committee: One structural • Reviewing and commenting on the model has the Public Advisory Committee assessment’s draft findings; performing peer review of socio-economic • Helping with public outreach on the issues only, while other models have it assessment; and providing input on all matters (California • Assisting with the next phase after the Coastal Conservancy 2001; Coastal assessment is done. Watershed Council 2003). Members may be volunteer representatives of key local Public Advisory Committee members should stakeholder groups (e.g., business, have local watershed knowledge and good landowners, agencies, environmental groups, communication abilities at the minimum. etc.) and/or at-large members of the public. Being willing to serve as an unpaid volunteer and having the requisite time and patience for Responsibilities for Public Advisory the process may be the most critical abilities Committee members may include: to possess. • Sharing their knowledge of the watershed;
“Lessons Learned—Pilot Watershed Assessment Process” by the Santa Clara Basin Watershed Management Initiative
This very large, urban group in the San Jose area prepared a “Lessons Learned” report in February 2003 based on its experience with pilot watershed assessments, which began in September 2001. Comments came from its Watershed Assessment Subgroup (WAS), a stakeholder group composed of representatives from agencies, municipalities, and nonprofit groups, and from Watershed Captains, who are members of the WAS and who have specific expertise and knowledge of the pilot watersheds being assessed. WAS worked initially with its Watershed Assessment Consultant on data gathering and evaluation, then on reviewing the draft assessment.
Some of the procedural lessons may be unique to this group’s experience, but the following lessons learned might also apply to other watershed assessment planning processes. • Establish preliminary review points for working drafts of the assessment’s chapters. Allow sufficient time to make changes in direction before it’s too late. • Once assessment steps begin, ensure that the same support staff and scientific experts are available for each meeting. • Ensure that sufficient copies of all relevant materials are readily available to participants in all meetings. • Make sure the experts, people with local knowledge, and the appropriate stakeholders are more involved in the review processes and meetings. • Establish clear communication channels for inter-subgroup or team relations and coordination of work products. • Have consultant offer feedback on issues brought up by commenters during the review process to make this phase move more efficiently and smoothly. • Give more time for review and comment on completed draft documents.
For more information: http://www.scbwmi.org
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Special Subcommittees: In addition to the group’s by-laws or other rules may already above committees, subcommittees may also state who has decision-making authority for be formed for special technical and public its efforts, including an assessment. If the purposes. Subcommittees may address: assessment is being done by an ad hoc or • Public outreach; temporary group, the decision-making • Sub-watershed advisory; authority might not be as obvious. Sometimes • Specific issue or topic areas (e.g., water public or stakeholder advisory committees quality, fish habitat, flooding, groundwater, have the impression (rightly or wrongly) that etc.); their recommendations are decisions rather • Monitoring and statistical analysis; and than advice that can be taken or ignored. • Report preparation. Without clarifying who makes what decisions and when during the assessment process, Membership and skill level are linked to the your watershed assessment may drag on subcommittee type, with skills ranging from unnecessarily, hit a dead-end, or not be the ability to translate technical reports to the accepted by important participants in the public to the ability to generate these reports. watershed community. How decisions can be made is discussed in section 2.4.2 below, Interim Task Force: A short-term task force, which also addresses the various roles of either technical or public advisory in nature, possible decision-makers. may also be needed during the assessment process. It may contribute to a portion of the 2.1.3 Contracting Analysis and assessment and then disband before the Coordination Work assessment is completed. Members may come from existing committees or It is possible that your assessment team will subcommittees, or they may be recruited only consist of people in your watershed group. for this purpose. Examples of possible However, for many assessments, a consultant functions might be: will be hired through a contracting process to • Developing the assessment process do part of the work. This person could fill a (before the coordinator, teams, and management and coordination role, or be a committees begin); technical analyst, or bring the information you • Collecting field data on selected have collected together in an integrated parameters or certain locations; assessment. Whatever the consultant does, there are some things to consider when • Working through a contentious topic; developing the relationship. • Developing new protocols, models, or
methods as needed. The assessment decision-makers (e.g., • Membership and skill level would be as technical advisory group or contract appropriate for the task force’s defined managers) should decide as many of the function. main topics and questions for the assessment as possible before contracted work starts. 2.1.2 Making Decisions Other parts of this Manual describe formulation of questions, identification of The above options for who coordinates, problems, and other types of conceptual work prepares, advises, and reviews the that the assessment decision-makers and assessment lead to the inevitable question: stakeholder committees can do before Who makes the decisions? Is it all of the contracting with consultants. One Bay Area above, the Project Coordinator, the technical watershed group spent more than $200,000 committee, the funder(s), an agency, or the on consultant time before it had formulated its entire watershed group? Make this primary assessment questions. After the fact, determination very clearly at the beginning of the group decided that this expenditure had the watershed assessment process. A
- 5 - California Watershed Assessment Manual, Chapter 2 August, 2004 been a waste and that group members could To evaluate possible analysts, check with have done the work without the consultant. references provided by the contractor or agency for similar projects. References can The role of analyst is an important one on the give you a sense of whether the information assessment team. Funding is limited for most provided by the analyst was relevant to the assessments, so often you must decide which project or decision-making process, whether analyst positions are most critical. the consultant can meet desired timeframes and communicate the work to diverse The types of analysis required and the audiences, and whether cost matches the amount of money needed to fund analysis are work expected. tightly tied to the primary questions of your assessment. For example, in two cases in Evaluate past analyses and reports in which Southern California, assessment developers the analyst did an identifiable part of the work. decided that the largest expenditure (one- This will help you decide if a past project is third of total funds) was to be on various kinds similar to the needs of your assessment. Look of hydrological modeling because their at research or other articles written by the projects revolved around local groundwater analyst. If the technical or scientific storage and improved water quality and communities are peer-reviewing the analyst’s conservation. work and approving it for publication, then other experts have already done part of the In a sprawling urban area, for example, the reference checking for you. impact of stormwater runoff on local stream water quality, channel integrity, and After choosing possibilities for the Project endangered aquatic wildlife might dominate Manager/Coordinator and analyst part of the the assessment. In this case, you would want team, you must establish a contract, which an understanding of the hydrology or can range from a contract with an individual to hydraulics of the system (hydrologist), an agreements with academic institutions or assessment of riparian and aquatic habitat agencies. One of the first questions in the condition (ecologist or geomorphologist), contracting process is usually about cost. surveys of plant and wildlife communities Individual or company consultants usually (botanist and/or wildlife biologist), someone charge higher hourly rates than universities or knowledgeable about contaminants in agencies, but these consultants also cover stormwater (toxicologist), and someone or a costs that may be part of the overhead costs group process to integrate the information to of the latter organizations. Universities also inform decision-making. charge an overhead rate, usually called “indirect costs”, but total rates are still usually Once you have identified the scientific lower than those of private consultants. expertise of the analysts needed for the Universities and agencies often have access assessment, you will face the most to resources not available to individual challenging aspect of team creation: deciding consultants (e.g., software licenses and who is qualified to carry out the work. interns). Ask for the actual hourly rate for Nonprofit organizations, water districts, and agencies and academics so you can local agencies have described their selection accurately compare these rates with those of of consultant analysts as an ad hoc process private consultants. based exclusively on reputation. This approach tends to favor larger, more well- The actual work expected should be detailed known public and private organizations, and agreed to in a Scope of Work (SOW) without necessarily reflecting the abilities of document. The more explicit the SOW, the these organizations to deliver the products more likely the finished product will reflect the expected or desired. needs of the assessment. Once contracts are underway, the SOW can be amended if
- 6 - California Watershed Assessment Manual, Chapter 2 August, 2004 needed to reflect changes in expectations or sediment sources so that staff members could new information. The SOW should lay out a do their own assessments and also train series of tasks with an explanation of the work others. In Oregon, the State’s manual to be performed as part of each task, the anticipated that most watershed assessments deliverables for each task, the timeframe for would be done at a fairly low cost by the deliverables, the time the task will take, watershed council members themselves, and the budget devoted to each task. The including staff, community members, and SOW should reflect expectations of both the technical members from local, state, tribal, consultant and the funder, the role the funder and federal agencies. As more funding will play in reviewing and approving became available, consultants became more deliverables, and what happens when involved. something important changes (e.g., a delay in funder review of deliverables). The SOW Minimizing scale, scope, time, and consultant informs the development of a budget, which use can reduce costs. However, each might include additional costs for assessment effort has certain minimum built- administration, supplies, equipment, and in costs no matter what the scale: project travel. management, public participation, data and information collection, analysis, report writing, The SOW, the budget, and the contract and draft and final report publication. While language together form the usual contracting perhaps tempting, using a per-acre cost of package. You should not expect work to estimating an assessment budget is probably commence before the contract between the not realistic. funder and the consultant is signed. Similarly, work after the contract has expired will only Costs of completed watershed assessments occur if the consultant agrees to continue vary considerably. The California Bay-Delta working. If changes to deliverables are Authority’s (CALFED) Watershed Program desired after the contract has expired, an has awarded grants in recent years (2001 & extension or amendment to the contract 2002) ranging from $96,700 to $771,000 for should be generated. The extension or projects described as watershed amendment may or may not provide for assessments. State grants are often for a additional funding, depending on the watershed assessment combined with a consultant. Keep in mind that most watershed management plan and some consultants will move on from your monitoring, so the separate assessment costs assessment fairly quickly—any changes in are difficult to determine. In the central coast, work or deliverables should be made as soon combined watershed assessment and as possible within the contract period. watershed enhancement plans that include field work performed by consultants generally 2.1.4 Keep Costs Under Control average about $200,000-250,000 for a 40 square-mile (26,000-acre) watershed. (Kate The cost of doing a watershed assessment Goodnight, Coastal Conservancy, pers. can vary greatly, depending on the scope, comm.) Some grant programs have set a scale, time, and use of paid consultants. A ceiling on the maximum the agency will spend few groups have kept their costs low by using on its share of an assessment and/or plan. experts (agency staff and academics) who have contributed their time for free, as well as In Oregon, assessments based on the state by receiving volunteer time from their manual have ranged from about $600 to members and the community. The Mattole almost $400,000 for fifth-field watershed-level Restoration Council in Humboldt County is a assessments (at 60,000-acre scale), with 90% good example of this approach. Geologists costing less than $100,000 and consultant- from Redwood National Park trained council prepared assessments at the higher end (Ken staff to evaluate erosion problems and
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Bierly, Oregon Watershed Enhancement TAC meeting #2 (mid-progress review) Board, pers. comm.). Draft assessment complete Review results—TAC and Public Advisory 2.1.5 Develop a Schedule Committee Release revised draft to public It’s important to be realistic about how much Revise and deliver final assessment time it takes to perform a watershed assessment, but estimating time required can The Santa Clara Basin Watershed be challenging. Experience has shown that Management Initiative had a slightly different simpler assessments performed in-house with experience than the example above. They sufficient expertise and information may take began outlining a detailed assessment four to eight months, while more complicated process in 1998, when the assessment was assessments or assessments where the only in its “gestational phase”; looking back process was not under tight scheduling five years later, the group concluded that it controls can take as long as 36 months. was “much smarter” about the detailed steps necessary to complete an assessment by the Whether you are doing the assessment time it began one in 2001. Instead of yourselves or having a consultant do it, you spending so much time at the beginning should establish a schedule of the different detailing the assessment process, the group steps or milestones from beginning to end. felt it should have spent that time producing a Assign a due date to each step. simple assessment workplan with work- product-specific trigger dates. When those Sample Milestones (adapted from California dates were reached, the group could have Coastal Conservancy 2001) developed an expanded action plan for the specific work product, adding more details as Start-up the group learned more about what it wants Initial project team meeting (define and needs in the assessment. approach) Public meeting #1 (review issues, A key scheduling lesson from this group’s concerns) experience (and others) is to allow more time Technical Advisory Committee (TAC) for review and comment on completed draft meeting #1 (review strategy) documents. Without sufficient time for this Begin assessment phase, unnecessary frustration in the process
Common Causes of Failure in Watershed Restoration Efforts
(from: Williams, Wood & Dombeck (1997). Watershed Restoration: Principles and Practices, pp. 10-11.) This list of common causes of watershed restoration failures also highlights the reasons for doing a good watershed assessment, and the critical elements that need to be included in your approach.
1. Failure to understand the ecological history of area, 2. Failure to look at proper scale (i.e., watershed scale), 3. Failure to treat root causes of degradation, instead of symptoms, 4. Failure to work with local communities and to solicit their support for project goals, 5. Failure to integrate ecological principles, 6. Failure to develop proper goals, 7. Failure to institutionalize commitments within local communities and agencies, and 8. Failure to monitor and adapt management accordingly.
- 8 - California Watershed Assessment Manual, Chapter 2 August, 2004 and lack of trust in the product could result story in the newspaper is a better method. due to unresolved issues. Designing public participation processes is an art as well as a science, and guides are 2.1.6 Involve the Community available to help you (e.g., Beierle & Crayford 2002; River Network’s Web site: Those who will be making decisions using http://www.rivernetwork.org). information in the assessment should be included, consulted, or at least considered Public workshops, where watershed when designing an assessment. From start to assessors explain the assessment process finish, the assessment should make clear how and progress and informally solicit comments, and why various steps were taken. This can serve functions of both outreach and approach has the benefit of getting all- input. Targeting public awareness campaigns important buy-in—stakeholders and decision- to groups representing people with a stake in makers are more likely to trust the the watershed’s condition—farming, ranching, assessment’s conclusions if they understand fishing, recreation, conservation, industry, the reasons various approaches were taken business, governing entities—through all the or they were involved in gathering data and means mentioned above may help increase information for each step. awareness and feedback. Public involvement can and will be different at different watershed Some watershed groups, such as scales. It’s easier to contact a high collaborative, community-based partnerships percentage of a small or rural watershed’s and most Coordinated Resource residents and users than of large basins or Management Planning (CRMP) groups, have population centers. On the other hand, media community participation built into their can broadcast well throughout metropolitan membership and their processes. Others may watersheds like the Sacramento River basin, not. The committee-subcommittee structures San Francisco Bay watersheds, and the Los discussed can formally incorporate members Angeles-San Gabriel Rivers basin. of the community into your assessment process. Data gathering is another means of Using the media to explain what a watershed public involvement—citizen volunteer assessment is, why people should be monitoring efforts are a popular example of a interested, and how they can best be involved hands-on contribution to an assessment. may require you to tap the expertise of public However, such volunteer work demands relations specialists. quality training, supervision, and scheduling for it to make a meaningful contribution to the 2.1.7 Record the Assessment Process assessment. Effectively tracking the progress of the Two-way communication—listening and assessment process for your group, for your informing—is a goal of community funders, and for the public is very important. involvement in the assessment. Informal The larger the scope and scale of your effort, outreach—telling the public about the the more critical this tracking becomes. Key assessment—can occur in a variety of questions to address for your recording efforts relatively traditional ways: newsletters, Web are: sites, press releases, flyers, photographs for • Who should be responsible for tracking? newspaper articles, videotape for television • How should progress be recorded? spots, speaker presentations, etc. Getting • When or how often should recording be input from members of the public not already done? involved in the process can require somewhat • Where should the records be maintained different approaches. The traditional method and accessed? is formal public meetings publicly noticed in • What form should the records take? the newspapers; getting a human-interest
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• Data and information sources being used Actions 2.1 for assessment • Assemble assessment team and • Explanation of how and why various steps committees were taken • If necessary, develop contracts • Public outreach efforts: past and proposed • Keep an eye on cost and schedule • Draft chapters as completed, or the full • Involve the community draft document • Record the process • Final assessment
2.2 Define the Purpose and Scope of Funding entities may have their own the Assessment and Develop a Plan for requirements for recording the progress of the Conducting the Assessment assessment. The Coastal Conservancy recommends that groups require their The next step in planning a watershed consultants to prepare quarterly reports. assessment is to agree on why one should be According to the Conservancy, “These reports done. This effort spawns many questions: come in handy to keep funding agencies What purpose will it serve? What is going to informed of progress and are also useful to happen with the assessment when it is done? provide to all interested parties, including your Who wants the assessment to be done and committees and the community.” why?
Web sites have become a common form of 2.2.1 Identify the Questions and Issues of accessible communication. Regular postings Concern can be put online under your home page’s Watershed Assessment heading. Postings Watershed assessments may be motivated by could include: one or more influences: • Assessment’s purpose/focus/issues • to evaluate watershed conditions from a • Assessment’s framework or outline; map neutral perspective, i.e., with no prior of assessment area assumptions; • Scope of work for the consultant and the • to address identified watershed issues or assessment’s budget problems; • Organization chart and members of • to meet a particular purpose, e.g., identify assessment’s team, committees, conditions that need to be improved in subcommittees, task forces; application order to increase drinking water quality; for membership • to meet a particular goal, such as • Identification of decision-makers and educating the public about natural and decision-making process human features of the entire ecosystem • Agendas and minutes of meetings; and assist in planning and decision- schedule of future meetings making. • Quarterly progress reports For many assessments, one or more issue-
“Watershed councils have completed watershed assessments in most basins of the state, helping to assure that restoration dollars are invested wisely ... Watershed assessments completed by local citizens have significantly helped to identify key limiting factors present in individual watersheds and guide local restoration activities.”
“The Oregon Plan for Salmon and Watersheds: 2001-2003 Biennial Report”, Oregon Watershed Enhancement Board, 2003, p. 42 & 54.
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Examples of five individual purpose statements for five different watershed assessments
“The purpose of the watershed assessment is to…”
A. Analyze conditions in the sub-watersheds of the basin and determine whether the waters of the basin are supportive of beneficial uses and community interests. B. Integrate historical information with new assessment data to create a comprehensive steelhead restoration plan. C. Educate the public about the human and natural features of the entire ecosystem, and assist planning and decision making. D. Inform stakeholders about the human and natural features of the entire ecosystem and assist in identifying areas in which additional data are needed. E. Gather and synthesize existing information on the historical and current environmental and land use conditions within the watershed.
As an exercise, decide how well each example answers the questions in 2.2.2. What could be changed to develop a “model” purpose statement? based questions usually drive the process. A or enhancement is recognized or in response set of questions may be as generic and to some commonly acknowledged problem general as, “What is the condition of our relating to the local waterway or aquatic watershed, and why is it that way?” More habitat. Such problems often relate to specific questions might be along the lines of, whether anything is perceived to be wrong or “Why did the salmon stop spawning in our whether dramatic (and detrimental) changes stream? Why did the big flood come from have been measured with respect to such a small storm? Why can’t we drink the streamflow, water quality, fish, or other stream water any more? Why does the aquatic organisms. stream now dry up in May when it used to flow until August?” Often, the cause of a recognized problem is readily apparent: a new subdivision has Questions based on observations and resulted in loss of wetlands and change in community concerns will direct the watershed local hydrology; a catastrophic wildfire assessment, which will in turn provide the removed 80% of the vegetation in the basis for solving known problems. The term watershed and the stream’s sediment load “problem” here means a potential or actual increased dramatically, a new reservoir was impact to the natural functioning of the completed and most of the annual streamflow watershed. If there are no fundamental is diverted out of the watershed; etc. questions guiding a watershed assessment, However, the causes of many other problems you may wish to reconsider the perceived are not so obvious and may result from the need for the assessment. The questions cumulative effects of many localized should be stated clearly enough to capture disturbances. In cases where there is a the prevailing concerns that led to wanting or dramatic water-related problem without an needing a watershed assessment. They obvious cause, a watershed assessment may should also open the door to the next step of be useful in identifying the causative agents defining watershed assessment approaches and may lead to possible solutions. appropriate to the questions and specific The problem(s) should drive the assessment. protocols that can be used to assess Again, any watershed assessment must have particular conditions. a reason for being conducted. This reason could be anything from meeting a narrow Watershed assessments are typically legal requirement (e.g., water quality conducted when an opportunity for restoration
- 11 - California Watershed Assessment Manual, Chapter 2 August, 2004 standards in an agricultural area) to a very should agree to and clearly state the general “watershed condition” assessment. assessment’s intended audience at the beginning of the process. In stating the 2.2.2 Develop a Statement of Purpose audience, it may become apparent that the audience needs to be more diverse than Watershed assessors should develop a clear originally envisioned. Initially, the audience purpose statement. A “fuzzy,” implied, or might be perceived as only the advisory and absent purpose statement that never gets decision-making bodies of a sponsoring clarified can lead to bigger and bigger agency or group. Then the general public problems (such as getting off target, or might be added. However, those people who creating misunderstandings about different will be translating the assessment into action expectations of the product) as the may need to also be a specific target assessment process continues. For this audience. Otherwise, the product might not Manual, the term “purpose” is basically be very useful for implementation when synonymous with “goal”. Questions (or completed. For example, state in the parameters) to help focus your purpose introduction that local restoration groups and statement are: landowners are intended audiences (and potential users) of a watershed assessment • What will occur during the assessment that is focused on identifying restoration process? What will be assessed? opportunities. Then be sure that the • What will the assessment product be used assessment process involves your target and for? expanded audience and the product is useful • How does it lead toward managing (e.g., to them. protecting, improving) the watershed? Will it make our effort in the watershed any 2.2.2.2 How Might the Assessment Be better? If so, how? Used? People sometimes want to use a watershed assessment to measure “watershed health”. Another factor to consider when developing a Watershed health is a subjective concept, statement of purpose is to identify the however, and defining it precisely can be potential uses for the assessment. challenging. Most references talk about it Assessments generally serve to inform certain without defining it. Here are two possible functions: definitions that might help your effort: • General watershed planning with multiple • “An index or estimate of the degree to purposes which the generation and transport of water • Regulatory concerns and its constituents within a watershed • Restoration or enhancement planning function in a relatively natural manner [so as • Monitoring program development not to impair beneficial uses]” • Management of risk areas and practices • “An index or estimate of the natural functioning of the watershed relative to a You may want your assessment to serve all reference or historic condition” these functions, or just one or two of them. The more functions an assessment serves, 2.2.2.1 Who Is the Intended Audience for the more complex it can become. The need to the Assessment Product? address many functions may reflect the complexity of the watershed, its problems, Identifying the target audience for the and possible solutions. As the assessor, you assessment is important both for refining the must show how the assessment can serve the assessment’s purpose and for developing and functions you identify as important. writing the assessment. Watershed assessors
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Balancing the needs of the community and governmental agencies
It is important to clearly identify who really wants the watershed assessment, and why they want it. Otherwise, misunderstandings can occur. For example, the impetus may come from the local level—from a cooperative group (e.g., a watershed council), a local agency (e.g., a resource conservation or water district), or other private or public stakeholders—for a variety of reasons. On the other hand, the driving force often comes from the state or federal level as a requirement of a grant program or a regulation. For example, funding agencies may require that a watershed assessment be done as a condition of funding a watershed plan or restoration projects. Often, the agencies’ intent is to help target limited public funds to what is most likely to succeed in meeting agency goals and get the most bang for the buck. Members of a watershed group, however, might feel that their intimate knowledge of the watershed has allowed them to develop a good restoration project without any formal assessment work. They are concerned that an assessment will take years to complete, and they don’t want to wait that long, nor seek that much funding. Thus one of the challenges of whether and how to do an assessment then becomes how to balance the needs and perceptions of the agencies with those of the community. Fortunately, this balance can be met, but it will require successful meshing of various desires for the content and use of the assessment. The local group may do some research and find that watershed assessment doesn’t have to take a long time or be expensive. The more defined and widely supported the purpose of an assessment, the less time and money it will take to conduct. Successive assessments can be done, each focusing on another issue as other problems are identified, or as funding becomes available. An incremental approach is often the norm these days due to political and financial realities, and it can also be scientifically defensible. Funding agencies can find satisfaction in having a scientifically defensible basis for further watershed efforts. In the end, all parties can reach agreement and get what they need from the assessment.
temperature) to come up with a ranking for Assessments have been prepared for a susceptibility of sub-watersheds to variety of uses in California. For example, the disturbance. This ranking was used to North Coast Watershed Assessment Program develop management recommendations for (http://www.ncwap.ca.gov) provided a the development of timber harvest plans baseline assessment of conditions in certain under the California Forest Practices Rules. watershed for use in restoration planning and implementation of existing regulations. This The Coastal Watershed Council (2003) assessment was not intended to be used at developed the Aptos Creek Enhancement the site or reach-specific scale, to result in Plan, which contained a watershed new regulations, or to describe risk assessment and was focused on salmonid management. restoration in the creek based on voluntary landowner participation (www.coastal- An example of a focused landowner watershed.org). watershed assessment is that for the Upper Mokelumne River (Foster-Wheeler • Using the Assessment to Develop a Environmental Corporation, 2002). In this Watershed Management Plan case, the consultant analyzed certain existing conditions (e.g., road interactions with Many local agencies and watershed groups erodible soils) and ignored others (e.g., the choose to develop a watershed management relationship between riparian vegetation and plan (WMP) to guide a variety of different
- 13 - California Watershed Assessment Manual, Chapter 2 August, 2004 activities in a given watershed. WMPs are The California Agency Watershed usually based on a previous watershed Management Strategic Plan (CalEPA and assessment, or one that is included in the Resources Agency 2003) also defines watershed management plan itself. There are “watershed management”: only general legal guidelines for the development and use of these plans, several “Watershed Management” of which are given below. • Effective watershed management results in successful projects that yield positive WMPs are different from watershed outcomes for the State’s watersheds. assessments. They represent the action • Watershed management is a process for corresponding to the evaluations in the making decisions about activities that will watershed assessment. California Water affect the health of a watershed. Code Section 79078 provides one definition • The process is characterized by of a “local” watershed management plan: considerations of how actions in one “(c) ‘Local watershed management plan’ location in a watershed will affect means a document prepared by a local conditions in other parts of the watershed watershed group that sets forth a strategy to or other watersheds. This process uses achieve an ecologically stable watershed, and open and transparent decision-making that does all of the following: involving collaborations among interested (1) Defines the geographical boundaries of parties by: the watershed. • Reliance on scientific description of (2) Describes the natural resource conditions conditions in the watershed and the within the watershed. application of scientific methods to (3) Describes measurable characteristics for develop decision support information and water quality improvements. tools; (4) Describes methods for achieving and • And by a process of planning, sustaining water quality improvements. implementation, assessment, and (5) Identifies any person, organization, or adaptive decision-making. public agency that is responsible for • The issues under consideration include implementing the methods described in ecological health (e.g., habitat, hydrologic paragraph (4). function, and aquatic life), land use (e.g., (6) Provides milestones for implementing the commercial, industrial, agricultural, and methods described in paragraph (4). residential uses), and resources use (e.g., (7) Describes a monitoring program designed recreation, water supply, water quality and to measure the effectiveness of the methods flood control).” described in paragraph (4).” Connecting Watershed Assessment With The San Diego Regional Water Quality Watershed Management Control Board defines watershed management plan similarly: Orange County has developed several watershed assessments embedded within “Watershed management plan—A planning watershed management planning processes. document that presents solutions for The plans focus on stormwater runoff, water addressing the water quality problems quality, and restoration of channel and identified in the state of the watershed report riparian function. The Aliso Creek Watershed for a single watershed management area or Management Plan portion thereof. This document includes (http://www.ocwatersheds.com/watersheds/ali assessment results, specific management socreek_watershed_management_toc.asp) strategies and corresponding stakeholder summarizes watershed conditions and lists roles for implementation to attain water quality specific actions that could be taken in certain goals.”
- 14 - California Watershed Assessment Manual, Chapter 2 August, 2004 reaches to improve functioning. The polluters and dischargers within the assessment findings and management watershed. A good TMDL will be based on a actions are not always linked, but the plan’s watershed-scale assessment of pollution structure and layout make it easy for the sources and resemble a watershed reader to make the connections. assessment.
To encourage implementation of effective The State of Washington developed its management actions, a watershed watershed assessment manual (Washington assessment that will inform watershed Department of Natural Resources, 1997) management planning should include the explicitly to deal with the impacts of logging following components: activities on anadromous fish. The manual describes how to assess watershed • Obvious connections between individual conditions in forested areas and how those assessment findings and potential WMP conditions might influence salmon spawning elements. Example: Analysis of erosion and rearing habitat. The State of California potential in connection with road has not yet adopted this approach. construction and maintenance practices. California’s Forest Practice Rules (FPRs) • Specific findings for geographic sub-areas require watershed assessment for long-term, within the assessment area for individual large-scale management plans for logging impacts or cumulative effects of operations on private lands. These disturbances. Example: “The impervious assessments are usually focused on habitat surface area for Urban Creek is very high concerns for endangered salmonids in relative to standards for stormwater runoff waterways affected by the operations. management.” Typically, the analyses are restricted to those • Assessment of processes at scales parts of watershed functioning where impacts appropriate for the scales at which are known to limit salmon spawning and decisions are made. Example: Waterway rearing habitat (e.g., riparian retention and effects of licensed water management erosion risk). Examples of these types of occur on hourly to centuries-long assessments include the Pacific Lumber timeframes, so multiple timeframes during Company’s watershed assessments for hydroelectric project analysis are creeks on its property in the redwood forest of important for licenses with fixed time coastal Northern California, the upper periods. Mokelumne River assessment for Sierra Pacific Industries lands (Foster-Wheeler • Using the Assessment to Support Environmental corporation, 2000), and the Regulatory Requirements Albion River watershed assessment for the Mendocino Redwood Company’s holding in Some regulatory processes require this basin (Mendocino Redwood Company watershed assessments. Under the federal 1999). Clean Water Act, for example, states must identify impaired water bodies and begin Sustained yield plans (SYPs) are a describing “total maximum daily loads” mechanism used by the state to regulate (TMDLs) logging activities on private lands. The Forest (http://www.epa.gov/region09/water/tmdl/) for Practice Rules state that SYPs are “a means pollutants causing the impairment. for addressing long-term issues of sustained Establishing TMDLs requires that Regional timber production, and cumulative effects Boards in California analyze pollutant loads analysis, which includes issues of fish and entering waterbodies on a watershed scale. wildlife and watershed impacts on a large The state must declare the maximum load landscape basis” (Article 6.75, FPR; allowed, and apportion the allowable load to http://www.fire.ca.gov/ResourceManagement/ doc/FPR200301.doc).
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Examples of Potentially-Regulated Impacts of Land and Water Uses
General Land/Water Use Regulatory Issue or Stressor Agriculture Row-crop Ground and surface water quality impacts, ground and surface water diversion and use Orchard/vineyard Ground and surface water quality impacts, ground and surface water diversion and use, woodland habitat loss Grazing Surface water quality, riparian vegetation loss, woodland regeneration
Housing development Ground and surface water diversion and use Road system Habitat fragmentation, stream channel alteration, erosion, stormwater runoff Ownership Fragmentation of responsibility/accountability and stewardship Wastewater Surface and ground water quality impacts
Logging Road system Habitat fragmentation, stream channel alteration, erosion, stormwater runoff Vegetation removal Erosion, stormwater runoff, nutrient cycling impacts, habitat loss and fragmentation, stream channel alteration, herbicide applications
Mining Hard-rock Changes to local sub-surface hydrology, mine pollutant drainage Hydraulic Excessive sediment contribution to streams, pollutant drainage (e.g., mercury), Changes to local surface and sub- surface hydrology Gravel Depletion of gravel from stream beds and floodplains, disturbance of benthic and riparian/floodplain habitat
Water Diversion & Storage Dams Block migration of aquatic organisms, interrupt natural flow regimes Reservoirs Change water chemistry, trap sediment heading toward lower reaches, harbor lake-dwelling fish predatory on young of river fish Pumps Mortality for un-screened fish Canals Removal of riparian vegetation, flow regimes intended for irrigation needs not aquatic life
The SYP must define a “watershed projects, on water quality, fisheries, and assessment area” and the “assessment shall aquatic wildlife.” The Board of Forestry has include an analysis of potentially significant included some detail on how the assessment adverse impacts, including cumulative under the SYP must be conducted. For impacts, of the planned operations and other example, one required data type is a “map of
- 16 - California Watershed Assessment Manual, Chapter 2 August, 2004 existing roads and approximate location and assessment for the upslope and in-stream miles of proposed new, reconstructed, and area surrounding the proposed restoration abandoned roads.” However, there are no site. Taking a watershed approach to prescribed analysis methods. restoration planning is essential in order to determine how upstream or downstream • Using the Assessment for Restoration processes and land uses may affect the and Enhancement Planning restoration area. If the restoration is focused on an area of a hill-slope or a reach of a river, While not all watershed assessments are the essential unit for assessment and intended to inform restoration planning, it is a planning is the watershed. For this reason, common goal of most watershed watershed assessment can support partnerships. Restoration is defined here as subsequent decision making about where, the renewal of a natural process (e.g., natural when, and how to restore natural processes fire regimes) or feature (e.g., native fish at specific sites or in larger areas (e.g., sub- species) through human actions. These watersheds) to benefit native wildlife. It can actions could include changing permitted land also inform decisions about how to monitor or water uses (e.g., developing on steep the effectiveness of the restoration action and slopes or diverting a majority of flow), how to maintain the action over time. restoring natural features (e.g., willow or gravel), or removing structures that are Some watershed assessments make explicit suspected or known to cause damage (e.g., connections between the analysis of existing roads or diversion dams). (or historical) conditions and specific actions that could be taken to restore natural The term “restoration” has been used to functioning. Conducting the watershed define numerous management strategies, assessment as if you are planning future from removing constraints, such as dams, and restoration projects will help connect breaching levees to planting native riparian components of the watershed assessment trees, but most river managers and scientists and the restoration plan. For example, if your agree that fully restoring watersheds to their assessments suggests that road construction pre-disturbance conditions will be extremely is resulting in multiple risks to natural difficult, if not impossible. For this reason, it is functioning (e.g., weed invasion and essential to define what is meant by increased erosion), then restoration actions restoration. Restoration science currently could consist of modifying existing roads to uses a definition such as “a return to accommodate natural processes, or changing sustainable processes,” while terms such as how and where new roads are constructed. “enhancement” are used for beneficial The Mattole Restoration Council, for example, actions, such as replacing exotic vegetation identified excessive sediment from roads on with native species, planting vegetation to private lands as a critical limiting factor for stabilize an eroding area, or placing spawning salmon reproduction. It established the “Good gravel in a river where gravel supply is limited Roads, Clear Creeks” program, where sub- by upstream dams. “Bioengineering” or “eco- watershed and parcel-specific assessments engineering” describes actions that include are used to prioritize road fixing or removal erosion control or channel bank stabilization projects using hard structures that incorporate (http://www.mattole.org/program_services/grc vegetation. Other terms often used to c.html). The council does this in collaboration describe sustainable beneficial actions in with landowners and reports a high level of watersheds include rehabilitation, success with owners of small to medium naturalization, or recovery. parcels (Chris Larson, personal communication). The ideal situation is for restoration planning to take place in the context of watershed
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• Using the Assessment to Support otherwise influencing in-stream processes. At Monitoring Programs one end of the impact spectrum might be ridgeline roads that connect to streams Watershed assessments are closely tied to through impacts to hillslope geomorphology past and current monitoring in watersheds. or pollutant runoff. At the other end of the The assessor relies on data and conclusions spectrum might be riparian developments drawn from monitoring programs to analyze (e.g., in urban settings) that have direct watershed processes and conditions. In turn, connections to channels and dominate the the assessment can form the basis for relationships between watershed hillslopes developing or updating monitoring programs. and waterways. This iterative process is part of an adaptive management and assessment approach that Watershed assessments or other inventories incorporates new information as it becomes of disturbance could reveal that certain available in order to make decisions. One human activities are particularly concentrated important caveat is that monitoring in an assessment area’s sub-watersheds. information can lead in rare cases to This could help focus monitoring efforts in regulatory action, which the these areas. Human activities that may impact assessor/monitoring team should explain to water quality include housing developments, the stakeholders involved. abandoned or current mining, agricultural operations, roads, and logging. Pollutant From the watershed assessment point of monitoring could take place downstream of view, it’s important to find areas in the the potentially impacted area within the sub- watershed that might impact waterway watershed (see boxed figure above), and, for condition (e.g., water quality). These areas comparison, in nearby un-impacted sub- will include both human-created and natural watersheds and upstream of the area of features that have the potential or are known concern. In addition, monitoring sites could be to be releasing material into a waterway or placed on the mainstem river above and below the confluence with the waterway originating from the area of concern (see figure) to measure the actual impact of the disturbance on the river. The data resulting from this combination of monitoring sites will provide information about the types and extent of impacts the site is causing on nearby waterways.
Ultimately, the watershed assessment should serve in part to inform monitoring programs by revealing potential and actual impacts of human and natural processes in the watershed. Water quality monitoring is a form Waterway of continuing assessment of one watershed condition, and is one way to measure the Background monitoring site effectiveness of protective actions taken on
Above confluence site the landscape.
Below confluence or concern site Other aspects of watershed monitoring may also tie into the assessment. These monitoring efforts include measuring and Area of concern evaluating variables that can change over time, such as streamflow, aquatic organisms,
- 18 - California Watershed Assessment Manual, Chapter 2 August, 2004 channel conditions, riparian vegetation, water Protection Agency, 1998). One outcome of use, and upland vegetation. It is important to risk assessment is exposing uncertainty and identify the type of monitoring (past, current, data gaps that were found in the analysis and proposed) because each type has a phase and presenting recommendations for different purpose (baseline, trend, dealing with them. The final step in the risk effectiveness, implementation, project, and assessment process is risk characterization, compliance) (MacDonald 1991). where “the information from all the steps is integrated and an overall conclusion about • Using the Assessment as a Risk risk is developed that is complete, informative, Management Tool and useful for decision-makers” (U.S. EPA 2003; CWAM chapter 6). An excellent tutorial Risk assessment is a relatively new analytical on watershed risk assessment is available field intended to support decision making in online at http://www.epa.gov/watertrain. the absence of a complete understanding of a system. It usually employs analytical The connection between risk assessment and approaches in combination with “deliberative” watershed assessment is that doing approaches, which are linked to value watershed assessment may involve analyzing judgments (National Research Council, risk to individual processes or features in the 1996). The U.S. EPA has developed a watershed as a result of human actions, or framework under which large-scale analyzing the cumulative risk of various “cumulative risk assessments” are done for actions on various watershed features or multiple “stressors” (sources of stress to a processes. A watershed assessment that system). Under this framework, cumulative includes risk analysis, and especially risk assessment is defined as “an analysis, cumulative risk assessment, can then inform characterization, and possible quantification management activities intended to manage of the combined risks to health or the risk from human actions. It is not essential environment from multiple agents or that risk assessment and management be stressors.” (U.S. Environmental Protection part of watershed assessment. However, Agency, 2003). This approach is similar in these concepts are often part of people’s concept to watershed assessments, and the picture of watershed assessment because two approaches could act in concert (see later managing risk influences many areas of in this chapter and chapter 6 for more detail). applied environmental science. The difference lies partly in the terminology, as many aspects of risk assessment can be 2.3 Basic Watershed Assessment found in watershed assessment. There is also Process a difference in substance – watershed assessment is often about actual impacts to The following sections address the question condition, whereas risk assessment often of: “How do I design the assessment?”. To stops at potential impacts. To the degree a summarize the process, the first step is to get watershed assessment estimates the a basic picture of the watershed, what we call potential for or actual harm caused by various an initial scoping. This includes clarifying the human activities and the resultant stressors, it assessment’s purposes, identifying the focus is quite similar to risk assessment. of the assessment, and developing a conceptual model or diagram that reflects the A sub-category of cumulative risk assessment relationships of key factors and processes in is ecological risk assessment, which is the watershed. Next comes the task of defined as a process that involves collecting and analyzing existing and new consideration of the aggregate ecological risk information and data. The final step is the to a target entity (such as aquatic biota) information integration phase in which all the caused by the accumulation of risk from information is assembled in some systematic multiple stressors (U.S. Environmental fashion to see what it means.
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2.3.1 Phase 1: Initial Scoping - Defining beginning so you have some sense how the Biological, Spatial, and Temporal much time and effort might be involved. This Scope of the Watershed Assessment initial assessment will help organize your team and your approach, show what might be We suggest that you begin with an initial gained from a more detailed assessment, and assessment or scoping of your watershed. provide some clues about which parts of a Defining the scope of the assessment more thorough assessment will be relatively involves identifying the breadth of your efforts. easy to perform and which parts will be more What temporal and spatial scale will you difficult. Taking an iterative approach to select? This involves identifying the assessing a watershed is usually an efficient boundaries of your watershed and use of personnel, consultants, and finances. determining time period over which data will be collected; both existing data and future In most cases, it is not obvious at the outset collection efforts. Like most parts of the how deeply your assessment must delve into assessment, you will likely revise your initial a particular problem. You must first learn estimate based on the availability of data and some basics about the problem before other factors. Nonetheless, it is valuable to deciding how and how hard to tackle that identify the scope of the assessment before problem. For some problems, a well-
Guidelines for Choosing a Starting Place
Getting started with a watershed assessment assumes there is something already going on in the watershed. Sometimes an appropriate sponsoring group for the assessment does not already exist or may not be apparent. An example from the Bay Area offers a way to look at the spectrum from “good” to “best” in opportunities for choosing the appropriate group as a “starting place” for a watershed assessment.
The starting place should help reduce the cost of getting started. The following conditions suggest the suitability of a starting place. The upper two sets of conditions, dealing with local, non-governmental interest groups and volunteers, are probably the most important for reducing costs.
Good Better Better Best There is a local interest group that includes all pertinent local agencies and non-governmental organizations and wants science support.
There is a local volunteer monitoring organization that focuses on watershed health care and has strong links to public education and pertinent local agencies.
There is a local legacy of environmental studies that includes a written natural history and the history of fire and flooding and the history of land use.
“Bay Area Watersheds Science Approach”, San Francisco Estuary Institute (1998)
- 20 - California Watershed Assessment Manual, Chapter 2 August, 2004 considered experimental design, a prolonged what piece of ground is under discussion can period of data collection, and rigorous head off many problems and arguments. hypothesis testing may be necessary. In other cases, existing data and earlier analyses may In determining your assessment area, offer a perfectly adequate answer for your consider only watershed boundaries—the purposes. The appropriate level of detail for perimeter of the area in which water drains to different parts of your assessment will depend some arbitrarily defined point. Do not confuse on the tradeoffs between the level of your watershed boundary with county lines, confidence you want and the effort required to property boundaries, rivers, highways, fences, obtain that level. vegetation-type edges, federal reserves, or any other non-watershed boundary. An initial scoping serves as the foundation on which all further work is built. In some cases, The availability of information used in an especially for watersheds where little assessment may vary across property- information is available, the watershed ownership or political lines, but you should assessment might consist only of this phase. still think about all parts of your This initial assessment or problem definition topographically defined watershed. Although phase involves identifying your purpose, information may be hard to obtain (or simply developing a basic picture of the watershed, doesn’t exist) for some areas of your identifying the valued watershed resources watershed, these areas may still play and processes about which you are most important roles in influencing the downstream concerned, and building a conceptual water bodies. diagram or “a descriptive picture” of the relationships between key factors within the 2.3.1.2 What Is the Watershed Boundary? watershed. Choosing a point along a stream or river that 2.3.1.1 Defining the Boundaries of the then defines the lowest point or downstream Watershed end of your watershed is the sole decision that defines a watershed. Once you choose Establishing the boundaries of your that point, everything upstream of it becomes watershed assessment area is a critical early your watershed. Your watershed includes all step. The only watersheds defined by nature land that drains downhill (or could contribute are those with a low point at the ocean or a water via gravity) to the point of your closed-basin lake. All others (including those choosing. Imagine there is a line extending contained within a “naturally-defined” uphill away from your point along the stream watershed) are defined by a human choice of on either side of which water flowing the lowest point (e.g., the map of the Yuba downslope will reach the stream above or River basin on the next page, from the below your point. This line may be hard to confluence with the Feather River). Not all visualize or accurately map (and the exact watershed boundaries are obvious, and location isn’t important for your assessment decisions about boundaries and other related because errors of a few feet are insignificant issues will have to be made early in your with respect to your entire watershed), but assessment process. Choosing the size or there is a physical micro-topographic divide “scale” of the watershed will determine where (or underground geologic structure, to pick the lowest point that defines the entire sometimes termed the phreatic divide) that watershed and vice-versa. Some watershed separates water to one direction or the other studies start at a point in the middle of the with respect to your point on the stream. This river, such as at a dam or a stream-gaging line will eventually reach a ridgetop, where it station, and evaluate the watershed above becomes obvious that water will flow either this site. Agreeing on the assessment area at into or away from your watershed—imagine the outset so that everyone knows exactly the Continental Divide where water on the
- 21 - California Watershed Assessment Manual, Chapter 2 August, 2004 west side flows toward the Pacific Ocean and Prominent ridges make the process very water on the east side flows toward the obvious and straightforward. Conversely, Atlantic Ocean. The same concept of a divide defining a watershed boundary in flat areas scales down to the smallest watershed you with all the topographic relief of the care to define with your chosen point. Sacramento-San Joaquin River Delta is nearly impossible. In flat areas such as the For mapping purposes, locate your point on a Delta, having an uncertain boundary is topographic map and draw a line away from probably adequate for most purposes your point separating the area inside your (imagine using a very broad crayon to mark watershed from that outside. Following along the divide on your map). the obvious ridgetop is generally easy, while connecting the ridgetop to your point along Another complication is the presence of the stream may not be so easy if the engineered water imports and exports. topography has little relief. See Water: A Aqueducts, canals, penstocks, storm drains, Primer (Leopold 1974) or Watershed and pipelines can interfere with the otherwise- Hydrology (Black 1996) for more details on clean delineation of a watershed. In such drawing watershed boundaries. Alternatively, cases, start with the natural, topographically almost all common GIS packages have a defined boundaries. Then consider the effects simple function for drawing watershed of the water diversions and append those boundaries given the defining point on the considerations to the natural watershed. For stream. example, if 100% of a neighboring watershed’s flow is captured and diverted into Obviously, delineating watershed boundaries your watershed, then you may wish to add the is much easier in steep terrain with lots of entire area of that other watershed to yours. If relief than in low-lying, nearly level areas. only a small fraction of the flow is imported
Watershed Boundary N Elevation (feet) 0 - 1000 ft W E 1000 - 2500 2500 - 4000 4000 - 5500 S 5500 - 7000 7000 - 8500 >8500 ft
10 0 10 20 Miles
- 22 - California Watershed Assessment Manual, Chapter 2 August, 2004 into your watershed, then you probably don’t on the local stream (simply because they want to adjust watershed area, but will occupy a greater proportion of the watershed instead deal with the imported water just as area). If you are primarily interested in broad quantity of water (and its constituents) added regional issues, you may wish to assess a from outside. In the case of water exports out single large watershed or river basin where of your watershed, you should usually impacts from small disturbances tend to be maintain the natural watershed area and diluted. consider the impacts of the diversion on aquatic resources. Your watershed will be part of one or more ecoregions—a term defined as “major So, how do you choose this all-important ecosystems largely determined by climatic point to define the watershed boundary? That conditions that affect the distribution of plant depends largely on the objectives of your and animal species” (Bailey 1995). Ecoregion assessment and the general area in which classification systems, such as those of Bailey you are interested. Common points to pick (1995) and Omernik (1995), distinguish areas are the mouth of a stream at an ocean or based on terrain, climate, and major lake, the confluence of a stream of interest vegetation cover. Although ecoregions rarely with another stream or a much larger river, a correspond to watersheds, the finer-scale point immediately upstream of a major water ecoregion characterizations provide much diversion, a stream-gaging station where information about vegetation and other flows have been measured for several years influential factors, as well as attributes of or decades, or a location where water quality aquatic habitats that should be useful in your samples have been consistently obtained. watershed assessment (Omernik & Bailey Sometimes, another entity (e.g., a funding 1997). Keep watershed boundaries in mind as agency) will pick the point for you. Also you seek ecological information from larger- consider using the state’s CalWater system of scale ecoregions. delineated watersheds if your watershed approximates one of the CalWater Table 2.1 watersheds. Be aware that topographic and Watershed Ecosystem hydrologic errors exist in some of the Assessment Endpoints watersheds in CalWater 2.2 and that there Purposes may be seemingly odd distinctions between Determine Reproducing “upper” and “lower” watersheds. Another sustainability of native steelhead source of information for defining watershed fish population in the population boundaries is the US Geological Survey. stream Each hydrologic unit in the U.S. is identified Determine ecological Viable population by a unique hydrological unit code (HUC) requirements of and condition of consisting of two to eight digits based on the riparian vegetation to cottonwood trees four levels of classification in the hydrologic aid in long-term unit system. You can get additional management. information about this system at Determine availability Amount of and http://water.usgs.gov/GIS/huc.html. of recreational lands accessibility to
urban parks Selecting the watershed boundaries is also Determine impacts to Species influenced by the objectives of the creek in the face of composition, assessment. You may wish to define rapid urbanization diversity, and watershed boundaries broadly or narrowly. organization of fish For example, if you wish to study the effect of and benthic local land-use changes, you may wish to macroinvertebrate assess several small watersheds where these communities changes will have a more noticeable impact
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2.3.1.3 Identify the Watershed Processes Often it is difficult to measure these endpoints and Valued Ecological Components to directly. For example, quantifying steelhead Focus on reproduction is a challenging task. So a series of measurements or monitoring data can be Once you have defined the purpose(s) of the substituted that reflect the condition or status assessment and geographically defined the of the endpoints that are the focus of the area of assessment, you can apply this assessment. information to identify the processes and components of the watershed that reflect the In one of the examples in Table 2.1, purpose and goals of the assessment. This stakeholders believed the population of native involves identifying the watershed processes fish was declining, which prompted their or components are most important to the watershed assessment. Because steelhead stakeholders. Watershed processes refers to were among the most visible native fishes in the natural physical, chemical, or biological the stream and are a listed species, they were processes that interact to form an aquatic selected as the ecological endpoint. However, ecosystem, such as the water cycle. Valued due to the difficulty of accurately measuring ecosystem components refers to the things steelhead population itself, the stakeholders within the watershed that stakeholders value, selected a number of other measurements such as fish, trees, or open space. Some that were relatively easy to collect that would watershed scientists have used the term serve as indicators or surrogate ‘ecological endpoints’ to refer to any measurements of the steelhead population ecological components or processes that are (Table 2.2). Without the appropriate habitat the focus of the assessment. We will use that and water quality conditions, it is unlikely a generic term or the related term “ecosystem viable population of fish could persist. endpoint” in this Manual. Measurements of stream morphology or water quality, for example, serve as useful There are numerous valued components and indicators because they reflect the conditions processes in a watershed. You could spend in the stream that are needed to support a forever studying them. By identifying a few viable population of steelhead AND are that are especially important, you can focus relatively easy to measure. your efforts and simplify the assessment. A few criteria are useful for selecting the 2.3.1.4 Develop a Conceptual Model ecosystem processes that will be the focus of the assessment. One of the last preliminary yet very important These should be: steps in the scoping process is the • Important to the health and sustainability development of a conceptual model. A of the watershed; conceptual model is a graphical • Related to the assessment’s purposes; representation of important relationships • Have societal value; in other words, are within the watershed. Once you have important to the community identified the ecological endpoints you are most interested in, you will need to think These ecosystem endpoints might include, for about how they are impacted by changes in example, benthic macroinvertebrate watershed processes and the stress that may communities, drinkable water, a species of result from human activities. The relationship fish or a plant that is important to the between human activities, watershed stakeholders, or, more generally, the overall processes, sources of stress (“stressors”), riparian corridor or upland habitats. Table 2.1 and the ecological endpoints are depicted in presents some possible purposes for the conceptual model. The term stressor conducting a watershed assessment and refers to anything, natural or human-induced, related ecosystem endpoints. that could cause harm to components and processes within the watershed. Watershed
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serves as a aid to your understanding Table 2.2 and a guide to the type of data and Purpose Ecosystem Measurement information you might want to collect Endpoint(s) or Data to be for the assessment. Collected Determine Reproducing Water Conceptual models can be developed sustainability steelhead temperature in a variety of ways. You should of native fish population Habitat develop one as part of the scoping population in suitability process. In the first example, the the stream Contaminant model below was developed to concentration, represent hypothesized relationships etc. in a small watershed where salmon Determine Species -Index of Biotic populations were declining. The impacts to composition, Integrity diagram shows the possible influences warm-water diversity, and (composed of of landscape and in-stream processes habitat in organization of 12 attributes) on salmon populations (Ziemer, 2004). creek in the fish and benthic - Invertebrate In this case, municipal water use, face of rapid macroinvertebrate community oceanic processes, roads, and logging urbanization communities index (based are the primary influences on success on 10 of salmonid reproduction and measurements) population health.
It quickly becomes clear that in order assessments typically focus on those to prepare these diagrams, you will need to stressors that are human-induced, since they understand the watershed processes or are the ones we have some ability to control. mechanisms that link human activity to The specific interactions will be unique to your changed conditions. For example, increases watershed, though experts and technical and in impervious surfaces (e.g., urban areas and scientific literature can provide you with many roads) can cause alterations in stream of the clues you need to understand the morphology as a consequence of changes in interactions. At this point, you should not draw peak flow rate and total surface. conclusions as to what the relationships are; you should think about what they could be. Using another example from the same conceptual diagram, the relationship identified The conceptual model can be a valuable between increased fine sediment from learning tool. When initially drawing the excessive erosion and mortality of salmon model, represent the relationship you think eggs and yolk-sac fry is based on an exist based on the initial scoping you have understanding that conditions of depleted done. It is not necessary to wait until you oxygen occur as fine sediment are deposited collect additional data and information. At this in spawning gravels. The knowledge required point, it is simply useful to hypothesize the to draw accurate conceptual models can be relationship between the human significant. That is why having a team of activities/land uses, altered conditions or people with varied backgrounds is very processes, and the potential effects of these helpful. alterations on the ecological endpoints.. Another example of a conceptual model Over time, as the team gains additional diagram is shown on the next page. It focuses information, you can modify the conceptual on the influences on domestic water quality in model to better reflect the reality in the the Mad River watershed (Reid & Zeimer, watershed. But in the beginning, it primarily unpublished).
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“The process of developing the diagram is more important that the final diagram itself. In building the diagram, individuals with different backgrounds and focus can identify where their knowledge contributes to the solution of a single issue. In [this figure], there are three major components potentially affecting salmon: land use, human predation, and ocean condition.” (Ziemer, 2004)
Shaded boxes and thickened arrows indicate relationships that you think exist, even if there the impact mechanisms that are expected to is little available data to support it. Based on be most important. Lines without arrowheads the model, you can identify key areas for indicate subsets within a category (e.g., which you need data. If such data exists, you coarse and fine sediment). In this case, can assemble it. If it is not available, you channel dynamics, sediment composition, might decide to collect it on your own. and the presence of pathogens have the most Second, the conceptual model is a ‘work in impact on the quality of the municipal water progress’; it will change as your supply. understanding of the watershed expands. Most conceptual models undergo numerous The key point is that the diagrams should revisions as the work proceeds and new identify hypothesized relationships between relationships are revealed. human activity, changed conditions in the watershed, and the potential effects of these 2.3.2 Phase 2: Plan Data Collection and changed conditions on the selected ecological Analysis endpoints. The previous section described conducting an When preparing a conceptual model, a few initial assessment. From this point on we will points should be kept in mind. First, the be discussing ways you can approach the development of the conceptual model is not main part of your assessment. data dependent. You are trying to reflect
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Bank Blue Lake stability sewage plant Road runoff
Mad Roads Freight spills River (?) Agriculture Septic Urbanization Herbicides Hatchery systems Logging
Gravel Korbel Sewage mining Mill (?) Sediment Toxics Nutrients Coarse Fine Grazing Turbidity Channel Water form treatment Pathogens requirements Proper function Humboldt Bay of Ranney Municipal Collectors Water District Water quantity Recreation (dilution)
Clean water for municipal & industrial use Other water users
The next step in planning your watershed assessment is actually writing a plan for The data collection and analysis effort analysis. Having laid the foundation for the constitutes the heart of the watershed assessment by focusing the assessment on assessment. The conceptual model or key issues of concern, defining the scope, diagram constructed as part of the initial and developing your conceptual model, the scoping can serve as a guide. Accordingly, as final step before actually commencing the you plan for the analysis phase of your assessment is to lay out a plan to do the assessment, you should identify the data and work. This section reviews the factors you information that must be gathered and outline should consider in developing your analysis the process for organizing and analyzing this plan. Each of the topics are discussed in material (discussed in more detail in chapters detail in subsequent chapters, which are 4 and 5). There are two primary forms of data identified in the appropriate section. One point and information you will collect based on your to keep in mind, as with everything in a conceptual model or similar plan. One is watershed assessment, is that this is an existing data and the other is new data. iterative process. To the best of your ability Existing data already exist for the watershed, and based on your present knowledge, lay though they may not have been collected to out a plan for analysis. But keep in mind that support an assessment. New data are it is likely you will need to revise it as you go collected to fill gaps in information and along and learn about factors you had not knowledge about how the watershed considered in the beginning. functions.
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The watershed assessment focuses in part on effluent from industry, or other contaminant to the potential harmful effects of human the targeted habitat. Biological alterations activities on watershed properties and that might be associated with harm could function. These effects occur when human include invasive species, pathogens, habitat activities cause changes in the physical, fragmentation, and changes in ecological chemical, or biological characteristics of the processes. A key function of the analysis plan watershed. is to focus attention on the relevant changes in processes and conditions and outline how Physical changes include water temperature these changes might affect the ecological and flow rate, sediment characteristics, endpoints, the valued ecosystem components stream channel shape and connectivity with and processes that you identified as the focus the floodplain, erosion and incision of the of your work. streambank, and any other physical characteristic that makes up the habitat on 2.3.2.1 Identify the Data to Collect which the watershed processes being evaluated depend. In determining what data you want to collect, one criteria you might want to consider is its Chemical changes include the introduction of relevance to the focus of the assessment, the pesticides, excess nutrients, oil/grease, ecological endpoints. The table on the
Issue Some Relevant Questions to Ask Topography What are the elevation profiles and slope angles? Hydrology and water use How much water is in the watershed and where does it go? What is the seasonal pattern of stream flow? Are there dams, diversions, and/or culverts that might affect flow and act as barriers to fish passage? What about floods and the floodplain? Sediment Sources and Has turbidity in the stream changed over time? Have the Transport characteristics of the streambed changed? Is there evidence of erosion upland or in the stream banks? Have fine sediments filled what were once pools or gravel beds? Riparian Vegetation What proportion of the watershed is covered by native vs. non-native species? What is the extent of the riparian corridor? Instream habitat, including Does it appear that the stream channel has been altered? water quality Does the water appear clear and of good quality? Is there a history of fish kills? Are there human activities close by that might degrade the water quality? Fish and wildlife Has there been a decrease in the diversity or abundance of fish in the stream? Have the number and kinds of birds and mammals in the watershed changed? Have the number of frogs and toads decreased? What changes have occurred in streamside vegetation? Are there invasive animals present? Historical and present land What was the land in the watershed used for historically? uses What is the legacy of these land uses? What are the present land uses? Could any pose a risk to aquatic life either directly or indirectly (i.e., releasing contaminants or increase sedimentation)?
- 28 - California Watershed Assessment Manual, Chapter 2 August, 2004 previous page contains a list of key issues 1. Is there temporal and spatial co-occurrence and examples of questions related to the of the stressors or altered conditions and the issues. It might serve as a useful exercise to ecological endpoints? ask yourself – To what degree are these issues and their related questions relevant to You should assess the pattern of stressors the focus of my watershed assessment? This occurring in space and time and the pathway table is not inclusive; there might be other by which this pattern might lead to harmful issues of importance in your watershed. effects on watershed processes. To do this, The above list is not comprehensive. In any ask yourself two questions. particular situation, there might be additional major categories of importance. However, the • Is it likely that the ecological endpoints are list highlights key topics that are likely to be present at the same time as the altered important in most watersheds. conditions/stressors and/or processes?
2.3.2.2 Decide How You Will Evaluate and An example can best be used to explain what Analyze the Data we’re getting at with this question. Assume changes in the riparian canopy have occurred The following section describes one approach as a result of changes in the hydrological to collection and analysis of data. It has been patterns in the watershed. The hydrological proposed in the U.S. EPA’s watershed risk changes have caused streambank erosion assessment guidelines (posted at: and loss of some riparian cover. www.epa.gov/watertrain). It is limited to Consequently, the summer temperature of the human effects on water quality and the water has increased. If one of the ecological impacts of water quality on waterway biology endpoints is anadromous fish, then it is (“ecological endpoints”). This simplified necessary to determine if this species was diagram illustrates EPA’s recommendations. present in the stream in the summer, during the period that the temperature was high. The diagram below reflects the relationship Although the water temperature might exceed between altered conditions and processes tolerance limits for this fish, if the fish isn’t associated with human activity, the potential present, there is no temporal coincidence, for exposure, either temporally or spatially, of and there is no opportunity for harm to occur. the ecological endpoints to these stressors, and the potential adverse effects that might • Is there spatial overlap between the result from this exposure. geographical distribution of the ecological endpoints and the altered conditions/stressors or processes?
For example, warm-water fish, such as bass, often prey on young salmon. Typically, the bass live at lower elevations, where the water is warmer than that inhabited by juvenile salmon, which need cooler waters. Although non-native bass and salmon share the same stream, if there is no/little spatial overlap, it is unlikely that invasive bass will act as a biological stressor on the salmon, except for the relatively brief period when the young The following questions might serve as a salmon migrate downstream and pass useful guide to determine the degree to which through the bass habitat. each of these issues is important in your particular situation.
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You might also want to consider the effect of processes or conditions, thereby causing secondary stressors or alterations in stress on the ecological endpoints of interest. evaluating possible harm. For example, acid Second, consider the temporal and spatial co- mine drainage in Northern California has occurrence of these stressors on the been a significant problem in certain areas. ecological endpoints. If there is no temporal During the rainy season, sulfuric acid spills or spatial overlap, it is unlikely the stressor into the rivers and creeks, depressing the will/does present a problem for the ecological water’s pH and causing significant toxicity to processes that are the focus of your aquatic life. Not only does the acid spill cause assessment. If there is co-occurrence, then it direct toxicity, but it also increases the is important to evaluate if theses stressors solubility of copper, zinc, and other potentially have an adverse effect on the ecological harmful metals. These metals are secondary endpoints. These are important issues to stressors and can independently cause review when planning data collection and toxicity to fish and invertebrates. analysis.
2. Is it likely or is there evidence to suggest 2.3.2.3 Scale: An Important Issue in that the altered conditions might have an Planning Your Analysis adverse effect on the ecological endpoints? One important consideration in developing an To make this analysis, you need to determine analysis plan is the question of scale. The whether conditions in the watershed have term scale has a variety of uses depending on been altered enough to reduce the viability of the context and need of the user. In ecology, the watershed processes that are the focus of the scale of measurement refers to the the assessment. You will want to understand classes or types of values that describe a the conditions in your watershed relative to feature or process. For example, soil classes those known to be protective of aquatic are an example of a “nominal” (naming) scale resources. One way to do this is to of measurement, whereas temperature is an characterize the stressor-response profile. example of an “interval” scale because values range across a numeric scale (Jongman et al. In summary, when planning your data 1995). There is also “spatial scale”, which collection effort, consider the value and refers here to the scale at which a place is appropriateness of collecting data on the measured or viewed. Temporal scale is the human activities (i.e., land uses) within the timeframe over which analyses or watershed that might alter watershed measurements are taken for a process. This
Examples of typical types of data collected in a watershed assessment and the optimal scale for these data
Type of Data Temporal/Spatial Scales Contaminants in water Throughout the year and immediately after rain events; above and below sites of concern (storm drains, road effluent, wastewater treatment plants). Ideally, regular monitoring over many years. Sedimentation In streambed, on hillslopes, below roads, primarily following storm events, in smaller streams and periodically in smaller and larger waterways Dissolved oxygen, Weekly or monthly in all sub-watersheds of the stream temperature Road maps 1:24,000, updated every five years
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Manual deals primarily with the latter two uses condition, but there probably won’t be data for of the term and qualifies the word where the whole watershed with fine enough needed. resolution to answer site-specific questions. These types of issue highlight the relationship The spatial and temporal scales used in a between the assessment questions and the watershed assessment must be appropriate spatial scale of your data. for the type of information being collected and the questions or problems being addressed. • Data scales
Different analytical approaches depend on You may be relying on existing data for your different scales of input data. Varying results assessment. In this case, you will not have an and conclusions are possible depending on opportunity to make a decision about scale. how fine or coarse the resolution of data This situation exists for topics like plant and collection is. The scale at which data and animal distribution across the landscape, as knowledge (what we know from the data) well as for topics like changes in water quality have been developed determine the kinds of over time. Academic definitions of studies, management, regulatory, or restoration including watershed assessments, often decisions that can be supported by a differentiate between those where the watershed assessment For example, if it is investigator can control some aspects of the likely to take six months before logging system (an experiment) and those studies activity potentially causes environmental where the investigator has no control of the changes, then data should be collected system and relies on already-collected data (a before logging begins, again six months later, “survey”; Jongman et al. 1995). This and at least one more time per season (for difference is important because cause and wildlife) or week and storm event (for water effect are harder to determine in surveys than quality) within several years of the activity. By experiments. collecting data over this period of time, there is a good chance that changes that might Watershed assessments will generally involve have resulted from the logging will be only survey data that has already been detected. collected. Data collected at scales that you cannot control constrains the use of that data • The link between the assessment in new analyses. However, much of the questions and scale information that an assessment relies upon as “data” may actually be products of computer This Manual is designed for watershed models (e.g., for wildlife habitat, fire hazard, assessments that support questions, and landslide risk), which potentially decisions, and implementing actions. The increases the range of uses of data, but not types of questions you ask in your necessarily the reliability. assessment, the decisions you expect to make, and the actions that might result will 2.3.3 Phase 3: Data Synthesis and determine the scale of data you need. If you Integration are assessing the condition of a 10,000-acre watershed in order to prioritize sites for Another part of the plan you develop should restoration, you may need to go beyond most contain your best estimate of the methods readily available spatial data sets and use you plan to use to integrate the data and custom digital spatial data or field data to identify relationships among watershed differentiate among areas within the processes and problems. Integrating data watershed. For large watersheds (e.g., 1 refers to the process of incorporating the million acres), the condition assessment may analysis of the physical, biological, and allow you to differentiate among sub- chemical conditions in the watershed into a watersheds for potential action and likely single useful estimate of the potential for
- 31 - California Watershed Assessment Manual, Chapter 2 August, 2004 adverse effects on the watershed processes Different methods are appropriate for different and features of interest. This topic is situations. Chapter 6 focuses on these discussed in more detail in Chapter 6. methods. The following list summarizes a few of the methods used for information The integrated assessment evaluates the integration and analysis likelihood that a potentially harmful event has occurred or will occur. Comparing data of 2.3.3.1 Models for Data Integration disparate types can be challenging. The difficulty of data integration is that the data • Team Mental Integration: Weighing the exist in a variety of forms that do not lend Evidence themselves to comparison. Data on water quality might be reflected in units of parts per Team Mental Integration is really nothing billion. Data on riparian vegetation could be more than using best professional judgment expressed in terms of percent canopy cover to analyzing and synthesizing the data. or area covered by invasive species. Data Pulling from the knowledge and experience of related to stream morphology might be the assessment team and appropriate expressed as particle sizes (mm), percent experts, a systematic weighing of the data fines, or percent change in pool volume. and information collected can help link the Information on land use might be expressed impacts on the watershed to potential causes. as acres of land use “x”. All of these watershed characteristics are important to the • The Relative Risk Model overall assessment, yet the basis for quantitatively comparing them is difficult The Relative Risk Model (RRM) methodology because you are, in effect, comparing apples assigns numbers or ranks to stressors and oranges. An unfortunate consequence is identified in the conceptual model so that the that many watershed assessments do not potential effects of a variety of chemical, include an information integration step. physical, and biological factors can be compared to each other. This method can be The data synthesis phase of the watershed applied to assessments with only limited assessment allows you to evaluate the nature amounts of data, as well as those with of the relationships you hypothesized in the significant amounts of data. conceptual model. For example, you might have speculated that high turbidity was • Knowledge-Base Models responsible for a decline in the population of a valued aquatic organism. However, in The Ecosystem Management Decision synthesizing all the data, you might learn that Support model (EMDS) is one knowledge- in fact, depleted food supply associated with based model that can be used to integrate changes in riparian cover is a more important and analyze data. The model evaluates the factor. Your initial speculation might have “truth” of an assertion about a place, such as been inaccurate. But you have identified “changed land uses impact aquatic those factor(s) that appear to be most ecosystems.” A knowledge base provided by important for protecting or restoring the the user guides the evaluation. The valued processes and resources in your knowledge base shows relationships among watershed. This prioritization is the real power the parts of the system under study. A variety of the data synthesis/integration step - it can of environmental conditions can be evaluated serve as a guide for action. with this model; all are integrated into a single analysis. Maps are then generated that reflect At present, there is not one single method of ranking of areas by watershed or process information integration that is widely used or conditions. accepted. A variety of methods have been used; each has its strengths and weakness.
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• The SCREAM Model (Southern California 2.4 Important Issues in Conducting a Wetlands Recovery Project) Watershed Assessment
The Southern California Riparian Ecosystem This section tells you about issues such as Assessment Method (SCREAM) is a GIS- uncertainty and data gaps that are important based tool to assess the ecological condition to cover in your assessment. Just as and stressors affecting riparian habitat at a important as what is known about a landscape scale. In the SCREAM model, watershed is what is not known. existing or new GIS data layers are compiled and organized, and the information contained 2.4.1 Uncertainty in those layers are used to calculate hydrologic, biogeochemical, and habitat The term “uncertainty” has a variety of uses in condition scores. The developers of the everyday language, in social and natural model, the Southern California Coastal Water sciences, and in statistics. The dictionary Research Project or SCCWRP, envision that defines “uncertainty” as literally a lack of the SCREAM tool will be used as part of a certainty about something. There is also a comprehensive assessment program to statistical meaning to the term that refers to evaluate the condition of and stressors the probability of an outcome occurring, for affecting wetlands and riparian ecosystems in which the variation in possible values might southern California. be known and specific statistical tools can be used to measure the uncertainty. One Although you can probably say for sure which statistics text considers “uncertainty to be approach you will eventually use, it is wise in synonymous with diversity” (Zar 1984). This the planning stage to review the various example presents one way to think about options and tentatively identify which one is uncertainty: Let’s say that there is a high most suitable to your level of expertise and probability of occurrence of salmon spawning the amount of data you plan to collect. in gravels between one and three inches in diameter that are deeper than 6 inches below In conclusion, the analysis or assessment the water’s surface and a low occurrence of plan should outline the key steps in the spawning anywhere else. The diversity of assessment and how they will be carried out. places that salmon spawned would be low As you proceed with the assessment, you will and the uncertainty about where salmon likely modify the plan as you gain new spawn would also be low. knowledge about the watershed or recognize things you might have initially overlooked. An There is often a great deal of uncertainty analysis plan is similar to a business plan or a associated with the measurement and work plan for a project in that it facilitates analysis of natural conditions. Some of this carrying out the assessment in a more uncertainty is associated with the systematic fashion. measurement and analytical approaches themselves, because we don’t know how Actions 2.3 to perfectly sample or represent complex • Conduct initial scoping for focus of systems. Some uncertainty comes from assessment incomplete measurements of the systems due to inadequate resource investment, • Develop a conceptual model for example, or inaccessibility of a place. • Plan collection and analysis of data Generally, most science and knowledge • Describe the spatial and temporal scales development aims to reduce uncertainty of the data (Dawes, 1988) and increase our ability to • Plan synthesis and integration of data to predict things around us, for which there is describe watershed condition a known or unknown probability.
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2.4.2 Data Gaps (how much data is needed) appropriately to actually answer the assessment questions. A critical part of any assessment is recording This is particularly true for water quality data. gaps in data or knowledge that become Although quality assurance is required for obvious when gathering and analyzing data collected by state-funded projects, there watershed information. These gaps may be is no requirement to calculate the sampling large enough to make the assessment intensity (number of samples and frequency insufficient for certain kinds of decision of sampling) needed to determine 1) the making. They may also form the foundation of actual value of a measured constituent, 2) future monitoring and data collection activities differences between or among mean values, that will allow for more comprehensive and 3) trends in values over time. The condition assessments. One approach to this approaches to calculating how much data is issue, suggested by Bingham (1998), is to needed for an analysis are available in inventory and collect existing data and, based statistical texts (e.g., Zar 1984) and on these data and on watershed management summarized in this Manual and should be goals, develop critical questions before understandable to most assessors with continuing the planning process (as described professional scientific degrees. in Section 2.2 on “Formulating Questions”). These questions will determine the amount For parts of the watershed assessment not and type of data that is needed to continue. dependent on comparison of measures of watershed condition, there are few standards 2.4.2.1 Data vs. Knowledge for determining data completeness. The approach to determining adequacy of the Data refers to “facts or pieces of information” available data should consist of first (Spellman & Drinan 2001), while knowledge is identifying the questions, then determining the the use of that information to form a mental data that are needed to answer the questions, picture of a process or phenomenon. Usually and finally comparing the available data to the monitoring programs collect data, which then list of data needed. Deciding whether or not must be analyzed and assembled in some there is a complete data set then becomes a way to provide knowledge about a place or job for professional judgment. process. 2.4.2.3 When do You Know Enough? 2.4.2.2 What is a Complete Data Set? Watershed assessment is a continuous A “complete data set” may be defined as process, reflecting the changing nature of the “sufficient data to answer the assessment subject. The minimum information needed to questions”. However, most investigators may answer the assessment questions may turn not have sufficient data to adequately address out to be a fuzzy concept, based on the assessment questions. They may also not people involved and the complexity of the have investigated the question of sufficiency questions. For example, resolving a question about the immediate and cumulative impacts “Where is the wisdom of new urban development in a sub- We have lost in knowledge? watershed might revolve around the Where is the knowledge timeframe for the question, the particular We have lost in information?” natural processes affected, and the likelihood ~T.S. Eliot that general plan and specific plan amendments that could modify the actual “Where is the information extent and layout of the development will We have lost in data??” occur in the timeframe of the question. An ~Anonymous example of a data gap in this case could be the actual developed area that will result and
- 34 - California Watershed Assessment Manual, Chapter 2 August, 2004 a knowledge gap could be the linkage observers and experts consider the current between the modification of the sub- condition relatively deteriorated. watershed and the response of a particular c) Vegetation maps show the plant natural process (e.g., seasonal drying-out of community type, but not the growth stage, the streambed). Whether or not you know canopy closure, human extraction activities, enough may be a research question. Detailing or fragmentation. the steps between developing critical e) Hydraulic models rely on a definition of assessment questions, collecting relevant channel shape characterized by cross-section data, and making linkages between the or topographic data, and the channel may questions and the data is the job of the have changed significantly in the past 60 assessment planning team. years since the survey data were collected.
2.4.2.4 Prepare a List of Data and Examples of how a data gap should be filled: Knowledge Gaps a) Establish flow gauging stations at the mouth of the major tributaries in cooperation A primary product in your assessment that with regional expert (university, USGS, DWR, should result from this section of the Manual water district). is a list of data and knowledge gaps. This list b) Develop and implement a water-quality should include the nature of the gap, how and monitoring program using a combination of why it was identified as a gap, what would be professional and volunteer monitors. required to fill the gap, and who should fill it. c) Take the vegetation map and add attributes This product tells you and future assessment for land condition and use based on local users how complete the data set and knowledge, recent aerial photos, and knowledge base were for the analyses recorded extraction activity (e.g., timber performed and judgments made. It also lays harvest plan) relying on GIS consultant or out what is needed in order for future staff. assessment to be more thorough. If this task d) Conduct field-work to resurvey channel is carried out thoroughly, it should lead cross-section or topographic data. directly to funding proposals and program development for monitoring and research into 2.4.2.5 Using Data Gap Information to watershed condition and processes. Inform Future Monitoring
Examples of data gaps: An explicit link should be made between the a) Flow data available for 50% of major watershed assessment process and the tributaries development or maintenance of a monitoring b) Water quality data available for1970 to program. This can be done by describing data 1990; no recent data is available and knowledge gaps and proposing resolution c) Plant community map does not show actual for the gaps. Thus new data collection fills condition or land use data gaps and develops knowledge about d) Cross-section survey data utilized in processes. For example, a monitoring hydraulic model collected in 1940 instead of program may intensify its existing sampling in 2004 and increase the number of sample sites in order to meet data needs identified in the Examples of how a data gap is identified: knowledge gaps part of the assessment. Or a) To run a hydrologic or hydraulic model, additional processes may be investigated to flow data are needed for all major tributaries aid in developing an understanding of how for water years representing a range of flows activities in a watershed affect natural for a minimum of 10 years. processes and other beneficial uses. b) Watershed development has occurred primarily since 1990. Long-time watershed
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2.5 REFERENCES (CWAP). Victoria, BC: Province of British Columbia, Forest Service. Bailey, R.G. 1995. Description of ecoregions of the United States. U.S. Forest Service British Columbia Ministry of Forests. 2001. Miscellaneous Publication No. 1391. Watershed assessment procedure Washington, D.C. guidebook. 2nd ed., Version 2.1. For. Prac. Br., Min. For., Victoria, B.C. Forest Practices Beierle, T.C. and J. Crayford. 2002. Code of British Columbia Guidebook. Democracy in Practice: Public Participation in Environmental Decisions. Resources for the California Coastal Conservancy. 2001. Future, Washington, D.C. http://www.rff.org Watershed Planning Guide. Oakland, Calif. http://www.coastalconservancy.ca.gov/Public Bingham, D.R. 1998. Watershed ations/ws_planning_guide.pdf management in U.S. urban areas. In Watershed Management, R.J. Reimold (ed.). California Department of Fish and Game. McGraw-Hill, NY. Pp. 169-201. 2003. Interim Restoration Effectiveness and Validation Monitoring Protocols, California Black, P.E. 1996. Watershed Hydrology. 2nd Coastal Salmonid Restoration Monitoring and edition. Lewis Publishers. Boca Raton, Fla. Evaluation Program. Fortuna CA. 320 p. 460 pp. California Environmental Protection Agency British Columbia Environment. 1995. Forest (CalEPA) and California Resources Agency. practices code of British Columbia: Coastal 2003. California Agency Watershed watershed assessment procedure guidebook Management Strategic Plan. Sacramento.
SUMMARY
DEVELOP your watershed assessment to: • Answer fundamental questions—let the problem drive the assessment • Address the cause and not the just the symptoms of your watershed’s problems • Understand why the current watershed condition seems to be the way it is • Interpret the physical, biological, and social interconnections within the watershed • Be useful for later decisions and actions
CLARIFY the: • Purpose of the assessment—Who wants it and why? Who will use it? • Structure of who will be involved and what their roles will be • Decision making—Who are the decision-makers? How are decisions made? • Recording of the process—Who, how, when, where? • Best options that will meet your needs • Reasonable expectations of the assessment product • Scope of the assessment
FOCUS on: • Your most critical or key issues, so the product is useful and not too general • Effects and processes occurring within your watershed boundaries • Using consensus effectively in your partnership group • Keeping costs under control and meeting timelines • Working with the public through two-way communications • Satisfying and helping the ultimate users of the assessment
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Community and Landscape Ecology. Callaham, R.Z., ed. 1990. Case Studies and Cambridge, U.K.: Cambridge University Catalog of Watershed Projects in Western Press. 299 p. Provinces and States. Wildland Resources Center Report 22. Berkeley: University of Kaner, Sam. 1996. Facilitator’s Guide to California. Participatory Decision-Making. New Society Publishers, Philadelphia, Pa. 255 pp. CH2M-Hill. 2003. Cottonwood Creek Watershed Assessment. Prepared for Know Your Watershed. Cottonwood Creek Watershed Group. http://ctic.purdue.edu/KYW/KYW.html Redding, Calif. 185 pp. Leopold, Luna. 1974. Water: A Primer. W.H. Coastal Watershed Council. 2003. Draft Freeman & Co., San Francisco. 172 pp. Soquel Creek Watershed Assessment and Enhancement Plan. http://www.coastal- MacDonald, L,H., Smart, A.W., and R.C. watershed.org Wissmar. 1991. Monitoring guidelines to evaluate effects of forestry activities on Dagit, R., K. Reagan, and C.A. Swift. 2003. streams in the Pacific Northwest and Alaska. Topanga Creek Watershed Southern USEPA 910/9-91-001. Seattle, Wash. Steelhead Trout Preliminary Watershed Assessment and Restoration Plan Report. Mattole Restoration Council. 1989. Elements Prepared for California Department of Fish of Recovery: An Inventory of Upslope and Game. 133 pp. Sources of Sedimentation in the Mattole River Watershed. Petrolia, Calif. 47 pp. Dawes, R.M. 1988. Rational Choice in an Uncertain World. Harcourt Brace Jovanovich, McCammon, B., J. Rector, and K. Gebhardt. Inc. Orlando. 346 p. 1998. A framework for analyzing the hydrologic condition of watersheds. USDI For Sake of the Salmon. http://www.4sos.org Bureau of Land Management Technical Note #405. Foster-Wheeler Environmental Corporation. 2000. Watershed Assessment Upper Mendocino Redwood Company. 1999. Albion Mokelumne River. Prepared for Sierra Pacific River Watershed Analysis. 158 pp. Industries. 124 pp. Meyer, J.L., et al. 2003. Where Rivers are Born: American Rivers White Paper. 24 pp. Hunsaker, C.T., Graham, R.L., Suter, G.W., O’Neill, R.V., Barnthouse, L.W., Gardner, Moote, Ann. 1997. Partnership Handbook. R.H. 1990. Assessing Ecological Risk on a Water Resources Research Center, College Regional Scale. Environmental Management of Agriculture, Univ. of Arizona. 14: 325-332. ([email protected])
Huntington, C. and S. Sommarstrom. 2000. National Research Council (NRC). 1996. An Evaluation of Selected Watershed Understanding Risk: Informing Decisions in a Councils in the Pacific Northwest and Democratic Society. Committee on Risk Northern California. Prepared for Pacific Characterization, Commission on Behavioral Rivers Council and Trout Unlimited. 131 p. and Social Sciences and Education. National http://www.pacrivers.org Academy Press, Washington, D.C. ISBN 0- 309-05396-X. Jongman, R.H.G, C.J.F. ter Braak, and O.F.R. van Tongeren (eds.). 1995. Data Analysis in
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Nehalem River Watershed Council. 2000. Watershed Assessments”, Watershed Nehalem River Watershed Assessment. Assessment Report – Volume Two. Appendix http://www.nehalemtel.net/~lnwcouncil/Asses B. http://www.scbwmi.org sment/AssessmentIndex.html Seaber, P.R., Kapinos, F.P., and Knapp, Omernik, J.M. 1995. Level III ecoregions of G.L.1987 (reissued). Hydrologic unit maps. the continent. National Health and Water-Supply Paper 2294. Reston, VA: U.S. Environmental Effects Laboratory, U.S. EPA, Geological Survey. 63 p. Washington D.C. Sierra Nevada Alliance. 1999. Watershed Omernik, J.M. and R.G. Bailey. 1997. Council Toolkit: A Guidebook for Establishing Distinguishing between watersheds and Collaborative Watershed Councils. South ecoregions. Journal of the American Water Lake Tahoe. Resources Association 33:935-949. http://www.sierranevadaalliance.org.
Oregon Watershed Enhancement Board. Spellman, F.R. and J.E. Drinan. 2001. Stream 2003. The Oregon Plan for Salmon and Ecology and Self-Purification: An Introduction. Watersheds: 2001-2003 Biennial Report. 2nd ed. Technomic Publishing Co. Salem, Ore. Pennsylvania. 257. p.
Regional Interagency Executive Committee. Tetra Tech, Inc. 1998. Upper Clear Creek 1995. Ecosystem Analysis at the Watershed Watershed Analysis. Prepared for the Scale – Federal Guide for Watershed Western Shasta Resource Conservation Analysis. Version 2.2. Regional Ecosystem District. San Francisco. Office, Portland, Ore. 26 pp. http://wim.shastacollege.edu/watershed- intro.aspx Riley, A.L. 1998. Restoring Streams in Cities: A Guide for Planners, Policymakers, and U.S. Department of Agriculture (USDA). 1996. Citizens. Island Press, Washington, D.C. 423 Mapping and digitizing watershed and pp. subwatershed hydrologic unit boundaries, National Instruction No. 170-304. Natural River Network. http://www.rivernetwork.org Resources Conservation Service, Washington, D.C. Robert, H.M. 1983. Robert’s Rules of Order. A Jove Book. New York. 204 p. U.S. Environmental Protection Agency, 1998. “Guidelines for Ecological Risk Assessment.” Runyon, John. Consultant to Oregon Risk Assessment Forum, Office of Research Watershed Enhancement Board. Personal and Development, Washington, D.C. communication. Eugene, Ore. January 2003. EPA/630/R- 95/002F. http://cfpub.epa.gov/ncea/cfm/recordisplay.cf Saint, S. and J.R. Lawson. 1994. Rules for m?deid=12384 Reaching Consensus: A Modern Approach to Decision Making. Pfeiffer & Co., San Diego. U.S. Environmental Protection Agency. 2000. 78 p. Watershed analysis and management (WAM) guide for tribes. Washington, DC: USEPA. San Francisco Estuary Institute. 1998. Bay Area Watersheds Science Approach. Version U.S. Environmental Protection Agency (U.S. 3.0. Richmond, California. www.sfei.org EPA). 2002. Watershed Academy. Office of Wetlands, Oceans, and Watersheds Santa Clara Basin Watershed Management (OWOW). Initiative. 2003. “Lessons Learned in the Pilot
- 38 - California Watershed Assessment Manual, Chapter 2 August, 2004 http://www.epa.gov/owow/watershed/wacade my/wsamap.htm Williams, J.E., Wood, C.A., and M.P. Dombeck, editors. 1997. Watershed U.S. Environmental Protection Agency. 2003. Restoration: Principles and Practices. Framework for Cumulative Risk Assessment. American Fisheries Society, Bethesda, USEPA EPA/600/P-02/001F. 01 Jan 2003. Maryland. 561 p. U.S. Environmental Protection Agency, Office of Research and Development, National Wondolleck, Julia M. and Steven L. Yaffee. Center for Environmental Assessment, 2000. Making Collaboration Work: Lessons Washington, D.C. 129 pp. from Innovation in Natural Resource http://cfpub.epa.gov/ncea/raf/recordisplay.cfm Management. Island Press, Washington, D.C. ?deid=54944 277 p.
U.S. Forest Service (USFS). 2000. Rating Zar, J.H. 1984. Biostatistical Analysis. 2nd ed. Watershed Condition: Reconnaissance Level Prentice-Hall, Inc. NJ. p. 718. Assessment for the National Forests of the Pacific Southwest Region. Region 5. Vallejo Ziemer, Robert R., and Leslie M. Reid. 1997. CA. 31 p. What have we learned, and what is new in watershed science? Pages 43-56 in: Sari Vannote, R. L., G.W. Minshall, K.W. Sommarstrom (ed). What is watershed Cummins, J.R. Sedell, and C.E. Cushing. stability? Proceedings, Sixth Biennial 1980. The river continuum concept. Canadian Watershed Management Conference. 1996 Journal of Fisheries & Aquatic Science, 37(1), October 23-25. Lake Tahoe, 130-137. California/Nevada. University of California, Water Resources Center Report No. 92, Washington State Department of Natural Davis. Resources. 1997. Standard Methodology for Conducting Watershed Analysis. Washington Ziemer, Robert R. 2004. Scale considerations Forest Practices Board. Version 4.0. Olympia, for linking hillslopes to aquatic habitats. Washington. Pages 22-32, in: Hermann Gucinski, Cynthia www.dnr.wa.gov/forestpractices/watershedan Miner, and Becky Bittner (eds.) Proceedings: alysis/index.html Views from the ridge: Considerations for planning at the landscape scale. General Watershed Professionals Network (WPN). Technical Report PNW-GTR-596. Portland, 1999. Oregon Watershed Assessment OR: U.S. Dept. of Agriculture, Forest Service, Manual. Prepared for Oregon Watershed Pacific Northwest Research Station. 133 p. Enhancement Board. Salem, Ore. http://www.oweb.state.or.us/publications/wa_ manual99.shtml
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Assessment Planning Check List
Organize the Assessment Team and Community Input 1) Assemble assessment team and committees 2) Develop contracts, if necessary, with outside consultants 3) Track itemized costs and schedule 4) Involve the community 5) Record the planning and implementation process
Define Purpose and Scope and Plan the assessment 6) Formulate questions about your watershed 7) Describe the purpose of the assessment 8) Identify the audience and users of the assessment 9) Describe the uses of the assessment
Basic Watershed Assessment Process 10) Conduct initial scoping for focus of assessment 11) Develop a conceptual model 12) Plan collection and analysis of data 13) Describe the spatial and temporal scales of the data 14) Plan synthesis and integration of data to describe watershed condition
Important Issues in Conducting a Watershed Assessment 15) Identify sources of uncertainty 16) Provide estimate of uncertainty and ways to reduce uncertainty 17) Develop list of data and knowledge gaps
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3 Watershed Basics
This chapter provides an overview of the Geographic investigations show that people main natural and social science disciplines tend to aggregate around certain features of and the main types of issues that come up their environment. For example, many during a watershed assessment. It towns have grown up around the discusses the watershed as a whole, as well intersections of roads, year-round as its component parts. Just as watersheds waterways, coastal bays, and fertile are naturally integrated, watershed agricultural areas. At these locations, assessments are interdisciplinary in nature. people engage in various types of social This means that components analyzed and economic interactions that may be separately need to come together through dependent on or independent of their integration and synthesis, as described in a surroundings. These interactions are the later chapter. subject of human geography.
Chapter Outline A common tool in geography is a geographic information system (GIS), which 3.1 Geography can be available as software that plots the 3.2 Hydrology distribution of human and natural features 3.3 Climate and processes across a place. GIS maps 3.4 Flooding and Stormwater show how different features (e.g., 3.5 Geology, Soils, and Sediment in vegetation types, road alignments, general Watersheds plan zones) are arrayed within a watershed. 3.6 Water Quality GIS can also reveal important clues as to 3.7 Aquatic Ecosystems why a particular effect is occurring—such as 3.8 Wetlands and Riparian Habitats why one sub-watershed has more erosion 3.9 Terrestrial Landscape and Habitats than others. In the case of erosion, slope 3.10 Human Land Uses steepness, precipitation, soil types and 3.11 Water Management and Uses other watershed features could indicate 3.12 Social and Economic Setting areas where erosion is naturally high, or 3.13 Historic Context and Analysis high due to human activity. These clues, 3.14 References combined with improved management of ______human activities in the watershed and monitoring, can lead to improved findings by 3.1 Geography future watershed assessors.
Geography—the distribution of plant, 3.1.1 Cumulative Watershed Effects animal, and human communities across a watershed—is integral to landscape and Many watersheds experience multiple watershed assessment. Geography also impacts from current and historical natural encompasses the relationships among a and human processes. All of these landscape’s processes (e.g., fire and human processes combined are called “cumulative development) and features (e.g., vegetation watershed effects” (CWE). When planning types and dams). Underlying processes land-use activities, private parties and some involving geological formations, hydrologic agencies are required to assess the flows, and ecological transformation result cumulative effects of their proposed actions in the presence of particular features, such and the actions of others in the past, as soil and plant types. Changes in the present, and anticipated future on the processes result in changes in the natural functioning of watersheds. distributions of these features.
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A watershed assessment must consider the will then behave similarly to rain. Most cumulative watershed effects on the precipitation will land on vegetation or other watershed processes of interest. Although elevated surfaces before reaching the soil each individual impact may be insignificant surface. Most of this “intercepted” water will with respect to the entire watershed, their drip or flow to the soil, but a small portion cumulative effects may be dire. For will be evaporated back into the example, changing runoff processes in a atmosphere. small fraction of the watershed (perhaps by converting a stand of trees to an agricultural Water that reaches the ground surface will field) or even adding a small quantity of a be absorbed, stored in small depressions, pollutant to a stream will not result in any or flow downslope over the surface. The detectable change at some point well absorbed water that has “infiltrated” into the downstream. However, changing many soil becomes “soil moisture”. This soil runoff processes or adding a small quantity moisture may remain in place, flow of the pollutant at many places along the downslope toward a stream, or “percolate” stream will produce a detectable change vertically to become “groundwater”. Some of downstream. the water temporarily stored in the soil may evaporate from the soil surface or be taken 3.2 Hydrology up by plant roots and “transpire” from the plant’s leaves. Understanding the general interactions between water and the landscape is Water can reach streams and lakes via fundamental to your watershed assessment. “overland flow” across the surface (minutes Hydrology is the study of the occurrence to hours), downslope flow through the upper and movement of water over and under the layers of the soil (hours to weeks), and land surface. In watershed assessments, release from groundwater (weeks to the basic hydrologic concerns are flow centuries). Some water in streams may (volume of water per unit of time), timing percolate into groundwater storage (when this flow occurs), storage (volume of elsewhere along the stream channel and water in groundwater, reservoirs, lakes, or perhaps emerge again into the channel snowpack at a particular time), and quality farther downstream. Groundwater and (what’s in the water besides just water). The surface water (water in streams and lakes) hydrologic cycle and the water balance (an are often regarded as completely distinct, abbreviated accounting of the hydrologic but in most watersheds, a lot of water cycle) are useful frameworks for thinking moves back and forth across the ground about how water moves through your surface and streambeds. Some surface watershed. The hydrologic cycle is a water will evaporate, but most of the water conceptual description of the ways in which that has made it to a stream channel will water moves around the world. Water is eventually flow to an ocean (or a lake generally moving in the hydrologic cycle, without an outlet, such as Mono Lake), although some of it may be in temporary where it will be available for evaporation, storage for a wide range of time periods. replenishing the atmospheric water where the cycle began. The Hydrologic Cycle The global hydrologic cycle can be fitted to Starting with water in the atmosphere, some your watershed as general concepts that of the water precipitates as snow or rain. describe the processes that affect the Once on the ground or other surface, such movement and storage of water through as a leaf, precipitation in the form of snow your particular watershed. When applied to will be stored until enough energy is a watershed, the hydrologic cycle is not a available to melt the snow. The meltwater closed system, but has quantifiable inputs
- 2 - California Watershed Assessment Manual, Chapter 3 August, 2004 and outputs. These inputs and outputs, estimated values you develop. You should along with temporary storages, can be expect the numerical values to be difficult to estimated in the simple accounting scheme estimate and highly uncertain. Water of a water balance (section 3.2.1). balances are sometimes called "water Estimating the water balance of your budgets", although that term has the watershed is a useful means of exploring its unintended implication of future prediction. hydrology. Some of the basic components A water balance or budget can be of the water balance (and hydrologic cycle) considered analogous to balancing one's are discussed in sections 3.2.1 to 3.2.3. checkbook—with deposits, withdrawals, and cash on hand being analogues to the key In addition to describing natural hydrologic components of a water balance. processes, your watershed assessment should consider how these processes have A general water balance equation starts as been altered by human activities and how WATER IN = WATER OUT +/- CHANGE IN the water, both in streams and STORAGE. The basic challenge of the underground, has been intentionally water balance is to fill in the details of what managed. Most land use alterations affect constitutes WATER IN, WATER OUT, and water’s infiltration into the soil and CHANGE IN STORAGE for your situation. evapotranspiration (evaporation from vegetation) in a small proportion of the WATER IN is almost always just watershed and thereby alter these precipitation, but it could also include components of the water balance a artificial imports of water from another relatively small amount over the entire watershed through canals or pipelines. watershed. However, changing the land use of many small fractions of the watershed will WATER OUT includes evaporative losses, eventually add up, and the cumulative effect streamflow, groundwater flow out of the of all those incremental effects can result in basin, and artificial exports of water through significant changes to the water balance. canals or pipelines. Engineering works, such as dams, canals, and networks of pumped wells, that allow CHANGE IN STORAGE includes soil deliberate management of water resources moisture, deeper groundwater, lakes, often change the water balance to a much reservoirs, and water temporarily flowing in greater extent than the indirect effects of stream channels. The CHANGE IN land use change. STORAGE term is usually important over shorter time periods (days to months), but 3.2.1 Overall Water Balance can often be considered negligible over a year or longer. However, you must consider Determining your watershed’s overall water whether storage is a quantitatively important balance is useful for understanding its basic term for the watershed and time period in hydrology because the water balance which you are working. describes the quantities of water affected by various processes in your watershed. An annual timeframe is perhaps most useful Although a written water balance is and easiest to work with. In most cases, instructive to a reader, the primary value of change in storage over a year will be a water balance is to the analysts who negligible, especially if you use the carefully think about the hydrologic conventional “water year” of October 1 pathways and processes. There is no other through September 30. In early autumn, thought process that yields an equivalent before the rainy season has begun in understanding of a watershed’s hydrology. California, streams tend to be at their lowest The conceptual description of the water flow and soil moisture is at a minimum. So balance is far more important than the
- 3 - California Watershed Assessment Manual, Chapter 3 August, 2004 this October 1 start date begins the water of the watershed, and the result will be ET. year at a time of minimal hydrologic activity. Precipitation = Streamflow + ET +/- change 3.2.1.1 Estimating a Water Balance in storage (assumed zero). Using the streamflow number from the Water balances and many other hydrologic example in the box (rounded to 9 inches), a quantities are commonly expressed in terms precipitation value of 30 inches, an of a depth of water. This is in order to assumed change in storage of 0, annual control for watershed area. Hydrologic evapotranspiration would be 21 inches. volumes (amount of water moved through waterway over a time period) are converted The value of the water balance exercise, to depth by dividing volume by the surface even with all its inherent uncertainties, is area of the watershed. Flow rates vary over that it provides a general idea of how much time, which also needs to be accounted for water comes into a watershed and where it (see box below). goes, and it can indicate how precipitation input is transformed within the watershed. In most parts of California, the largest Obviously, with a more detailed water output of the water balance is evaporation. balance, these factors (e.g., fate of the The term evapotranspiration (ET) is often water) can be estimated more precisely. used to describe the role of evaporation from vegetation. Good estimates of ET are Good general reference books on hydrology difficult to develop, so in simple, conceptual for the non-hydrologist include Leopold water balances, ET is often the leftover (1974, 1993, 1997), Mount (1995), and quantity of water after accounting for Gordon, McMahon, and Finlayson (1992). changes in storage. For a typical, quick- and-dirty water balance calculation, 3.2.2 Surface Water estimate average precipitation over the watershed, assume changes in storage are Many watershed assessments are negligible, subtract depth of streamflow out conducted because of some perceived
An example of converting average annual streamflow to depth
1 cubic feet per second for 1 year = 1 ft3 / s x 3600 s / hour x 24 hours / day x 365 days / year = 31,536,000 cubic feet per year.
A useful (and very common) unit for water volume is the acre-foot, which is the volume of water that would cover an acre of surface area one foot deep. An acre is 43,560 square feet, so an acre-foot is 43,560 cubic feet (1 cubic foot = 7.48 gallons).
To convert the volume of streamflow above to acre-feet, divide by 43,560: 31,536,000 cubic feet per year / 43,560 cubic feet per acre-foot = 724 acre-feet per year
Finally, to convert the volume of streamflow to depth of water over your watershed, divide by the area of the watershed:
If your watershed is 1,000 acres in area: 724 acre-feet per year / 1,000 acres = 0.72 feet per year or 8.7 inches per year
- 4 - California Watershed Assessment Manual, Chapter 3 August, 2004 problem with surface water (streams and pathways by which a raindrop can reach a lakes)—there’s not enough of it, there’s too stream or be returned to the atmosphere much at the wrong time, its availability has without contributing to streamflow. The most shifted seasonally, or it is polluted, for direct route into the stream is for the example. Surface water also supports raindrop to fall directly into the stream aquatic life—a primary issue driving many channel. However, stream channels occupy watershed assessments. Availability of a small proportion (usually less than 1%) of surface water for supplying municipal and the overall area of most watersheds, so industrial uses, irrigation, and hydroelectric most of the total rainfall volume falls on facilities is a major social and economic land. Vegetation or other surfaces cover concern throughout most of California. much of the land area, so some of the Human demands for surface water rainfall is “intercepted” on leaves or other resources resulted in the investment of material above the soil surface and may hundreds of billions of dollars in evaporate. When rainfall exceeds the infrastructure to store, divert, transport, and capacity of intercepting surfaces to store treat water from the state’s streams. water, the excess drips or flows to the soil surface. Rain that arrives at the soil surface The aspects of surface water typically may “infiltrate” (pass through the surface addressed in watershed assessments are into the soil), be stored on top of the soil volume, timing, and quality. In most cases, surface in small depressions, or begin to water volume is not reported as sheer flow downhill over the soil surface—these volume only, but rather as volume over alternatives also interact over time and some period of time. In streams, water is space. For example, water stored in small flowing—we can picture some volume of depressions may later infiltrate, or water water moving past a fixed point in some flowing over the surface may infiltrate into amount of time. However, even where water more porous soil somewhere downslope. isn’t obviously flowing, as in lakes and Some of the water flowing over the surface reservoirs, the water level (and will collect in small channels that in turn join corresponding volume) go up and down, so larger channels and eventually feed the time must be considered. Similarly, water main streams. Some of the water in the soil stored as snowpacks or in the soil changes will move downslope below the surface and with time. But time is most obviously later enter a surface channel. involved in streamflow, both at a particular moment and in changes throughout a storm Human activities can alter the physical or a year. Concerns about watershed processes that generate streamflow in a condition are often raised when someone variety of ways—removing or adding notices that the timing of streamflow intercepting surfaces, such as vegetation appears to have shifted compared to some and leaf litter, changing the “infiltration baseline in the past—streams seem to rise capacity” of the soil (ability of soil to absorb more quickly after a particular amount of water), changing the storage capacity of the rainfall, or spring snowmelt runoff seems to soil, changing the transmission capacity of occur a couple of weeks earlier than it did a the soil (ability of the soil to allow water to decade ago. move through it), changing the ability of vegetation to remove water from the soil 3.2.2.1 Streamflow Generation and release it to the atmosphere, changing the density of small channels that collect A basic understanding of how rainfall or surface flow, for example. Compacting soil snowmelt is transformed into streamflow is is a common result of foot and vehicle traffic important in evaluating how human activities that reduces the ability of the soil to absorb, may alter the processes that generate store, and transmit water. As less water streamflow. There are many possible enters the soil, more water runs off into
- 5 - California Watershed Assessment Manual, Chapter 3 August, 2004 channels, thereby increasing streamflow records of depth. A gaging station may cost over shorter time intervals than would occur tens of thousands of dollars to install and in the absence of compaction. Sealing soil thousands of dollars per year to operate. with concrete, asphalt, or buildings can These high costs explain the paucity of prevent any water from entering the soil and long-term streamflow records. USGS causes almost all the rain to flow quickly to maintains the most accessible streamflow a stream. The amount or proportion of records (e.g., http://water.usgs.gov). Other impervious (watertight) surfaces in a streamflow records are available from the watershed is a common indicator of the California Department of Water Resources degree to which runoff-generating (http://cdec.water.ca.gov/stainfo.html). processes have been altered. A watershed assessment should consider both how In assessing streamflow data, important intense (for example, reducing infiltration capacity by 50%) and how extensive (for Annual hydrographs example, changing 30% of the surface area Upper Truckee River near M eyers of the watershed) a particular alteration Oct 2000 through Sept 2001 might be. A single parking lot may direct 250 90% of the rainfall that falls on its surface 200 into a small stream, but if the lot occupies only 0.1% of the watershed area, the net 15 0 impact on streamflow at the gaging station is negligible. 10 0
3.2.2.2 Streamflow Measurement 50
0 Streamflow is generally expressed as volume per unit of time, typically cubic feet Rainbow Creek near Fallbrook per second. You may also see streamflow Oct 2000 through Sept 2001 45 reported as cubic feet per day or acre-feet 40 per year. Streamflow reporting must also 35 include a particular time and geographical 30 location. Streamflow changes from day to 25 day (sometimes minute to minute), as well 20 as up and down a stream channel. Knowing 15 when and where streamflow is measured is 10 critical to thinking about surface water. 5 0 Local water districts, hydroelectric utilities, the U.S. Geological Survey, and a few other Storm hydrograph entities measure streamflow at gaging Storm runoff Big Sulphur Creek near Cloverdale April 19 through 23, 2004 stations, locations where the depth of water in a stream is measured and recorded at 100 90 regular intervals (15 minutes is common) 80 )
and where occasional manual s 70 measurements of water velocity and the 60 area of the cross-section of the channel 50 through which water is flowing have been 40
Discharge (cf 30 made that allow a relationship to be 20 developed between the depth and the flow. 10 This relationship, known as a rating curve, 0 allows calculation of the streamflow from the
- 6 - California Watershed Assessment Manual, Chapter 3 August, 2004 characteristics to consider include long-term downslope (roughly parallel to the soil averages, extremes of high and low flows, surface) and changes the localized water seasonal patterns, trends over time, and content en route. sudden changes (e.g., construction and operation of a diversion). A useful means of Infiltration (the passage of water through the examining streamflow data to discern some soil surface) is an important factor of the above characteristics is plotting a determining how watersheds transform stream hydrograph. Hydrographs plot rainfall into streamflow and is readily altered streamflow over time. The most common by human activities. The maximum rate at type is an annual hydrograph (figures which water can enter the soil, known as the above) that depicts changes in flow over the infiltration capacity, depends on both the course of a year. A storm hydrograph (figure physical properties of the soil and how above) that shows the rise and fall of a much water is already in the soil. If the rate stream over a few days may be useful in of rainfall is less than the infiltration assessing how your watershed responds to capacity, then all the rainfall will be a rainfall input. absorbed. If the rate of rainfall is greater than the infiltration capacity, then infiltration 3.2.3 Subsurface Water occurs at the capacity rate. The additional rainfall ponds on the soil surface and begins Water below the surface of the ground to flow downslope toward a stream channel. exists within the pore space (holes or voids) In general, the water flowing over the soil between or within the solid materials of the surface enters streams much faster than soil or rock. Subsurface water is commonly water flowing through the soil. Through the separated into one of two categories: soil process of infiltration, soils greatly affect the moisture or groundwater. Soil moisture is volume of streamflow resulting from a found relatively close to the surface storm, the timing of this streamflow, and the (generally within 10 feet, although there can maximum rate of streamflow. In other be wide variation depending on soil words, soils can strongly influence the size characteristics and geology) and is usually and shape of the storm hydrograph. in an unsaturated condition (the pores Infiltration can be easily changed (almost contain both air and water). In contrast, always decreased) by human activities, groundwater is found at greater depth and including compaction of soils by vehicles or under saturated conditions (the pores livestock, removal of vegetation and leaf contain only water or an insignificant litter, plowing, burning, and covering the soil amount of air). You may also see the terms with an impervious surface such as unsaturated zone or vadose zone vs. concrete. saturated zone or phreatic zone. Water movement through the soil depends 3.2.3.1 Soil Moisture on the structure of the openings within the soil and the moisture content. The open Soil moisture, the water in the pore space or space within the soil, which often accounts openings between and within the solid parts for 40% to 50% of the total soil volume, of the soil, is a relatively active part of the consists of small spaces between individual hydrologic cycle. The water content can particles of soil; larger voids between vary several-fold over a few hours to a few clumps or aggregates of soil; tubes carved days. Precipitation that enters the soil can by worms, insects, and rodents; and holes rapidly fill the available pore space. left after roots have decayed. The size, Irrigation adds additional water in shape, and degree to which these pores of agricultural fields. Soil moisture is withdrawn various types are connected are primary by plant roots and subsequently transpired. influences on water movement within the Water moves through the soil vertically and soil. The rate of water flow generally
- 7 - California Watershed Assessment Manual, Chapter 3 August, 2004 decreases as the size of the pores rise and fall with changes in water volume in decreases. Air within the pores restricts the the pore space. The top of water in the flow of water, so as air is displaced by saturated zone is called a water table, and incoming water, the rate of water flow unconfined aquifers are also known as generally increases. Some soils with high water-table aquifers. Other aquifers are moisture contents and large, well-connected confined by a relatively impervious layer pores or channels can transmit water that overlays the more permeable aquifer. downslope to a stream within a few hours Water in confined aquifers tends to be after infiltration in a process called under pressure as a result of the confining subsurface storm flow. Most water layer acting as a cap, and the water will rise movement through soils occurs at a slower in a well that penetrates the confining layer. pace and contributes to the underlying groundwater or to a stream over a period of Groundwater in unconfined aquifers flows days to months. from areas of higher elevation to areas of lower elevations or in the downslope 3.2.3.2 Groundwater and Aquifers direction of a sloping water table. In confined aquifers, the pressure is combined The term groundwater usually refers to with the elevation to determine the direction water within the saturated zone of the and driving force of groundwater movement. subsurface where water fills all the pore Groundwater flow rates are also controlled space. A less formal use of the word by the aquifer’s cross-sectional area sometimes refers to all water below the soil permeability (capability to transmit water). surface. This Manual uses the standard hydrological definition of groundwater, A water balance for a groundwater basin or which is water in the saturated zone. an aquifer can aid in understanding the Groundwater accounts for about 30% of inflows and outflows of groundwater and the California’s water supply in an average year resulting changes in storage in a manner and about 40% in dry years (Department of similar to a water balance for a watershed Water Resources 2003). Even though (section 3.2.1). groundwater is a slow-moving and slowly changing part of the hydrologic cycle, the Groundwater storage remains fairly role of groundwater in your watershed’s constant from decade to decade in relatively hydrology and water resources undisturbed watersheds that have little or no management should be evaluated in your groundwater pumping. In smaller watershed assessment. Recommended watersheds, groundwater storage may vary introductions to groundwater hydrology between seasons and between wet years include Heath (1983) and Department of and dry years. The subsurface water Water Resources (2003). balance is readily affected by human activities—both indirectly and through active Groundwater exists in geologic formations use and management of groundwater called aquifers that contain and transmit resources. Recharge of groundwater can be “significant” quantities of water. Use of the increased by excessive irrigation, filling of word “significant” is vague, but implies that reservoirs, and artificial recharge with aquifers can be used for water supply. An infiltration basins and injection wells. aquifer can be composed of hard rock or of Groundwater recharge can be reduced by unconsolidated materials, such as sand and limiting infiltration, covering the soil with gravel. Aquifers vary widely in the total impervious surfaces, draining wetlands and amount of pore space filled with water and lakes, reducing leaks from canals and the degree of connectivity that allows water pipes, and channelizing streams. The big to flow between pores. Aquifers can be variable under the control of people is unconfined, where the water level is free to groundwater extraction through wells. The
- 8 - California Watershed Assessment Manual, Chapter 3 August, 2004 number or density of wells, the depth of the usually considered the “average” weather of wells, and the pumping rate of the individual a region, including the variations between wells all combine to control the volume of seasons and years and the known water extracted over a certain period of extremes. In conducting a watershed time. The condition of declining storage assessment, the most important aspects of called “groundwater overdraft” occurs when climate to consider are precipitation, solar more water is withdrawn by pumping than is radiation, air temperature, relative humidity, recharged over a period of years. and wind. Groundwater overdraft has become common throughout most parts of California 3.3.1 Precipitation (Department of Water Resources 2003). As overdraft persists, pumping costs increase, Precipitation is the water entering your wells need to be deepened or replaced, the watershed from the atmosphere as rain, land surface may subside and the aquifer’s snow, hail, and fog drip (cloud droplets storage capacity may permanently decline, captured by trees in sufficient quantity to remaining groundwater may become more form drops that reach the ground—it can be brackish, and, in coastal areas, seawater significant under coastal forests). may flow inland. Precipitation characteristics of greatest interest in assessing a watershed include Surface water and subsurface water are annual average precipitation, variability from thoroughly interconnected and exchange year to year, seasonal distribution, type water back and forth across the ground (rain vs. snow), frequency of rainfall of surface in different parts of the watershed. different intensities, storm totals, and storm Much of the interaction occurs within and durations. Estimates of these characteristics adjacent to stream channels. At different can reveal, for example, how much water is locations along a channel and during available to the watershed in an average portions of the year, water infiltrates through year and how that amount can vary, or the streambed to recharge groundwater. At whether multi-day, low-intensity storms are other locations and during other times of the more typical than short-duration, high- year, groundwater may flow into the stream. intensity cloudbursts. Interchange of water between a stream and its bed can influence the temperature, Precipitation over a watershed can be dissolved oxygen content, and chemical surprisingly variable, especially if the composition of the stream. Interactions of watershed covers an elevation range of groundwater and surface water can be more than a few hundred feet and is larger difficult to observe and measure; the effects than a few square miles. Precipitation of these interactions on water supply and amounts from a single storm per unit area water quality need to be understood (U.S. (e.g., acre) can range by two to ten-fold Geological Survey 1998). across a watershed. Variability of precipitation from a single storm (ignoring 3.3 Climate topographic influences) can be expected to be least in northwestern California, where Regional climate exerts a controlling most storms are widespread and can last influence on a watershed’s hydrology by several hours or days, and greatest in the determining water and energy inputs. southeastern part of the state, where highly Precipitation provides the raw material that localized thunderstorms may pass through becomes streamflow or deep groundwater, in a few minutes. Several rain gages spread or that is returned to the atmosphere around a watershed would be desirable to through evapotranspiration. Energy assess the variability and obtain a (ultimately from sunlight) is needed to reasonable estimate of watershed-wide evaporate water and melt snow. Climate is precipitation. However, precipitation is
- 9 - California Watershed Assessment Manual, Chapter 3 August, 2004 routinely measured at only a few hundred can be taken up by plant roots and moved locations throughout the entire state, so to the leaves. precipitation information for your watershed is likely to be sparse and may need to be Snowmelt is another major result of energy inferred from neighboring areas. exchange in the hydrologic cycle. Snow melts primarily in response to inputs of solar 3.3.2 Energy Exchange radiation. Properties of the snow surface, such as the size and shape of the snow Energy from sunlight is the driving force of grains and the presence of impurities (e.g., the hydrologic cycle. Energy is absorbed, dust, pine needles), and the angle of the moved, released, and changed into different sun determine how much solar radiation is forms as water moves through the absorbed and how much is reflected. Snow hydrologic cycle. “Energy exchange” is the melts slowly (if at all) in the winter when the common term for the various physical surface is composed of new snow grains mechanisms involved in hydrologic and the sun angle is low. Snow melts processes such as evaporation and relatively rapidly in the spring when the snowmelt. Most of these processes occur surface is composed of large grains and on water surfaces in contact with the debris and the sun angle is high. Another atmosphere. Therefore, energy exchange is complicating factor is the conversion of intimately linked to atmospheric processes sunlight (which has a relatively short and properties such as radiation, air wavelength) into longwave radiation. If temperature, humidity, wind, and sunlight is absorbed by a rock or tree, that precipitation. The physics of energy object warms up and emits longwave exchange are well beyond the scope of this radiation, which is completely absorbed by brief introduction to hydrology, but the snow. An example of why this conversion basics of energy on the earth’s surface can can be important in a watershed be found in any text on physical geography assessment is the effect of forest or hydrology. Two examples of the harvesting. Trees shade the snowpack from importance of energy exchange in the sunlight. If half the trees are removed, more hydrologic cycle will be mentioned— sunlight reaches both the snowpack surface evaporation and snowmelt. and the trunks of the uncut trees, which in turn emit longwave radiation to the snow. Evaporation from open water or a wet The combined effect of these changes in surface or from within leaves of a plant energy exchange is a marked increase in (evapotranspiration) doesn’t just happen. the rate of snowmelt. Relatively little Sufficient energy must be available and the snowmelt occurs directly in response to air air immediately above the surface must not temperature. The principal exception is be saturated (filled to capacity) with water when the air is saturated with water vapor vapor. Water loss to the atmosphere from and wind speeds are high—typically during both wet surfaces and plants (often lumped warm storms when rain is falling on the together in the term evapotranspiration) is snowpack greatest when solar radiation, air temperature, and wind speed are all high, 3.3.3 Climate Cycles and relative humidity is low. The amount of water loss (often termed actual People have long been interested in evapotranspiration) is controlled by both the forecasting the weather and have looked for energy and atmospheric conditions (which repeating patterns or cycles in weather can be used to calculate the potential behavior that might offer clues about future evapotranspiration) and the amount of water weather. In early childhood, we recognize available at the surface and in the soil that seasonal cycles of day-length, temperature, and precipitation. Other cycles of climate
- 10 - California Watershed Assessment Manual, Chapter 3 August, 2004 are not so easy to discern. In the late temperature is associated with a calming of nineteenth century, geologists in Europe the trade winds near Indonesia and began to find signs of ice ages that abnormally high air pressure over the indicated great swings of climate causing western tropical Pacific Ocean and the growth and decline of continental-scale abnormally low air pressure over the ice sheets. A few decades later, Milutin eastern tropical Pacific (the Southern Milankovitch of Serbia calculated cyclic Oscillation part of the name). These variations in the amount of solar radiation changes in the ocean and atmospheric reaching the earth based on regular conditions alter the weather in regions far variations in earth-sun geometry. With removed from the tropical Pacific, including rough intervals of 20,000, 40,000, and reducing the number of hurricanes over the 100,000 years, these so-called Milankovitch Atlantic and usually increasing precipitation cycles were later correlated with dozens of in Southern California. During most El Niño glacial advances. Over the past few winters, the jet stream and storms track decades, scientists around the world have across the southwestern part of the United searched for evidence of past climates in a States instead of across their more typical variety of sources: sediment deposits in northern location. Because there are so lakes and oceans, pollen, fossilized many interacting factors that contribute to plankton shells, coral reefs, dust layers, tree weather, El Niño conditions are not a sure rings, and, most successfully, in deep cores thing for increased rainfall in California. from ice sheets in Greenland and Some El Niño years, such as 1965 and Antarctica. These various indicators of 1991, have been droughts. Conditions global climate, primarily air and ocean lumped under the name La Niña represent temperatures, have supported the regularity the opposite extreme of atmospheric and of the Milankovitch cycles, but have also ocean circulation within the ENSO cycle. suggested a complex array of feedback mechanisms involving carbon dioxide, Another large-scale ocean-atmosphere reflection of sunlight by ice cover, sea level, pattern recognized in the past few years is biological processes, and other factors. The the Pacific Decadal Oscillation (PDO) that current consensus among climatologists affects the northern part of the Pacific seems to be that the slight changes in Ocean (Mantua et al. 1997). This cycle sunlight received at the earth’s surface are consists of two phases, apparently strongly amplified by the other factors to persisting for 20 to 30 years each. During a trigger the cyclic ebb and flow of the ice “positive” phase, the ocean along the west sheets. coast of North America is warm, and sea surface temperatures in the central north Besides the vast time scales of the ice Pacific are cool. The relative temperature ages, other apparently cyclical variations of differences are opposite in the “negative” climate have been observed within the phase. The north Pacific is currently in a average human life span. As the historical negative phase. The preceding positive climate record incrementally increases, phase lasted from 1977 to 1997. climatologists have greater opportunity to Precipitation tends to be above-average seek patterns within the record. One of the during the negative phase in Washington large-scale climate patterns that is widely and Oregon, with a less-distinct signal in discussed is the El Niño/Southern Northern California. An analysis of a broad Oscillation (ENSO) phenomenon. Every few range of Pacific Northwest climate records years, the ocean temperatures off the coast extending over more than a century of Peru and sometimes thousands of miles identified the ENSO and PDO cycles at five- to the west become unusually warm, to seven- and 20- to 25-year periods, as generally beginning in December and well as other apparent oscillations at two to persisting until June. This change in ocean three years and 50 to 75 years (Ware
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1995). Still other weather patterns have community. During the 1990s, physical been associated with 11-year sunspot evidence and modeling results rapidly cycles and 18-year lunar cycles. accumulated for a strong case that human activities were changing the climate 3.3.4 Climate Change (Intergovernmental Panel on Climate Change 2001). Climate was widely regarded throughout most of the twentieth century as stable, with A variety of human activities that are only minor variations around an average extensive in nature, such as conversion of condition. Many climatologists held a tropical forests, conversion of lands to philosophical belief that climate was self- desert, and production of dust and soot, are regulating and, if perturbed (for example, by believed to affect atmospheric processes a huge cloud of volcanic ash), would and feedback mechanisms. However, the “naturally” return to its average state. generation of carbon dioxide from the However, as weather records lengthened burning of fossil fuels is the greatest and and indicators of past climates emerged most immediate human influence on the from sediment and ice cores, coral reefs, atmosphere. Atmospheric measurements and other sources, climatologists found and calculations of carbon dioxide release signs of distinct trends, as well as signs of from the quantity of oil, coal, and natural abrupt changes, suggesting that climate is gas burned over the past century show a not nearly as stable as was broadly dramatic increase in carbon dioxide accepted not long ago. In addition to the concentrations in the atmosphere over the gradual swings between ice ages and past few decades. interglacial warm periods over tens of thousands of years described above in Carbon dioxide, water vapor, methane, and section 3.3.3, recent theories suggest that a few other gases affect temperature in average air temperatures have changed by upper layers of the atmosphere by several degrees over periods of a few absorbing some of the longwave (infrared) decades following sudden shifts in ocean radiation emitted by the earth (all objects circulation (Committee on Abrupt Climate emit radiation in these “long” wavelengths in Change 2002). proportion to their temperature). The gas molecules warm and re-emit longwave Suggestions that human activities could radiation in all directions, including back alter the climate have been made for at toward the earth’s surface. The role of these least a century, but were largely ignored gases in reducing the loss of longwave until the past two decades. In the late radiation, especially at night, was 1800s, Svante Arrhenius of Sweden recognized 140 years ago by John Tyndall. calculated that the burning of coal could Although these gases do not function in the eventually increase carbon dioxide in the same manner as the glass of a greenhouse atmosphere and that doubling the (which traps hot air rather than radiation), concentration of carbon dioxide could raise the term “greenhouse gases” and global temperatures by 5-6oC. In 1961, “greenhouse effect” are now commonplace, Mikhail Budyko, the famed Russian even in scientific literature. Increasingly climatologist, published a warning that complex mathematical models of humans were warming the atmosphere atmospheric processes have calculated through burning fossil fuels and other temperature increases associated with energy use. In 1971, Budyko provoked his increasing concentrations of greenhouse colleagues by proclaiming that human- gases. Most current estimates of global induced global warming was unavoidable. average temperature rise associated with a Two decades passed before these warnings doubling of carbon dioxide concentration were generally accepted in the climatology relative to pre-industrial levels (280 parts
- 12 - California Watershed Assessment Manual, Chapter 3 August, 2004 per million) are in the range of 1.4o to 5.8oC over millennia. Floods represent the upper (Intergovernmental Panel on Climate extreme of runoff generation and produce Change 2001). A recent modeling study most of the sediment erosion, transport, and using a fine-scale regional climate model deposition within a watershed. suggests a temperature rise of 1.4o to 3.8oC in California for a doubling of carbon dioxide Stormwater runoff is the “excess” rainfall (Snyder et al. 2002). that exceeds the infiltration capacity and flows over the ground surface. It is the Water supply agencies in California have portion of runoff that causes the initial rise in been concerned about the potential effects a storm hydrograph and usually causes the of climate change on the state’s water peak flow in the receiving stream. In the resources for almost two decades. Most urban context, stormwater runoff often agency and researcher attention has contributes to flooding because the streets, focused on changes to the snow hydrology parking lots, and storm drains generate far of California’s mountains. A recent more (often 10 to 1,000 times more) surface synthesis of research results noted, “Higher runoff than would have occurred prior to temperatures will have several major development and paving. The collection and effects: increase the ratio of rain to snow, conveyance of stormwater runoff in efficient delay the onset of the snow season, storm drains also delivers water to streams accelerate the rate of spring snowmelt, and much faster than a natural channel would. shorten the overall snowfall season, leading Therefore, the lag between rainfall and to a more rapid and earlier seasonal runoff” runoff is greatly reduced, and the peak flow (Kiparsky and Gleick 2003:9). Other is usually increased. The creation of large expected consequences of climate change impervious surfaces and storm drains in in California include increases in average urban areas may generate flooding annual precipitation, greater variability in (overbank flows onto the floodplain) from precipitation, increased storm intensity, much smaller storms than would have increased evapotranspiration, and changes occurred in the absence of development. in vegetation cover (Kiparsky and Gleick 2003). Evaluations of these and other 3.4.1 Flooding Frequency possible hydrologic effects of climate change and how water agencies, In a very broad sense, streamflow exceeds communities, farmers, businesses, and the capacity of a stream’s channel and rises natural systems will accommodate or above its banks about every 1.5 to 2 years, respond to those effects should be included on average. However, this frequency must in a watershed assessment. not be considered as a consistent interval. It is better to think that streamflow will rise to 3.4 Flooding and Stormwater Runoff the “bankfull stage” and inundate the floodplain whenever there is sufficient river Flooding is a natural attribute of rivers. flow. Overbank flow occurs every year on Flooding is defined as flow that exceeds the some rivers, and infrequently on other capacity of the channel, i.e., when flow rivers. On average, flow rises to bankfull inundates the floodplain. A flood is a about 50-65 times in 100 years, or in any streamflow event where there is more water given year, there is a 50% to 65% chance flowing in the stream than the channel can that flow will equal or exceed bankfull handle. Under these flood conditions, water capacity. spills over the streambanks onto the adjacent floodplain, which can be As floods get bigger, they occur less considered as part of the natural channel frequently. Accordingly, a magnitude- that is periodically used by the stream and frequency relationship can be estimated on that has been constructed by the stream streams with long-term flow records, or
- 13 - California Watershed Assessment Manual, Chapter 3 August, 2004 more crudely estimated given flood data absorb rainfall, and more of the precipitation elsewhere in the general region. A flood of a quickly enters a stream channel. particular magnitude is often described as a Construction of forest roads compacts soil 10-year, 25-year, or 100-year event. The and drastically reduces infiltration, which, in concept behind this type of description is turn, leads to greater and faster surface that a flood of the given magnitude occurs runoff. once in the particular time period, on the average. However, the “on the average” In urban areas, much of the landscape is part is often ignored, so we recommend converted to impervious surfaces (e.g., thinking that a big flood (for example, a 100- streets, parking lots, and rooftops). Most of year event) occurs 10 times in 1,000 years, the resulting stormwater runoff is directed or that there is a 1% chance that such an into storm sewers that empty into stream event could occur in any given year. But channels and deliver much greater these ways to describe floods are merely quantities of water at much faster rates than statistical constructs. There is no physics (or occurred under natural conditions. Urban physical hydrology) involved. The stream channels may also be confined by combination of conditions that generates levees, bridges, construction, and debris in large floods just doesn’t happen very often. the channel. Reduction of the channel However, there is no physical reason why capacity forces water to rise and spill over two floods of some very large and rare the banks at lower flows, which the natural magnitude couldn’t happen in the same channel could have handled. Very often, the year or three years apart or 200 years apart. floodplain is occupied by houses and All these statistical descriptions of flood various structures that reduce flow capacity magnitude and frequency involve an and further augment flood damage. assumption of “stationarity”—that climate, landscape, channel, and measuring 3.5 Geology, Soils and Sediment in conditions won’t change. However, that Watersheds assumption is obviously flawed, particularly as time periods of analysis lengthen. California’s watersheds span 11 geomorphic provinces—each with distinct 3.4.2 What Causes Flooding? geology, tectonic setting, topography, climate, soils, hydrology, vegetation, and Beyond the usual magnitude-frequency land use history. These factors combine in characterization of floods, watershed complex ways, causing each watershed and assessments must also consider the each sub-watershed to be unique. This physical mechanisms of flood generation— Manual describes approaches toward the hydrologic processes involved in understanding physical processes and producing an overbank flow event. In changes over time that alter sediment general, an unusually large amount of dynamics and linkages in California’s rainfall or unusually intense rainfall is diverse watershed systems. Every required to produce a flood. But other watershed has a natural disturbance factors can contribute to or influence flood regime—or a combination of factors that magnitude and timing. For example, a influence how and why geomorphic previous storm may have left the soil processes, such as sediment erosion and saturated or a wildfire may have reduced deposition, change. In many cases, humans the infiltration capacity. Human activities accelerate or alter these natural processes, may also influence factors that cause or in turn altering ecosystem dynamics that augment flooding. For example, deforesting depend on these processes. an area minimizes transpiration, resulting in greater soil moisture. In turn, there is less available storage capacity in the soil to
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3.5.1 Geology forces also create lowland areas, such as the Central Valley and the San Francisco The physical character of watersheds is Bay-Delta Estuary. The different topography dependent on processes acting on the in California’s geomorphic provinces, underlying material over time. The lithology coupled with climatic and vegetative (rock type) underlying a watershed variation, lead to differences in the dominant influences hillslope stability, erosion processes of erosion and sediment processes and rates, and the background- transport. For example, in the Southern level sediment supply to rivers. Watersheds California Transverse Ranges, chaparral- underlain by resistant bedrock supply less vegetated watersheds have a semi-arid sediment to rivers than do watersheds Mediterranean climate, and dry ravel (dry underlain by erosive material. The highly sliding of sediment under the force of erosive Franciscan Formation, a geologic gravity) or fluvial (channel and floodplain) unit representative of California’s tectonic processes commonly transport sediment history, underlies watersheds with extremely following wildfire, while infrequent high- high erosion rates. The high erosion rates intensity rainfall produces debris flows translate to high rates of sediment supply to (Florsheim et al., 1991). In contrast, in rivers—the Eel River, for example, has the coastal streams in the relatively humid highest suspended sediment yield in northern Coast Ranges, episodic erosion in California. forested watersheds produces sediment through processes such as debris flows, California is influenced by active tectonics earth flows, and debris slides. (forces that deform the earth’s crust) that Understanding the influence of watershed create a diversity of watershed geology on the dominant erosion and morphologies (shapes) such as the high sedimentation mechanisms throughout relief and rugged topography in mountain California is critical in distinguishing natural ranges like the Sierra, Klamath, Transverse processes and the natural disturbance and Peninsular, and Coast. These tectonic regime from anthropogenic (human-caused) disturbances and land use- caused changes.
3.5.2 Soils
Soils form through interactions of physical, chemical, and biological processes. They are important as a resource for California agriculture and as the growth medium for vegetation throughout the state.
A soil profile includes layers, called “horizons”, of mineral and/or organic constituents of variable thickness that differ from the parent material in morphology; physical, chemical, and mineralogical properties; and biologic character (see box below).
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Soil development is dependent on geologic properties, such as bedrock lithology and topography, climate, vegetation and other organisms, and time. Soils exist in various degrees of development. For example, thin, poorly developed soils may not contain a B horizon (see box), and in other locations, soils may not have formed at all.
Land use activities may accelerate surface erosion of soil where vegetation and its binding root structure are removed. In such cases, this additional contribution of fine section 3.5.2.3) and ecology. Connectivity sediment to rivers raises the suspended between hillslopes and floodplains and sediment load and turbidity, and aquatic between hillslopes and channels provides a habitat may become degraded. Other land direct route for sediment to the fluvial use activities compact soils or pave them system. Connectivity from tributaries to over, reducing the water’s ability to infiltrate downstream channels is sometimes between soil particles during storms. In this interrupted by dams that trap sediment, case, a reduction in infiltration leads to whereas increased upstream erosion from increased surface runoff and erosion in various land uses sometimes supplies too downslope areas. much sediment that fills in downstream
pools and estuaries. 3.5.3 Hillslope and Fluvial (Channel and
Floodplain) Processes and Morphology On a watershed scale, geomorphic
processes are affected by upstream Geomorphologists are scientists who study controls, such as climate, geology, earth surface processes and landforms, topography, land uses, and vegetation, and including landslides on hillslopes or erosion downstream controls, such as changes in and sedimentation in rivers. sea level (baselevel). Throughout the Geomorphologists take a “watershed watershed, areas of erosion and sediment approach” to assessment and planning that storage are continually in flux in response to recognizes that within a watershed, storms that create hillslope runoff, river flow, everything is connected. The connectivity and floods. Sediment transport, or “routing,” and linkages between hillslope and channel through a watershed does not occur at a and floodplain systems are important in constant rate. In California, the episodic controlling the input of water, sediment, nature of hydrologic processes dictates woody material, and other constituents that rates of sediment erosion, transport, and determine the character of river and deposition. So while average rates of floodplain morphology (see explanation in
- 16 - California Watershed Assessment Manual, Chapter 3 August, 2004 geomorphic change are sometimes useful, Mass movement on a hillslope occurs when predicting the possible range in magnitude the forces resisting movement are of change is essential for planning overcome by the driving forces. This purposes. For example, estimating an threshold may be crossed due to intrinsic average magnitude and rate of channel bed processes, such as weathering over time, or erosion may describe long-term river by extrinsic factors, such as high-intensity channel changes. But actual changes occur rainfall. While the hillslope erosion episodically during individual events. Thus, processes that shape the landscape over during some storms, there may be time are natural, human activities may lower substantially more geomorphic change than the erosion threshold and reduce the time it the average amount, while at other times, takes for sediment generated on hillslopes there may be less. This variation in rates to reach channels. Moreover, human and magnitudes of processes is a normal activities may reduce hillslope resistance to part of California’s rivers and should be erosion, concentrate runoff, or increases recognized and accommodated in order to slope moisture. These responses may result minimize hazards and maintenance and to from activities such as removal of maximize habitat and safety. vegetation and root networks, or hillslope grading for road construction. 3.5.3.1 Sediment Erosion and Transport Understanding how human activities affect on Hillslopes hillslope stability and the connectivity between hillslopes and channels is critical in Erosion is a natural process that loosens watershed assessment. and removes sediment from hillslopes or the channel bed and banks. Erosion and 3.5.3.2 Erosion, Transport, and transport occur by physical and chemical Deposition Processes in Rivers: weathering, abrasion, or entrainment of Interactions with Morphology particles by running water. Hillslope erosion processes include rain splash, overland As water flows in river systems, it interacts flow, incision of rills and gullies, and a broad with the bed, banks, and floodplain. This category of processes called mass wasting, interaction is affected by the size of the which includes landslides and debris flows. particles on the channel’s bed, the shapes Features created by mass wasting are of the channel and floodplain, vegetation, classified depending on whether they occur and structures, such as bridges or bedrock, in bedrock or soil, whether they occur in protruding into the channel. unconsolidated or consolidated materials, and by their water content and rate of During floods, flow strength increases to the movement (Varnes 1958). A complete point where a river gains the ability to move description of types of mass movement sediment particles on its bed, banks, or process types is contained in Selby (1993). floodplain. Flow strength is an important Additional detailed descriptions of mass measure of the ability of a certain wasting processes are included in Ritter et magnitude of flow to move sediment. al. (1995) and in other watershed Geomorphologists measure flow strength assessment guides such as Appendix A of along the interface, or boundary, between the Washington Forest Practices Board the flow and the channel or floodplain. The Manual (Washington State Department of point where flow strength is large enough to Natural Resources, 1997) and in the lift particles off the channel bed and Sediment Sources Assessment Chapter of transport them downstream is called the” the Oregon Watershed Enhancement Board threshold of entrainment.” Above the Watershed Assessment Manual (Watershed threshold, the bed material begins to move Professionals Network, 1999). in the direction of flow. In rivers, sediment transport from upstream to downstream
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transport sediment further downstream act on these elements.
The streambed itself is biologically active, providing shelter for many aquatic organisms. For example, freshwater crayfish and dragonfly larvae occupy the spaces between and beneath gravel and larger-sized sediment. A mix of gravel with maintains the shape and pattern of small amounts of cobbles and fines (sand, channels, or “channel morphology,” and is silt, and clay) provide optimum spawning one of the most important processes in substrate for trout and salmon. The creating the form of the watershed substrate size these organisms depend landscape. upon may differ, but those native to streams with good water quality are harmed by Channel bed lowering, or “incision,” occurs excessive fine-sized sediment. Streambeds when individual grains are mobilized from covered with silt or clay-sized sediment one portion of the river, but not replaced by cannot maintain the exchange of water and sediment transported from upstream, or air from the surface to the pore spaces when a river’s ability to transport sediment between the gravels. This subsurface flow is is greater than the sediment supply. essential because it replenishes oxygen and Deposition occurs when the flow strength nutrients and removes wastes. Sensitive during a flood decreases below the organisms, like mayfly larvae and trout threshold of entrainment, or when the eggs, can suffocate or get trapped under supply of sediment is greater than the river’s finer sediment layers. Over time, the fish ability to transport it downstream. and aquatic insect species occupying a sediment-impacted stream may shift toward The figure in the text box above depicts the less sensitive species, like midge-fly larvae interactions between flow, sediment, and (Gordon et al. 1992) vegetation as a dynamic cycle because each element interacts with the others, Depending on the size of sediment particles mutually adjusting to changes in the system. relative to flow strength, sediment moves in Stream power, shear stress, and velocity channels and on floodplains along the bed are measures of flow strength and represent (bed material load), in suspension within the the force needed to entrain and transport flow (suspended load), and as solutes sediment. In turn, sediment erosion, (dissolved load). Mobilization of bed transport, and deposition are the dynamic material during floods maintains the quality processes that create and maintain channel of substrate (the base upon which morphology. The channel’s morphology and organisms live) habitat for aquatic the floodplain’s topography form the invertebrates and fish that spawn in river physical structure of habitat. Every flood has gravel by flushing out finer clay and silt. A the potential to modify channel morphology critical issue in maintaining aquatic habitat and riparian vegetation, providing a supply is preserving the balance of coarse to fine of sediment and large woody material to particles. An oversupply of fine sediment, downstream areas. The cycle continues as from soil erosion, for example, may cause a flows with the strength to entrain and fining trend that overwhelms the natural processes that bring the system back to
- 18 - California Watershed Assessment Manual, Chapter 3 August, 2004 balance. Watershed assessment helps determine the natural range of variability in Bank erosion is a type of disturbance that is substrate size and can help identify the an essential part of a functioning watershed conditions responsible for ecosystem, but it becomes a hazard when substrate changes over time. The human activity encroaches on the width the disturbances caused by erosion, sediment river requires to accommodate natural transport, and deposition during floods are a processes. Human activity that removes requirement for ecological sustainability in riparian vegetation and its binding root dynamic rivers; thus, watershed network will accelerate bank erosion to the assessment should consider the benefits of extent that the system may attain its former these natural processes and changes. balance. Contributing to this cycle, many human interventions that are intended to Bank erosion is a natural process that stop bank erosion actually promote erosion occurs due to the force of water against the in other areas by deflecting the force of flow bank. The rate of bank erosion depends on or by generating turbulence around hard such factors as the resistance of bank edges of the structure. material and the presence of vegetation. Riparian plants’ root systems promote bank 3.5.3.3 Flooding and Sediment stability. Dynamic rivers maintain their morphology through erosion and Flooding (often called the “flood pulse” by sedimentation, and the disturbance caused ecologists) is a natural attribute of rivers. by removing vegetation from one area and Most sediment erosion, transport, and creating new bare patches promotes deposition occur during floods. Flooding, riparian succession. If these natural defined as flow that exceeds the capacity of processes, called “disturbances” by the channel, occurs when flow inundates ecologists, knock the system out of balance, the floodplain. Infrequent large floods other natural processes acting as feedback reconfigure channel morphology and often restore the system to a new balanced maintain or create side channels and state. These natural disturbances are floodplain topography. Moderate floods essential for sustaining ecosystems. In maintain channel bedforms and spur the contrast, chronic or pervasive disturbances evolution of river channel pattern. Frequent caused by human activity may continue to small floods sustain ecosystem function. cause instability over time, or may knock the The relation between floods and sediment in system off balance to the extent that it watersheds depends on the connectivity in cannot achieve a new balance. the longitudinal, lateral, and vertical
“Dominant” Discharge: the range of flow magnitudes that determines channel cross section width and depth (Wolman and Leopold, 1957).
“Bankfull” Discharge: the flow magnitude that is contained within a channel without overtopping its bank (Leopold et al., 1964).
“Effective” Discharge: the range of flow magnitudes that transports the majority of a river’s annual sediment load over the long-term (Wolman and Miller, 1964). In a gravel bed stream, this is the discharge that transports the greatest quantity of bedload.
In some alluvial rivers, the dominant, bankfull, and effective discharge are equivalent, and generally correspond to frequently occurring flow magnitudes. However, this assumption is not valid in all rivers, for example in disturbed channels or rivers in semi-arid or arid environments.
- 19 - California Watershed Assessment Manual, Chapter 3 August, 2004 dimensions. Human activities alter that in addition to the large floods that connectivity in numerous ways. For typically receive attention, small to example, in the longitudinal dimension, moderate floods are capable of channel dams trap sediment and reduce supply to change. In fact, floods contained within a downstream reaches; in the lateral natural channel are significant in creating dimension, levees concentrate flow into one and maintaining channel morphology and main channel and limit connectivity between associated riparian and aquatic habitat as rivers and their floodplains; in the vertical are larger overbank floods to other aspects dimension, an influx of fine sediment in a of channel morphology and to floodplains. gravel bed river infiltrates into the spaces Altering the prevailing relationships between between larger sediment particles and sediment supply, transport, and discharge reduces the oxygen supply to anadromous magnitude, frequency, and duration will alter fish eggs. the shape of a channel through erosion and sedimentation processes. Care should be The shape of natural alluvial channels is taken when applying these concepts to adjusted to accommodate a range of disturbed channels or to rivers in semi-arid frequently occurring floods. This range of or arid environments. For example, in an flood magnitudes is often is simplified to a incised river, the bankfull discharge may be single discharge called the “dominant significantly larger than the effective discharge.” The dominant discharge is discharge. In semi-arid environments defined as the flow responsible for creating where vegetation is sparse, the the characteristic width and depth of the characteristic channel morphology may be channel and is sometimes equivalent to the formed during large infrequent floods rather flow that transports the majority of sediment than smaller floods that occur frequently. over time. This important definition stems from a comparison of the magnitude and 3.5.4 Morphology frequency of a range of sediment transporting floods conducted by Wolman The dynamic interaction between water, and Miller (1960). The magnitude- sediment, vegetation, and woody material frequency concept suggests that in many creates the shape of the channel and rivers, moderate sediment transporting floodplain referred to as “morphology.” floods that occur frequently are most Because of the continual changes in water effective in transporting sediment over time, and sediment supply and transport, in contrast to larger floods that transport morphology is not a static feature in fluvial large volumes of sediment, but that only systems. Rather, morphology is dynamic occurs infrequently. Thus, a large flood that and changes in response to erosion and erodes and deposits sediment may alter sedimentation during the range of flow channel morphology in the short term, magnitudes. Conserving and whereas frequent small floods accommodating or allowing dynamic approximately equal to the flow that governs morphology is a key to preserving riparian channel shape and size over the long-term. ecosystem diversity. Leopold et al. (1964) found that the shape and size of many natural alluvial channels is Whereas the morphology (shape) of river adjusted to a flow that fills the channel from channels along the profile from the bank top on one side of the channel to the headwaters to estuaries forms a continuum other side. They found that the “bankfull” that incorporates considerable variability, flow has an average recurrence interval of classifications of these morphologies help about 1.5 years, often ranging from about 1 identify the dominant processes responsible to 3 or more years. for their formation and help in the The importance of these concepts to characterization of fluvial systems needed in watershed assessment is the recognition watershed assessments. A number of
- 20 - California Watershed Assessment Manual, Chapter 3 August, 2004 books that contain descriptions of formed by bedforms, such as riffle-pool morphology and the processes that create sequences, and other aspects of physical and sustain fluvial landforms are included habitat, such as overhanging banks, for with the references at the end of this various portions of their life cycle. chapter. Understanding the type of bedform that is characteristic of a certain portion of a river is Channels required before assessing the effects of human activities and before predicting the Channels begin in the headwaters of type of bedforms that may be stable during watersheds because of springs, seepage restoration of disturbed systems. Land use erosion, or overland flow in gullies. Some activities may affect the bedform continuum channels begin in association with hillslope through alteration of channel slope, channel processes near ridge tops in swales called width and depth, particle size distributions, “colluvial hollows” (Dietrich et al. 1986). pool depth and frequency, and water and Headwater channels are usually steep and sediment discharge. For example, narrow and contain bedrock or boulders. channelization often obliterates bedforms They are directly influenced by hillslope that created heterogeneity of aquatic habitat processes. Headwater streams are needed in functioning riparian ecosystems. extremely important ecological zones (Meyer et al., 2003) as they provide water, Whereas understanding the processes and sediment, nutrients, and energy into the physical conditions necessary to sustain system. In forested northwest California, characteristic river bedforms is a necessary morphology in headwater streams is greatly component of watershed assessment, by influenced by large woody debris (Keller & itself, bedform classification does not give a Swanson, 1979; Montgomery et al.,1996). complete picture of aquatic habitat in many watersheds. Bedforms describe the The morphology along the longitudinal longitudinal changes in morphology of a profile of a riverbed contains a continuum of channel. However, to understand the morphology called “bedforms,” (see box to interactions of a river with its banks and with right) which adjust to the flow and sediment its floodplain (when present), supply. This bedform continuum changes geomorphologists also investigate river longitudinally with the capacity of the river to channel pattern, the shape of the river when transport sediment and as slope, particle viewed from above. size, and roughness decrease, and channel width and depth increase. The bedform continuum is often simplified by Bedforms are associated with the type of geomorphologists in a hierarchical bed material (bedrock, boulders, gravel, classification that includes cascades, step- or sand) and the slope of the channel, pools, plane-beds, riffle-pools, and dune- among other factors. ripples (Montgomery & Buffington 1997) that describes the physical characteristics of the Cascade – bedrock or boulder bed, slope channel bed. Fish biologists use other greater than 0.08; classifications that describe the way fish Step-pool – boulder bed, slope greater utilize bedforms, e.g. riffle-pool, glide, and than 0.02 (<0.08); run. Riffle-pool – gravel bed, slope greater than 0.01 (<0.02); The type of bedform present is a reflection Dune-ripple – sand bed, slope less than of the location within the watershed and the 0.01. physical processes active in the fluvial system. Most importantly, aquatic Modified after Montgomery and Buffington (1997) organisms utilize specific micro-habitats
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River Pattern naturally formed or engineered levee. The anabranching pattern is typically found in Classifications of river pattern usually define low-gradient rivers with floodplains. It was four endpoints in order to simplify the common in many lowland California rivers continuum of river morphology. Straight, prior to the construction of levees that meandering, and braided patterns refer to concentrated river systems into single the channel, while the anabranching pattern channels. that contains multiple channels must be considered in the context of a floodplain, Documenting and understanding the effect described further below. of human activity on channel pattern are critical in predicting potential future river- “Straight” patterns occur in channels without system processes, especially in restoration bends and are sometimes associated with activities. geologic or structure control. Channelized rivers are often straightened in order to Floodplains and Estuaries increase flow velocity for flood control, whereas, natural channels are not usually Floodplains are integrally linked to their straight over long distances. channel systems, and separating floodplain morphology from channel morphology is an “Meandering” patterns occur in channels artificial distinction. Floodplain classification that contain bends that evolve through a is based on stream power and sediment combination of bank erosion on the outside particle size in the adjacent channels of bends and sediment deposition on the (Nanson & Croke 1992). inside of bends. These processes lead to meander migration, the movement of a Floodplains contain a diverse assemblage channel across its floodplain through of sediment deposited by a variety of erosion and deposition. Understanding processes that occur during floods. One natural processes of meander migration is process, vertical accretion, occurs as important in order to anticipate the effects of overbank flow brings fine material human interventions. For example, using suspended in the water onto the floodplain. hard structures, even the rock and large This fine material is deposited in zones of woody debris that are often promoted as a low flow strength that may occur where natural way to prevent bank erosion, inhibits vegetation slows flow. Other vertical meander migration and may lead to erosion accretion processes include deposition in in a different area as the river adjusts to its “crevasse splays,” or sand splays, fan- imposed pattern. shaped deposits of sand that occur as a river breaches a natural or artificial levee, “Braided” patterns occur when flow splits scours an area immediately adjacent to the around in-channel bars. Braided patterns breach, and deposits its sediment load over are common in streams with high sediment older floodplain sediment. Another process, loads and high slope, and they tend to be lateral migration, occurs as sediment is very unstable. eroded on the outside of bends and is deposited on the inside of downstream “Anabranching” rivers have multiple channel bends. Over time, the channel channels separated by islands (composed migrates in the direction of the eroding of the same material as the floodplain, in channel bank, leaving behind a bar on the contrast to braided rivers, where flow splits inside bend, called a point bar, that around in-channel bars). In anabranching continues to build in height until only rivers, the dominant geomorphic process is overbank floods are deep enough to “avulsion,” or the dynamic switching of inundate and deposit sediment in that channel location through a breach in a location. Floodplains contain a stratigraphic
- 22 - California Watershed Assessment Manual, Chapter 3 August, 2004 record documenting variability in these bank erosion. Sediment storage is the processes over time. Prior to their sediment in channel bedforms and bars, the development for agriculture or other land floodplain, and terraces. The output, or uses, floodplain surfaces contained “yield,” from a basin is a measure of the topographic relief that created high and low sediment leaving the watershed. The time areas supporting diverse ecosystems period over which the sediment budget is relevant must be defined based on the Many rivers in California form estuaries, a timeframe of the input data. Because biologically rich ecotone (transition zone) sediment erosion, transport, and deposition where freshwater and saltwater mix in the are dependent on the magnitude, portion of a watershed farthest downstream frequency, duration, and intensity of storms, from the headwaters. The San Francisco the components of the sediment budget Bay-Delta Estuary in California is the must be placed in the context of California’s downstream portion of the large episodic flood regime. Sacramento-San Joaquin River watershed. Smaller California watersheds also contain A sediment budget generally provides an important estuaries, such as the Klamath order of magnitude estimate of sediment River Estuary to the north and the Tijuana volumes produced, stored, and transported River Estuary to the south, and the Navarro, through a watershed. Although exact Garcia, Russian, and numerous other small quantification is usually not possible, the estuaries in between. Estuaries are affected sediment budget is a useful framework for by sediment deposition, dredging, identifying important processes and the subsidence, shoreline stabilization or linkages between processes that affect alteration, and changes in upstream sediment in a watershed. The sedimentation watershed flow and sediment regimes. For rate and residence time of sediment in example, an increase in a river’s sediment storage is critically important and can be load may fill in an estuary, while a decrease addressed through watershed assessment in river flow may increase salinity. to evaluate the effects of land use changes. Moreover, a sediment budget may be used 3.5.5 Sediment Budget Framework to document changes in connectivity, such as loss of sediment supply following A sediment budget is a mass balance of construction of a dam. sediment supply, storage, and yield over time (Reid & Dunne, 1996). Specific 3.6 Water Quality components of a sediment budget may be used to address the effects of natural Water quality encompasses the physical processes or human-cause disturbances and chemical characteristics of water in (Reid & Dunne, 1996). waterways or in water entering a waterway. Aspects of soil and atmospheric water The sediment budget is useful to account quality are not included here, although the for watershed sediment through the relation: geochemical cycles occurring in the atmosphere and the soil and geology of a I – O = ∆S watershed are critical controlling forces in Where I is the volume of sediment input, O determining the quality of water in streams. is the volume of sediment output or yield, Measuring water quality is important in and ∆S is the change in sediment storage assessing watershed condition because over a particular time period. “changes in water quality indicate a change in some aspect of the terrestrial, riparian, or Sediment input, or supply, is a measure of in-channel ecosystem.” (Naiman et al., the material produced by hillslope mass 1992). Water quality is one of the primary movement and upstream channel bed and
- 23 - California Watershed Assessment Manual, Chapter 3 August, 2004 measurable, non-biological indicators of the state’s waterways, including listing watershed condition. waterways under section 303(d) of the CWA (http://www.swrcb.ca.gov/quality.html). This section covers legal and regulatory Listing waterbodies means that the state issues, but first provides information on key has determined that there is sufficient scientific concepts related to water quality. scientific basis for calling individual These include: waterbodies impacted to invoke their legal protection. • Classes of contaminants • Major effects of the contaminants on U.S. EPA has adopted the ambient water aquatic life quality criteria, which are water quality • Information on evaluation of chemical standards for the protection of aquatic life contaminants in water (http://www.epa.gov/waterscience/pc/revco m.pdf). These standards can be used to Protecting or improving water quality often evaluate water quality in the context of an includes protecting and restoring natural overall watershed assessment. Where functioning to watersheds. Activities related standards don’t exist, indicators can be to understanding impacts to water quality drawn from technical and scientific literature often involve figuring out where in the to inform the analysis. watershed impacts are occurring. According to the U.S. EPA, nonpoint source pollution The characteristics of water vary across is “pollution from numerous widespread watersheds and according to time of day, locations or sources that have no well- season of the year, and human activities defined points of origin. The pollution may that might affect water quality. To account originate from land use activities and/or for this variability, it is usually necessary to from the atmosphere. Examples include collect many samples at many times in leaching of excess fertilizer from fields and many places in order to characterize water acid rain.” In contrast, point source pollution quality. comes from a specific, identifiable source or site. In many places, nonpoint source Sometimes waterways in a region (e.g., the pollution is the primary source of water Central Coast) are chosen as reference quality problems. sites because they have many or all of the expected natural processes (e.g., frequent The concept of water quality is embedded in fire) and features (e.g., anadromous fish federal (Clean Water Act, CWA, 1973) and populations). Data collected from a state (Porter-Cologne Act) law, which reference monitoring site can be compared require that state agencies and permittees to data collected from sites of concern to meet certain standards for managing establish how much the sites of concern chemical inputs and other forms of pollution have deviated from the natural state. that might impact “beneficial uses.” Beneficial uses generally refer to the 3.6.1 Nutrients “fishability,” “swimmability,” and “drinkability” of water, but also include protection of Naturally occurring chemicals that aquatic life and habitat. contribute to instream plant and bacterial growth include nitrogen-containing If water quality is impaired or threatened compounds (e.g., nitrates) and with impairment from point or nonpoint phosphorous-containing compounds (e.g., sources, then the state must act to protect phosphates). The cycling of these or improve water quality. In California, the chemicals, or nutrients, through terrestrial State Water Resources Control Board is and aquatic ecosystems is a natural responsible for managing water quality in process that can be influenced by
- 24 - California Watershed Assessment Manual, Chapter 3 August, 2004 modifications of vegetation, soils, and rock adult insects, amphibians, fish, and other formations; changes in the flow rate and aquatic animals. This point varies with other physical characteristics of waterways; geography and species. Rapid temperature changes in the biological conditions in changes can also have adverse effects. The waterways; and the introduction of nutrients temperature of a waterbody will affect the from outside sources. Human activities concentration of dissolved oxygen (colder usually increase nutrient concentrations, water has more oxygen) and the instream resulting in increased potential for the portion of nutrient cycles growth of algae and other plants in waterways. Excessive growth of algae, By changing the vegetative cover, bacteria, or vascular plants can result in hydrologic cycle, and rate and timing of secondary impacts to dissolved oxygen instream water flow, human activities can concentrations and downstream organic influence the water temperatures of streams carbon concentrations, due in part to the and rivers. Removal of upslope or riparian breakdown of plant material. When vegetation (e.g., by logging or dissolved oxygen levels become too low, development), for example, results in the normal physiological functions of aquatic increased sunlight on the water surface, animals are impaired, resulting in mortality which heats the water, and increased wind in some cases. The U.S. EPA’s ambient speed across the water surface, which water quality criteria include nitrates and decreases the benefits of riparian shading if phosphates. the air is warm (Holtby 1988). Water diversion and storage reduce instream flow, 3.6.2 Temperature which can have serious impacts if these reductions are in the summer when the air Water temperatures must remain within a is warm anyway. Reduced natural storage certain range in order for native aquatic of water as snow or in shaded soils can also organisms to maintain healthy populations result in lower flows in the summer. and distributions. This temperature range varies from species to species, and Water temperature can fluctuate over 24- sometimes from population to population hour periods, weather events, seasons, and within a species. Temperatures within a climate cycles. It can also fluctuate over given body of water vary naturally due to short lengths of a stream. These seasonal and diurnal influences. The fluctuations can complicate measurements temperature of inflowing water, flow rate, and analysis of water temperature in still wind speed, air temperature, and riparian and moving waters. shade influence water temperature. When natural or human processes affect these The mean weekly average temperature factors, temperatures may rise or fall. (MWAT) and the summer pool temperatures Relationships between landscape condition (where pools are providing cool-water and water temperature exist, but have not refuges) are two common methods for been well characterized for all habitat types tracking water temperature. The standards of California. for these indices vary depending on where the waterway is in California and the Temperature changes and temperatures species of concern. For example, in the above a certain point have particular direct North Coast region in 2001, the RWQCB and indirect effects on the health of had the following standard for temperature: instream aquatic communities. “At no time or place shall the temperature of Temperatures above a certain point will any COLD water be increased by more than have sub-lethal impacts (e.g., reduced 5oF above natural receiving water growth rate, impairment of physiological temperature. At no time or place shall the function) or lethal impacts on embryonic and temperature of WARM intrastate waters be
- 25 - California Watershed Assessment Manual, Chapter 3 August, 2004 increased more than 5oF above natural needed for photosynthesis by algae and receiving water temperature.” (North Coast vascular plants, 3) the spreading of Regional Water Quality Control Board, pathogenic microbes and toxic metals 2001). In other regions, there may be bound to the surface of particles, 4) different standards, and the basis for the increased costs for water purification, and 5) standard may vary. the filling of downstream reservoirs.
3.6.3 Suspended Material Two approaches for investigating the potential for suspended sediment problems Both organic (e.g., leaves) and inorganic in watersheds are to: 1) monitor in-stream (e.g., silt) material enters streams and can concentrations periodically and during and affect the clarity of the streams, as well as immediately following storm events and 2) the sediment budget for a waterway or develop a risk assessment or similar map- watershed. “Total suspended solids” refers based modeling approach using information to all the material suspended in the water, about slope steepness, precipitation, soil and “total suspended sediment” refers to and geology, land cover (vegetation), and just the inorganic portion. Suspended land use. Data from both approaches can sediment is sometimes defined as including be collected in the same watershed and, in both organic and inorganic particles combination, can reveal potential or actual (Spellman & Drinan, 2001), so the use of impacts of suspended sediment on aquatic either term must be accompanied by a communities. definition. Just as with temperature, suspended Suspended sediment is a natural part of an sediment concentrations can fluctuate aquatic ecosystem; as with most aspects of widely over short time periods and water quality, it is the concentration and distances. This can complicate duration that matters. Natural understanding natural and human-induced concentrations of suspended sediment will erosion processes and transport of vary with geological and soil formations, sediment through stream and river systems. precipitation, upstream slope steepness, and land cover. Human activities, including 3.6.4 Dissolved Oxygen road construction and maintenance, logging operations, agricultural operations, housing Aquatic ecosystems must contain oxygen in construction, mining, grazing, and changes order to sustain the lives of all animals and in flow (reservoir releases or water diversion) can result in changes in suspended sediment in -stream. It is natural for landscapes to erode and for vegetation and other organic material to enter streams, and for these materials to become suspended or settle in response to flows. However, modifications of these processes through land and flow disturbances can cause negative impacts to aquatic communities and human uses of water. The negative impacts of excessive suspended sediment include: 1) the smothering of embryonic and larval stages Humbug Creek, Yuba River watershed of insect, amphibian, and fish species in the Photo by David Fallside benthic sediment, 2) the blocking of light
- 26 - California Watershed Assessment Manual, Chapter 3 August, 2004 plants (but not all bacteria). The Standards for dissolved oxygen concentration of oxygen dissolved in water concentrations are usually based on the depends primarily on the temperature of the needs of aquatic organisms present in a water and the waterway’s elevation (which particular watershed. For example, trout affects atmospheric pressure). Oxygen is populations and their prey depend on naturally introduced into aquatic oxygen concentrations >6.5 mg/L ecosystems from the atmosphere and from (milligrams per liter) in order to survive. photosynthesis by algae and vascular plants Populations of warm-water fish, such as growing in the water. Oxygen is naturally largemouth bass, will not grow at dissolved limited in the water of benthic (bottom of the oxygen concentrations <6.5 mg/L, but can waterbody) sediments because it must tolerate lower concentrations than cold- diffuse in from the water above, and it is water fish. simultaneously used up by respiring animals and microorganisms, as well as by chemical California’s Regional Water Quality Control reactions. Boards use two different kinds of standards for dissolved oxygen. One is a saturation There are two primary units for measuring standard. For example, waters must the concentration of oxygen in water: 1) average >85% saturation in the Central milligrams per liter, “mg/L”, which refers to Valley region. The other standard requires the amount of oxygen dissolved in one liter that concentrations be above a certain of water, and 2) % saturation, which refers standard. For example, in the Central Valley to the proportion of the theoretical maximum region, dissolved oxygen be >5 mg/L for the concentration of oxygen that is present. Sacramento River at the Delta to >7 mg/L for the upper Sacramento River. Human activities can contribute to the depletion of dissolved oxygen (DO) from Besides causing the loss of fish and other waterways. For example, dams and aquatic biota, oxygen depletion can promote reservoirs contribute to depletion of oxygen unwanted chemical reactions. For example, through microbial action in the deep water anoxic (no oxygen) or hypoxic (low oxygen) and bottom sediments. Water released from sediments are more likely to host the deep in a reservoir to a stream or river can methylation of mercury (a chemical be very low in oxygen. In addition, reduced modification of mercury atoms) by bacteria, flows during the summer can result in which allows mercury to enter the food increased water temperatures, which will chain through bacteria and algal food result in lower concentrations of oxygen and sources for aquatic animals (D’Itri, 1990). possibly excessive algal growth, which will eventually rot and further deplete the 3.6.5 Inorganic and Organic Pollutants oxygen. Excessive nutrients can also contribute to bacterial, algal, and vascular I. Classes of Contaminants plant growth, which can deplete nighttime oxygen in the benthos (bottom of the Contaminants are any chemical that can waterbody). When the excessive growth have an adverse effect on aquatic life if dies off, the rotting material will result in present in sufficient concentration. oxygen depletion in or near the benthos. “Sufficient concentration” is the key phrase. Settling of fine sediments between larger In small enough quantities, most chemicals gravel in benthic sediments reduces the are harmless. In larger quantities, chemicals flow of water through the gravels and that might be essential for life can be very hinders the replenishment of oxygen toxic. This well-documented pattern is the depleted by benthic organisms. basis for the slogan “the poison is in the dose (or concentration)”. One classic example of this is the metal copper; it is an
- 27 - California Watershed Assessment Manual, Chapter 3 August, 2004 essential mineral for all living organisms, but The U.S. EPA has developed benchmark above a certain concentration, it becomes values, those considered safe for most increasingly toxic, especially to aquatic aquatic life, for both short-term (acute) and animals. Most contaminants of concern are long-term (chronic) exposures. toxic at low concentrations, typically in the parts per billion (ppb) range. II. Organic Contaminants
Contaminants can be divided into two major Organic compounds that are contaminants groups of chemicals: organic and inorganic. play no normal role in the functions of Organic chemicals contain carbon and aquatic organisms.They are often designed include most pesticides, dioxins, PCBs to kill insects or other animals. Alternatively, (polychlorinated hydrocarbons), PAHs many serve as ingredients in various (polycyclic aromatic hydrocarbons), oil and manufacturing processes or are grease, and surfactants and plasticizers. constituents of commercial products. Over The metals that are of greatest concern with time, organic contaminants will be broken respect to aquatic life are typically heavy down to less harmful substances. metals, such as zinc, copper, mercury, and lead, as well as other groups of metals that However, some can persist for decades. include arsenic. Those that persist for long periods of time can accumulate in the tissue of animals and Aquatic contaminants can be acute and/or be passed up the food chain. The tables chronic toxicants. Acute toxicity causes above contain an abbreviated list of mortality, while chronic exposure to lower common organic contaminants found in levels of the contaminant can cause harm to waterbodies, their sources, the type of the reproductive, nervous, or other effects they have on aquatic life, and physiological system. reference information to collect additional details.
Organic Chemical Environmental Effects Special information Source Organophosphate Lawns, golf courses Neurotoxin, Very water soluble, pesticides (diazinon, acutely toxic persists in water for malathion, weeks-months chlorpyrifos) Pyrethroid pesticides Lawns, golf courses Neurotoxin, Not easily dissolved in (esfenvalerate, acutely toxic, water, found in permethrin) some cause sediment, persists in chronic toxicity sediment up to a year (reproductive harm) Organochlorine Pesticides, many Neurotoxin, but Very insoluble in water, pesticides such as DDT, are also many commonly found in currently illegal to other chronic sediment, persists for use adverse effects long periods (75 years)
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Organic Chemical Environmental Source Effects Special information Polycyclic aromatic Combustion by-product Carcinogen, Insoluble in water, hydrocarbons (PAHs (gasoline, wood, burning can cause found in sediment, such as of just about any organic tumors in fish persists for benzo[a]pyrene) material) decades under certain conditions Dioxins Combustion by-product Carcinogen, Insoluble in water, involving reaction with disrupts normal persists for long chlorine; by-product of hormone periods of time in synthesis of some function sediment if herbicides, found in (endocrine shielded from light bleached pulp mill disruptor) effluent, incinerator emissions PCBs (polychlorinated Hydraulic fluid, coolant, Carcinogen, Very insoluble in biphenyls) insulator, historically numerous other water, very used in transformers, harmful effects persistent in the current source is sediment manufacturing waste, currently illegal to use Surfactants Numerous Can interfere Water soluble, are (detergents) commercial/residential with not persistent uses; enter water via reproduction in wastewater treatment aquatic animals plants Plasticizers Commercial uses, makes Reproductive Low solubility in (phthalates) plastics more pliable; toxicant in fish water, associated wetting agent; found in and with sediment, wastewater effluent invertebrates persists for less than 1 month in most cases
III. Metals of water affect the solubility and availability of metals to be absorbed by invertebrates Metals are natural substances, many of and fishes. Water hardness is a key factor which are essential nutrients. However, if that affects the solubility of metals. present in aquatic ecosystems in sufficient Hardness refers to the concentration of quantities, they are harmful. Unlike organic positively charged atoms (calcium, compounds, metals are not biodegradable. magnesium, etc.) dissolved in water. If the Unlike organic compounds, metals persist concentration of a metal is hardness- indefinitely. They also tend to dependent, then special considerations bioaccumulate, or collect, in fish tissues. must be made in assessing harmful levels in a specific water body. Another important The toxicity of metals in water and sediment consideration when looking at metals is that is complicated because normal constituents they are often found in greater
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Metal Environmental source Hardness- Toxic effects dependent Arsenic Naturally occurring; used in No Acute toxicity, some pesticides and reproductive toxicant herbicides, wood preservatives Lead Mining, incineration of Yes Acute toxicity, batteries, pigments neurotixcant, impairs reproduction Mercury Fungicide; many No Methyl mercury form of manufacturing processes; greatest concern; mining endocrine disruptor, not acutely toxic Cadmium Used in a variety of industrial Yes Acute toxicity, a variety processes; most common in of physiological effects urban watersheds with long term exposure, including deformities of young Copper Mining, dormant sprays; Yes High toxicity with acute fungicide used on boats exposure; interferes with function of gills Zinc Mining, electroplating, roads Yes Acutely toxic; teratogenic (from worn tires), with chronic exposures manufacturing of brass, steel, and iron alloys; dormant sprays Chromium Numerous manufacturing hexavalent form Acutely toxic, possible processes, including tanning not affected by carcinogen leather, manufacturing steel, hardness; aircraft industry trivalent form less water soluble, toxicity hardness dependent concentrations in the sediment, bound up The table above lists key metals of concern, with other particles, than in a free (or their environmental sources, whether the soluble) form in the water. Over time, the metal’s concentration in water is dependent bound metals in the sediment leach out into on water hardness, and toxic effects of the water. Many invertebrates and various metals. life stages of fishes live in the sediment. Consequently, it is important to examine the IV. Evaluating Contaminants in Water as potential toxicity of metals in both the Part of a Watershed Assessment sediment and water column. If there are land uses or activities within the watershed that might be associated with the
- 30 - California Watershed Assessment Manual, Chapter 3 August, 2004 release of contaminants, or if there is bacterial species, Escherichea coli, may evidence within the waterway that cause intense gastrointestinal problems if contaminants might be a problem, there are ingested. a number of steps that can be taken to determine if contaminants are a problem. U.S. EPA has established standards for water quality in waterways used for 1. Check with the Regional Water Quality recreation and as sources of drinking water. Control Board, local Water Districts, These standards are based on generalities Municipalities, Sanitary Districts, Regional about the consumption of water containing Urban Runoff Programs, and Local Publicly bacteria and the sensitivity of people Owned Treatment Works (POTWs), to potentially exposed. If waterways exceed determine if they have conducted these standards, then the state has a legal monitoring within the watershed. If data responsibility to protect residents from already exists, independent monitoring may potential harm by notifying the public of the not be necessary. problem through signs and other advertising and by then identifying sources of the 2. Collect water to perform a toxicity test. problem and implementing cleanup through These tests utilize invertebrates and/or fish regulatory or restoration activities. More to determine whether something in the information on this topic is posted at: water or sediment causes acute toxicity. http://www.swrcb.ca.gov/beach/index.html. Although the test is not specific for any particular contaminant, it does reflect the 3.6.7 pH overall quality of the water. When possible, it is best to perform the tests with both water pH is a measure of the relative acidity or and sediment samples from the waterbody. alkalinity of freshwater. pH is literally the concentration of hydrogen ions in water. 3. If the toxicity tests are positive, further Hydrogen ions have a positive electrical analysis can be done to identify the cause charge, allowing them to associate with of the toxicity. Toxicity identification negatively charged ions, such as nitrate and evaluations (TIEs) can be performed to chloride ions. The pH depends in part on initially identify the class of contaminant the relative concentrations of electrically responsible. For example, TIEs will charged compounds present in the water differentiate between metals, certain types and can therefore be affected by natural of pesticides, or other harmful chemicals. and human processes that influence the Once the class of contaminants is concentrations of these compounds. determined, a variety of analytical techniques can be used to determine the In California, pH naturally ranges around specific “bad actor(s).” neutral pH (pH = 7.0) by about 1 pH unit. Most Basin Plans for the various State 3.6.6 Pathogenic Bacteria Water Resources Control Board regions record a pH range of 6.5 to 8.5 as ideal for The primary bacteria types of concern in maintaining the health of aquatic waterways are fecal coliform and communities. Violation of drinking water enterococcal. They usually originate from standards is not an appropriate indicator for deteriorating septic systems, incomplete pH problems because changes in pH can wastewater treatment, the presence of affect aquatic organisms before reaching a livestock, or stormwater flooding of level that humans can’t tolerate. wastewater treatment facilities. They may also be associated with natural sources in a Acid mine drainage, microbial processes at watershed, such as dense congregations of the bottoms of lakes and reservoirs, and birds or other wildlife. Certain strains of one effluent from wastewater treatment plants
- 31 - California Watershed Assessment Manual, Chapter 3 August, 2004 and industry are possible sources of pH lead to low flow rates among the particles change in a watershed. Erosion of certain and limit dissolved oxygen concentrations. geological features, such as serpentine Small particles are more easily mobilized in outcroppings, can also change the pH of low flow rates, resuspending and resettling receiving waters. Changes in pH outside the in the turbulent stream and river flows. range of 6.5 to 8.5 are usually associated Large particles have large pore sizes with identifiable sources that can be readily among them. They usually don’t limit flows investigated. and the availability of dissolved oxygen to benthic organisms. 3.6.8 State Programs and Regulations That Affect Water Quality Measuring the proportion of benthic [THIS SECTION IS UNDER sediments of different sizes and the rate of CONSTRUCTION] downstream sediment transport are important ways to characterize stream 3.7 Aquatic Ecosystems condition. These physical measures of habitat condition often accompany studies Although waterways constitute a small of benthic macroinvertebrates, one proportion of a watershed’s total size, they biological measure of the aquatic integrate many of the human and natural ecosystem’s condition. processes in the watershed, and they are often the political and social focus of Flow, the physical movement of water, watershed efforts. Aquatic ecosystems impacts many other aquatic ecosystem include physical (e.g., temperature), characteristics. Low flows can result in chemical (e.g., nutrient concentrations), and warming of water, reduced sediment biological (e.g., fish populations) transport, and physical barriers to the components. The physical and chemical movement of migratory fish. High flows can constituency of an ecosystem in large part increase the rate of sediment transport, determines the various plants, microbes, replenish depleted dissolved oxygen, and vertebrates, and invertebrates that live provide deeper water for fish movement. there. In turn, interactions among the various organisms determine the aquatic 3.7.2 Chemical community structure. Most of the important chemical 3.7.1 Physical characteristics of aquatic ecosystems are presented in the water quality section Many factors in an aquatic ecosystem can (chapter 3.6). be described as “physical,” such as temperature, suspended and benthic Changes in stream chemistry can determine sediment, and flow. Some of these are the well-being of the aquatic ecosystem. described in more detail in the water quality Individual organisms may not tolerate either section (chapter 3.6). changes in water quality (e.g., pH, dissolved oxygen, and nutrients) or the absolute Benthic sediment is an important values for these water quality parameters. component of aquatic ecosystems. While Other organisms may be quite tolerant of difficult to characterize, benthic sediment is wide variations in water chemistry. Changes critical to the health and well-being of native may originate from human activities (e.g., organisms. The structure and composition nutrient runoff from an agricultural area), of benthic sediments determine the size of natural processes (e.g., growth and spaces among sediment particles and, in decomposition of aquatic plants), or a part, the rate of particle movement. Small combination of both (e.g., excessive growth particles result in small pore sizes, which of algae due to excessive nutrient inputs. A
- 32 - California Watershed Assessment Manual, Chapter 3 August, 2004 critical part of watershed assessment is availability can affect the growth of these understanding the nature of water chemistry aquatic plants. Low flows and excessive in the watershed and the causes of high or inputs of nutrients from various land uses low values or changes in values for specific and point sources may result in high parameters. Many water quality standards temperatures, reduced mechanical stress are based on human health considerations (from flow), and excessive growth. and not on ecological effects of changes in Excessive growth can cause changes in pH, waterbody chemistry. Therefore, standards reduced dissolved oxygen concentrations in relevant to aquatic organisms must be used the bottom sediments, and production of when analyzing pH values in the watershed. particulate and dissolved organic carbon as the plants grow, die, and decompose. 3.7.3 Biological Although fungi and bacteria may occur in The biological components of aquatic the water column (millions of individual cells ecosystems are the microbes, plants, per liter), most of the important microbial invertebrates, and vertebrates that inhabit activity occurs on the surface of or within the water column (the water above the the bottom sediments (Horne & Goldman bottom) and the benthos (the bottom of the 1994). Decomposition of plant material from waterway). These grow and change relative terrestrial vegetation and from aquatic to each other depending on the physical plants is an important process in the slower- and chemical conditions in the waterway moving major rivers and lakes, however, it and can therefore indicate conditions or may also occur in waterways, such as changes in the watershed. Understanding mountain rivers, if the water is warm enough the natural biological condition of waterways and there is sufficient material. Microbes on is often challenging, as there are few the surface of decaying vegetation are an “reference” waterways, that is, streams and important food source for invertebrates rivers in a relatively natural state. However, grazing or filtering food from the water and many scientists use the biological sediment (Horne & Goldman 1994). High composition of aquatic ecosystems to levels of microbial activity can alter the determine whether or not a watershed or chemistry of water within the bottom waterway is deviating radically from a sediment and of water near the bottom. This natural state (Karr 1981; Moyle & Randall activity is one of the main reasons that 1996) and may be in need of restoration water deep in lakes and reservoirs is (Adaniya et al. 1997; Murray et al. 2001). oxygen-depleted.
Plants and Microbes Viruses are not usually thought of in the world of watershed assessment, but they Plants in aquatic ecosystems occur in are present in freshwater and can pose several main forms. Phytoplankton, single- risks to wildlife and humans alike. Hepatitis celled algae suspended in the water and animal influenza viruses are just two of column, grow in slow-moving waterways many pathogenic viruses that can be and lakes. Periphyton, single-celled and transmitted through freshwater, usually as a multi-celled algae, occurs attached in films result of inputs of animal and human waste or filaments to rocks in still or moving water. (Horne & Goldman 1994). Vascular plants (plants with true stems) can grow from lake, river, and stream bottoms. Benthic Macroinvertebrates All these plants use nutrients and gases dissolved in the water and light from the sun Benthic macroinvertebrates are the larger in order to photosynthesize (make food invertebrates (animals without backbones) using light as an energy source) and grow. dwelling at the bottom of waterways. Changes in flows, temperature, and nutrient Several major animal groups fall into this
- 33 - California Watershed Assessment Manual, Chapter 3 August, 2004 group, including insects and crustacea (1973), or are of concern locally (arthropods), mollusks, and worms. (http://www.dfg.ca.gov/whdab/html/lists.html However, most people using this term are ). Most watersheds include fish, which may referring primarily to the aquatic larval forms be viewed by the watershed assessor as of various insects (e.g., stone flies, caddis another resident of the watershed, as a flies, and dragonflies). Aquatic invertebrates commercial or social resource, or as a legal are a major food source for many aquatic problem. Anadromous (“up-running”) fish and terrestrial organisms. Their well-being migrate between different environments can determine how well these other animals (i.e., the ocean and inland freshwater) to do. They are also interesting from a carry out particular parts of their lifecycle. watershed assessment perspective Salmon (chinook and coho) and steelhead because they can function as indicators of are anadromous species, spending their watershed condition. Certain benthic larval and juvenile phases in freshwater and macroinvertebrates are sensitive to change, their adult years (1-4 years) in the ocean. i.e., watershed degradation, and can be Their primary needs in California monitored for their presence and relative watersheds are unimpeded travel routes abundance to give a measure of watershed from the ocean, good quality spawning health integrated across generations of the habitat (i.e., gravel bars for laying eggs), organisms. sufficient quality and quantity of rearing habitat (cool sheltered pools and riffles), Vertebrates and downstream transport to coastal estuaries and the ocean. Land and water Aquatic vertebrates include fish, amphibians management activities can impact these and reptiles, mammals, and birds. The various life cycle needs depending on their presence of individual species depends on location, type, extent, and timing of geography, hydrology, management activities. Assessments of watersheds conditions, presence of other species, and supporting these species should therefore other factors. All species, with the exception incorporate evaluation of conditions in the of anadromous fish, eventually rely on plant waterways and on the landscape that might productivity within the waterway itself or on impact and could limit anadromous fish plants adjacent to the waterway that fall or reproduction. are washed in. They also rely on certain aspects of the waterway’s physical or Many native fish in California lakes, rivers, chemical makeup. There are many and streams also deserve the attention that connections between watershed landscape anadromous fish receive (Moyle et al. condition and waterway habitat condition, so 1995). Their habitat requirements may be impacts to aquatic vertebrates are often just as narrow as those of salmon. These measured using other condition indices habitat requirements are often generalized (e.g., physical structure of the channel, in Basin Plans as “cold-water fisheries”, riparian vegetation, or water quality). “warm-water fisheries,” migration of aquatic Simplification (loss of natural complexity) of organisms”, “spawning, reproduction, and/or watershed and waterway conditions through early development”. For some of these habitat loss and modification (i.e., from land requirements there are broad ranges (e.g., and water management) has led to the 35oF to 70oF for “cold-water fisheries”). absence of many species from significant Each species has its own ecological “niche,” parts of their historic range in California. composed of its preferred habitat, the prey it eats, and how it reproduces. Individual fish Many watershed assessments focus on species range in their needs, so assessing freshwater fish, usually because the fish are habitat conditions and the potential impacts useful indicators of aquatic health, are listed to these conditions for many species is under the federal Endangered Species Act more complicated than for one species
- 34 - California Watershed Assessment Manual, Chapter 3 August, 2004 alone. Some common impacts to fish sight to a grade-schooler, but not species are loss of historical habitat (e.g., necessarily to the person who has to from dam construction), fragmentation of maintain an agricultural slough or diversion. existing habitat (e.g., from culverted road Mammals’ habitat needs and population crossings), loss of prey, degradation of dynamics (how populations of a species existing habitat (e.g., from reduced flows change over time) may be poorly and excessive sediment input), competition understood, leading an assessor to guess at from non-native species and diseases, and relationships between these species’ habitat over-fishing. Measuring all of these impacts needs and watershed conditions and use. for individual fish species may seem Aquatic birds (e.g., ducks, geese, daunting, but it is important for mergansers, cormorants, dippers, herons) understanding a watershed’s condition. are in a similar boat, with few species having complete descriptions of their Amphibians and reptiles often inhabit the preferred habitats. For both birds and margins of waterways. Some species are mammals, many general statements can be listed as endangered or threatened, or made about their habitat requirements and Species of Special Concern, while others roles in a watershed. For example, where have no special designation or protection beavers are particularly active, they can (Jennings & Hayes 1994; affect how riparian areas function by cutting http://atlas.dfg.ca.gov/). Examples of native down riparian trees and contributing to local aquatic amphibians and reptiles include the changes in channel structure and flow. In Arroyo toad, Cascade frog, California tiger turn, beavers are affected by the salamander, western pond turtle, and two- composition of the riparian forest in terms of striped garter snake. Their habitat has been size and species of trees. Otters do not do reduced or degraded in many places by very well in places where there are few land and water uses that affect riparian smaller fish and aquatic invertebrates, vegetation, sedimentation processes, prey which are the food for the larger fish the availability, and habitat connectivity (usable otters prey on. connections among habitat areas). In some instances, they have fallen prey to invasive Invasive and Introduced Organisms and/or exotic vertebrates and pathogens. [THIS SECTION IS UNDER Just as with fish, they rely on a particular set CONSTRUCTION] of physical (e.g., temperature) and biological (e.g., insect prey) conditions to 3.7.4 Anadromous Fish – Salmon & survive. For individual species, these Steelhead conditions could be a wide window or a very [THIS SECTION IS UNDER narrow one. If these conditions are altered CONSTRUCTION] significantly, abundance and presence will change. The job of the watershed assessor 3.8 Wetlands and Riparian Habitats is to find out what changes are significant. [THIS SECTION IS UNDER CONSTRUCTION] Aquatic mammals and birds often play significant roles in an ecosystem, either by 3.9 Terrestrial Landscapes and Habitats physically manipulating the waterway (e.g., beavers) or by functioning as a top predator The majority of watershed area is (e.g., river otters, herons). Many mammals composed of the terrestrial landscape—the were killed off by trappers in the last uplands, hillslopes, and ridgelines. Although century. Their return has been hampered by almost all watershed assessments discuss land and water uses and by public conditions of the landscape outside of perceptions of their role in modern riparian and wetland areas, very few tackle waterways. Beavers may be a delightful terrestrial plant communities and habitat
- 35 - California Watershed Assessment Manual, Chapter 3 August, 2004 condition, except when discussing erosion. present. One notable exception is the There are many processes in the terrestrial California Department of Forestry and Fire landscape that interact directly with Protection’s “hardwoods” map, which waterways and the riparian zone. These includes these types of data. Assessments include erosion, nutrient cycling, input of in large watersheds may not have the organic material, evaporative water loss, resources to support surveys or mapping of and movement of wildlife back and forth. actual plant species presence and The condition of the upslope vegetation and demographics. These plant surveys might soil can critically affect the capability of the be carried out in monitoring stations or watershed to retain moisture and meter associated with specific restoration projects. surface and subsurface runoff into streams. Assessments of smaller watersheds, In fact, the role of vegetation management especially where there are plant to water supply and control is one of the communities of concern (e.g., redwood original research topics of the emerging field forests and vernal pools), may allow the of watershed management in the early 20th generation of high-resolution maps. More century (Colman 1953). detailed and diverse information obviously allows post-assessment decisions to have Characterizing Terrestrial Plant more detail and greater resolution. Communities Changing Conditions For botanical diversity in California, the Jepson Manual (Hickman 1993) describes The terrestrial landscape is undergoing 24 climatic zones and 50 geographic units constant change—there is no equilibrium or contained within three floristic provinces stasis in these landscapes. Both human (California, Great Basin, and Desert). activities and natural processes can cause Individual plant species are often grouped changes in the terrestrial landscape. Even into communities—they often form where the natural state has been largely “associations” among each other (i.e., they converted (e.g., in urban areas), over long live together) because of similar habitat enough time periods, natural features have requirements or because they have a changed and will continue to change due to biological interaction. These communities fluctuating climate, changing human values, are represented in fairly general vegetation and invasions by new species. maps (e.g., “CalVeg 2000”) that show the location of plant community types. Some Plant communities may be replaced by agencies have created more spatially another or undergo “succession” following refined maps for plant community types extreme disturbance. This means that one (e.g., vernal pools, wetlands, and oak species may take the place of another, such woodlands), usually because human as the growth of chaparral following a fire activities threaten the habitat type. Specific that removes a conifer forest. Plant plans for urban area development may have communities also age, which leads to even more precise maps for locations of changes in the plant and animal species plant community types because of legal that can thrive there. obligations to have the information. These maps are created by on-the-ground A watershed assessment should measure surveying, or by using remote sensing (e.g., this change as thoroughly as it represents satellite photographs). the “snapshot” of watershed condition. While it is often difficult to predict or even to Most plant community location maps don’t measure change, there are various tell anything about the age of trees, the indicators that are useful in assessing this percentage of vegetation cover (how much dynamic state. For example, varying tree ground is covered), and actual plant species ring widths show changes in growth rates in
- 36 - California Watershed Assessment Manual, Chapter 3 August, 2004 a forest region—changes that could be California Natural Diversity Database related to climate, frequency of disturbance (NDDB, (e.g., fire), or competition with other trees. http://www.dfg.ca.gov/whdab/html/cnddb.ht Understanding how forest complexity might ml)—the main statewide database for have changed over a period of time will give wildlife occurrence—relies on the voluntary a recent history of the physical structure of submission of observations by qualified that forest and provide clues as to wildlife biologists. However, this database vegetative cover, wildlife presence, nutrient includes only species of management cycling, erosion, and other ecological concern, is not based on a surveying processes. protocol, and is biased toward areas where the number of observers is high (e.g., urban Wildlife areas). Within the CNDDB, records of rare plant and animal species within your Six hundred and forty three vertebrates watershed boundaries (location, dates occur in the state (California Wildlife Habitat observed, ecological descriptions, legal Relations, California Department of Fish status, population information, land and Game, 1994). Assessing habitat ownership, data sources) can be searched conditions for terrestrial wildlife (here for using CDFG’s RareFind3 software. defined as all animals) or including (http://www.dfg.ca.gov/whdab/html/rarefind. information about individual species’ html) presence and abundance is usually not a watershed assessment priority. However, The best response for a watershed because a watershed’s area is mostly land assessment that lacks readily available and not water, it makes sense to complete wildlife data because of the problems listed the description of the landscape by above is to go and collect these data. This describing the animals that live there. Many might involve collecting databases of them are indicators of the condition of the maintained by agencies that manage land vegetation and natural processes in the (e.g., the USDA Forest Service), that build watershed. A few of them will have and maintain infrastructure (e.g., the observable influences on the ecology of the California Department of Transportation), or landscape (e.g., deer). After identifying that plan and regulate development (e.g., those wildlife species found in your jurisdictions and their consultants). watershed, their status can be found on lists Developing a complete landscape of threatened, endangered, or species of assessment database might also involve special concern hiring a wildlife biologist to conduct surveys, (http://www.dfg.ca.gov/whdab/html/lists.html which is feasible for smaller watersheds ). (i.e., less than 10,000 acres).
One of the main data and knowledge gaps Without these data, a watershed encountered in landscape assessments is a assessment will be incomplete, and lack of easily obtainable data about the analyses and decisions that affect plant actual distribution, abundance, and community structure and wildlife habitat will population dynamics of individual wildlife be open to question. species. Even such models as the California Wildlife Habitat Relations model (CWHR), Natural Disturbance which maps potential wildlife occurrences [THIS SECTION IS UNDER based on the presence of plant CONSTRUCTION] communities, rely on incomplete knowledge of habitat requirements and behavior, and Human Disturbance they may not reflect actual species [THIS SECTION IS UNDER presence, let alone abundance. The CONSTRUCTION]
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3.10 Human Land Uses be the predominant influence on natural watershed processes. Human land uses can potentially affect many aspects of the hydrologic cycle. Residential development often occurs Precipitation is the least subject to human alongside commercial and intervention. Large-scale earth-moving business/industrial development. From a operations for commercial and residential watershed perspective, these developments development and open-pit and mountaintop may have similar impacts to natural mining can change topography and systems. From a socio-economic geology. More commonly, watershed perspective, how these different assessors are concerned with changes in components develop may be important. The vegetation that affect evapotranspiration, proportion of residential to changes in surface conditions that affect commercial/industrial development can infiltration, and changes in channel influence traffic patterns, infrastructure conditions that affect water conveyance. It is development, and local economic wellbeing. important to distinguish between temporary For the most part, when people don’t live disturbances, from which hydrologic near work/school/community, they tend to recovery is possible, and land use travel by road to get to those places. In conversions, where the hydrology remains addition, as the focus of communities altered unless the conversion is reversed. changes from commodity production (e.g., farming) to other economic activities (e.g., As with other land use changes, the technology development), the perceived proportion of the watershed altered and the costs and benefits of certain activities on the proximity to stream channels determine the landscape may change. impacts on water quantity, timing, and quality. Development can have significant impacts on watersheds. Impervious cover, such as 3.10.1 Residential, Commercial, and roads, driveways, rooftops, and walkways, Industrial Development can greatly reduce the land’s ability to absorb rainwater, resulting in increased Building houses is a fundamental volume and rate of stormwater runoff. component of the interaction between Stormwater that would otherwise percolate humans and their environment. From the into the soil now ends up in waterbodies, scale of the individual parcel to that of a carrying a wide variety of contaminants. The town or city, the impacts to the environment amount of water entering stream and creeks and benefits to quality of life are relevant to often increases significantly, causing assessing conditions in California numerous changes to the shape and watersheds. Residential development can characteristics of the physical environment occur on remote parcels hundreds of acres in and around the stream or creek. In in size, in suburbs on the periphery of general, the more that land is developed— growing towns, and deep in inner cities. The converted from its natural state—the more development process is locally governed, is likely it is that natural watershed functioning guided by state planning rules, and usually will be negatively impacted. responds to a housing, political, or financial need of local communities and landowners 3.10.1.1 General Plans (Fulton 1999). This use of land is [THIS SECTION IS UNDER sometimes called land “conversion” CONSTRUCTION] because of the extreme nature of the impacts (e.g., grading and covering an area with asphalt), and in sub-watersheds may
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3.10.2 Agriculture Some people argue that it is better to have land in agricultural production than have it Agriculture usually converts land use in the developed for urban/suburban uses. long term, if not permanently, for the Agricultural land use provides socially production of food and fiber. Certain valuable open space and, if proper alterations to watershed conditions result management practices are followed, can from this conversion. Native vegetation is have limited impacts to water quality, water replaced with actively cultivated crops of supply, and certain fish and wildlife habitat. commercial value. Changes in transpiration To validate this perspective, it may be vary with the particular crop and seasonal useful to analyze the impacts of urbanized nature of production. Because more water is or urbanizing areas relative to agricultural available where irrigation occurs, actual areas and both relative to less-impacted evapotranspiration generally increases. areas. Infiltration capacity generally declines because of compaction from farm Other effects of agriculture often include machinery. However, in some cases, active leveling of floodplain topography and filling tilling may break up a naturally occurring of secondary channels and sloughs. Thus, soil layer that restricts infiltration. Depending in agricultural areas today, single channel on the nature of cultivation practices, fine rivers are often separated from their sediment can also be washed off floodplains by levees, and they lack the agricultural lands and into waterways. topographic diversity that once sustained Where excess irrigation takes place, ecosystem diversity. subsurface water delivery to streams may increase. This irrigation return flow 3.10.3 Timber Management (irrigation water returning to a waterway) may contain high levels of pesticides and Commercial timber management, or fertilizers. logging, is a land use that causes a recurrent disturbance rather than a Many of the most harmful chemicals, the complete conversion of land use. A forestry majority of which require permits, are used operation may completely change in agricultural settings. Pesticides, which vegetation type, species mix, and age persist in the environment for long periods structure of the forest. However, forest of time, and sprays containing metals are management generally aims to optimize the frequently used in orchards and on row growth and yield of selected tree species crops. If not properly controlled, these and periodically cut them—a situation not chemicals end up in water that seeps out of radically different in a hydrologic sense from agricultural soils and/or stormwater and a natural forest. Logging has dramatic eventually drains into natural waterways. impacts on the water balance of the immediate site. But as analyses increase in In some areas, wetlands have been spatial scale, consequences to the artificially drained to allow for the cultivation watershed are not as obvious. Most current of agricultural crops. Subsurface drains that forestry operations do not affect a significant maintain a lower water table may alter water proportion of a watershed in a single year or delivery to streams by providing a faster, decade. As with other land use changes, more efficient route for water than natural the proportion of the watershed logged groundwater flow. As with other land uses in compared to the entire watershed and the this section, the area affected by agricultural proximity of the logging to stream channels conversion and its proximity to streams may determine the impacts on water quantity, be more important than the intensity of timing, and quality. While cutting trees in hydrologic changes at the fields. isolation may not have dramatic hydrologic consequences, the associated activities of
- 39 - California Watershed Assessment Manual, Chapter 3 August, 2004 road construction, stream crossings, yarding that those of clear-cuts because the residual (collecting logs for transport), slash trees remaining after the selection logging treatment, and mechanical site preparation use soil moisture and provide some may have much more serious impacts. protection to the soil surface (Anderson, et al. 1976). Forest practices on private land are regulated by the state Board of Forestry and Hydrologic processes altered by logging Fire Protection and the California begin a slow recovery as young trees grow Department of Forestry and Fire Protection on the disturbed site. After vegetation under the Forest Practices Act, the Regional becomes re-established on logged sites, it Water Boards under the Federal Clean restores a forest cover’s hydrologic benefits, Water Act and Porter-Cologne Act, the such as absorbing soil moisture for California Department of Fish and Game, evapotranspiration, providing protection of the U.S. Fish and Wildlife Service (for listed soil from raindrop impact, adding organic species), and NOAA-Fisheries (for listed matter to the soil, and supporting soil salmon and steelhead). The state recently masses on slopes with their roots. completely an assessment of the status, trends, and challenges to California’s forest Logging can increase annual water yield to resources that also addresses timber streams by reducing losses to the harvesting (California Department of atmosphere. Tree removal eliminates the Forestry and Fire Protection, 2003; possibility of any interception losses http://www.frap.cdf.ca.gov/assessment2003/ (evaporation of rainfall captured on leaves) ). in the area previously covered by tree canopies. Cutting trees reduces Impacts to the watershed that have been transpiration in rough proportion to the areal documented to result from timber harvest extent of harvesting and the ability of the include effects on sediment, water remaining plants to consume water. Forest temperature, in-channel volumes of organic soil depth and moisture storage capacity debris, chemical contamination, increased largely control the change in nutrient concentrations, the amount and evapotranspiration that results from physical nature of aquatic habitat, and harvesting (Zinke 1987). Removing trees in increases in peak discharge during storm shallow soils that have little moisture runoff. While certain of these impacts can storage capacity impacts hydrology much be minimized or mitigated through the use less than removing trees that had access to of good management practices, the major lots of water in deep soil. The harvest area’s concern today with logging in California is position on a hillslope is also important. the potential for adverse cumulative effects Harvesting trees at the base of a slope near at the watershed scale (Dunne et al., 2001). a stream will allow much of the soil water As a result, watershed assessment (also formerly used by the trees to enter the called “watershed analysis”) is being stream. However, harvesting trees near the increasingly used as a predictive tool in the top of a slope will probably only provide state by those responsible for management more water to the trees lower on the slope and protection of the State’s terrestrial rather than to the relatively distant stream. ecosystems (North Coast Watershed Assessment Program, 2001). In addition to changes in annual water yield, timber harvesting can affect peak flows. Soil The type of cutting also affects the degree moisture is greater where trees have been of hydrologic impacts. Hydrologic impacts of removed. Accordingly, less rainfall is selection harvests (where scattered required to satisfy soil moisture storage individual trees are selected for cutting) are before runoff may begin. This effect is most generally considered to be less of a problem likely to have a measurable impact during
- 40 - California Watershed Assessment Manual, Chapter 3 August, 2004 small and moderate storm events and in Logging on public lands in most California small watersheds (Hewlett 1982). During watersheds is now almost exclusively big, intense storms, differences in soil “thinning” and “salvage” operations. Fire risk moisture storage between cut and uncut is the primary reason given for removing as areas are almost incidental compared to the many as half of the trees in any given stand. massive amounts of rainfall that tend to Although short-term negative impacts to overwhelm any effect of land-use change wildlife (e.g., small carnivores) and natural (Ziemer 1981). At the scale of larger river processes (e.g., soil nutrients and water basins, flood peaks depend mostly on the retention) have been shown to occur with synchronization of contributions from these practices (e.g., Kaye et al. 1999), the tributaries, which can be affected by longer-term effects are harder to measure, dramatic changes in land use but are not and less well-understood. predictable without a detailed model of the channel system. In watersheds with shallow Removal of forest cover by logging results snowpacks, timber harvesting can augment in decreased evapotranspiration (use of peak flows by altering the distribution of water by plants) and increased streamflow snow and the energy available for melt. (Bosch & Hewlett 1982; Callahan 1990; More snow accumulates in open areas than Stednick 1996; Swank et al. 2001; Troendle in areas under forest canopy; hence, more et al. 2001). In one watershed study, water storage. During warm storms, greater removal of 24% of forest in small clearcuts wind speeds in forest openings compared (3-7 acres) and haul roads resulted in a with dense forests generate more snowmelt 17% increase in streamflow (water volume) in the openings than under trees (Harr from the watershed (Troendle et al. 2001). 1981). This was partly due to increased peak flows during storms, but mostly due to increased Logging can increase sediment production duration and frequency of water release. from both surface erosion and mass These changes mean a net dehydration of movements. Tree canopy loss can allow the watershed and increased chance of greater raindrop impact on the soil with “scouring” flows in the affected creeks, consequent soil displacement, but there is which may negatively impact terrestrial, usually a thick layer of organic debris left on riparian, and aquatic plant and wildlife the soil after logging that absorbs the communities. energy of falling drops. Landslides occur after harvest because soil moisture is 3.10.4 Mining greater in the absence of transpiration and because roots no longer help stabilize the Mining operations can be split into surface soil after they decay. This structural support and underground mining. Surface mining seems to be at a minimum about nine years techniques, such as dredging, quarrying, after timber harvest, on the average, when strip mining, open-pit mining, and heap decay of roots of harvested trees has not leaching, are used when the mineral ores been compensated by growth of new roots are located within a few tens of feet (Ziemer 1981). (sometimes hundreds of feet in giant open- pit mines) of the surface. In all cases, the Sediment from clearcuts, logging roads, removal of vegetation and topsoil skid trails, stream crossings, and ditches accelerates erosion. If runoff is not may be transported to streams, rivers, and contained, sediment yield from surface lakes by water (Swift 1988; Waters 1995) or mining can be enormous. wind (Steedman & France 2000). Nutrients may also increase in streams flowing from Underground mining involves excavation of commercially logged watersheds (Swank et vertical or inclined shafts and/or horizontal al. 2001). tunnels and mechanical extraction of ore to
- 41 - California Watershed Assessment Manual, Chapter 3 August, 2004 the surface. In another type of underground increased, and incision of the channel bed mining, a solvent is injected underground to occurs, extending in the upstream direction dissolve the mineral of interest, and the (a process called headcutting). Thus resulting solution is pumped out for instream aggregate extraction commonly processing. Excavation exposes tunnel causes channel bed erosion in both the walls and the extracted tailings to oxygen upstream and downstream reaches. and water, allowing chemical reactions to Secondary effects of the incision include occur at far higher rates than with intact loss of spawning gravels and an increase in rock. Mining activity also allows the bank height and bank erosion. Channel products of these reactions to be leached incision may initiate a lowering of the water into groundwater and streams. The table and associated losses of riparian surrounding rock’s mineral content and vegetation. Gravel pits that are outside of an chemistry determine the potential for toxic active channel can contribute significant metals (e.g., arsenic, chromium, lead, amounts of sediment to a stream during copper, etc.) and acids to be released from mining activities, and sometimes present a the site. Few areas in California have the flood hazard, through “pit capture.” acid mine drainage potential that is common Floodplain aggregate extraction results in a in the Rockies. loss of floodplain wetland habitat.
The principal mining activity in California is Suction dredging for gold in streambeds sand and gravel extraction, the value of continues as an activity, more recreational which far surpasses the combined value of than commercial, in the Klamath and Trinity all metallic minerals mined in the state river systems and in many streams on the (McWilliams & Goldman 1994). Because west slope of the Sierra Nevada. While less sand and gravel are critical to most types of intensive than commercial instream modern construction, they are used in aggregate mining, the continuing almost every road and building project. disturbance of the streambed can potentially Utilizing aggregate sand and gravel sources harm aquatic habitat, such as spawning and near construction sites greatly reduces rearing sites for salmonids. transportation costs, so this mining activity is dispersed throughout California. Watershed assessments should inventory and study both the current effects of active Sand and gravel are often extracted from mines and the persistent effects of past stream channels because deposits located mining. In areas once subjected to hydraulic within stream channels tend to have fewer mining, for example, some slopes may still impurities and are more durable than be eroding at rates much greater than hillslope deposits. Aggregate mining in untouched hillsides, while downstream, stream channels and floodplains has a large sediment deposits may still form variety of direct and indirect geomorphic unstable terraces high above a stream consequences (Collins & Dunne 1990; channel. Mercury may persist in stream Kondolf & Matthews 1993; Florsheim et al. channels where placer mining occurred and 1998; NOAA Fisheries 2003). Excavating below ore-processing sites. Transformation gravel or sand from a streambed changes of this elemental mercury to methyl the channel’s hydraulic properties and mercury, a form more easily taken up by interferes with the natural transport of biota, introduces the toxin into the food sediment through the stream. For example, chain and is the subject of current research. sediment in transport from upstream fills in Heavy metals and other toxic leachates may the excavated area, reducing sediment be found in streams and groundwater below supply to downstream reaches. Moreover, some mines and processing sites. Tailings at the upstream edge of the excavated piles and deposits should be checked for reach, channel slope and flow velocity are potential water pollutants. A good general
- 42 - California Watershed Assessment Manual, Chapter 3 August, 2004 reference on watershed impacts of mining is the vegetation and subsequently the Nelson et al. (1991). channels tend to recover remarkably well. A dramatic exception is where gullying has 3.10.5 Grazing progressed to the point where the water table has been lowered, and the streamside Livestock grazing on California’s rangelands meadows or riparian strips are literally high can cause watershed impacts through and dry. changes in vegetative cover and soil conditions. When the number of animals The loss of vegetation cover and soil and their access to streams and riparian are compaction also accelerates surface limited, the watershed impacts are modest erosion. Many studies in the western United and usually not noticeable. When the States have documented dramatic grazing pressure is great enough to restrict increases in sheet erosion and gully vegetative regrowth and compact the soil or development in overgrazed sites compared cause direct impacts to streams and riparian to ungrazed sites (Fleischner 1994). The areas, then the term overgrazing is erosional effects of overgrazing add large descriptive. Overgrazing can remove most amounts of sediment directly into the of the vegetative cover of an area, leaving stream. The fine sediments tend to clog the soil exposed to raindrop impacts, stream gravels and diminish spawning reducing infiltration, and accelerating habitat for certain fish. erosion. The hooves of hundreds or thousands of livestock can also compact the Concentrations of livestock in and around soil, especially when the soil is wet. The streams provide a direct pathway for combination of soil exposure and nutrients and pathogens to enter the water compaction can decrease infiltration and (Springer & Gifford 1980). Animal wastes increase surface runoff. If infiltration tend to be high in nitrates, a nutrient that is capacity is severely limited on a large a water pollutant of concern. High nitrate fraction of a watershed, the extra runoff can loads promote the growth of aquatic algae, quickly reach streams and generate higher which can clog streams at low flow, as well peak flows (e.g., Davis 1977). as ponds and lakes. High levels of coliform and other bacteria have been found in Most of the concern about grazing impacts streams with large numbers of livestock in is associated with the riparian zone. adjacent areas. Good range and livestock Livestock gather in riparian areas for the management practices can help prevent or water itself, as well as for abundant food reduce impacts of grazing on the and shade. Excessive streamside grazing watershed. California recently completed a that causes loss of trees, shrubs, and decade-long assessment of the status, grasses along a stream affects the stream’s trends, and challenges to California’s shading and temperature and the stability of rangelands (California Department of its banks. Without the protection of Forestry 2003). aboveground vegetation during high flows and the structural support of roots, stream 3.10.6 Recreation banks erode back and develop shallower angles. This bank erosion eventually leads Impacts from recreational activities fall into to channel shapes that are much wider and two general categories: 1) localized effects, shallower than those of intact streams with such as vegetation damage, soil vigorous riparian vegetation. Alternatively, compaction, and stream alteration that some overgrazed streams begin an erosion result from individuals visiting an area, and cycle that results in a deep gully. When 2) large-scale effects, such as vegetation riparian areas are fenced off from other removal or conversion, creation of pastures and allowed to rest for a few years, impervious surfaces, and engineered
- 43 - California Watershed Assessment Manual, Chapter 3 August, 2004 modification of stream channels that result timing through snowmaking. Each of these from developing facilities to support changes leads to changes in streamflow recreational activities. volume, timing, and quality.
The individual recreational activities tend to 3.11 Water Management and Uses have the greatest potential for watershed effects when they occur in and adjacent to a Management of surface water resources stream channel. Water is often a focal point occurs in the waterway and differs for recreational activities, and streamside fundamentally from management of the areas receive a disproportionate amount of landscape and resources other than water. recreational use within a watershed. Although land use changes and other Campgrounds, picnic areas, hiking and resource management activities alter equestrian trails, and other facilities located vegetation and soil properties that near a stream provide easy access to water subsequently affect streamflow, water and contribute to degradation of riparian management avoids the intermediate steps vegetation. As more people congregate and intentionally and directly changes the along streams, the banks are trampled and hydrologic regime. In many watersheds, this the vegetation dies back, with impacts direct manipulation of the surface water similar to riparian overgrazing (erosion alters flow, timing, and quality to such a accelerates and the channel changes form). great extent that the indirect consequences of land use change are incidental. In most Off-highway vehicle use has both more cases, the measurable changes in intensive and more extensive effects on streamflow or sediment delivery from a vegetation and soils than does non- timber harvest or subdivision or other motorized traffic, resulting in more loss of changes on the landscape are small vegetation, more soil compaction, and more compared to the hydrologic effects of dams erosion. Operation of vehicles in stream that can store a large fraction of the annual channels kills aquatic and riparian runoff or diversions that can dry up a vegetation, mobilizes sediments, and stream. decreases channel stability. Large-scale commercial recreational Management of groundwater resources is developments cause watershed impacts conceptually straightforward—deliberate similar to those of other land use changes control of input (recharge through ponds, and conversions. Trees are cut down, roads canals, and injection wells) and output and parking lots are built, topography is (pumping of wells). In practice, there is little reshaped, drainage channels are true “management” of groundwater. In most constructed, and people congregate near areas, wells are just pumped to satisfy water. These effects lead to changes in demand within any cost constraints, and streamflow, accelerated erosion, and there is no coordination or control of degraded water quality. Some pumping. Groundwater management is developments require a substantial water rarely part of a watershed assessment but supply, which may deplete local streamflow in many places should be. You should or groundwater. Two examples of large- consider whether the topic warrants study in scale recreational developments are golf your watershed. courses and ski areas. Golf courses can transform the vegetation cover from deep- 3.11.1 How Surface Water Is Managed rooted species to shallow-rooted grasses requiring artificial irrigation and fertilizers. Water management includes all activities Developing a ski area involves permanent intended to change natural streamflow timber removal, major earthwork, extensive volume, timing, and location for the purpose parking lots, and alteration of streamflow of supplying water for human demands.
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Water is rarely available directly from nature periods. However, larger water storage at a desired quantity, time, and place. structures usually involve both storage and Human individuals and societies have gone diversion. to extraordinary efforts to change the natural availability of water to be more Reservoirs dramatically change a stream’s suitable for their needs. Great engineering sediment transport properties. When a river works have been constructed to hold back enters the placid water of a reservoir, it floods, store water for the growing season, deposits almost all the sediment it was and deliver water hundreds of miles away carrying. from its source. Streams below dams contain much less Dams and diversions (any structure that sediment than they would in the absence of facilitates removing water from a stream for the dam. Accordingly, they have an the purpose of transporting the water to enhanced capacity to erode and transport another location) alter streamflow in a particles from the bed and banks of the variety of ways. A stream’s hydrograph (a downstream channel. Progressive lowering graph of how flow changes over time) is of the riverbed often occurs below new very different above and below a dam or dams. Further consequences that can result major diversion. include reduction of groundwater levels and consequent loss of riparian vegetation, Dams are constructed to alter streamflow reduction in overbank flooding, deposition of timing. Water generated during the rainy or sediments and nutrients, bank erosion, and snowmelt season is captured behind the loss of adjacent land (Galay 1983). Severity dam in a reservoir and released later to of channel lowering depends on the size of meet downstream needs (irrigation, particles in the bed, channel characteristics, municipal supply, hydroelectric generation, reservoir operation, and the sequence of or instream flow, for example). flood events following construction. The alteration of sediment supply and transport Depending on a dam’s size and flood changes the streambed conditions that reservation (management guidelines that many fish require for successful spawning. keep part of the reservoir unfilled at different The unnatural channel and bank conditions times of the year as related to the flood created by the sediment alterations can also risk), peak flows may be entirely captured negatively impact the establishment, behind the dam and slowly released later in growth, and survival of riparian vegetation. the year at a controlled rate. Smaller dams In some cases where dams prevent high lack the capacity to have much effect on the flows from scouring the channel, the stream hydrograph of large floods, whereas can become choked with vegetation. downstream of a big dam, there may be no indication of the floodwaters pouring in 3.11.2 Aquatic Habitat upstream. During the portions of the year when flows would be low under natural The aquatic system in any stream has conditions, water releases from a reservoir evolved in response to the natural may increase streamflow several fold above hydrologic regime—long-term average flows its natural level. and timing, as well as extremes. Water management is designed to alter those While dams primarily affect streamflow attributes of streamflow. Impounding water timing, diversions send water elsewhere, behind a dam converts riverine habitat into reducing natural instream flow. Individual an artificial lake. The continuity of aquatic water user’s diversions not associated with and riparian habitat is abruptly cut by the large dams may have little effect on dam and its reservoir. Organisms that hydrograph timing except during low flow migrate in the channel or along its banks
- 45 - California Watershed Assessment Manual, Chapter 3 August, 2004 may no longer move freely up or the irrigated area. These application rates downstream. The dam greatly alters the vary widely by crop and location around the flow of water and sediment downstream. state (see box). The county farm advisor The temperature and chemical content of and district offices of the California water released below the dam may also be Department of Water Resources should very different from the natural conditions. have good crop water demand estimates for Such changes fundamentally alter the local conditions. If you are estimating conditions for aquatic and riparian irrigation water use within your watershed, organisms. Inevitably, water management most of that amount can be assumed to impacts aquatic communities with dramatic evaporate. changes in community structure, species mix, and populations. 3.11.4 Hydroelectric Generation
3.11.3 Irrigation Generating electricity from water and gravity requires a different management regime Providing water for irrigation is the main than storing water for irrigation. Although reason for impounding water in California, large, multipurpose water projects generate particularly in the reservoirs of the Central electricity in concert with releases for Valley Project. The vast majority of dams in irrigation, projects intended primarily for the state were originally intended to store hydropower release water to maximize water from the winter wet season and revenue. Such projects aim to generate release it for irrigation during the summer electricity at times when electric demand dry season. Irrigation requires massive and rates are highest, such as on summer volumes of water—about 33 million acre- afternoons. Unlike most other sources of feet each year in California (Department of electricity, hydropower-generating facilities Water Resources 1998). Much of this can be turned on and off relatively quickly. amount is diverted dozens to hundreds of Below some hydroelectric powerhouses, miles from its source. Where farms are discharges related to power demands can located adjacent to streams and rivers, the fluctuate drastically over a few hours. In irrigation water will be diverted locally, and such cases, there is usually an afterbay your watershed will include both the source immediately downstream that regulates and area of use. Typical water application releases back into the river. rates range from 3 to 5 feet of water over The process for the federal relicensing of hydroelectric projects under the Federal Typical application rates of irrigation Energy Regulatory Commission (FERC) water for various crops in California. provides an opportunity to re-evaluate flow (Source: Department of Water release schedules from these types of Resources 1998) dams.
Crop Range of Applied Water 3.11.5 Municipal (feet) Corn 1.5 to 4 Water storage and diversion for municipal Cotton 2.5 to 6 supply influence streamflow in many Rice 4.5 to 7 watersheds. Timing of this demand differs Tomatoes 2 to 5.5 from irrigation in that there is a base level of Grapes 1 to 5.5 demand year-round, but water use for Orchard Crops 1 to 6.5 landscaping increases significantly during Alfalfa 2 to 10 the summer growing season. This may Pasture 1 to 9 stress aquatic environments during the summer, when temperatures may become
- 46 - California Watershed Assessment Manual, Chapter 3 August, 2004 too high due to reduced flows. Runoff from also includes an adaptive management urban areas (e.g., for landscape irrigation) program that adjusts streamflow volumes may turn seasonally dry streams into and frequency of releases based on actual perennial waterways. use. Streamflow in the Mokelumne River is now regulated on certain days at flows Municipal water supply utilities may be a desired by recreationists—yet another potential partner in watershed management variation on natural streamflow. Increasing and restoration activities because of their summer flows to support whitewater boating need for high-quality water. are unlikely to mimic the low-flow conditions that were naturally present before the 3.11.6 Recreation reservoir was built.
Managing water for recreational purposes is 3.11.7 Import and Export generally interpreted as maintaining high water levels in large, multipurpose Trans-basin diversions can import water into reservoirs during the summer boating a watershed or export water out of it. season. Inevitably, there are management Imports and exports can have major effects tradeoffs that attempt to balance irrigation, on the water balance. Water entering or hydropower, flood management, and flat- leaving the watershed through engineered water boating in such reservoirs. Flood channels can also alter the timing of flows in control agencies prefer empty reservoirs. natural channels, assuming there is some Irrigators, power companies, and boaters all storage facility involved in the water want reservoirs filled to capacity, but the diversions. boaters prefer that level to be constant and the power producers and irrigators want to 3.12 Social and Economic Setting drop that level in response to their respective demands. Water releases from a Watershed assessments rarely focus on dam are closely associated with the human communities, or, if they do, it is reservoir levels. The interests of different usually to list the resource activities groups of recreationists conflict over communities are involved in. There are reservoir management. Lake boaters and many facets to characterizing watershed lake fishers prefer that reservoir levels communities. Some of these are economic remain high, but whitewater boaters and descriptions, how people in a watershed stream fishers prefer that reservoir levels make money, how many people don’t make drop to provide greater streamflow. very much, and the net exports or imports of commodities. Some are demographic Downstream of some recently re-licensed pictures, showing more about who the hydroelectric projects, water releases are people are, their ethnicity, their population designed to benefit white-water boating. A centers, their age, education, and income significant example is the July 2000 distributions. The hardest to quantify is the settlement agreement on the Mokelumne part of the community picture that shows River. As conditions for obtaining a new how involved people are in watershed license to operate a series of powerhouses, protection activities and therefore how likely dams, and diversions, the operator (Pacific it is that particular restoration, monitoring, or Gas & Electric Company) will modify the management approaches will succeed if operation of its system specifically to community participation is required. enhance recreational opportunities on the river. The agreement establishes an annual 3.12.1 Watershed Communities schedule of water releases at levels requested by whitewater boating Because watersheds literally cover the enthusiasts and businesses. The agreement earth’s landscape, everybody lives in one.
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The watersheds usually bear the name of process. The guide’s principles include: the primary waterway, but human towns and “holistic, place-based environmental cities only occasionally do. People may not protection efforts will lead to more effective identify with their watershed by name, but if long-term protection,” “approaches [that] there is any topography around, they are integrate ecological issues with local often aware that they are near a creek or economic and social concern” help resolve river with a name. Certain economic, or prevent environmental problems, and political, and social relationships depend on “tailoring environmental protection efforts to waterways and watersheds, for example, local realities and partnering with the water diversion, county boundaries, and community members leads to greater public locations of towns and agricultural areas. support and involvement and, ultimately, to The influence of the location of water on better environmental protection (U.S. EPA human geography is probably obvious. In 2002). The handbook describes ways to the past, many towns sprang up where characterize communities in terms of there was a water supply and fertile areas to community capacity, demography, grow or catch food (e.g., old floodplains and economics, and governing structures and coastal areas). Now that water can be provides various quantitative and qualitative moved around in canals and pipes, and assessment tools to develop a “community food can be imported, this is less of an cultural assessment.” issue. Another index of a community’s character is Describing the interactions between human the nature of its political activity. For communities and watersheds is important example, Proposition 50 authorized the sale because human activities and humans’ of bonds to protect watersheds and water perceptions of their environment are critical supply. If 74% of the residents of a drivers in many ecosystems. Understanding watershed voted against this proposition, how people are interacting with your then a watershed group planning Prop 50- watershed will provide information about funded projects might want to spend some potential impacts, likely future scenarios, time doing outreach and education to possibilities for reduced impacts or restoring communities within the watershed to let past impacts, and benefits to human them know what is happening. Information communities of a naturally functioning about community voting records at a watershed. watershed scale can be readily obtained with a GIS containing both the watershed 3.12.2 Economic Activity and Measures boundaries and records from voting [THIS SECTION IS UNDER precincts. Because particular propositions CONSTRUCTION] can’t really be called partisan in nature, they provide a politically neutral way to measure 3.12.3 Characterizing Communities voter sentiments. There are other more direct and expensive ways to get this type of If you characterize who lives in the information. For example, surveying watershed, you will have information to watershed residents about their preferences inform your decision making about for watershed protection and restoration restoration planning, the feasibility of could provide important clues. If the monitoring, the need for education and watershed contains public lands, then the outreach, and whether or not there is a surveying should also include people constituency for watershed protection. The outside the watershed who would then have U.S. Environmental Protection Agency’s a direct interest in management options for “Community Culture and the Environment: A the watershed. Guide to Understanding a Sense of Place” (U.S. EPA 2002) offers methods for this
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Although it may seem that information like role of fish and popular fishing sites. Initial this would only be interesting to a observations from the first wave of sociologist, the information might tell the European visitors (as noted in personal watershed assessor a lot about likely diaries, army reports, etc.) can offer attitudes and priorities for people in the valuable insights into the condition of watershed. Some of these will be obvious to vegetation, streamflow (with extremes of a stakeholder group that represents the drought and floods most commonly noted), range of interests in a watershed, while and wildlife, for instance. Sometimes crude some will be surprising. The worst-case maps were drawn to identify trails or scenario (which isn’t really so bad) is that boundaries, and some useful landscape the watershed group discovers things they impressions or landmarks were perhaps already knew, but now have numbers and noted (e.g., “hills covered with timber”; other data to reinforce their intuitive “creek dry”). Of course, geographic place knowledge. names on old or current maps are another source of which natural resources in that 3.13 Historic Context and Analysis area seemed to initially impress the pioneers: “Deer Creek”, “Salmon River”, The condition of your watershed today “Dry Gulch”, or “Beaver Valley”, for needs to be interpreted in the context of examples. historic changes since at least the time that European exploration and settlement The next step is to identify the location, began. Native American occupation timing, and the extent of changes in land appears to extend back 10,000 to 12,000 and natural resource uses that could have years, and their former use of the watershed affected the watershed’s condition between is also important to understand, where settlement and the present. Such human possible. For some areas of California, uses include: roads, mining, logging, European settlement began in the 1700s farming, grazing, urbanization, water with the Spanish and Mexican occupation development and use, hydropower, fishing, while in other areas, it was primarily the hunting, etc. Patterns of landscape discovery of gold in 1849 that triggered the disturbances also need to be described, huge “American” influx. However, in the such as the dates and size of wildfires, early 1800s, the Hudson Bay trappers came floods, and droughts. A chronology of down from Oregon and extensively trapped events by year or decade can summarize the native beaver out of most of the state’s the major changes. Old maps and streams where beaver could be found. landscape photographs can depict the Removing (or decimating) much of the changes even better. population of this one aquatic mammal, which has a tendency to form woody debris Without knowing the context of land, water, dams in streams, may have had a profound and other environmental changes over time, effect on stream channel conditions, water our interpretation of the watershed’s storage, and hydrologic processes decades condition today could be missing the real before the arrival of the gold miners and reasons or causes. A devastating fire back other early settlers. in the 1920s might have altered the soil and therefore the vegetation types in one area; Identifying the condition and use of a gravel mining to help surface a new watershed’s resources at the time of highway in the 1960s might have rerouted settlement can be a type of “baseline” for the channel; a small dam built in 1900 but your assessment, though it will necessarily removed in 1970 might still be causing be a fuzzy one. Accounts of local tribal sediment and channel impacts. These are customs may indicate the role of fire as a just a few examples of the richness in tool for hunting or acorn production, or the interpretation that can be gained in your
- 49 - California Watershed Assessment Manual, Chapter 3 August, 2004 watershed assessment through a good historical evaluation of natural resource California Department of Forestry and Fire uses and changes. With this understanding, Protection. 2003. The Changing California then the “ah-hah!” light bulb may go on and Forest and Range 2003 Assessment. we can become more realistic in the next phase after the assessment – what to do Callahan, R.Z. 1990. Case studies of next. watershed projects in western provinces and states. Report 22. Wildland Resources 3.14 References Center, University of California, Berkeley, CA. Adaniya, N.L., Rathbun, J., and French, R.D. 1997. Using aquatic habitat surveys for Collins, B. and T. Dunne. 1990. Fluvial improving selection of rehabilitation geomorphology and river-gravel mining: A projects. Proceedings of the Water guide for planners. Special Publication 98. Environment Federation 70th Annual Sacramento: California Division of Mines Conference & Exposition, vol.70, Vol. 4, part and Geology. I, pp.243-253. Colman, E.A. 1953. Vegetation and Anderson, H. W., M. D. Hoover, and K.G. watershed management. Ronald Press Co., Reinhart. 1976. Forests and water: Effects NY. 412 p. of forest management on floods, sedimentation, and water supply. General Committee on Abrupt Climate Change. Technical Report PSW-18. Berkeley, CA: 2002. Abrupt climate change: Inevitable U.S. Forest Service, Pacific Southwest surprises. Washington, DC: National Forest and Range Experiment Station. Academy Press.
Behnke, R.J. 1983. Impact of livestock Davis, G.A. 1977. Management alternatives grazing on stream fisheries: problems and for the riparian habitat in the Southwest. In solutions. In Proceedings: Workshop on Importance, preservation, and management livestock and wildlife-fisheries relationships of the riparian habitat: A symposium, edited in the Great Basin, edited by J.W. Menke, by R.R. Johnson and D.A. Jones, 59-67. 170-173. Agricultural Sciences Special General Technical Report RM-43. Fort Publication 3301. Berkeley: University of Collins, CO: U.S. Forest Service, Rocky California. Mountain Forest and Range Experiment Station. Birkeland, PW 1999. Soils and Geomorphology. Oxford University Press, Department of Water Resources. 1998. New York. California Water Plan Update. Bulletin 160- 98. Sacramento: Department of Water Bosch, J.M. and J.D. Hewlett. 1982. A Resources. review of catchment experiments to determine the effect of vegetation changes Department of Water Resources. 2003. on water yield and California’s groundwater. DWR Bulletin 118 evapotranspiration. Journal of Hydrology, update 2003. Sacramento: Department of 55: 2-23. Water Resources.
California Department of Fish and Game. Dietrich, W.E., C.J. Wilson, S.L. Reneau. 1994. California Wildlife Habitat 1986. Hollows, colluvium, and landslides in Relationships Database system. Computer soil-mantled landscapes. In: Hillslope database and program. Sacramento: Processes. Binghampton Symposia in California Department of Fish and Game.
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Geomorphology International Series, vol. 16, pp. 361-388. Harr, R.D. 1981. Some characteristics and consequences of snowmelt during rainfall in D'Itri, F. M. (1990). “Biomethylation and western Oregon. Journal of Hydrology Cycling of Selected Metals and Metalloids in 53:277-304. Aquatic Sediments.” In: Sediments: Chemistry and Toxicity of In Place Heath, R.C. 1983. Basic ground-water Pollutants. CRC Press, Inc., Boca Raton, hydrology. Raleigh: North Carolina Florida. Department of Natural Resources.
Dunne, T., J. Agee, S. Beissinger, W. Hewlett, J.D. 1982. Principles of forest Dietrich, D. Gray, M. Power, V. Resh, and hydrology. Athens: University of Georgia K. Rodrigues. 2001. A scientific basis for the Press. prediction of cumulative watershed effects. Report 46. Berkeley: University of Hickman, J. C. (ed.) 1993. The Jepson California, Wildland Resources Center. Manual: higher plants of California. University of California Press, Berkeley. Fleischner, T.L. 1994. Ecological costs of 1,400 pages. livestock grazing in western North America. Conservation Biology 8:629-44. Holtby, L.B. 1988. Effects of logging on stream temperatures in Carnation Creek, Florsheim, J., Goodwin, P., and Marcus, L., British Columbia, and associated impacts 1998. Geomorphic effects of gravel on the coho salmon (Oncorhynchus extraction in the Russian River, California. kisutch). Canadian Journal of Fisheries and Aggregate Resources: A Global Aquatic Sciences. vol. 45, no. 3, pp. 502- Perspective. Bobrowsky, Peter. T. (ed.), 515. A.A. Balkema Publishers, The Netherlands, pp. 87-99 Horne, A.J. and C.R. Goldman. 1994. Limnology. 2nd ed.. McGraw-Hill Inc., New Florsheim, J., Keller, E., and Best, D., 1991. York. 576 p. Fluvial sediment transport in response to moderate storm flows following chaparral Intergovernmental Panel on Climate wildfire, Ventura County, southern Change. 2001. The scientific basis: IPCC California. Geological Society of America, third assessment report. Cambridge UK: Bulletin, 103(4):504-511. Cambridge University Press.
Fulton, W. 1999. Guide to California Jennings, M.R. and M.P. Hayes. 1994. Planning, 2nd ed. Solano Press Books, Point Amphibian and reptile species of special Arena, CA. 373 p. concern in California. California Department of Fish and Game, Inland Fisheries Division. Galay, V.J. 1983. Causes of River Bed 255 p. Degradation Water Resources Research Vol. 19, No. 5, p 1057-1090. Karr, J.R. 1981. Assessment of biotic integrity using fish communities. Fisheries, Gordon, N.D., McMahon, T.A., and B.L. 6:21-27. Finlayson. 1992. Stream hydrology: an introduction for ecologists. New York: John Kaye, J.P., S.C. Hart, R.C. Cobb, and J.E. Wiley & Sons. 526 p. Stone. 1999. Water and nutrient outflow following the ecological restoration of a Harden, D. R., 1998. California Geology. ponderosa pine-bunchgrass ecosystem.. Prentice Hall, Inc, New Jersey, 479 p. Restoration Ecology, 7(3): 252-261.
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Division of Agriculture and Natural Keller, E.A. and F.J. Swanson. 1979. Resources. Effects of large organic material on channel form and fluvial processes. Earth Surfaces Meyer, J.L. and 10 others, 2003. Where Processes, 4:361-380. Rivers are Born: The Scientific Imperative for Defending Small Streams and Wetlands. Kiparsky, M. and P.H. Gleick. 2003. Climate Publication sponsored by American Rivers change and California water resources: A and Sierra Club, 23 p. survey and summary of the literature. Oakland: Pacific Institute for Studies in Montgomery, D.R. and Buffington, J.M. Development, Environment, and Security. Channel Reach Morphology in mountain drainage basins. Geological Society of Knighton, D., 1998. Fluvial Forms & America, Bulletin. 109:596-611. Processes, Arnold, New York, 383 p. Leopold, L.B., Wolman, M.G., and Millar, Montgomery, D.R., Abbe, T.B., Peterson, J.P., 1964. Fluvial Processes in N.P., Buffington, J.M., Schmidt, K.M., and Geomorphology. W.H. Freeman and Stock., J.D. 1996. Distribution of bedrock Company, 522 p. and alluvial channels in forested mountain drainage basins. Nature, 381:587-589. Kondolf, G.M. and W.V.G. Matthews. 1993. Management of coarse sediment in Mount, J.F. 1995. California rivers and regulated rivers. Report 80. Davis: streams: the conflict between University of California, Water Resources fluvial process and land use. Berkeley: Center. University of California Press. 359 p. Leopold, L.B., Wolman, M.G., and Miller, J.P., 1964. Fluvial Processes in Moyle, P., Yoshiyama, R.M., Williams, J.E., Geomorphology. W.H. Freeman, S.F., 522p. and E.D. Wikramanayake. 1995. Fish species of special concern in California. 2nd Leopold, L. 1974. Water – A Primer. San edition. Prepared for California Department Francisco: W.H. Freeman and Co. 172 p. of Fish and Game, Rancho Cordova. 272 p.
Leopold, L. 1993. A view of the river. Moyle, P.B. and Randall, P.J. 1996. Biotic Cambridge MA: Harvard University Press, integrity of watersheds. In: Sierra Nevada 298 p. Ecosystem Project: Final Report to Congress, vol. II, pp. 975-982. Leopold, L. 1997. Water, rivers, and creeks. Sausalito CA: University Science Books. Moyle, P.B., 2002. Inland Fishes of 185 p. California. UC Press, Berkeley, CA. 502 p.
Mantua, N.J., S.R. Hare, Y. Zhang, J.M. Murray, K.S., Fisher, L.E., Therrein, J., Wallace and R.C. Francis. 1997. A Pacific George, B., Gillespie, J. 2001. Assessment interdecadal climate oscillation with impacts and use of indicator bacteria to determine on salmon production. Bulletin of the sources of pollution to an urban river. American Meteorological Society 78:1069- Journal of Great Lakes Research, 1079. Vol.27(2), pp. 220-229.
McWilliams, B. and G. Goldman. 1994. The Naiman, R.J. 2001. River Ecology and mineral industries in California: Their impact Management, Lessons from the Pacific on the state economy. Publication CNR Coastal Ecoregion. 705 p. 003. Berkeley: University of California,
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Naiman R.J. and 8 others (1992). Singer, M.J., and Munns, D.N., 1996. Soils, Fundamental elements of ecologically 3rd ed. Upper Saddle River, NJ, Prentice healthy watersheds in the Pacific Northwest Hall. coastal ecoregion. In: “Watershed management: balancing sustainability and Snyder, M.A., J.L. Bell, L.C. Sloan, P.B. environmental change. Ed. R.J. Naiman. Duffy, and B. Govindasamy. 2002. Climate Springer-Verlag, NY. Pp. 127-188. responses to a doubling of atmospheric carbon dioxide for a climatically vulnerable Nanson, G.C., and Croke, J.C., 1992. A region. Geophysical Research Letters genetic classification of floodplains. 29(11), 10.1029/2001GL014431. Geomorphology 4:459-486. Spellman, F.R. and J.E. Drinan (2001). North Coast Watershed Assessment Stream ecology & self-purification. 2nd ed. Program, 2001. North Coast Watersehd Technomic Publishing Co. Inc. Lancaster. p. Assessment Program. 257. http://www.ncwatershed.ca.gov Springer, E.P. and G.F. Gifford. 1980. Nelson, R.L., M.L. McHenry, and W.S. Unconfined grazing and bacterial water Platts. 1991. Mining. In Influences of forest pollution: A review. In Symposium on and rangeland management on salmonid watershed management 1980, 578-87. New fishes and their habitats. W.R. Meehan, York: American Society of Civil Engineers. editor. 425-458. Special Publication 19.Bethesda, MD: American Fisheries Stednick, J.D. 1996. Monitoring the effects Society. of timber harvest on annual water yield. Journal of Hydrology. 176: 79-95. NOAA Fisheries, 2003. Sediment Removal from Freshwater Salmonid Habitat. May 9, Steedman, R.J. and R.L. France. 2000. 2003. SWR Sediment Removal Guidelines, Origin and transport of Aeolian sediment Draft. 98 p. from new clearcuts into boreal lakes, northwestern Ontario, Canada. Water, Air, Norris and Webb, 1990. Geology of and Soil Pollution, 122: 139-152. California. John Wiley & Sons, Inc., 541 p. Swank, W.T., J.M. Vose, and K.J. Elliott. Pethick, J., 1984. An Introduction to 2001. Long-term hydrologic and water Coastal Geomorphology. Edward Arnold quality responses following commercial 260 p. clearcutting of mixed hardwoods on a southern Appalachian catchment. Forest Reid, L. M., and Dunne, T., 1996. Rapid Ecology and Management, 143: 163-178. Evaluation of Sediment Budgets. GeoEcology, Catena Verlag, GMBH, 164 p. Swift, L.W. Jr. 1988. Forest access roads: design, maintenance, and soil loss, eds. Ritter, D. F, Kochel, R.C., and Miller, J.R., W.T. Swank and D.A. Crossley, Jr., Forest 1995. Process Geomorphology. Wm. C. Hydrology Brown Publishers, CT., 544 p. and Ecology at Coweeta, Springfer Verlag, New York., 313-324. Selby, M.J. 1993. Hillslope Materials and Processes, 2nd ed. Oxford University Press, Troendle, C.A., M.S. Wilcox, G.S. Oxford., 451 p. Brevenger, and L.A. Porth. 2001. The Coon Creek water yield augmentation project: implementation of timber harvesting
- 53 - California Watershed Assessment Manual, Chapter 3 August, 2004 technology to increase streamflow. Forest Wolman, M.G. and Leopold, L.B., 1957. Ecology and Management, 143: 179-187. River floodplains: some observations on their formation. USGS Professional Paper U.S. EPA, 2002. Community Culture and 282C:87-109. the Environment: A Guide to Understanding a Sense of Place. (EPA 842-B-01-003), Ziemer, R.R. 1981. Storm flow response to Office of Water, Washington, DC. 280 road building and partial cutting in small pages. streams of northern California. Water Resources Research 17:907-17. U.S. Geological Survey. 1998. Groundwater and surface water: A single resource. Zinke, P. 1987. Soil moisture budget: An Circular 1139. Denver: U.S. Geological example of timber harvest and regrowth. In Survey. Proceedings of the California watershed management conference, edited by R.Z. Varnes, D.J., 1958. Landslide types and Callaham and J.J. DeVries, 86-88. Report processes. Highway Research Board, 11. Berkeley: University of California, Special Report (Washington DC, 29:20-47. Wildland Resources Center.
Ware, D. M. 1995. A century and a half of change in the climate of the NE Pacific. Fisheries and Oceanography 4(4):267-277
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Watershed Professionals Network (WPN). 1999. Oregon Watershed Assessment Manual. Prepared for Oregon Watershed Enhancement Board. Salem, Ore. http://www.oweb.state.or.us/publications/wa _manual99.shtml
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4 Collecting and Organizing Existing Data
Collecting and organizing data is a key part Gaps in knowledge—questions that cannot of a watershed assessment. It makes sense be answered within the project timeframe to begin by collecting existing data. If you and currently available budget—should be identify data gaps and if you have the identified to indicate the nature of any resources, you might decide to collect new remaining uncertainty and to prioritize data data as well. This chapter addresses the needed for future assessment. issues of how to collect and manage all types of data. Specific approaches for 4.1.1 Types of Data collecting new data in association with a watershed assessment will be discussed in Data types can be broadly classified as detail in the Appendix to the Manual. numeric and spatial. Numeric data can be highly quantitative, semi-quantitative, or Chapter Outline qualitative. Examples of quantitative data include most water quality and flow data. 4.1 Overview and Key Considerations Semi-quantitative data might include data 4.2 Sources of Numerical Data and that involves scoring habitat characteristics Information based on standards that might be 4.3 Archiving and Managing Numerical interpreted differently by different people. Data For example, characterizing stream bank 4.4 Anecdotal Information stability might involve an estimate of the 4.5 Types and Sources of Landscape percentage of the bank covered with Data vegetation. Frequently, this is estimated 4.6 Geographic Information Systems visually, not by actual measurements. and Spatial Data Biological surveys often fall into this 4.7 References category. Qualitative data is descriptive. ______For example, anecdotal data describes conditions based on observation of a single 4.1 Overview and Key Considerations or a few individuals. The observation that the pools in the stream have filled up with Data are “known facts or things used as a sediment over the past 20 years is one basis for inference or reckoning.” Data example. This is very useful information, pertinent to watershed assessment may even though it is not quantitative. Spatial include quantitative measurements, data is data that has a geographic reference qualitative information (e.g., observations of point. It can be quantitative, semi- a species’ presence), maps, anecdotal quantitative, or descriptive data that is information, photographs, and other “facts” located at a point or area on a map. relevant to the watershed assessment. As data are collected, they should be Collecting data can be both time consuming organized in a manner that suits the and labor intensive. Therefore, you should questions being asked and the users’ focus your efforts on the specific questions needs. Because watershed assessment you’ve identified for your watershed. The usually involves the collection of several extent of your data collection will hinge on different types of data, consider developing how complex and detailed your assessment file organizational systems for each type of will be. There should be a direct path from data that conform to a single standard for the questions you are asking about the categories (e.g., wildlife habitat, water watershed to the types and amounts of data quality, land use). One way to keep track of you collect within the project timeframe. information collected is to make a database
- 1 - California Watershed Assessment Manual, Chapter 4 August, 2004 of the category types. If you will be may seem to be in conflict, based on collecting data for aquatic and terrestrial different methods, objectives, assumptions, systems and of various different types (i.e., dates, biases, etc. from text to digital spatial data), then keeping track of the types of data and the Consider establishing a record/database of areas they cover will help in both organizing information attributes that describe its the data and describing how much of the usefulness (e.g., date of collection, source, watershed they cover. purpose, scale, peer-reviewed, etc.). An example of this is in the North Coast 4.1.2. Evaluation of data Watershed Assessment Program Mattole watershed assessment report Once you find a few reports or data sets for (http://www.ncwatershed.ca.gov, select your watershed, look them over with a Mattole watershed and the table is in the critical eye. When examining past reports, Appendix) and an excerpt is shown in the ask yourself if the conclusions make sense box below. and whether the supporting evidence justifies them. Check to see whether there When citing information for your was any sort of external or peer review. It is assessment, check the original document important that collection of data include a for its methods and conclusions. Avoid critical analysis of the methods used to contributing to the all-too-common rumor obtain the information. Sample design, chain of many environmental documents frequency of sampling, exact type of that sequentially misrepresent an original measurement made, and analytical reference by citing a secondary source that technique, can all affect the usefulness of misinterpreted the original. Do not ignore or data you find and want to use. Not disregard data just because they don’t seem infrequently, streamflow gauges are not to “fit” or because they run counter to serviced regularly and therefore, produced preconceived expectations of what the data unreliable data on flow rate. Verify their should say. During the Data Analysis accuracy with knowledgeable people. process, the various data sources can be Compare findings from different reports to evaluated for quality and deficient sources see if they corroborate each other. There can be discarded. may be a legitimate reason why two reports
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Data obtained over the internet, a common Shasta College’s WIM project, source of information, has particular http://wim.shastacollege.edu/default.aspx; limitations. Until the mid-1990s, most U.C. Berkeley’s Digital Library Project agencies and organizations did not put their http://elib.cs.berkeley.edu/). The University data and reports online. Only a small of California’s MELVYL online catalog does number of older reports have been scanned not go back earlier than 1971 for the in, such as for special digital libraries (e.g., documents it lists, although its vast
Sources for Watershed Assessment Information
Previous watershed assessments
Local Government
County or city General plan Master environmental assessments Specific plans and environmental impact reports for projects Local enhancement or restoration plans Departmental documents and data (planning, public works, agriculture, environmental health) Flood control plans, documents, and data Water supply, irrigation, and other special districts—reports and data
Local Organizations
Resource Conservation Districts (RCDs) —annual reports and documents Watershed groups—documents Conservation groups (e.g., Friends of the XXX Creek/River) —reports
State of California Agencies
Regional Water Quality Control Boards Basin plans Monitoring studies Total maximum daily load (TMDL) studies and determinations State Water Resources Control Board Water quality reports and data Water rights reports and data California Department of Forestry and Fire Protection—timber harvest plans (THPs), maps, data, and documents State Park Management Plans California Department of Transportation Highway environmental impact reports Monitoring data on road runoff California Department of Fish and Game—documents and data, land management plans California Geological Survey (Division of Mines & Geology) —documents and data California Department of Water Resources—documents and data California Coastal Commission and Coastal Conservancy—documents and data California State Lands Department—documents and data
- 3 - California Watershed Assessment Manual, Chapter 4 August, 2004 collection of historic documents and maps for California goes back to Spanish land grant days. You should consider seeking out data by visiting and looking through traditional libraries and agency filing cabinets. They frequently contain historical data and information that can be invaluable.
4.1.3 General Sources of Data
One good place to start collecting data is to use an Internet search engine like Google to search for the names of rivers and their tributaries in your watershed, as well as other risk), which potentially increases the range relevant place names and topics. Your of uses of data, but not necessarily the search results may return thousands of links reliability. so it is important to selectively narrow your search terms until you find items of interest. Frequently, you will encounter a mix of data You may find that reports you really want scales. Some spatial data will be low are only available in libraries and at local resolution and tell you only generally what agency offices. The U.S. Geological Survey kinds of plant community, land has an online database of publication ownership/use, hydrology, and geology are abstracts that can be searched by theme or present. Some temporal data, say for water location quality, may be high resolution if they were (http://usgspubs.georef.org/usgsns.htm). collected continuously or at frequent regular Many state agencies and federal agencies intervals over a long time. Your knowledge post reports online—use the search engines of flow in your watershed will probably be for their sites to search for the name of your based on very few regularly maintained watershed or waterway. streamflow gaging stations, due to the gradual loss of this critical data resource in 4.1.4 Spatial and Temporal Scale of Data California. On the other hand, water quality monitoring may have taken place in your Data collected at scales that you cannot watershed, with regular collection of periodic control constrains the use of that data in and storm event measurements. Most new analyses. Your task as the assessor is information about non-point source pollution, to know the scales at which data were natural condition, and decisions about collected and determine the kinds of combined land and water management analyses you can conduct and the decisions comes from the combined measurement of you can make based on these data. The flow and water quality constituents. scale of data will be associated with any Sometimes water quality data alone are the well-developed set of data or obvious from basis for management decisions. the data distribution (e.g., monthly water quality samples from the same 10 sites in In general, when you combine scales, the the watershed over 3 years). Be aware that, resolution of your analysis product is the some of the information that an assessment same as the lowest resolution input data. relies upon as “data” may actually be products of computer models (e.g., for Provided below are some guidelines for your wildlife habitat, fire hazard, and landslide actions related to watershed assessment
- 4 - California Watershed Assessment Manual, Chapter 4 August, 2004 based on the more established principles in The NRCS data would provide good the scientific disciplines where scale is resolution for a large watershed assessment important. where the goal was decision-support at the creek sub-watershed, agricultural parcel, or • Spatial Scales U.S. Forest Service road-segment scale. However, at finer spatial resolution, say for The term spatial scale refers to two hillslope stabilization, small timber harvest characteristics. In everyday usage, the term planning area, and protection of rare plant refers to the extent of the area covered by a communities in developing areas, you might dataset, which is useful when talking about want a new field survey of soils that has a the “scale” of a project or analysis. However, finer spatial scale. more technically, spatial scale refers to the fineness of the resolution of the data. For In some cases, the accuracy of commonly- example, the Natural Resource used spatial data can be a concern. For Conservation Service (NRCS) is gradually example, the quality of road data is mapping soil formations across the country generally poor in California, in terms of at a resolution of 1:24,000, which translates actual road position, road type and to a six-acre minimum unit size for a soil condition, and road length. At the scale of a area creek watershed, it might be critical to know (http://soils.usda.gov/technical/manual/). the points of interactions between the roads The spatial scale at which this data should and the creek, riparian areas, and slopes. be used is a minimum of six acres. In The map example above shows the data ecology, this characteristics is referred to as available from the TIGER database the “grain” of the spatial data. You could use (1:100,000 TIGER data from the Teale Data the data at finer scales (e.g., one acre), but Center, in red or light color) and those uncertainty would increase because the data developed by the Tahoe National Forest was designed only to provide a coarse (TNF) (in black, from a combination of GPS overview of soil types. To use this relatively and aerial photos). Within the TNF, road coarse data to describe soils in smaller units system and watershed analysis can take could lead to misrepresentation and errors. advantage of higher resolution data, Therefore, it is important to consider the potentially leading to higher resolution grain of the data when you collect spatial decision making. Outside the TNF boundary data so you can use it appropriately when within the same watersheds, only TIGER you get ready to analyze your findings. data is available, so the data scale coarsens
Examples of typical types of data collected in a watershed assessment and the optimal scale for these data
Type of Data Temporal/Spatial Scales Contaminants in water Throughout the year and immediately after rain events; above and below sites of concern (storm drains, road effluent, wastewater treatment plants). Ideally, regular monitoring over many years. Sedimentation In streambed, on hillslopes, below roads, primarily following storm events, in smaller streams and periodically in smaller and larger waterways Dissolved oxygen, Weekly or monthly in all sub-watersheds of the stream temperature Road maps 1:24,000, updated every five years
- 5 - California Watershed Assessment Manual, Chapter 4 August, 2004 and the analysis suffers resolution, leading conditions today and will be relatively stable to lower resolution decision making. (potentially over years) unless there is an abrupt removal or replacement of the If you are fortunate enough to be able to vegetation due to plant community collect new data using a monitoring or restoration, logging, fire, agriculture, or assessment program, you can set the scale urban development. The time scale over of data collection to match your analysis and which new data are collected is another decision needs. Selecting the correct scale consideration. A one-time grab sample may for monitoring isn’t easy. Some of the be all you are able to collect, and it is better material referenced in this manual might be than nothing. However, it will provide a of use, but you should seriously consider limited picture of reality. For example, in consulting with an expert so you can get the some eastern Sierra Nevada streams, most from your investment of time and episodic events of low pH are associated money. with snowmelts that are of short duration, but may be lethal to trout. In this case, • Temporal Scales collecting samples that reflect the extreme conditions, not the average pH, is crucial. Most data that you will use will have a time Sampling over a short timeframe could element. It will either be a single point in totally miss these events. Data should be time for an observation or measurement, collected over the period of time in which multiple points in time (e.g., daily or weekly) you would expect to see changes and/or over a certain period, or continuously when there is the greatest likelihood of measured. A water quality measurement or detecting infrequent, but important, events. grab sample is a snapshot of conditions, which may be accurate for that hour or day, The sample list in the text box below is an but loses accuracy as you generalize across easy way to keep track of key time (e.g., to a month). Measurements of considerations when evaluating the scale of aquatic insect communities may be accurate your data. It will be particularly helpful later for estimating conditions over the population in the assessment when you begin data and individual life spans (months to years), analyses and integration. WQ refers to water but only in extreme lethal conditions will it quality evaluation; LFA refers to limiting tell you much about shorter timeframes factor analysis, which is a way of (e.g., days). A satellite image that is used to discovering environmental conditions that model likely plant communities captures are limiting survival of a species (e.g., salmon). These kinds of metadata
Scale Reference List
Data type Use Spatial scale Temporal scale Spatial units Time units
Dissolved WQ, LFA Station Monthly, hourly, event Oxygen
Temperature WQ, LFA Station Continuous
Road map GIS, erosion 1:24,000 5-year update
Employment GIS, community census blocks 10-year update Sectors characterization
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(information about your data) are important Categories of data include: suspended when deciding on appropriate uses of the sediment, temperature, dissolved oxygen, assessment and additional data collection. nutrients (e.g., phosphates), organic and inorganic chemicals such as pesticides and 4.2 Sources of Numerical Data and pharmaceuticals, dissolved organic carbon, Information pH, etc. Changes in these water quality parameters can occur in response to natural The availability of hydrologic and water- processes, human activities, and the quality data on the Internet has thoroughly interaction between human activities and transformed the hunt for watershed data in natural processes. The data can be recent years. Rather than conducting long collected through grab sampling (i.e., searches and even longer copying and scooping up a volume of water) and transcription sessions in libraries of distant continuous sampling/measuring. universities and archives of local agencies, an amazing amount of material is now The importance of data on the water column accessible from any computer connected to is clear—fish and most other aquatic the Internet. Online resources do not organisms live in and breathe the water. eliminate the need to seek specialized and Water quality problems can affect these unpublished information from a variety of organisms’ respiratory (gills), excretory sources, but your office computer is now a (kidney), reproductive, nervous, and convenient place to start your search for cardiovascular systems. Often, the effects data. of poor water quality on the organism(s) of interest are not obvious. If poor conditions The U.S. EPA’s “Surf Your Watershed” Web persist, however, or if the concentration of site the harmful constituents is high enough, (http://cfpub.epa.gov/surf/state.cfm?statepo mortality will result. Many toxic chemicals stal=CA) is a good place to begin. An found in surface and ground water are interactive map will direct to your region. carcinogenic, can cause tumors in fish, This site provides links to a variety of other and/or attack the nervous or endocrine Web sites and resources that may be useful systems. in your search for watershed data. The number of links on EPA’s site varies Sediment contaminants have the potential tremendously, depending on the to affect all aquatic organisms as well. watersheds. Also, smaller watersheds tend Frequently, invertebrates living in sediment to be combined together with other ones to will accumulate contaminants. These form larger units. Data records may be animals are subsequently eaten by fish, incomplete. which concentrate the contaminants, so the fishes’ exposure is actually greater than the The U.S. Geological Survey (USGS) is a chemical’s presence in the environment. In repository for the nation’s water data. Your this way, fish (or things that eat the fish) that search for USGS data can begin at normally wouldn’t be exposed to a http://ca.water.usgs.gov or contaminant can be harmed. http://waterdata.usgs.gov/ca.nwis/nwis. The USGS Web site contains primarily flow Many non-water soluble contaminants are information, although for some sites there is primarily found in sediment. Pesticides, water quality data as well. such as DDT (now illegal), persist in sediment for very long periods of time. 4.2.1 Water and Sediment Quality Data Sediment contaminants can diffuse into pore-water, the water between streambed Water quality data include information on particles. Depending on the contaminants’ both the water column and sediment. solubility, diffusion occurs at different rates.
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Compounds found primarily in sediment The current STORET program is available include PCBs, DDT, dioxins, and many to users who wish to organize their water polycyclic aromatic hydrocarbons, quality data under the STORET protocols byproducts of fossil fuel combustion. on their own computers. Users can upload Pyrethroid insecticides, such as these local files to the central STORET esfenvalerate, and metals are also primarily system and make the data available through found in the sediment. Measurements of the STORET Web site. As of July 2004, the these chemicals in the water column do not “Modernized STORET Data” site did not give a true picture of their presence in the contain many California data, in contrast, waterway because their highest the “Legacy STORET Data” site did. concentration is in sediment or pore-water, the water found between the streambed Both the LDC and STORET contain a wide material. range of chemical, biological, and physical data under the broad heading of water Water and sediment quality data will quality. A diverse assortment of people, generally be used to evaluate conditions by agencies, and organizations collected these comparing data from your watershed to data for a myriad of purposes with the standards. These standards, promulgated common goals of making the data available by the U.S. EPA, USGS, and/or the State to the public. Each water quality value is Water Resources Control Board, contain associated with information on where the benchmark values for acute and chronic sample was taken (geographic coordinates, exposure to dissolved oxygen, nutrients and state, county, USGS Hydrologic Unit Code, other conventional water quality parameters and a brief site identification), when the as well as contaminants such as organics, sample was collected, the medium sampled pesticides, and metals. These benchmarks (e.g., water, sediment, fish tissue), and the reflect the highest concentration of a name of the organization that collected the contaminant to which an aquatic organism sample. In addition, STORET contains can be exposed without risking adverse information on why the data were obtained; effects and will allow you to estimate sampling and analytical techniques used; whether water and sediment conditions the laboratory that analyzed the samples; pose a risk to the important ecological the quality control checks used when resources included in the watershed sampling, handling the samples, and assessment. analyzing the data; and the people responsible for the data. EPA’s general 4.2.1.1 Sources of Information on Water description of the STORET database and Sediment Quality (http://www.epa.gov/storet/descript.html) provides additional details. The 1. STORET Pennsylvania Department of Environmental Protection's Web site offers detailed The primary source for water quality data is instructions for navigating through both the the U.S. EPA’s STORET system LDC and STORET (http://www.epa.gov/storet/dbtop.html). (http://www.dep.state.pa.us/dep/deputate/w STORET has recently been split into two atermgt/Wqp/WQStandards/STORET- separate entities: the Legacy Data Center Access.htm). (LDC), a static archive containing historical data collected through 1998, and STORET, Depending on your data requirements and the modern system. computing options, there may be some advantages to obtaining the EPA STORET STORET contains data collected since (both legacy and modern systems) on CD January 1, 1999, and older data that have instead of via the EPA website. Two received current levels of documentation. companies publish CDs of the EPA water
- 8 - California Watershed Assessment Manual, Chapter 4 August, 2004 quality data (http://www.earthinfo.com and can first choose “Monitoring Data” for http://www.hydrosphere.com). dozens of water quality parameters organized under categories of conventional 2. USGS water quality, freshwater invertebrates, hydrocarbons, metals, and organic Water quality data from discrete samples chemicals. This path allows you to compare are accessible from the USGS’s Web site summary values among sampling locations. http://waterdata.usgs.gov/ca/nwis/qw. Under the “Tutorial” button are instructions for The SWRCB is developing the Surface accessing water quality data in watersheds. Water Ambient Monitoring Program You can get to your watershed of interest (SWAMP) quickly if you already know the USGS (http://www.swrcb.ca.gov/swamp), a Web- hydrologic unit code. Otherwise, navigate to based source of water quality data that aims your watershed by starting with your county. to coordinate and compile data programs of Depending on what, if any, data are several agencies within California into a available for sites in your watershed, you common database. SWAMP and a broader can specify a variety of output formats to Water Information Network are anticipated meet your needs. The USGS has a good to be active in the near future. summary of its procedures for sample collection and onsite measurements at Water quality standards for each stream in http://ca.water.usgs.gov/archive/waterdata/t California, based on Regional Board basin ext/onsite.html. More detailed information plans, can be found on a GIS-based can be found in the USGS reports, inventory developed by Caltrans’ Techniques of Water-Resource Environmental Program Investigations, at (http://endeavor.des.ucdavis.edu/wqsid/). http://water.usgs.gov/pubs/twri/. Queries can be by waterbody name, beneficial uses, regional board, county, or USGS has 35 sites in California equipped keyword search. with continuous monitoring sensors and telemetry gear that allow reporting of near- Finally, the Regional Boards perform toxicity real-time measurements and the record of tests in accordance with U.S. EPA the past 31 days guidelines on rivers and streams throughout (http://waterdata.usgs.gov/ca/nwis/current/?t the state. Although not presently published ype=quality). Under the menu for “Available anywhere, this data is public information. data from site”, select “Recent daily” to obtain daily values of the onsite 4. Additional Sources of Water Quality measurements for up to two years. Most of Information these sites only report water temperature, but some also measure conductance, • Water Data Library Web site dissolved oxygen, pH, and turbidity. (http://wdl.water.ca.gov/)—California Dept. of Water Resources (DWR). Water quality 3. State Water Resources Control Board data, access to hydrologic data (searchable (SWRCB) and Regional Boards by station and county) collected by the Division of Planning and Local Assistance Water quality data from the Central Coast and other groups within the department, and Regional Water Quality Control Board’s information on a wide variety of chemical Central Coast Ambient Monitoring Program contaminants, such as pesticides and is available at http://www.ccamp.org. Here metals, as well as conventional parameters, you can navigate to a sampling location or such as conductivity and hardness. water body and then view a summary table of attributes and values. Alternatively, you
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• The California Digital Conservation Atlas • United States Forest Service (local (http://www.legacy.ca.gov) —the Legacy offices)—water quality studies and Project at the California Resources Agency. monitoring on local water bodies for An Internet map-making site with a wide watersheds that include any national forest variety of water quality data (under the lands. Environmental Stressors tab) for certain waterbodies in California; data from the • Data from aquatic bioassessment work Musselwatch Program, Toxic Substances (http://www.dfg.ca.gov/cabw/cabwhome.htm Monitoring Program, and others can be l)—California Department of Fish & Game. identified on stream and waterbody maps of As of 2003, a centralized results database streams and waterbodies throughout the did not exist, but SWRCB has recognized state; information on contaminants in water the need for such a database (Tetra Tech, and data on toxicity tests, which involve 2003). exposing model organisms, such as a water flea or amphipod, to water or sediment 4.2.1.2 Hydrological and Climate Data samples and measuring mortality or other biological endpoint. These tests do not Information and data about your identify the reason for the toxicity, but they watershed’s hydrology are critical are an excellent way to determine if components of any watershed analysis, anything in the water/sediment might pose a although data have not been collected for risk to aquatic life. You will need to many, if not most, watersheds. Streamflow determine the cause of the toxicity is particularly important for addressing independently. concerns about flooding, aquatic communities, and water quality in your • Surface Water Monitoring Program watershed assessment. The availability of database hydrologic data largely depends on whether (http://www.cdpr.ca.gov/docs/sw/surfdata.ht some agency thought the water in your ml) —The Department of Pesticide stream had some utility, either locally or for Regulations. Data on pesticide export. If there are major or formerly concentrations in waterways throughout proposed water engineering projects in or California, not just agricultural regions. near your watershed, then there is a high likelihood of current or historic stream • Drinking Water Program gauging stations. If your stream is an un- (http://www.dhs.ca.gov/ps/ddwem/technical/ dammed tributary that doesn’t supply water dwp/dwpindex.htm) and Drinking Water to municipalities, hydroelectric facilities, or Source Assessment and Protection irrigation districts, the stream is unlikely to Program have a gauging station. The main exception (http://www.dhs.ca.gov/ps/ddwem/dwsap/D is if flooding concerns exist. Many small WSAPindex.htm)—the California streams and creeks near urban areas Department of Health Services. Information contain gauging station for flood control and data on the quality of water used for purposes. In general, where there is drinking water supplies. The Web site of the concern about the waterway, there are more Drinking Water Program also has a fairly gauges and measurements. thorough directory of other potential sources of data Flow Data (http://www.dhs.ca.gov/ps/ddwem/dwsap/D WSAP_directory.htm). Contact your county Streamflow data come from three basic health department and local water-supply types of measurements: 1) continuous utilities for water quality data for local water records of stage (water level) and discharge supplies (surface water and groundwater). at a calibrated cross-section, 2) spot measurements, and 3) crest-stage gauges
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(where only the highest water level is direction as the contributing area increases. recorded). From a watershed assessment These longitudinal studies are also useful perspective, the most useful data comes for measuring the effects of diversions, from a long-term continuously recorded irrigation return flow, and subsurface stream gauge (#1 above) that has hydrogeology (where the stream is naturally measured daily or monthly streamflow for gaining or losing water to the alluvial the past few decades. Gauging stations aquifer). typically record stream stage at 15-minute intervals. Corresponding discharge is then Maximum water levels (high water marks) calculated from a rating curve based on from crest-stage gauges generate data manual measurements of instantaneous useful in flood studies where installation and discharge across the channel cross-section maintenance of many recording stream and stage at time of the measurement. gages is not feasible. Crest-stage gauges Some stream gauges may not have a can be as simple as a vertical pipe recording device, but instead rely on manual containing a ruler and a marker with a few observation of a staff gauge (basically a holes in it to allow water to flow in and out. well-anchored ruler from which an observer This marker can be something that floats, can read the water level) approximately such as cork particles, and adheres to the once a day. Such gauges are common in ruler at the highest water level or something irrigation ditches and sites with full-time that dissolves in water and has been staff. Chapter 3 presents fundamentals of applied to the ruler. After an increase in stream gauging. For more detailed streamflow, a hydrographer (one who information, see Dunne and Leopold measures water) removes the ruler and 1978:594-598;Hornberger, et al. 1998:100- records how high the water rose in the pipe 103) or the USGS Web sites: (and therefore the stream). Estimating the http://ca.water.usgs.gov/archive/waterdata/t corresponding discharge is difficult and ext/explain.html and involves considerable uncertainty (often +/- http://water.usgs.gov/pubs/twri/. If the 50% or more). Nevertheless, such data are gauging station is in close proximity to a often the only estimates of peak flows. dam or diversion, both the actual flow at the location and a calculated value that includes Although not strictly streamflow, another diverted water or changes in reservoir common type of hydrologic data is storage may be reported. estimates of volume in lakes and reservoirs. Similar to stream gauging stations, the Spot measurement data is generated from lake’s or reservoir’s water level is observed occasional measurements with a current (either visually on a staff gage or with a meter (device that measures the local water-level sensor and recorder), and the speed of the flowing water) or other volume is calculated from an equation or technique (e.g., Herschey 1985). Unless table relating water level and volume. there is little streamflow variability, such measurements do not reveal much The USGS is primarily responsible for the information about the long-term nation’s water data, including streamflow. characteristics of streamflow. If such data Navigating USGS streamflow data is easiest are all you have, interpret them with caution when you have the USGS gauge numbers, because a lot can happen in between the which have a structure similar to USGS measurements. Spot measurements can be hydrologic unit codes for watersheds. From valuable longitudinally along a stream when USGS entry portals http://ca.water.usgs.gov streamflow is measured at several places or http://waterdata.usgs.gov/ca.nwis/nwis, up and down a channel on the same day. In you can easily get to a site selection page this case, you can learn how much and enter your county or a pair of latitudes streamflow changes in the downstream and longitudes to begin your search for
- 11 - California Watershed Assessment Manual, Chapter 4 August, 2004 stream gages in your watershed. USGS to: http://waterdata.usgs.gov/ca.nwis/sw or publishes a series of schematic diagrams of http://nwis.waterdata.usgs.gov/ca/nwis/disc the major river basins in California that are harge. very helpful for understanding the Graphical output is also an option. A tutorial geographic arrangement of tributaries, on accessing historical streamflow data is stream gages, and major dams and available at diversions. http://nwis.waterdata.usgs.gov/tutorial/histor ical_streamflow.html. Keeping a copy of the relevant schematic(s) for reference while navigating USGS data In addition to daily streamflow values, archives will aid your search. These USGS also publishes data of the highest schematics can be found within four annual flows over the period of record for regional volumes (Vol. 1 – Southern selected sites. Access the peak streamflow California, Vol. 2 – Central and North Coast; database at Vol. 3 – Southern Central Valley and Great http://waterdata.usgs.gov/ca/nwis/peak. Basin from Walker to Truckee; Vol. 4 – Again, your progress will be fastest if you Northern Central Valley and Northern Great already have the station ID number. Basin) for California. Volumes for 1999 You can specify the output format and file through 2002 can be downloaded as .pdf information. files from http://ca.water.usgs.gov/archive/waterdata/. Depending on your data requirements and Older volumes can be found at most computing options, there may be some university libraries and in some offices of advantages to obtaining USGS streamflow public agencies. on CD instead of via the USGS Web site. Two companies publish CDs of USGS daily Another important piece of information streamflow and peak flow data within these volumes is the list of (http://www.earthinfo.com and discontinued gauges (online at http://www.hydrosphere.com). http://ca.water.usgs.gov/archive/waterdata/9 9/disc_sw.html). Information about stream Other sources of streamflow data include gages, or what the USGS calls a “station water districts, municipal utility districts, manuscript” (precise location, drainage irrigation districts, hydroelectric generating area, period of record, summary of companies, the U.S. Forest Service, and extremes, etc.), that were in service any other local entity that needs to measure between 1994 and 2001 can also be found streamflow. Data from such sources may at not be available online and may require a http://ca.water.usgs.gov/archive/waterdata/ personal inquiry to the agency or company. The search function here works best if you Some records are not considered public have the gauge number or if the name is information and may not be available. In unique. Common names like “Clear Creek” cases where the data are not public will yield thousands of results. records, be prepared to make a good case for your need, demonstrate that release of Although the USGS portal the data will not be harmful to the supplier, (http://ca.water.usgs.gov/archive/waterdata/ and be prepared to pay for staff time to copy ) provides annual tables (flat files) of daily or otherwise prepare the data for you. discharge values for gauges operated between 1996 and 2001, you may wish to Local or regional flood control agencies may obtain more data in a format that can be also have streamflow and stage data. This manipulated on your computer. For access data is often available on the city/county to more thorough data after you know what websites and serves as a warning system sites and periods of record are available, go for local residents. Because some stations
- 12 - California Watershed Assessment Manual, Chapter 4 August, 2004 may not be maintained carefully due to local 4.2.2 Riparian Vegetation and Wetlands budget constraints, ask local public utilities Data department engineers about the data’s accuracy. The riparian zone is where the aquatic and terrestrial landscapes come together and The California Department of Water where species from both environments Resources’ Division of Flood Management benefit. As a result, riparian data collection maintains the California Data Exchange generally reflects both aquatic and Center (CDEC) at http://cdec.water.ca.gov, terrestrial ecosystems. Description of which provides very recent and real-time riparian habitat generally involves data in response to flooding (i.e., real-time interpretation of aerial photography for large river stages) and for water project watersheds (>100,000 acres) and field operations. If you need current daily and surveys for small watersheds (10,000 acres) monthly streamflow and reservoir data, see or parts of large ones. this site. Commonly collected characteristics of Climate Data riparian data include: • Plant species (native and introduced), Climate data are also available from CDEC • Plant community (e.g., cottonwood at http://cdec.water.ca.gov. Select riparian, mixed conifer riparian), “Precipitation/Snow” from the menu “CDEC • Tree canopy cover (average as a Resource Directory” for a list of precipitation percentage), stations where you can select an individual • Tree canopy closure over stream (or station and obtain the latest data. At the other index of stream shading) bottom of a page for a particular station, • Tree size, select “Historical Data” to get to the “Bulk • Large woody debris (including potential Data Selector”. Using the three-letter station for more wood to enter the stream code from the previous page, specify the channel), data, period of record, and output format. A • Stream bank erosion, pair of interactive maps for locating stations • Average width of riparian zone, with available data can be found at • Disturbances (type, extent, and http://cdec.water.ca.gov/cgi-progs/mapper. intensity),
The Western Regional Climate Center in • Fragmentation of riparian habitat, Reno, Nevada, is the other major source for • Water impoundments, precipitation, temperature, and other climate • Stream bank structure and stability data. Begin your search at http://www.wrcc.dri.edu/CLIMATEDATA.htm Data about riparian vegetation and other l. Interactive maps with locations of climate characteristics of riparian areas are likely to stations are available for Northern California be scarce for your watershed. In the past, (http://www.wrcc.dri.edu/summary/climsmnc there has been little demand for systematic a.html) and Southern California surveys of riparian areas (National (http://www.wrcc.dri.edu/summary/climsmsc Research Council 2002). The California a.html). After selecting a particular site, you Riparian Habitat Conservation Program was will obtain a monthly summary over the created within the Wildlife Conservation period of record and a menu for accessing Board (WCB) at the Department of Fish and more detailed information for the site. Game in 1991 (http://www.dfg.ca.gov/wcb/california_riparia n_habitat_conservation_program.htm.) with the objective of assessing the current amount and status of riparian habitat
- 13 - California Watershed Assessment Manual, Chapter 4 August, 2004 throughout the state. However, this canopy cover, and tree size using DFG extensive mapping effort has not yet stream habitat survey data (see above), occurred. This program is partnering with aerial photograph interpretation, and new the state-federal-private Riparian Habitat field data where needed. FRAP’s Forest Joint Venture, which is riparian bird habitat and Range Assessment 2002 developed a protection effort. The Joint Venture also single GIS data layer for vegetation that aims to identify riparian areas in the state, includes riparian categories by merging but it has not yet compiled a database multiple sources of data. (http://www.prbo.org/calpif/htmldocs/rhjv). Challenges include the difficulty of mapping The most complete information and data land cover statewide with sufficient about riparian vegetation are usually found resolution to characterize the narrow for areas downstream of hydroelectric riparian zone and the cost of doing this high projects that have been through or are resolution work. currently in the relicensing process. As part of the relicensing effort’s environmental Riparian areas have been mapped for parts review, the Federal Energy Regulatory of the state through several projects Commission (FERC) and U.S. Forest conducted by CDF’s Fire and Resource Service (if the project is on national forest Assessment Program (FRAP) land) generally require a thorough (http://frap.cdf.ca.gov). It has developed a assessment of riparian resources that have California Hardwood Rangeland Riparian been affected by the hydroelectric operation Vegetation Database, where riparian is one to date or that could be impacted if the of the seven database fields mapped in project continues. The basic information is 1990 using satellite imagery. usually found in an appendix to the http://frap.cdf.ca.gov/foofoo2/veg_data/ripari Environmental Impact Statement. If this an_metadata.html. It also mapped and description is not detailed enough, you may assessed several north coast watersheds be able to obtain raw survey data from the for riparian vegetation conditions through personnel or consultants who worked on the the North Coast Watershed Assessment riparian assessment. Program (http://www.ncwatershed.ca.gov). Using existing U.S. Forest Service and CDF Environmental documents for proposed new vegetation maps, FRAP updated species, projects are another source of information,
The San Joaquin River Riparian Habitat Restoration Program
(http://www.usbr.gov/mp/cvpia/sjr/) serves as a case study for using riparian data sources. The program evaluated historical riparian habitat conditions and changes through the use of soil surveys, historical maps, and historical aerial photographs going back to 1937 (Jones & Stokes 1998a). Geographically corrected maps at a scale of 1:24,000 were compiled for riparian soils, habitat, and land use for several dates during that period of time. Data were entered into a GIS database, which allowed the changes in areas and types to be quantified for those years. A second riparian study analyzed how physical processes, such as flow conditions and sediment regimes, shaped the San Joaquin River and affected the riparian habitat patterns along 150 miles of the river below Friant Dam to the confluence with the Merced River (Jones & Stokes 1998b). Low-altitude aerial reconnaissance flights were made to record current vegetation patterns, as well as geomorphic and hydrologic features. Ground-level surveys recorded riparian vegetation structure, condition, dominant species, and relation of species to channel geometry, in addition to physical channel measurements.
- 14 - California Watershed Assessment Manual, Chapter 4 August, 2004 though in very limited areas. Environmental online bibliographic search may yield leads Impact Reports (EIR) for new project require to other scientific papers, such as the user- surveys of existing conditions and potential friendly riparian research Web site by the impacts of the project. All EIRs are to be University of Washington with over 8,000 filed in the State Clearinghouse maintained citations by the state Office of Planning and (http://riparian.cfr.washington.edu/). Research (http://www.opr.ca.gov). These EIRs could be a source of useful information Aerial photography is a potential source of on riparian and other habitat. The local raw data about riparian vegetation (primarily county planning department often keeps an vegetative cover and human disturbances), archive of such reports as well. You can although it requires a lot of effort to interpret also search for documents prepared under the images (e.g., Nelson & Nelson 1984, the California Environmental Quality Act at Grant 1988). Sources of archived aerial http://www.ceqanet.ca.gov. photography include offices of the USFS, the BLM, the CDF, county planning If your watershed includes some federal departments, the Earth Science and Map land, there may evaluation or monitoring Library at U.C. Berkeley, and the Map and data for selected riparian areas at your local Imagery Library at U.C. Santa Barbara. Forest Service or Bureau of Land Videotapes of a few California river Management (BLM) office. Most national corridors under study for Wild and Scenic forests have conducted stream surveys for River status filmed from helicopters by the parts of their forest, both in a systematic National Park Service are available at the process as well as for specific projects. Water Resources Center Archives at U.C. Prior to the mid-1990s, little of this data was Berkeley. There are also “digital ortho collected or archived in a consistent format. quarter quads” (DOQQs) and “digital raster In the past few years however, a procedure graphs” (DRGs) available for the state, known as Stream Condition Inventory have which are types of satellite or aerial been used to characterize riparian photographs that you can use in GIS. These conditions. Contact hydrologists, botanists, can be downloaded from the state GIS and fisheries biologists in the local district or repository (California Spatial Information supervisor’s office to check on the Library, http://gis.ca.gov/data.epl) in various availability of stream and riparian survey forms. This site also has a variety of other data for your watershed. The BLM also has statewide data. a continuing program for assessing riparian conditions on the lands it administers. The The National Wetlands Inventory (NWI) of BLM approach is known as “proper the U.S. Fish and Wildlife Service provides functioning condition” (PFC), which can be information about wetlands throughout the evaluated on the adequacy of vegetation, United States. About 90% of the wetlands of landform, or large woody debris to serve the continental U.S. have been mapped, certain functions (U.S. Department of the with much of the information available in Interior BLM 1995). This assessment digital form online (http://www.nwi.fws.gov). method tends to be used on public lands With the exception of southern desert areas, and some private rangelands. most of California has been mapped as of November 2003, with digital information There is a chance that some sort of riparian available for about half the state. Other research may have been conducted in your potential sources of wetlands information watershed. Many of the riparian studies in and data include county planning California during the 1970s and 1980s were departments, the Natural Resources reported on or referred to in a series of Conservation Service, and the U.S. Army conference proceedings (Sands 1977, Corps of Engineers. Warner & Hendrix 1984, Abell 1989). An
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4.2.3 Physical, Channel, and Habitat very involved and can be comprehensive Conditions only for small watersheds. For large watersheds, field work could be used to Geologic and topographic information are calibrate a more generalized (e.g., GIS- essential components of watershed based) description of classes of sub- assessment. California maps are readily watersheds. available from a variety of agency and private sources—and are always useful in Stream channels and associated habitat an overview-scale assessment. Data that vary tremendously throughout California as provide a physical overview of watershed a result of the variability in climate and characteristics are available from USGS tectonics that differentiate the landscape, topographic maps and specific sediment erosion, deposition, (http://ask.usgs.gov/maps.html) and and morphologic conditions cannot be geologic maps from various agencies. The generalized without very specific regional USGS site also provides numerous thematic and local knowledge. Moreover, stream maps, such as geology, groundwater channel conditions vary longitudinally from resources, seismic, and vegetation maps the headwaters to the lowlands and laterally that may or may not be available for your from the low flow-high flow channels to the watershed. The California Geological floodplain, and data collection in one area of Survey has specialized geology maps at the watershed system may not represent various scales conditions in another area. For example, (http://www.consrv.ca.gov/CGS/information/ measurements of suspended sediment or geologic_mapping/index.htm). Other bed material load at one gauging station will important geologic maps that are available not represent downstream conditions if a statewide but are not online include the dam traps sediment or a tributary is a California Resources Agency Geologic Map source of sediment between the two areas. Sheets (scale of 1:250,000). But because of the wide range of natural spatial and temporal differences, Historic and current aerial photographs are extrapolating information from short-term another valuable source of watershed-scale data sets needs qualification. An overview data that helps characterize a watershed’s of the USGS sediment collection program is physical character (as well as vegetation summarized at and land use character). Topographic data http://ca.water.usgs.gov/projects02/ca004.ht and photographs are available online from ml. Geomorphic and sediment-related data http://terraserver-usa.com/ sponsored by can be stored in spreadsheets where it can USGS and other groups. County planning be easily accessed to report as a table or in departments, museums, Caltrans, NRCS, a graph. and a variety of agencies and private firms can sometimes provide historic and current 4.3. Archiving and Managing Numerical aerial photographs that may be used to Data evaluate trends and changes in physical watershed characteristics over time. Use of a database or spreadsheet is very helpful in managing the data you have Collecting data on physical channel and collected. Spreadsheets are easy to use, habitat conditions at the scale of individual but lack the ability to conduct a focused river reaches or habitat units involves search or queries that are the hallmark of a primary reconnaissance and field work, as database. For example, you may wish to these features cannot easily be discerned examine particular attributes, locations, from aerial photographs or maps and very sampling dates, or numeric values within or little online or existing information is typically above a certain range. Databases are available. Field surveying for these data is made to support these types of analyses. A
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Table 4.1. Example of tabular streamflow and suspended sediment data
Location Year Day Discharge Suspended sediment concentration (cfs) (mg/L) Clear Creek 2001 1 10 4.0 Clear Creek 2001 2 11 2.2 Clear Creek 2001 3 19 12.1 Clear Creek 2001 4 12 22.5 useful introductory reference on starting date (so you could assign a date to environmental data management is Michael each successive entry), and the units of the (1991). Environmental databases: design, values. implementation, and maintenance. Lewis Publishers. Boca Raton FL. A more A more common file structure is a table with comprehensive reference on this topic is multiple rows and columns (or records and Michener, et al. (1994). fields in database terminology). Simple data tables are often called “flat files”. In the If you are able to take advantage of a streamflow example above, some or all of reliable online source of data (e.g., USGS the metadata could be entered in columns daily streamflow records) or a CD archive of (table 5.1). The day of the year would be data, it is often best not to copy the data on unique for each record, but the location, to your computer. A great advantage of year, and units would be common for all these vast databases is their easy and long- records. The metadata would still need to term accessibility. In most cases, a link to include the start date of the year (calendar the data is as good as having it on your year on January 1, water year on October 1, hard drive. There are a lot of exceptions to rainfall year on July 1) and the headings for this general recommendation, the main one the columns (which are usually not part of being that if you want to integrate or overlap the table). data among “disciplines” (e.g., land-use and water quality), then it makes sense to have A wide variety of database management it all in one place. systems have been developed, primarily for business needs. Environmental data Existing environmental data will be stored in archiving and retrieval needs can usually be some sort of file structure or database, with accommodated by these systems, although the particular details dependent on the type there may not be an ideal match. Most of data, the agency archiving the data, the common database management systems needs of data users, and the dynamic (Microsoft Access, FileMaker Pro, Oracle nature of the variable being assessed. The etc.) can result in relational databases and simplest data structure is usually a single use Standard Query Language (SQL). The column of values, such as daily average relational structure allows use of many data streamflow for a year at a single gage tables that are linked together by one or station. In such a file, there would be 365 more common fields. These linked data records (lines or rows) with a single number tables reduce the need to enter redundant in each line or row. Metadata (information data, such as location, in every record. about data) would be associated with this Questions or queries can be asked of the file to allow you to interpret the data. In this database through SQL (usually via some example, to make sense of the single simple-to-use interface) without writing a column of numbers, you must know the program to perform the search. In addition, location of the stream gauge, the year, the the database management software
- 17 - California Watershed Assessment Manual, Chapter 4 August, 2004 facilitates data entry, updating, deletion, People who have lived in the area for a long simultaneous processing of commands from time and enjoy the rivers or streams are multiple users, import and export of large walking resources for certain kinds of amounts of data, and recovery from system information. Neither resource may give you crashes. quantitative information. But in the absence of or in combination with other information, it 4.4 Anecdotal Information is useful to at least know the presence or absence of watershed processes and the Anecdotal information may provide potential range of natural processes (e.g., knowledge about watershed processes and flooding). This information is best recorded conditions that might otherwise be lacking. with some associated index or coding for Common types of anecdotal data include: the type of information and where in the 1) The change in the extent of salmon runs watershed it is relevant. The data can be in river before and after building of a organized using the index or codes, dam or bridge, allowing for more efficient retrieval later on. 2) Change in turbidity of streams and rivers Data interpretation will depend heavily on over time, the source of information, the type of 3) Changes in land use, information it is, and the questions you are 4) Changes in riparian vegetation, addressing. You will probably use these 5) Changes in the frequency or size of data for “yes/no” questions about the floods watersheds more often than “how much” kinds of questions. The interpretation is Anecdotal information has been useful in probably best done by someone who has many assessment efforts. For example, familiarity with both the data source and the fisheries scientists in the Central Valley watershed feature being discussed. It is have re-constructed the history of salmon important for credibility with all stakeholders runs in the Valley over the past 170 years to qualify your findings and statements from archaeological site findings (i.e, fish when you use of anecdotal data in your bones) and written accounts in newspapers, analysis, reports, and presentations. diaries, technical reports, and letters to government agencies (Yoshiyama et al. 4.5 Types and Sources of Landscape 1996 & 2001). The South Yuba River Data Citizens League has provided a more detailed account for the Yuba River basin The majority of the area in any California based on a similar approach watershed is the terrestrial landscape. (http://www.syrcl.org/majorissues/SalmonRe Terrestrial landscape data are often port.htm). In both cases, the results of visual collected for entire watersheds. It may also observations by anglers and others were have been collected initially at individual combined with more contemporary fish survey sites (e.g., soil or vegetation) and surveying methods to assess the condition then subsequently generalized to areas. of the salmon populations in the Central Currently, most contemporary data about a Valley watersheds relative to historical watershed landscape are collected with a distributions. geographic reference point. In contrast, historic data may be very valuable, but lack If you plan to include historical or easily usable or identifiable reference contemporary anecdotal information, your points. main tasks will be finding, organizing, and interpreting the data. Public libraries Historic maps inform analyses of change (including holdings at universities and and historic condition. Unless these maps agencies) have extensive archives of have been transferred to an electronic newspapers and other written records. format, they are on paper and may be
- 18 - California Watershed Assessment Manual, Chapter 4 August, 2004 challenging to use to compare with present information can be summarized and day conditions. interpreted for later analysis. Paper maps are probably most useful when they show Local and regional governments maintain high-resolution information about local data on land uses. They reflect past or occurrences. For most watershed current zoning ordinances and present a assessments, collecting all paper maps reasonable estimate of activities occurring available isn’t feasible. You may want to within the watershed. Land use categories collect maps for select areas where, for include industrial, open space/parks, low example, you are interested in the historical density residential, and commercial. Land condition or for features where digital use maps are usually maintained as GIS information is not available. files. They can be very helpful in a watershed assessment because they Older data can be digitized to create digital suggest possible practices that could impact maps, which allows historical data to be the waterways. The State’s online GIS incorporated into a contemporary database. center is a good source of land-use maps According to the Information Center for the (http://gis.ca.gov). The Department of Environment (ICE, U.C. Davis, Conservation and county agriculture http://ice.ucdavis.edu), digitizing costs about commissioners have maps for rural and $0.50 per acre. Another way to store data agricultural regions of the state. from paper maps is to code the data and store that information. Coding refers to 4.5.1 Data Types attaching a value or code to a particular map feature. For example, if a feature’s Spatial data comes in a variety of types, position has not changed (e.g., a public including paper maps, digital spatial data roadway), but its type, use, or condition has (“GIS data”), tables of attributes of areas (e.g., paving the public roadway), then the (such as vegetation types), the results of feature can be identified and recorded in a summarizing or condensing data (e.g., by table, and the corresponding coding can be computer models), and anecdotal data (e.g, recorded with it. For landscape features that un-mapped descriptions of place). Each may not have precise position information, data type requires different storage and you can use nearby positional information organizational strategies (described in more (e.g., property name, township name, road detail below). Typically, each data type is number, etc.) to code the data. If data is associated with different levels or available on clear acetate sheets, then it is complexity of analysis. For example, in a possible to overlay various kinds of data for simple and rapid assessment, you might analysis. As always, you should record the rely on paper maps and anecdotal process you use to extract or summarize information, while for a comprehensive the information from the paper map source assessment involving computer models and to inform future users of your extracted multiple questions, you might rely on digital information. spatial and water quality data. 4.5.1.2 Digital Spatial Data 4.5.1.1 Non-Digital Spatial Data Digital spatial data are electronic versions of Historically, spatial data was non-digital. a paper map and shows the relative position These maps still have useful functions and of mapped features (e.g., roads, rivers) in a often can be converted into a digital format. geographical location (e.g., a watershed). Many local, state, and federal agencies These data are often used in watershed have archives of paper maps. You can mapping for watershed assessments and collect copies of these maps and make plans. However, they are useful for much digital versions of them. Alternatively, the more than just cartography (mapping). They
- 19 - California Watershed Assessment Manual, Chapter 4 August, 2004 can be used in modeling and understanding and are a form of data. When recording the distributions of features across the these data, it is important to record the landscape and how things interact with each origin of the values so they are not treated other. as measurements or the results of surveys, which may have been the case for the base 4.5.1.3 Non-Spatial Data information used in the modeling. Again, describing the data can be as important as Some of your watershed data may have the data values themselves. This been collected for a project where the exact “metadata” (description of the data) is its position of surveying was not critical and own form of information that can inform where sub-sampling of an area was used. decision making about data quality, For example, a botanist may have surveyed quantity, and sufficiency. The condensed or native and exotic plant communities across derived data that results from modeling or a ranch or sub-watershed and provided lists analysis may be summarized for specific of species present and estimates of percent geographic locations spread throughout the cover for each of them. This is valuable watershed (e.g., erosion risk for all sub- information for this place, but the data watersheds), or may be summarized only cannot be attributed to particular places for certain features of the watershed (e.g., except the area being assessed. You can stormwater runoff from developed areas). collect data like these and record them by survey area. In cases like this, collecting 4.5.2 Sources of Landscape Data data and placing it in tables might be the best way to organize it. There are a wide variety of sources for data about landscapes. However, these sources There may be other kinds of data that are are not always easy to find. Large agencies more suitable to list over a timeframe. For or institutions may hold data, which may be example, if you are interested in flooding available online. Local agencies or private occurrence but not in the area that is organizations are other data sources. inundated, then just recording the However, these organizations and agencies approximate location of the flooding, the may require a more direct approach to date, and perhaps a ranking for severity explore their databases and retrieve may be enough. Certain data will be best information (i.e., negotiating in person). A collected only on a time “map”, for example, list of potential data sources is below, but number of returning salmon per year, flood this list is not exhaustive—there are frequency, number of landslides per year, hundreds of different possible sources of number of storm events per month summed data in California. In all cases, when you over the last four decades, etc. access and organize data, maintain a log of where you got the data, make sure you get 4.5.1.4 Condensed or Summarized Data the metadata, and set up a filing system that is easy to use and intuitive. A list of data Many agencies and academic institutions source websites is posted at: have conducted analyses and models of http://cwam.ucdavis.edu. natural and human processes. Condensed or summarized data is new information 4.5.2.1 Federal Sources generated from analysis or modeling. For example, maps of vegetation types, Common federal sources of land cover/land precipitation, fuels moisture, and use data are land-management agencies, temperature permit estimates to be made of such as the US Forest Service, Bureau of fire risk, which can result in a new map of Land Management (BLM), National Park fire risk. The values in the fire risk map are Service (NPS), Bureau Indian Affairs (BIA), derived from the values in the other maps and US Fish and Wildlife Service (USFWS),
- 20 - California Watershed Assessment Manual, Chapter 4 August, 2004 regulatory agencies, such as NOAA- 4.5.2.3 University Resources Fisheries, and the Army Corps of Engineers, and research and technical Academic institutions can have rich mines agencies, such as US Geological Survey, of information, but it is not always easy to Natural Resource Conservation Service find the right people because they are often (NRCS), and National Oceanographic and spread out among departments. If the Atmospheric Administration (NOAA). university has a directory of faculty research interests on their website, this is a good The local offices of these federal agencies place to identify experts. If such a directory are a good place to begin assembling data does not exist, an alternative approach is to about the watershed landscape. These data go to the webpage for the relevant may be in map (spatial) or non-map format. department website, The departments may There are usually several natural science be divided among different colleges or professionals (e.g., a soil scientist or a schools (e.g., “Agriculture and wildlife biologist) who can answer questions Environmental Science” at U.C. Davis). about the data and direct you to the Departmental websites usually contain web appropriate staff for retrieving data. pages for each faculty member or research However, in larger offices, there may not be program. Reviewing these can help you find a central directory of all available data, and people who may have conducted research you may have to dig around a bit before you in your watershed or nearby. Call or email find everything you want. Some data may them—they will usually be happy to provide be called ‘draft’ or described as unavailable you with information or forward you to to the public. In some cases, you may be someone who can help. If you are lucky, able to gain access to these data anyway they may have already conducted analyses for analysis purposes, especially if the in your watershed, the products of which agency has pledged cooperation to your may be useful to your assessment. Student watershed group. theses and dissertations are another source of detailed information about a specific topic 4.5.2.2 State Sources and may be found in campus libraries.
State land management and regulatory 4.5.2.4 Local and Regional Agencies agencies also have a variety of types of data available online or upon request. Local agencies are sometimes the richest Examples are the California Department of sources of local data, though not always in Forestry and Fire Protection (CDF) Fire and the format you want. Only recently has GIS Resource Assessment Program, which has become common among county, municipal, data for vegetation and fire risk, the and district agencies. The data are not Department of Conservation (DOC), which always free (e.g., if the local agency has has information about landscape conditions bought it from a data provider) and may and disturbance (e.g., mined areas, have less predictable barriers for access agricultural preserve lands), and the than you might encounter with state or Department of Fish and Game (DFG), which federal agencies. However, these data can has data about wildlife and plant sometimes be of finer resolution and more communities. As with the federal agencies, current than larger-scale efforts by state or technical staff are familiar with the data the federal agencies. In this case, it is important agency has, but you may need to talk with to check the standards used to generate several people to discover everything and update data so that even if these available. Local offices are generally the standards don’t meet state or federal best places to begin. standards, you know what they are.
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4.5.2.5 Private Sources understand the opportunities and limitations of this approach. Private companies, utilities, or nonprofit organizations in your watershed may collect 4.6.1 Definitions and maintain their own databases about their holdings, the region, the county, or the GIS One older definition of GIS is “a watershed. These data may be easy to system of hardware, software, data, people, access (e.g., from a nonprofit organization) organizations, and institutional or nearly impossible (e.g., from a large arrangements for collecting, storing, landowning company), depending on the analyzing, and disseminating information data owner’s level of trust as to how the about areas of the earth”. (Dueker & Kjerne data will be used and what the owner may 1989, from Lillesand & Kiefer, 1999). lose from certain uses. The watershed Another is “a GIS combines layers of assessor should work with the stakeholder information about a place to give you a watershed group (if one is present) to better understanding of that place” access certain privately held data that are (http://www.GIS.com, a project of deemed critical or important to answering Environmental Systems Research Institute). questions about watershed processes or These two definitions capture the uses of disturbance. Data sharing may improve if the term GIS in this Manual. One important the data are not associated directly with point is that a GIS is not simply a repository landowner names. Even if you think getting of maps or a software package for making the data is a long-shot, it can’t hurt to ask. and printing maps, which might be better termed “digital cartography.” It is an 4.6 Geographic Information Systems analytical environment, populated by data and Spatial Data that you provide, data that are spatially referenced to a place on the earth (ESRI, The term “GIS” (geographic information Inc. 1995). A GIS for your watershed is system) gets used a lot in the watershed something you can use to find out things world. To some it means a single digital that are otherwise difficult or laborious to do map; to others it refers to a series of maps manually (e.g., which roads lie on steep on a computer and includes analysis of slopes). spatial data. The spatial data often originates from remote sensing of the earth, Digital map An electronic version of a from digitization of features from paper paper map and shows visually the relative maps, or from using global positioning positioning of mapped features (e.g., roads) system (GPS) units to geo-reference points in a place (e.g., watershed). or lines on the ground. The history of GIS includes people taking pictures of Spatial data Data about a space, such as battlefields from balloons (remote sensing), distribution and kinds of vegetation growing putting pins in maps for the locations of in a watershed, that can be displayed in a features (geo-referencing), and the digital map. development of rapid automated calculations with computers. Computer- Remote sensing The “science and art of operated GIS was created when these obtaining information about an object, area, capacities were refined and paper maps or phenomenon through the analysis of data could no longer capture processes on earth. acquired by a device that is not in contact If you are responsible for conducting a with the object, area, or phenomenon under watershed assessment that involves GIS, investigation” (Lillesand & Kiefer, 1999). you should become familiar with the terms Satellite imagery is an obvious example of and system descriptions below in order to remote sensing information. Remote sensing relies on the detection of
- 22 - California Watershed Assessment Manual, Chapter 4 August, 2004 electromagnetic radiation (e.g., visible light 4.6.2. Using Spatial Data and radar) that is either originating or reflecting from surfaces (e.g., leaves on Non-digital spatial data trees in the Amazon). Properties and changes in the properties of the Many maps available to an assessment electromagnetic radiation can be used as team will not be in digital form. Some of the surrogates for measuring properties of the most useful maps of historical activities or thing under investigation (e.g., plant type). conditions may only be in paper form. These can be valuable resources even if Digitizing The process of making a paper they are never digitized and used in a GIS. map usable in an electronic GIS by Useful maps will relate to common location manually drawing and transferring map schemes, such as the quadrangle, features into an electronic form using township, range, and section maps of the mapping software. This process attributes USGS, or latitude and longitude real-world coordinates to the points or lines coordinates. In order to analyze data on a map, which are stored as an electronic contained on these maps, you may need to data table, which, in turn, can then be transfer some of it to digital form (e.g., a visualized as a digital map. Digitizing could table of logging activity by sub-watershed), take place on the computer screen, where a or to acetate overlays, a cheap and non- drawing is created on top of a base map of digital way to create a GIS. What such a some kind, such as an aerial photograph of system loses in precision (lost during a place, or it could be done by tracing the copying) and accuracy (actual points and lines on a map using a desktop representation of ground features) may be digitizing tablet. made up for in speed and cost of acquisition. However, just as with the most GPS A global positioning system is a expensive GIS, the quality of the analysis satellite-based system that allows someone will be determined by the quality of the data holding a GPS receiver unit to determine and process of assessment. It is important latitude and longitude of their location on the to record actions and results so that others earth’s surface. The unit receives distance may easily tell how something was done information from at least four satellites, and why a certain result was obtained. which allows it to determine its position on the globe. Positional data from the unit Digital spatial data allows the user to “GPS” the location of features of interest on the ground (e.g., Once information is entered into a computer landslide) for later entry into a GIS. database with spatial descriptors, it becomes digital spatial data and can be Geo-reference Information referenced to used in a computer GIS. This provides the earth, or “geo-referenced” by relating many opportunities both to simplify your points, such as the corners of a map, to a assessment and to make it more coordinate system for the earth’s surface, complicated. Analyzing sets of data in such as latitude and longitude. Points are various combinations from visual overlays to thus associated with “coordinate pairs” or a calculated or modeled relationships value for each of the north-south and east- becomes somewhat easier. Because west axes (e.g., longitude and latitude). different types of information about a place Once information about a place is geo- are being used in such a way that the referenced, it can be overlaid by other location is the commonality, you may maps, enabling analysis to be done that discover relationships and qualities about a relates to a specific location or area. place that otherwise weren’t obvious. For example, if you had a database of street addresses for parcels within your watershed
- 23 - California Watershed Assessment Manual, Chapter 4 August, 2004 and a map of the streams, and you wanted The Federal Geographic Data to find all of the riparian owners, you could Committee use your GIS to combine these two sets of digital data that have a common spatial “The FGDC develops referencing scheme (e.g., latitude and geospatial data standards for the longitude) and find the landowner National Spatial Data Infrastructure addresses within a certain distance from a only when there are no externally stream. developed standards appropriate for Federal use. FGDC standards are Development of new spatial data should be developed in consultation and done in accordance with Federal cooperation with State, local, and tribal Geographic Data Committee (FGDC; governments, the private sector and http://www.fgdc.gov) guidelines. This academic community, and, to the committee is responsible for coming up with extent feasible, the international common standards for data development, community. FGDC standards are storage, and description. If the guidelines intended to be national in scope and go are not used, then data sharing becomes beyond individual agencies and the limited, and the utility of the data declines. Federal government enterprise. Federal agencies are required to use Types of digital data FGDC standards.
There are two main types of digital State and local agencies are information: 1) “spatial,” which tell you not required to use FGDC standards, where something is, and 2) “descriptive,” but are encouraged to do so to which tell you about the something. There promote data sharing between different are also two primary types of data used in levels of government.” GIS: 1) raster data, which refers to information that is distributed into “cells” The standards are online at: arranged in a grid pattern across the earth’s http://www.fgdc.gov/publications/docu surface, and 2) vector data, which is ments/standards/endorsed.html information occurring in a series of coordinate points termed “point” (single (FGDC Web site, 2003) coordinate pair), “line” (two coordinate pairs), and “polygon” (one coordinate pair on the ground (Lillesand & Kiefer, 1999). If per angle/corner) features. data for a map were collected by digitizing features from aerial or satellite photographs, Each data type allows for different types of then the spatial resolution of the recording data distribution and calculations. It is device is important, since this determines possible to convert between raster and the limits of the data’s use. The resolution of vector forms, though some information may particular films and digital recording be reduced in value or resolution depending devices, the height of the camera, and on the scales of the original data type and variables, such as atmospheric conditions, new data type. determine the actual resolution of the resulting photographs and derived maps. In 4.6.3 Data Scale and Resolution addition, remotely collected data may be aggregated into blocks of multiple pixels of Not all spatial data have been collected at a similar land-cover type or that are the same spatial resolution. In this case, dominated by one land-cover type. This “spatial resolution” refers to the ability of a process decreases the data’s resolution and sensor (e.g., a camera) to separate detail affects the data’s subsequent use.
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Scale refers to the relationship between resolution aerial photographs (1:2,000) of distance on a map or photograph compared your county and low-resolution maps of soil to the actual distance on the ground. An series or geological formations (1:250,000) example of scale is “1:24,000”, which that you want to combine in analyses (e.g., means that one inch on a map is equivalent percent of housing development on erosive to 24,000 inches, or 2,000 feet, on the areas). If data sets have been collected at ground. If map data are derived from different scales, use caution in any analyses photographs, then the resolution of the involving two or more with different scales. photographs will determine the map In an extreme case, 1:500,000 scale data resolution or scale. In general, the smaller should not be referenced to a 1:24,000 data the scale ratio, the higher the resolution, set because this represents an artificial assuming similarities in the resolution of the increase in accuracy. However, it is possible recording devices. A map derived from a to surrender data accuracy and use high- 1:5,000 aerial photograph may have higher resolution data (e.g., 1:24,000) at a reduced resolution than one derived from a scale of 1:500,000 if that is the only way to 1:500,000 satellite photograph. However, if perform an analysis. the resolution of the satellite camera is 100 times that of the aerial camera, then the 4.6.4 Metadata resulting data will have similar spatial resolution. In other words, the analyst can Metadata refers to the information discriminate between objects just as well in describing the data. Various information the satellite photograph as in the aerial about scale, how the data were created, photograph. how they are stored, purpose of the data, source of the data, originating As you collect data into a database and agency/organization/individual, and updates GIS, it is likely that they will vary in their should be included in the metadata. The scales and resolutions. You may have high- FGDC has developed standards for documenting spatial data. Most state and federal agencies follow these or similar Vector data standards and formats when describing data. It is critical to standardize these Point metadata so that the data can be used beyond a single person and that limitations and opportunities for uses are understood. Line An example of this would be the Calwater
2.2 system.
Polygon 4.6.5 Developing your Watershed GIS
Raster or “grid” pattern When developing a new GIS, a good starting point is to ask yourself two questions: “What questions do I intend to answer with this GIS?” and “How much do I have to spend?” Answers to the first question will tell you the scope of your GIS
project and help inform the second question. Costs for a GIS can vary widely and this is where there may be the least amount of information for the watershed group to make fiscal decisions. For example, you may decide you want to
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Questions for Your Watershed GIS sorting, and updating the files associated with a GIS. It is possible to accumulate 1) Location information (e.g., zip code, thousands of files and take up gigabytes of watershed, county) disk space. The key to managing this is organization of your files in a structure. 2) Location of important features you Once you have created a logical plan to characterize (e.g., road-less architecture for your GIS, organizing it areas, fragile soils, roads crossing should be relatively straightforward. streams) Filing systems 3) Trends in a place over time Just as with the filing system in your local 4) Spatial patterns and distributions library, the best GIS filing system is one that (e.g., fish populations and water storage) has an intuitively obvious structure and can be understood by users. There is no one 5) What would happen if you changed perfect way to create such a system, but things on the landscape (e.g., added a there are sets of rules that can be used to road or other disturbance) guide the construction. (ESRI, 1997) Develop categories that match your expectations for the types of data you will collect digital spatial data and do simple analyses (e.g., where roads cross streams) with an emphasis on visual presentation of Free GIS Software map information. In that case, your cheapest route is to use free GIS software “a complete index of Open Source / Free on a donated computer, taking advantage of GIS-related software projects” spatial data online and printing on a color http://www.opensourcegis.org inkjet printer. Being able to do this requires a basic education in GIS, which you can get “GRASS GIS (Geographic Resources cheaply or for free online. At the other end Analysis Support System) is an open of the spectrum, you may want to spend source, Free Software Geographical $10,000 to $100,000 hiring staff or a Information System” consultant to do all of this for you on a http://grass.itc.it purchased computer, using licensed software, and presenting your maps in large “MapServer is an OpenSource printed format and online using a map development environment for building server. A likely outcome of hiring a spatially enabled Internet applications.” consultant is that a GIS professional will do http://mapserver.gis.umn.edu/index.html a good job more quickly than someone local having to learn GIS. At the same time, if “open-source GIS-based applications GIS is likely to be part of your planning, you can download written for a variety of monitoring, and management work for platforms and in various languages” several years, it may make more sense to http://gislounge.com/ll/opensource.shtml train a volunteer or staff person to carry out the GIS in order to increase local capacity. “IDRISI, developed by Clark Labs, is an innovative and functional geographic 4.6.6 Data Organization modeling technology that enables and supports environmental decision making Most people who have used GIS for a while for the real world” are familiar with the problems of storing, http://www.clarklabs.org/
- 26 - California Watershed Assessment Manual, Chapter 4 August, 2004 be collecting, analyzing, and storing. The characteristics and land cover; elevation FGDC (http://fgdclearhs.er.usgs.gov/) uses and derived products; environmental the following categories: administrative and monitoring and modeling; facilities, buildings political boundaries; agriculture and farming, and structures; geodetic networks and atmospheric and climatic data; base and control points; geologic and geophysical scanned maps and charts; biologic and information; human health and disease; ecologic information; business and imagery and aerial photographs; inland economic information; cadastral and legal water resources and characteristics; ocean land descriptions; earth surface and estuarine resources and characteristics;
- 27 - California Watershed Assessment Manual, Chapter 4 August, 2004 society, cultural, and demographic Dueker, K.J. and D. Kjerne 1989. information; tourism and recreation; Multipurpose Cadastre Terms and transportation networks and models; and Definitions. American Society for utility distribution networks (see box above). Photogrammetry and Remote Sensing and American Congress on Surveying and If you don’t have limitations on electronic Mapping. Falls Church, VA. storage space, there are several ways to deal with using and modifying digital maps Dunne, T. and L.B. Leopold. 1978. Water in after their initial acquisition or creation. One environmental planning. San Francisco: is to maintain the original versions of maps W.H. Freeman and Company. in separate backup directories so that you can always go back to the original. Later, or ESRI, Inc. 1997. Understanding GIS – The “final”, versions of maps that are the most ARC/INFO Method. 4th ed. Environmental recent can be retained in a unique directory. Systems Research Institute Inc. Redlands, This will make updating maps easier as CA. modified versions can replace the most recent version. Any modification should of Grant, G. 1988. The RAPID technique: a course be accompanied by an update of the new method for evaluating downstream metadata describing the changes and giving effects of forest practices on riparian zones. the date. General Technical Report PNW-220. Corvallis, OR: U.S. Forest Service, Pacific Develop a structure rationale that fits Northwest Forest and Range Experiment people’s expectations for the system. The Station usual structure is a hierarchical, or tree structure. The diagram below shows an Herschey, R.W. 1985. Streamflow example of this type of structure, using measurement. London: Elsevier. FGDC categories and samples of data types you might have. Hornberger, G.M., J.P. Raffensperger, P.L. Wiberg, and K.N. Eshleman. 1998. In conclusion, the nature of your watershed Elements of physical hydrology. Baltimore: assessment should guide your collection The Johns Hopkins University Press and organization of the various kinds of data. The questions you ask in your Jones & Stokes Associates, Inc. 1998a. assessment determine the kinds of data you Historical riparian habitat conditions of the need (e.g., water quality, mapped sources San Joaquin River. San Joaquin River of pollution, projected human activities). The Riparian Habitat Restoration Program. level of complexity and nature of the Sacramento. analyses determine the data types (e.g., digital vs. paper maps), which, in turn, Jones & Stokes Associates, Inc. 1998b. determine your strategy for data Analysis of physical processes and riparian organization. habitat potential of the San Joaquin River. San Joaquin River Riparian Habitat 4.7 References Restoration Program. Sacramento.
Abell, D.L. (ed.) 1989. Proceedings of the Lillesand, T.M. and R.W. Kiefer 1999. California riparian systems conference: Remote Sensing and Image Interpretation. Protection, management, and restoration for 4th ed., John Wiley & Sons, Inc., NY. Pp. the 1990s. General Technical Report PSW- 724. 110. Berkeley: U.S. Forest Service, Pacific Southwest Forest and Range Experiment Michael, G. 1991. Environmental data Station. bases: design, implementation, and
- 28 - California Watershed Assessment Manual, Chapter 4 August, 2004 maintenance. Lewis Publishers. Boca Raton State Water Resources Control Board, FL. 98 p. Division of Water Quality.
Michener, W.K., J.W. Brunt, and S. Stafford U.S. Department of the Interior Bureau of (eds.). 1994. Environmental information Land Management (BLM). 1995. Riparian management and analysis: Ecosystem to area management: process for assessing global scales. New York: Taylor and proper functioning condition. Tech. Ref. Francis. 1737-9, Denver CO. 60 p.
National Research Council. 2002. Riparian University of Washington. 2003. Stream areas: functions and strategies for riparian bibliography. Center for Water and management. National Academy Press. Watershed Studies, with USFS Stream Wash. DC. 428 p. [//www.nap.edu] System Technology Center, http://riparian.cfr.washington.edu/ Nelson, C.W. and J.R. Nelson. 1984. The Central Valley riparian mapping project. In Warner, R.E. and K.M. Hendrix. 1984. California riparian systems: Ecology, California riparian systems: Ecology, conservation, and productive management, conservation, and productive management. edited by R.E. Warner and K.M. Hendrix, Berkeley: University of California Press 307-13. Berkeley: University of California Press. Yoshiyama, R., E. Gerstung, F. Fisher, and P.B. Moyle. 2001. “Historical and present Sands, A. (ed.) 1977. Riparian forests in distribution of chinook salmon in the Central California: Their ecology and management. Valley.” CDFG Fish Bulletin 179. Publication 15. Davis: University of California, Institute of Ecology. Yoshiyama, R.E. and P.B. Moyle. 1996 in Sierra Nevada Ecosystem Project: Final Tetra Tech. 2003. The status and future of Report to Congress, Vol. III. University of biological assessment for California CA, Davis, Centers for Water and Wildland streams,final report. Sacramento: California Resources
Collecting and Organizing Data Check List
Collect Data Identify sources and gather numeric data on water quality, hydrology, riparian and wetland areas as well as physical/habitat conditions Identify sources and gather anecdotal information on any topic relevant to the assessment Identify sources and gather landscape data, in both digital and non- digital forms Evaluate the quality of data Archive Data Store numeric data in a database management system Store, organize and categorize spatial data in a file structure Store metadata
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7 The Assessment Report
Reporting the assessment questions, approaches taken, findings, and Basic Watershed Assessment Report conclusions is one of the most critical Components parts of watershed assessment. Other Problem statement than people involved in the assessment process, nobody else will understand Watershed and watershed assessment definition what you did unless you clearly report it. A question or series of questions about watershed condition Chapter Outline Reasons for conducting the assessment, such as supporting planning 7.1 Alternative Forms of Report The likely or intended audience for the 7.2 Presentation of Data assessment 7.3 Assessment Report Evaluation Planning and management process used for 7.4 Report Release and Publication assessment
7.5 References Descriptions of Watershed Attributes ______Methods Used in the Assessment 7.1 Alternatives Forms of Report Data and Information Collection Sources of existing data Many different types of studies have Collection of new data been called watershed assessments. Catalog of pertinent data Because of the broad scope of the Monitoring methods definition of the term, many of them Methods used for data analysis contain elements that are legitimately Statistics/trend analysis GIS assessments of watershed condition. Modeling Because of the various goals an assessment could have, funding Watershed Conditions – Historical and Present source(s), and types of issues or Geography problems in a watershed, there are a Cultural and economic conditions variety of ways of presenting the results. Management and policy context The following section briefly reviews Land use various types of reports. Climate Hydrology 7.1.1 Watershed Assessment Geomorphology Water quality
Aquatic habitat In this Manual, we have defined Riparian habitat watershed assessment to be a process Upland habitat and wildlife for analyzing a watershed's current Sources of uncertainty condition and the likely causes of these Critical information gaps conditions. We have defined the watershed assessment report Results of the Assessment – Key Findings as documenting the findings of the Comparison of conditions/processes to watershed assessment process benchmarks or historical or reference The box to the right gives some basic conditions Result of information integration components of a watershed assessment Overall watershed condition or sub-watershed report. They are not intended to show condition the exact order, so much as important things to include. Conclusions, recommendations, and next steps
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The basic report structure is the description 7.1.3 Existing Conditions Report of the problem or question, the methods used to collect and analyze information This type of report often leads to a about watershed attributes, description of subsequent assessment containing conditions for watershed attributes, key analyses of future scenarios and/or a findings and results of integrating condition management plan. It is a form of watershed information, conclusions, and assessment in that it can be a description of recommendations. the conditions within a watershed, which could be used for certain types of watershed Examples of watershed assessment reports management decisions. As with the scan be found at: http://cwam.ucdavis.edu. disturbance inventory, there are a couple of One report that has similar organization to things to keep in mind. that proposed in this Manual is the Millerton • If an existing conditions report is Area Watershed Assessment report intended to support a later watershed (http://www.sierrafoothill.org/watershed/draft assessment or watershed management _assessment.htm). plan, explicit connections should be made between elements of the 7.1.2 Disturbance Inventory conditions report and components of the assessment or plan. A disturbance inventory, as its name • An important element of the report could suggests, is a listing and description of the be recommendations for watershed types of natural and anthropogenic analysis and development of models disturbances in a watershed. The inventory addressing future scenarios. could be used to determine the goals of a future assessment, based on the kinds of 7.1.4 Watershed Management Plan disturbances identified. In limited circumstances, it could also function as an Assessments often form the basis for a assessment if it describes where and how watershed management plan (WMP). The the disturbances are occurring. A WMP will typically describe actions that can disturbance inventory could precede a be taken by decision-makers to address watershed assessment by detailing the impacts to watershed condition, restore basic characteristics of the watershed and various parts of watershed function, or to the natural and human disturbances describe negative actions and occurring there. accompanying mitigations. The assessment • If a disturbance inventory is intended to may be embedded within the WMP as one support a later watershed assessment, component of the overall planning process. explicit connections should be made between elements of the inventory and Here are some things to consider when components of the assessment. developing a watershed assessment as part • If the disturbance inventory is to stand of a WMP: alone, then it can list the disturbances in • Steps should be taken to make clear the watershed without necessarily going distinctions between the findings to the lengths described in this Manual contained within the assessment phase of linking conditions to potential sources and the recommended actions in the of problems or stress. WMP. You will also need to make connections between the assessment findings and the recommended actions in the WMP. • There will be WMP recommended actions that are linked to different kinds
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U.S. EPA’s Description of Required (9) Elements of a Watershed-Based Plan:
To ensure that Section 319 projects make progress towards restoring waters impaired by nonpoint source pollution, watershed-based plans that are implemented with Section 319 funds to address 303(d)-listed waters must include at least the elements listed below. The watershed planning process should be dynamic and iterative to assure that projects whose plans address each of these nine elements may proceed even though some of the information in the plan is imperfect and may need to be modified over time as information improves. Existing plans may be used as building blocks for plans that meet these nine elements. U.S. EPA believes that these nine elements are critical to assure that public funds to address nonpoint source water pollution are used effectively.
a. An identification of the causes and sources or groups of similar sources that will need to be controlled to achieve the load reductions estimated in this watershed-based plan. b. An estimate of the load reductions expected for the management measures described under paragraph (c) below. c. A description of the NPS management measures that will need to be implemented to achieve the load reductions estimated under paragraph (b) above and an identification (using a map or a description) of the critical areas in which those measures will be needed to implement this plan. d. An estimate of the amounts of technical and financial assistance needed, associated costs, and/or the sources and authorities that will be relied upon, to implement this plan. e. An information/education component that will be used to enhance public understanding of the project and encourage their early and continued participation in selecting, designing, and implementing the NPS management measures that will be implemented. f. A schedule for implementing the NPS management measures identified in this plan that is reasonably expeditious. g. A description of interim, measurable milestones for determining whether NPS management measures or other control actions are being implemented. h. A set of criteria that can be used to determine whether loading reductions are being achieved over time and substantial progress is being made toward attaining water quality standards and, if not, the criteria for determining whether this watershed-based plan needs to be revised or, if a NPS TMDL has been established, whether the NPS TMDL needs to be revised. i. A monitoring component to evaluate the effectiveness of the implementation efforts over time, measured against the criteria established under item (h) immediately above.
You may also refer to the full text of the Section 319 guidelines that is available on EPA's NPS website at: http://www.epa.gov/owow/nps/Section319/319guide03.html
of assessment findings. For example, 7.2 Presentation of Information impacts may be observed for which specific remedial actions are How you present your data will determine a recommended. There may also be large part of how much people will accept recommendations for local ordinances, your findings and use the assessment to monitoring programs, and site-specific inform their decisions. Identifying restoration projects. presentation formats that are • Part of the WMP should be devoted to understandable to a broad audience is the describing how assessment will goal. continue as management actions are carried out. 7.2.1 Audience
Different audiences and purposes require Action 7.1 different approaches for presenting the • Name your assessment results of your watershed assessment. Be based on its actual content prepared to deliver the results of your
- 3 - California Watershed Assessment Manual, Chapter 7 August, 2004 watershed assessment to a wide variety of detailed and technical information. audiences, from schoolchildren to renowned researchers. For example, you may present Throughout your report, balance is needed to watershed committees, groups, and between quickly reaching your audience councils, which are usually composed of and presenting lots of technical material. people with some level of watershed This Manual intentionally goes into detail on knowledge and experience. However, you some topics to provide adequate resources may also need to present your assessment for those seeking detailed information, but it to people who did not have time to be is not a good model for your watershed involved in the process of developing it. assessment. Too much emphasis either They will not be as familiar with the issues, way may weaken the effectiveness of your data, and results, or their significance so assessment product. they may require more in-depth presentation (e.g., in a workshop). Local Formatting and presentation can be as officials, on the other hand, may only have important as content, even though most of time for a five-minute presentation. Be your effort up to the report writing phase has prepared and careful when presenting your been on content. Too often, budgets for story to the press. Stories in the local technical reports like assessments media can do wonders for political support underestimate the time and cost that are of your watershed work. However, many needed to do a good job in presenting the journalists are looking for a catchy headline findings. The writing and presentation effort that may not accurately represent your can be a full one-third of the assessment’s findings. costs, especially if multiple drafts are required. Keeping a style manual handy for 7.2.2 Text guidance on proper sentence structure, tense use, and other grammar issues is a One way to start writing your report is to good idea. Many are available, but two good develop an outline of the components that ones are Strunk and White (2000) and the you expect to include (see box on first page Chicago Style Manual (2003). of this chapter). You can fill in this general outline to make it more detailed and assign Hiring a technical editor is usually authors to various sections as you collect worthwhile. This person can help the the assessment material. Early in the assessment authors at each stage of the process, consider how you will use maps, preparation. If multiple authors are involved, graphs, charts, etc., and plan your text this assistance is even more critical. Ask the accordingly. In this process, balance brevity technical editor to provide you with Editorial with the need to present lots of technical Guidelines before you begin writing your material. Consider an Executive Summary assessment. Such guidelines can clearly for overview and appendices for very address: target audience, tone and style,
“A Vivid Description of Watershed Processes: Hot Salsa in the Mattole”
The Mattole Watershed Council’s watershed assessment and plan for the estuary, Elements of Recovery (1995), represents a well-written document, with minimal jargon, that attests to the importance of language in helping the reader visualize a key concept.
“…the Mattole estuary / lagoon feels the effects of events upslope. Sometimes these effects persist long after the upstream impacts have ceased, as the forces unleashed continue to work their way through the system like the chili peppers of hot Mexican salsa revisiting the diner the next day. Lasting recovery will require that the impacts oozing down from the hillsides and roads diminish throughout the watershed.”
- 4 - California Watershed Assessment Manual, Chapter 7 August, 2004 writing tips, formatting conventions, style same amount of information presented on guidelines, and standard terms, spellings, one map would likely be difficult to decipher. and acronyms. An effective writing style can really improve the readability of your report. Lengthy tables, (those longer than one Try to avoid a dry, jargon-filled style for your page), should probably be placed in an general audience. appendix.
Having the topic “Limitations of the A graphical presentation of data and Assessment” as your last chapter is highly findings can be a very effective recommended. Each watershed communication tool (Kerr 1995; text box assessment is limited by duration, scope, below). Simple plots that require a minimum detail, scale, and analysis level due to of explanatory text in the caption usually are constraints in budget, time, access, and most effective. One criterion for judging overall resources. Acknowledge how your simplicity is whether you could understand particular assessment process and product the graph’s message if all the text and were limited, and how these limitations also labels were in a different language. provide opportunities for improvement for future assessment efforts. The Gualala Graphs can be great! River Watershed Assessment’s last chapter • Graphical displays are valuable for provides a helpful example of how to revealing patterns that might be missed. address this issue (North Coast Watershed • Clearly illustrated and labeled graphs Assessment Program, 2003). can say a thousand words in a relatively small space. 7.2.1 Tables & Graphs • Three-dimensional and color plots can be particularly effective in some cases. Tables can quickly summarize important quantitative or qualitative data in a logical When creating a graph, be sure to: order and reduce the need for text. For • Make the graph easy to follow like a example, the table below provides a readily good story. readable indicator of which streams and • Make a point. stream reaches contain what limiting factors • Avoid excess complexity, such as fancy (based on previously-collected data). This options with computer graphing.
Example of a Qualitative Table: Limiting Factors for Steelhead and Coho Salmon, Aptos Creek stream system, Santa Cruz County (excerpt from: Conrad & Dvorsky (2003) Aptos Creek Watershed Enhancement Plan) Location Sediment- Sediment- Adult Spring & Summer Large Spawning Rearing Passage Summer Water Woody Barriers Streamflow Temperature Material Lagoon No Yes No Yes Yes Yes Mainstem Yes Yes Yes- Yes Yes Yes to Moores drought Gulch only East Yes Yes No Yes No Yes Branch to (Yes for coho) Hinckley Creek Hinckley Yes Yes Yes Yes No Yes Cr.
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The best uses of different graph types (adapted from Kerr, 1995). Type of Graph Best Uses Line graph To emphasize the relationships between data points and illuminate trends in data. (Also called a “scatter plot” in software such as Excel.) Bar graph To put more emphasis on the individual points. Useful for comparing quantity at one site over time, or multiple sites at one time, and for displaying summarized data. Stacked bar graph To show data as proportions of a whole. Especially useful to show comparisons between several similar stacked bars. 3-D bar graph Preferable for slide show or poster, but not useful for trying to read the actual numbers. Three-axis graph helpful in visualizing the data set as a whole, though takes longer to digest. Pie charts Easy for general public to understand, but can only be used for data that can be expressed in terms of proportions, or percentages, of a whole. Types of data that work well are land uses, population by species at a site, and pollutant loadings.
• Avoid a misleading graph, such as one watershed. Most landscape data (e.g., that exaggerates small differences. vegetation types) are best viewed as maps. • Find graphing software programs that Waterway data (e.g., for water quality) can are capable of producing the kind of be attributed to the waterway on a map as a product you want. way of visualizing some property of the • Use the appropriate scale for your data; waterway. For example, if the average don’t combine more than one parameter water temperatures for particular creeks are on a graph if the scales are very considerably warmer than for some other different. creeks, then the temperature values can be • If you are comparing between time incorporated into the information about the points or you are looking at trends, be streams in your GIS. These values can then sure to include the results of statistical be represented by map colors that show the tests of significance of your findings. range of temperatures.
7.2.2 Maps Certain types of maps may be very useful for funders, legislators, supervisors, or other Many watershed attributes can be best people who need succinct information in expressed in map form, especially since this order to support recommended projects. is the way many people picture their Examples of this would be the locations of fish passage impediments and some “For information displays, design indication of the relative habitat value that reasoning must correspond to scientific would be gained upstream if the impediment reasoning. Clear and precise seeing is removed, or locations and graphic becomes as one with clear and precise indicators of sediment sources and their thinking…It also helps to have an relative contribution of sediment (such as endless commitment to finding, telling, larger circles for higher volume sources). and showing the truth.” These can help “make the case” graphically ~ Edward Tufte (1997) Visual for high priority projects and are useful to Explanations, p. 53 include in grant proposals.
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7.2.2.1 Common Map Features 7.2.2.2 Designing the Informative Map
The point of your maps is to convey a story Once you have the basic information down to the viewer. Your assessment maps will for the watershed map, you will overlay or live on past your immediate use of them and underlay particular information about the may be used in ways you did not anticipate. watershed, sub-watersheds, or areas within Make sure that they unambiguously show the watershed. Although the human eye can what you want them to show. Make sure detect differences between a wide array of map features are obvious. Make sure the colors, there is only so much information the map can speak for itself and does not need brain can handle at once. It is best not to you to interpret it. overdo the amount of information in a single map. It is possible to include two or three A good way to convey information in a very concepts about the watershed (e.g., where direct way is to use a wide range of colors human populations are high and water and textures (e.g., hatching) for different quality is poor); this can be done by using features. You could have a random variety colored or hatched polygons (areas) for of colors for things that are not on a gradient certain concepts, and lines for others. (e.g., vegetation types), or a range of Although you may want to include more intensities of a single color for things on a than three concepts on a map, you should single gradient (e.g., average income). instead create several related maps. However, don’t overdo the number of colors or the intensities of a single color. Your Certain map components and concepts are readers can only deal with about five color easier to display together, while others will intensities or perhaps a dozen different be more challenging. Combining several colors per map before they will be data sources with the same symbol type overloaded. (e.g., line or point) will be more difficult than using several different symbol types in A readable legend is critical to a good map. combination. It may be necessary to have If the map is used alone, the legend may several kinds of points and lines on the contain the only description of the map’s same map to make a particular point. In this contents that a reader will see. The legend case, try to develop classes or groups of should have a title, a scale bar, a compass symbols to match the classes of features rose, a description of each type of feature you are representing. For example, you can on the map (e.g., lines, roads, and streams), use shades of grey and black to represent units, publication date, and the name of the roads and towns, shades of blue to analyst/mapper. represent different kinds of water-related features, and shades of green and red to Most people relate to certain watershed represent natural features and potential features, so these things should also be risks to these features respectively. included on your maps as basic components. Important components of a 7.2.2.3 Publishing the Maps watershed map include the following: a) watershed and sub-watershed boundaries, There are several ways to publish your b) waterbodies, c) highways and major map, online within an internet map server, roads, d) topography, and e) urban centers. online as an image file, in your report, and You can represent (a) through (d) with as a poster. different colored lines, (d) with shading, and (e) with dark polygons. 1) Internet map servers are increasingly common ways to present multiple layers of mapped information. They can be very complex if they include all the information
- 7 - California Watershed Assessment Manual, Chapter 7 August, 2004 for a watershed. One way to deal with the to take a fair amount of time and to involve complexity is to split the map server project your assessor(s) as (s)he or they respond to into several pieces which may contain comments. In this case, time may equal common elements. For example, a) money and so the review process should be hydrology – including locations of included in the overall budget. waterways, waterway-associated vegetation, locations of potentially impacting 7.3.1 Performance Indicators land uses, locations of roads, ownership; b) land use – including vegetation, hydrology, An assessment report must meet certain developed areas, county general plan land expectations for its support of future allocation, parcel boundaries. Consider decisions. This is the “performance” of the maps as portals to other information (e.g., assessment. There are indicators for this tables and text narratives). performance, some of which are: 1) An easy to follow structure to the assessment and report so that the users Action 7.2 can follow the logic used by the assessor(s). • Develop an outline 2) The connections between • Write text suited to the audience questions/issues, data collection, data that accurately and concisely analysis, conclusions, and any describes your approach and recommendations should be clear. findings 3) The presentation of data, analytical • Develop tables and graphs techniques chosen, and analysis products summarizing data analysis and should be very clear. 4) If conclusions are developed from findings quantitative information, then statistical tests • Map watershed information and should be included as the basis for the publish online or in your report conclusions.
7.3.2 Draft and Partial Products 7.3 Assessment Product Evaluation There will probably be many parties A watershed assessment report should involved directly or indirectly in the analysis contain the why, how, and who of the and decision-making phases of your analysis and data collection effort. All assessment. They should be apprised of the aspects of the assessment should be progress and direction your assessment is reviewed with different standards and taking during the process. Intermediate and potentially different reviewers. For example, draft products should be reviewed by an assessment intended to support stakeholders and assessment team watershed management planning by a members. If you choose to have this review watershed group may need different take place then make sure you also reserve performance standards than one intended time to respond to their queries and for decision-support about pollution comments. discharge. Because assessments should include a very wide array of types of Possible checkpoints for external review information, reviewers from a range of could be the following: disciplines should be employed. After review, an edited version of the report • An assessment plan and outline. Detail should be developed and provided to the the questions, data collection, analysis reviewers to ensure that their comments and presentation approaches. Describe were adequately addressed. You should potential audiences and management or expect the review and revision process itself policy connections.
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to the issues in the watershed examined in • An internal draft assessment. Show the the assessment. They should also be both data collected, the sources for the data, familiar with the management and policy the data analysis completed, and the aspects of the assessment and not invested preliminary findings. in the outcome of the assessment. For example, a forester might make a good • A public draft assessment. Finalize data reviewer for an assessment of a heavily- collection and analysis, integrate the logged watershed, but only if (s)he was not data if desired, show data and connected in any way to those doing the knowledge gaps, describe findings logging. relative to original questions and otherwise, detail recommendations. Here are some guidelines to consider when choosing reviewers for your report: Once these documents have been 1) The number of reviewers should presented to the technical team, correspond roughly to the number of issues stakeholders/watershed group, and/or the raised in the assessment and the public, a process for accepting comments complexity of the assessment. should be described and a clear statement 2) The range of reviewer experience should made about whether or not these comments include people with extensive field can result in changes to the assessment. If experience in the watershed to people doing the assessment will lead to management academic research in relevant scientific activities, many stakeholders may want this disciplines. chance before feeling comfortable with your 3) The reviewers should commit in writing at moving on. the beginning of the process to providing a written review of part or all of the report by a Assessing watershed condition should be a certain deadline and be willing to check the continuous process. However, once you responses to their review. have summarized your findings in a report, 4) The reviewers will preferably have done released the final draft, and accepted and similar reviews before and be familiar with responded to comments, it is okay to state working with watershed groups and/or the that monitoring or management actions may watershed scale. occur before the next assessment is 5) The reviewers should show some completed several years later. enthusiasm about the review process and working with the assessor(s). 7.3.3 Peer-Review 6) Reviewers should be chosen with the knowledge or agreement of the committee Peer-review of publications is a common of interested parties (e.g., a watershed occurrence in scientific and technical fields group). and watershed assessment should be no different. There will obviously also be a There are several basic steps to carrying significant amount of internal review before out a report review process. A) Adopt a a report is released for external review. protocol for the review and revision. B) Carry out recruitment and selection of The selection of reviewers is a critical task reviewers. C) Communicate with the in this process. Expert reviewers willing to reviewers to remind them to actually do the spend their precious time reading your review and send their critique. D) Provide a assessment report may be hard to come by. summary and complete list of comments to There are various ways to capture their the assessor(s) and the steering committee. attention, from recognition to paying them a E) Decide which comments will be stipend for the review. The reviewers should addressed and by whom. F) Follow-up with come from a range of backgrounds related those doing the revision to make sure it is
- 9 - California Watershed Assessment Manual, Chapter 7 August, 2004 happening. G) Incorporate revisions into a reader will be reading your report on a final draft version of the assessment report screen and that you will have to invest effort and review internally. H) Send the final into developing an assessment Web site. revised draft to the reviewers to ensure that their comments were addressed. I) 3) Hard-copy reports are the traditional way Incorporate any new changes and publish to report on assessment work. They are the final report. what people are used to reading and can be distributed widely (assuming you have a Action 7.3 good printing and mailing budget). • Use performance indicators and Hyperlinks and large volumes of material a peer-review process to are more difficult to manage with this format. In addition, because there is an evaluate interim and final expectation that reports will be published products online, a search of watershed assessments will not find yours. 7.4 Report Release and Publication The best publication scenario may be to You have several primary options for combine 2 or 3 of the above possibilities. publishing and releasing your assessment This will both increase the breadth of your report. These include CD-ROM, online, and audience stretch your publication budget. If as a hard-copy report. You may choose one you already have an organizational website or several options depending on your needs or have access to part of another and budget. organization’s or agency, then contemporary software can be easily used 1) CD-ROMs are an efficient way to widely to publish the report online. For example, if distribute your assessment report, including you are reading this text online, it was large volumes of text, pictures, maps, and written in MS Word, converted to PDF appendices. You can you use hyperlinks format (Adobe), and both file formats saved embedded in your report to connect your to a server containing the CWAM website. reader with background and reference The time to do that was less than it would material important for understanding your take to print and bind the report or burn and assessment. Other than developing the label a CD. In most cases, it is probably not report, copying CDs is your main cost, worth converting your report to an HTML which includes the CD-writer. One format as your Word document could look disadvantage of this approach for some of and perform (e.g., links to other material) your readers will be that (s)he will be the same way. In whatever form you think is reading the report on a screen rather than a best, post your report on your organization’s paper page. Web site.
2) Online publication is one way to reach a Action 7.4 wide assortment of people who you may or may not know, who may be forwarded the • Choose a publication type to URL for the report or who may find it using match your budget and intended an online search. Examples of online audience watershed assessment reports are given on the CWAM website under the “watershed assessments” button: 7.5 References http://cwam.ucdavis.edu. This approach th allows for the same large volumes of Chicago Manual of Style. 2003. 15 ed. material and hyperlinking as CDs. Two University of Chicago Press. Chicago, IL. disadvantages of this approach are that the 956 p.
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Conrad, M. and J. Dvorsky. 2003. Aptos Creek Watershed Assessment and Enhancement Plan. Coastal Watershed Council and Swanson Hydrology and Geomorphology. Santa Cruz, CA. 82 p.
Kerr, M. 1995. Using graphs to tell your story. Volunteer Monitor (Spring 1995).
Mattole Watershed Council. 1995. Dynamics of Recovery: a plan to enhance the Mattole Estuary. Petrolia CA.
North Coast Watershed Assessment Program. 2003. Gualala River watershed assessment. Gualala Assessment and Support Team, California Resources Agency and CalEPA, Sacramento. 367 p. plus appendices.
Strunk, W. and E.B. White. 2000. Elements of Style. 4th ed. Pearson Higher Education, Upper Saddle River, NJ. 105 p.
Tufte, E.R. 1997. Visual explanations: images and quantities, evidence and narrative. Graphics Press, Chelsire, CT. 156 p.
THE ASSESSMENT REPORT CHECKLIST
Select a report format Write the Report o Outline the content, including texts, figures, etc. o Develop a draft Obtain internal and external review of the draft Develop a final report based on feedback Publish the report online, on CD, or as a hard-copy
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6 Information Integration
Once you have collected all the data effect on the conditions to be able to needed or available to answer your integrate this information. But bringing watershed assessment questions, you face together information on the conditions is the challenging step of integrating the very valuable in and of itself. It is easier to information in a way that informs decision- work with a combined information set making. Information could be numerical because reference values are available for data, or some other form of data. Data many conditions thus facilitating analysis analysis comes before integration (see and integration of information. Chapter 5). Chapter Outline “Information integration” here means combining or linking information about 6.1 Choosing the Integration Approach various watershed processes and attributes 6.2 Understanding the Modeling in a way that leads to conclusions about Process overall watershed condition and why the 6.3 Cumulative Watershed Effects watershed is that way. You could integrate 6.4 Methods for Data Integration and information for particular processes, like the Synthesis movement of sediment from hillslopes 6.5 Sensitivity Analyses and Developing through waterways until it is deposited and Future Scenarios the impacts of that transport and fate, for 6.6 References example. You could also combine multiple ______processes and potential impacts in a system using indicators for potential impacts (e.g., 6.1 Choosing the Integration land use), system stressors (e.g., water Approach temperature), and impacts (e.g., aquatic biota). Without integrating individual While assessments typically involve processes (or separate disciplines or information integration of some kind, there specialties) into the watershed assessment, are few formalized approaches to it may fail to identify potential causes of the integration. In this section, methods are watershed’s condition and important presented that might fit your needs and linkages among watershed processes. available resources. we present several examples of approaches that scientists and Integrating information about your watershed partnerships have used in watershed’s condition aids in decision California. None of them is necessarily making that transcends management or “right” or always usable; they are listed here restoration actions associated with a single to inform you of the range of available process or problem. For example, moderate choices. levels of resource extraction, agriculture, urban development, water management, The relative condition of watersheds and and permitted waste discharge may waterways can be expressed in a variety of individually result in measurable impacts, ways, but it is commonly measured using but may not result in legal concerns about such indicators as drinking water standards, any one of these processes. However, their aquatic community composition, terrestrial cumulative impacts on a waterway may be and riparian vegetation condition, and sufficient to make the water unusable by constraints on the free flow of water. A wildlife and humans. In some cases, there majority of watershed or waterway will not be enough knowledge about the monitoring and restoration projects are relationships among processes and their based upon definitions of “health” that are
- 1 - California Watershed Assessment Manual, Chapter 6 August, 2004 either explicit (e.g., water quality standards) whether or not to integrate if you choose to or implicit (often expressed as deviation pursue integration for describing watershed from “historical condition”). Any risk or condition: condition assessment scheme should make these watershed health definitions explicit 1) Take on information integration only if so that stakeholders understand and you (or your technical advisors) have prior support the relevance of the findings or experience in doing so or in doing products of the assessment activities. something similar. Making these overall watershed 2) Integrate only if you have adequate assessments will require the development information about the component systems of a scheme for integrating the information. and knowledge about how they interact with each other. There are many possible ways to integrate 3) Be sure that integrating information information, from qualitative to highly answers a scientific or management quantitative, from informal to formal. Many question about something that relates to watershed partnerships contain a group of more than one watershed process. experts from different disciplines who can 4) Test whether or not you have enough evaluate information and form professional knowledge about the system to proceed by opinions about watershed condition(s) and developing a conceptual model and diagram the potential causes of those conditions. for the watershed. See how many of the Other watershed assessments rely on boxes and arrows have mathematical computer modeling for most of the relationships associated with them, as processing of information and then base opposed to guesses. conclusions on the products of these models. Some assessment programs 6.2 Understanding the Modeling develop models that return evaluations of Process watershed condition as the final product. Many methods of data integration involve When Not to Integrate the use of models. A model is a scaled representation of a system, just as a model Some watershed experts interviewed during boat is a scaled model of a real boat. The the development of this Manual argued term “model” covers a lot of conceptual and against the integration of watershed data. computational territory. You could model Their position was based on the generally using only mental processes, or you could poor understanding of how many natural rely on a physical model intended to systems work in California and the represent a system, such as a watershed. inadequate data and knowledge available to When you developed the picture, or most assessors doing the integrating. They conceptual diagram (chapter 2) of your also believed that by doing a good job of watershed’s processes and influences, you investigating individual processes in a were modeling, even if the picture was only watershed, the typical assessor and group in your head. or agency will find out enough to make good decisions about management and There are many types of models. The four restoration. By pursuing an integrative main categories of models are: a) component, there is the risk that the conceptual, b) verbal, c) mathematical, and assessor could invest large amounts of time d) physical or mechanical (Shenk & Franklin and end up producing a questionable or 2001). useless product. The argument against • Conceptual models are mental pictures integrating has merit and deserves of how a particular system works, which acknowledgment here. Here are several often get put into a diagram (see Ch. 2 suggestions for dealing with deciding for more details).
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• Verbal models are narrative • An aid for evaluation and decision- explanations of systems. making • Mathematical models are equations or • Dependent on the quality of inputs series of equations that describe rate processes (amount of something over A model is not: unit time) or relationships among • A replacement for understanding a processes. system • Physical models are based on • Independent of experts measured rules driving a system as well • A substitute for good science and field as data from the system and are work intended to represent the system. • The answer Physical models must be calibrated using data that accurately describe 6.3 Cumulative Watershed Effects existing conditions. Considering how the effects of human Following calibration, and periodically activities may combine to have greater throughout their useful life, models must be consequences than the individual effects is verified by demonstrating that they central to the watershed approach. Thinking accurately predict existing conditions about processes and impacts in the (Michael 1991). watershed context usually involves combining individual, seemingly isolated One part of understanding modeling is events. having an appreciation for its limitations. Probably one of the best rules for any kind Irrigators and water diverters have been of modeling is “garbage in, garbage out.” aware of cumulative watershed effects for This means that a model is only as good as thousands of years. As individual farmers the modeler’s knowledge of the system successively diverted water out of a stream used to construct the model and the data to irrigate their fields, they quickly noticed supplied to run the model. A system where that less water was available downstream. there is very little overall understanding of None of the individual diversions had much function and not much data available is not of an effect, but the combination of dozens a good candidate for computer modeling. to hundreds of diversions could dry up a However, if it is similar in some ways to stream. nearby systems, then you may be able to develop a conceptual model sketch for it. The first known scientific evaluation of Models sometimes are perceived as “black cumulative watershed effects was a study of boxes” because the assumptions, the downstream consequences of hydraulic uncertainties, and methods are not clearly mining in the Sierra Nevada foothills during identified. Without clearly identifying what the 1860s. Geologist G.K. Gilbert (1917) factors contribute to the development of the described how sediment from hundreds of model, there won’t be much public trust and hydraulic mines raised the beds of rivers in confidence in the results. the Sacramento Valley and, in combination with the unintended side-effects of levee A model is: construction, caused widespread flooding of • A representation of a system towns and farms. Gilbert (1917) also • Based on understanding the types and recognized that the combination of mining magnitudes of relationships debris and reclamation of tidal marshes • Created mentally, visually, or with around San Francisco Bay significantly computers reduced the cleansing actions of tides in the Bay—a combination that continues to have
- 3 - California Watershed Assessment Manual, Chapter 6 August, 2004 water quality implications a century later Adding Up the Impacts (Reid 1993). The comprehensive nature of cumulative Policy Context effects analysis is both the benefit of carrying out the analysis as well as the The National Environmental Policy Act of difficulty. We are accustomed to thinking of 1969 mentions that cumulative impacts watershed processes and impacts in a must be addressed in assessing a project’s piecemeal manner rather than holistically. environmental consequences. A couple of For example, when we think about years later, the Council on Environmental agricultural impacts, we might traditionally Quality defined “cumulative impact” used in focus on irrigation water withdrawals or the Act as “the impact on the environment pesticide residues. When considering which results from the incremental impact of cumulative effects in an agricultural the action when added to other past, watershed, we need to think about all the present, and reasonably foreseeable future water uses, pesticide and herbicide actions regardless of what agency (Federal applications and chemical transformations, or non-Federal) or person undertakes such fertilizers, tillage practices, soil compaction, other actions. Cumulative impacts can result management of agricultural waste, fuel from individually minor but collectively spills, buffer strips, associated roads and significant actions taking place over a period buildings—all the other land uses and of time “(CEQ Guidelines, 40 CFR 1508.7, impacts in the watershed, and the issued April 23, 1971). distribution of everything in space and time.
The U.S. Forest Service Soil and Water At a conceptual level in a watershed Conservation Handbook (FSH 2509.22) assessment, the primary task is to defines “cumulative watershed impact” as recognize that the impact of a particular “all effects that occur away from the human activity does not occur in isolation locations of actual land use which are and must be considered in the context of all transmitted through the fluvial system. other impacts and natural events. A Effects can be either beneficial or adverse watershed assessment should examine the and result from the synergistic or additive immediate, local impact of the activity, effects of multiple management activities potential or risk of off-site (i.e., downstream) within a watershed.” This language has impacts, similar impacts elsewhere in the been simplified by a Forest Service watershed or on the same site in the past or hydrologist by asking, “How much future, persistence of the impact(s), and disturbance can occur in a watershed whether there is potential for recovery from before bad things happen?” A variety of the impact over some time period. For other definitions and interpretations are example, will the activity accelerate erosion compiled in Reid (1993) and Berg, et al. on site? Will the eroded soil leave the site (1996). and end up in the stream? Are other sites in the watershed producing sediment at A recent University of California panel of unnatural rates? Will the erosion continue scientists defined cumulative watershed for years and will the sediment remain in the effects as “significant, adverse influences on channels? Will the site recover and produce water quality and biological resources that less sediment over time? arise from the way watersheds function, and particularly from the ways that disturbance You should also consider how natural within a watershed can be transmitted and events can affect the impacts. Wildfire, magnified within channels and riparian insect and disease outbreaks, and climatic habitats downstream of disturbed areas extremes can add to or even overwhelm the (Dunne et al. 2001). human impacts. With most water balance
- 4 - California Watershed Assessment Manual, Chapter 6 August, 2004 and sediment effects, the impacts’ size and sediment, biodiversity, or another watershed duration are affected by the magnitude and component (Dunne, et al. 2001). timing of storm events (Coats & Miller, 1981). A site might be stripped of vegetation Assessing cumulative watershed effects can and compacted, but the severity of erosion take the form of prospective or retrospective will still depend on rainfall. If there are no analysis. Prospective analysis involves the big, intense storms over the several years characterization of present conditions as a when vegetation is re-growing on a tool for estimating potential cumulative disturbed site, that site might not contribute impacts of human activities in the future. any sediment to the local stream. On the Retrospective analysis, in contrast, involves other hand, an intense storm during grading analyzing the existing conditions that are of a subdivision could generate vast associated with physical, chemical, and amounts of sediment from that single site. If biological stressors. many sites are in a disturbed state during that intense storm, the local stream could Unfortunately, there is no straightforward become severely clogged with sediment. procedure for assessing how various Sediment storage is another complicating impacts may combine in a watershed. All factor. For example, sediment from papers and reports on the topic readily accelerated erosion may accumulate for acknowledge the great difficulty of years in ephemeral and small channels evaluating cumulative effects. A variety of before being flushed out into the larger methods for addressing cumulative channels by a major storm. A thorough watershed effects have evolved over the description of sediment-related cumulative past two decades (reviewed by Reid 1993, effects may be found in Bunte and Berg et al. 1996, and MacDonald 2000), MacDonald (1996). largely in response to particular agency directives or regulations governing logging. Most work to date on cumulative watershed None of these methods are comprehensive, effects has focused on increases in peak and most are tailored to specific situations. flows and sediment delivery. However, Although one of the earliest papers on cumulative effects may just as well involve cumulative effects (Coats & Miller 1981) decline in dry-season streamflow, water recommends that assessment temperature, nutrient loading, availability of methodologies factor in grazing, agriculture, dissolved oxygen, toxic organic and heavy mining, construction of roads and buildings, metal pollutants, introduced species, large and water diversions, almost all procedures woody debris and channel stability, fishing to date focus on logging. pressure, riparian vegetation, and a host of other aquatic ecosystem attributes. For Equivalent Roaded Areas example, many amphibian species are believed to be in widespread decline One of the most common approaches to throughout the Sierra Nevada. These evaluating cumulative watershed effects potential extirpations and extinctions appear with respect to logging activity is the to be a cumulative effect of such factors as Equivalent Roaded Area (ERA) procedure. fragmentation of habitat by dams and roads, The ERA method was developed for and widespread and persistent fish stocking, has been widely applied to national forests exotic diseases, and airborne pesticide drift. in California. The original ERA concept focused on channel destabilization in Cumulative watershed effects need not relation to increased peak flows caused by always be considered in a negative light. In soil compaction. Accordingly, it used area some areas, there could be a sufficient covered by roads (thoroughly compacted number of successful restoration projects to surfaces) as an index of watershed have a positive cumulative effect on disturbance. Other types of impacts were
- 5 - California Watershed Assessment Manual, Chapter 6 August, 2004 expressed as road-equivalents. For conceptual level, the watershed assessor example, one acre of fresh clear cut might need only think through the possible be equivalent to 0.3 acres of road; one acre linkages among multiple impacts by type, of five-year-old clear cut might be equivalent location, and timing to progress well beyond to 0.1 acres of road; and one acre of one- the typical, piecemeal approaches of the year-old 50% selection harvest might be past. At a minimum, you should know the equivalent to 0.1 acres of road. These watershed’s disturbance history; where the coefficients are highly subjective and site most sensitive lands are located and the dependent. The coefficients are multiplied history of disturbance on those lands; the by the areas of the corresponding extent, timing, and location of proposed land disturbance types (e.g., clear cut), and use changes; and the observation record of those products are added together. The hydrologic and geomorphic events. Simple resulting sum is the Equivalent Roaded comparison of the disturbance history to the Area. This area is usually divided by the hydrologic record may suggest some watershed area to obtain a percentage of associations worth considering as possible the watershed disturbed to the equivalent of causal mechanisms. Such associations do a road (%ERA). In many applications, this not imply cause and effect, but merely percentage is compared to another provide pointers for where to look for percentage called the Threshold of potential causes. For example, you might Concern, an index of watershed sensitivity find a steady increase in impervious surface to disturbance. The threshold is compared and a corresponding increase in peak flows, to the %ERA to help assess whether the and there are physical reasons for watershed can handle further disturbance or hypothesizing a relationship between these is in need of rest and restoration. Despite two processes. Other trends might be the subjectivity and uncertainty in the completely coincidental and should be values, the ERA method has proven to be a regarded as such unless you have a solid useful accounting procedure for watershed physical explanation. Even then, cause-and- disturbance (Menning et al. 1996). Based effect relationships should be presented as on results of a study linking ERA possibilities rather than certainties. calculations within 300 feet of a stream to measures of aquatic biodiversity (McGurk & Most of the methods described in this Fong 1995), the Forest Service has been Manual support a retrospective analysis of modifying the ERA method to examine the cumulative effects of human activities on near-channel effects separately from upland waterways. The cumulative effects include effects (Menning et al. 1996). The ERA a variety of types of stressors and their methodology is not intended to act as a effects on various characteristics of the predictive indicator of watershed condition watershed. For example, in an urban area, and would probably have little role in one way of understanding cumulative watershed assessment beyond comparing effects is to consider the contribution of disturbance indices between sub- numerous small residential or commercial watersheds. developments to the condition in a waterway. Each new project makes a small Integrating the Effects contribution to what, when taken together, could cause a significant impact on the To conduct watershed assessments, watershed. Integrating data on these types operational watershed management, and of cumulative effects involves considering logging regulation, the ability to estimate the source of the stressors (i.e., human cumulative impacts of past activities, activities, land use changes), the type of alternative management scenarios, and alterations in conditions that result, and their proposals for future land use changes are impacts on the valued ecological endpoints. necessary (Dunne et al. 2001). At a Trying to assign a percent contribution of
- 6 - California Watershed Assessment Manual, Chapter 6 August, 2004 various sources of stress is difficult; models cumulative watershed effects (Dunne et al. are being developed in an effort to address 2001). this problem. At present, it is possible to gain a sense of the relative contribution of 6.4 Methods for Data Integration and various human activities to the existing Synthesis conditions by using a number of different available models discussed in this chapter. There are several possible reasons for integrating information about processes and 6.3.3 Using Models for Cumulative conditions in your watershed. One is to find Watershed Effects areas within the watershed that are likely to be in worse overall condition than other While holistic thinking about watershed areas because of a combination of different conditions or processes is difficult in its own activities located there. Another is to give a right, the next step—attempting to quantify relative ranking for a watershed compared the combined effects of multiple to other watershed evaluated in the same disturbances—is highly complex as well as way to aid in regional prioritization. A third is uncertain. Nevertheless, steady progress in to investigate possible causes of measured the capacity to model biophysical processes impacts in the watershed. is beginning to offer some possibilities for rigorously calculating cumulative effects. This last can be quite difficult. Frequently, The key to such estimates is to calculate historical, hidden, or multiple factors various stream or watershed attributes (e.g., contributed to observed conditions. It is annual stream-flow, peak flows, sediment appropriate to make assumptions about yield, water temperature, nutrient cause and effect; this is necessary when concentration, aquatic biodiversity indices, developing your conceptual model. For etc.) under natural conditions and under example, attributing streambank erosion as various levels and types of disturbance. one cause of sediment input to a creek is a Most of these calculations necessarily logical first guess. However, your data involve assumptions about climate during might show instead that roads caused most the period of disturbance. A variety of storm of the sediment input. The assessment scenarios can be coupled with the alterative needs to clarify the linkage between what it disturbance types, intensities, extents, is about the roads that has caused, or is locations, and timing. Another way to causing, sediment yield to the stream. Is it examine cumulative effects is to explicitly erosion from the fill slope, cutslope, dirt road consider whether a particular disturbance surface, inboard ditches, stream crossings, increases the risk of adverse impacts blown-out culverts and road fill, slope above (higher peak flows, more and larger the road, landslides, streambank erosion landslides, higher water temperatures, etc.) undercutting the road, poor road under alternative climate scenarios (Dunne maintenance practices, or what? Does all et al. 2001). of the road erosion end up in the stream (as “sediment yield”), or does it get deposited in Harr (1989) suggested the use of other areas with less connection to the mathematical models to gain insight into drainage system? A good road erosion cumulative watershed effects at a time inventory can help identify, at both a coarse when hydrologic models were primarily a and a fine scale, these more detailed research tool. In the past 15 years, the state causes within this category of “roads.” This of the art of hydrologic, geomorphologic, greater detail about road causes will provide and ecologic modeling has advanced more useful information for your watershed significantly. In watersheds with adequate assessment and any subsequent plan. data, application of new models offers great potential in estimating some types of
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Sometimes, the initial hypothesis used to 6.4.1 Team Mental Integration develop the conceptual model is not supported by the data. The responsibility of Just about every watershed assessment will the assessment team is to make these involve some sort of team mental important evaluations – the question is: integration. The Team Mental Integration how is this best accomplished? Testing a method is really nothing more than the hypothesis using a statistical procedure assessment team and appropriate experts usually offers the most certainty or systematically reviewing the data and, using confidence in evaluating a suspected cause best professional judgment, assessing the and. Looking for significant relationships relative condition of different parts of the between various factors (e.g. road density watershed and impacts of various and sediment inputs) with available data in alterations in the watershed on natural your watershed could be performed. There processes. In many watersheds, a collection are many useful references to help you in of experts may provide more detailed and this process (e.g., Leopold 1994; Gordon et accurate knowledge about influential al. 1992; Center for Watershed Protection processes than the best computer model. 1998). However, a sound statistical This may be partly due to the absence of approach can be difficult to apply in a non- adequate data and the lack of a model that research setting due to lack of controls and truly represents real world conditions, and inadequate data, funding, or resources. As because expert knowledge is still superior to an alternative indicator of cause and effect, mathematical models in many cases. you can cite relevant research that has been able to make statistically significant One of the strengths of the ‘team mental inferences about cause and effect. If others integration’ method is that, in most cases, it have studied the issue relevant to your can be performed by members of local watershed under more controlled watershed groups without engaging in conditions, you can utilize this knowledge in expensive consultation or more your analysis. sophisticated methods of statistical analysis.
This section of the Manual presents various On the other hand, this approach has methods for integrating information about certain limitations. There is not a single, watershed conditions. One of the most widely-accepted approach for evaluating the common methods is to assemble a team of weight of the evidence for an assessment. experts in particular disciplines, collect and Also, it may be difficult to ascertain whether analyze information about watershed the team members have sufficient processes and conditions, collectively draw knowledge to thoughtfully interpret the data. conclusions about potential reasons for the If your team does not have the right present circumstance, and suggest actions qualifications, the insight gained from that could be taken to improve or protect the integration of their knowledge and situation. Recently, more quantitative information will be limited. Competency is methods and models have been developed. best measured in the amount of formal Several of these approaches will be training in one or more scientific disciplines, reviewed in this section. Which of these field experience, the amount of time spent methods might be useful depends on the understanding the watershed or watersheds amount of data that has been collected, the like it, and the ability to see watershed level of expertise of the assessment team or functioning from more than one perspective. its consultant, and available financial resources. The suggestions in the following list address some of the potential benefits and pitfalls of the expert team approach:
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• Record whatever approach you use in a An early step in the team integration way that will allow a reader of your process should be to review and revise the assessment, or a future assessor, to conceptual model, assuming one was understand exactly what you did. This developed for the watershed. The means describing both the details of the conceptual model clearly identifies what you data considered and the analyses believe to be possible relationships between chosen and rejected, as well as a altered conditions or processes in your summary of the approach taken by your watershed and adverse effects on team. watershed processes or value attributes. • The composition of your team There are no hard and fast rules for how to determines the quality of your do this. However, having a conceptual assessment. Include team members’ model as a starting point in such a team qualifications, experience, and training approach will facilitate communication as part of the assessment so readers among disciplines. It will also possibly lead can assess for themselves how much to accurate evaluations of relative risk or confidence to put in the conclusions harm to particular sub-watersheds and drawn. potential causes of observed or measured • Comparing professional judgment with impacts. One way to investigate “cause and numeric modeling approaches can be effect” relationships in the context of this done in various ways, where the most team approach is through the “weight of common (and possibly easiest) method evidence” approach. involve turning each set of information into rank values and comparing these Weighing the Evidence values using readily available statistical tests. There is no one widely accepted way to go • Because you will rarely get a group of through the process of weighing evidence. experts together again to discuss your However, the US EPA has developed some watershed, take advantage of this guidelines that recommend one approach. opportunity and make sure they stretch The EPA has developed methods for their brains. Encourage them to think identifying cause and effect relationships about novel ways that data and (US EPA Stressor Identification Guidelines, knowledge about individual processes 2000; posted at: can be brought together. Record the full http://www.epa.gov/ost/biocriteria/stressors/ spectrum of their suggestions, from stressorid/pdf). The Stressor Identification speculation with little data to sturdy approach involves reviewing a series of conclusions based on a lot of data, questions about data on each of the analysis, and expertise. conditions evaluated. Depending on your • Find ways to express professional answer to these questions, you can identify judgment graphically so people can factors or stressors that appear to be visualize their ideas. This will help make related to the observed conditions. The US the knowledge of experts about the EPA is also developing a new website that watershed more broadly supports this approach, the Casual Analysis understandable. Diagnosis/Decision Information System • Promote diversity in your team by (CADDIS). As of August, 2004, CADDIS including members from a wide range of was still in the development stage, but will disciplines, ages, and organizational be available to the public in the near future. origins. This is bound to lead to raising The approach recommended by the US critical questions, involving a range of EPA is based on the weight-of-evidence, approaches, and creating interesting i.e., the greater the number of factors that discussions. support a relationship, the more confidence you have in that relationship.
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based on your answer to each of the above If your team chooses a cause-and-effect questions, ranging from very unlikely to approach to evaluating watershed condition, maybe to very likely (--, -, 0, +, ++ for then the following table may be useful. It example). You can then assess if the contains a list of criteria, which if met, evidence is sufficient to identify a cause and provide evidence of a cause and effect effect relationship. This process can also relationship. help identify data gaps – what types of new data you might need to gather – to be able The US EPA recommends assigning a rank to draw conclusions regarding cause and effect. The strength of the relationships CRITERIA FOR EVALUATION OF between various human activities, CAUSE AND EFFECT alterations in different watershed processes RELATIONSHIPS and conditions, and adverse effects on Factor to Question to Ask ecological endpoints can be sorted out Consider using this process. By reviewing the data Spatial Co- Did the stressor or and evaluating the weight of the evidence, occurrence altered process and the you will develop a group of hypotheses harmful effect occur at about the most likely causes of the the same place or in impairments. reasonable proximity? Temporal Did the stressor or In some cases, this is as far as your co- altered process occur assessment will go, and in many cases this occurrence prior to the observation is all that is necessary to get a basic picture of effects? of the key stressors or alterations in watershed processes and the likely causes Consistency Is the effect associated of these changes. of with the alteration or
association stressor at more than Remember that at some point, your team one place in the same must produce an integrated assessment. location? Your watershed assessment will not be Biological When you get farther complete if it consists of a series of chapters gradient away from the source of that have no obvious connection to each the stressor (e.g., other and no actual integration step for the particular land use), is information gathered and the knowledge the observed effects gained. It might help to have a group of reduced or not as authors who can write effectively together, severe? or a single author who can pull all of the Route of Is there a logical way for parts together and have the product exposure the ecological endpoint checked by the rest of the team. to be exposed to the
stressor or for the 6.4.2 Ecosystem Management Decision altered watershed Support: A Knowledge-Base Model process to affect the
ecological endpoint? One process for evaluating watershed Experimental Is there independent condition involves using a new modeling evidence experimental evidence approach designed both to reflect inexact to support the knowledge about natural processes and to association between be based upon expert knowledge of a potential causes and system. The approach is embodied in the effects? software tool “Ecosystem Management
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Decision-Support” (EMDS)1 (Reynolds et is in turn based on component information. al., 1996 & 1999). EMDS has been used in For example, (2) could include a) human the North Coast Watershed Assessment activities and structures that affect habitat, Program (NCWAP) to evaluate the condition b) water and aquatic habitat quality, and c) of and restoration potential for salmon natural processes that affect habitat. habitat in several North Coast watersheds Eventually, to assess watershed condition, (http://www.ncwap.ca.gov/default.html) and sub-categories would have to attach to data by UC Davis to evaluate watershed that described conditions in the watershed. condition and risk to that condition in the Yuba watershed, EMDS is based on a “knowledge base” of (http://snepmaps.des.ucdavis.edu/snner/yub interactions among components and a/StateYubaLands.pdf). It has also been processes in a system based around a used to prioritize restoration sites for single question or assertion about the mercury remediation in the Sacramento system. EMDS develops and make explicit River basin a set of assertions used to evaluate a (http://www.sacriver.org/subcommittees/dtm concept, such as water quality. An example c/documents/DTMC_MSP_App5.pdf). of such an assertion could be: “where are potential sediment sources in the Knowledge Base watershed?” The main idea behind the knowledge-base is to pull together a set of A knowledge base is a collection of the best raw data about the system, such as water available information about a system or quality and biological data, into a single process. It explicitly lays out the number that measures the broad concept of connections between categories of things in watershed condition. the system and describes the relationships thought to be present between them. There The main assertion in the knowledge base is often a hierarchical structure to a is split up into sub-assertions that further knowledge base, starting at the top with the define the main assertion. Example of a broadest concept. This could be “watershed sub-assertion might be: “where are sites of condition”. Branching off from this concept mass-wasting?” and “where have human is supporting knowledge about factors that structures been built on fragile sediments?” contribute to determining watershed The explicitly defined relationships among conditions. For example, watershed sub-assertions are based on a combination condition could be based on a combination of published literature and expert opinion. of 1) valued ecological components and The criteria for evaluating the assertion are processes and 2) human and natural defined in the structure of the knowledge- disturbances. Each of these sub-categories base. These criteria are generally based on a specific set of state or federal water 1 A group of Powerpoint presentations explaining quality standards, identified risks from land the EMDS model and the most recent release uses, and other threats to ecosystem (version 3.0) are posted at: processes identified in the scientific and http://www.fsl.orst.edu/emds/. There are two technical literature. The final product of an usable versions of the EMDS software: versions EMDS analysis is an assessment of the 2.0 and 3.0. Both versions are free. Version 2.0 primary assertion’s “truth-value”, which is a is an extension of the GIS software ArcView 3.2 number ranging between –1.0 (completely and uses grid data. Version 3.0 interacts with false), 0 (undetermined), and +1.0 ArcGIS and can be used with either polygon or (completely true). The truth-value can be grid data. Version 2.0 is no longer being offered thought of as an index for measuring risk to on the website, although it can be obtained from the authors. ecological function or watershed condition.
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In the figure below, a reference curve for analysis, permitting ready comparisons temperature impacts to salmon is illustrated. between and among watersheds. The truth-value is plotted on the y axis and Component values may also be grouped represents the suitability of certain according to a common feature (e.g., temperatures for salmon. This example is physical vs. chemical) and the relationship from a North Coast Watershed Assessment among components (e.g., nitrates, study that used EMDS, posted at: phosphates, sulfates) within a group (e.g., http://ftp.dfg.ca.gov/outgoing/whdab/ncwap/pu nutrients). This analysis produces a range blic/watersheds/EMDS_Appendix_1.16.pdf. of values from a single index value for the In this example, when water temperature combined water quality components to remains between 50-60 F, it is suitable for individual values for each component. salmon and is “true” for suitable water temperature (truth value = 1). When it falls Decision-Support below 50 or goes above 60, temperature starts acting as a stressor and has a EMDS was designed with management correspondingly reduced truth-value. When decisions in mind. It is sufficiently flexible to the temperature reaches less than 45 or be used for many types of decision support greater than 68, it is very unsuitable for and evaluations. The main product of the salmon, causing a variety of adverse analysis are maps containing “answers”, in physiological effects, and is false for the form of different values for pixels or grid suitability (-1). The condition within any cells on the map, for the assertion and sub- single waterway can be evaluated on this assertions. How much confidence you put curve to determine the truth-value for in these values depends on your confidence suitable temperatures. A series of such in the quality of the base data and your values can be accumulated, reflecting a knowledge of the system, both of which variety of conditions in a stream or were used to develop the knowledge base. conditions in several streams in a Like all models, and especially ones that watershed. integrate a lot of information, its products should be used with caution The advantage of this approach is that all components of a watershed’s condition With large complex models and places, you (e.g., water temperature and habitat may not be able to arrive at an assessment fragmentation) are scaled to a –1 to 1 product simply by analyzing everything in range, which allows for the combination of your head. With well-understood processes the component values into a single index for and high-quality data, the modeling product each watershed and for each period of is at least good enough to base next-step decisions on, like where to do a Maximum Weekly Average Temperature field evaluation. If the input data and your knowledge are of similar quality across the 1 watershed, then the product can also allow you to compare 0.5 areas within the place. If you 0 have moderate or less 30 35 40 45 50 55 60 65 70 75 80 confidence in your knowledge -0.5 of the processes and similar truth value confidence in data quality, then -1 the product may still be water temp (F) valuable as a tool to understand what you don’t know about the watershed. One group using
- 12 - California Watershed Assessment Manual, Chapter 6 August, 2004 this approach found that identifying the (Wiegers et al., 1998; Landis & Wu, 2003). knowledge and data gaps was a very useful The RRM is based on numerical ranks so part of the whole modeling exercise (Girvetz that data on different types of risk (eg., & Shilling, 2003). chemical, invasive species, etc.) can be compared without regard to the metric or 6.4.3 Relative Risk Model units of the original measurement (Landis & Wu, 2003). Background The RRM was designed to serve as an The Relative Risk Model (RRM) was initial screen or assessment of stressors originally developed as a tool for watershed within a watershed. It is especially useful risk assessment (WRA). WRA is a process when there is limited in-stream data. It is for estimating risk associated with chemical, very useful for estimating which stressors physical, and biological stressors affecting are likely to be most important, for ecological systems (Harwell & Gentile, identifying which land uses and human 2000). Stressors are physical, chemical, or activities are most likely associated with biological factors that may cause adverse adverse effects, and for prioritizing which effects on natural systems (e.g., fish habitat) stressors should be the focus of future and components of these systems (e.g., investigation. One of the products of this individual fish populations). WRA lays out a analysis is a group of hypotheses that can process for using science to inform be used as a guide for future monitoring and environmental decision-making concerning analysis. The basic steps in using this watershed features (components of a model are the same as those suggested in system, like plants or waterways). WRA is this Manual: defining the purpose of the intended to answer the questions: analysis, selecting ecological endpoints, • What is the current state of the developing a conceptual model, and gather watershed? existing or new data. The conceptual model • What are the possible causes of the is particularly important because it forms the current conditions or processes? basis for identifying stressors as well as different land uses and human activities that Watershed risk assessment follows a basic are assigned a risk scores in the model. 3 step process very similar to the more general watershed assessments described Using the Relative Risk Model for in this Manual: problem definition, analysis, Watershed Assessment and risk characterization. Risk characterization is essentially the same as The discussion of the RRM in this chapter data synthesis and integration. A variety of will focus on the principles and basic outline methods are used by risk assessors to so you can determine if it would be useful estimate risk associated with various for your situation. Details of how to perform stressors. The US EPA has developed an the analysis, including all calculations, are online training manual on watershed issues, included in the Appendix. The following which includes one module on watershed review of key steps to use the RRM is risk assessment. It is posted at: drawn from Landis & Wu (2003). http://www.epa.gov/watertrain. Step 1: Make a map of the watershed and The RRM model was developed to evaluate break it into regions based on a combination risk factors at different locations in the of hydrology and human activities. watershed, ranking the importance of these If you are using a GIS, identify sub- locations, and combining this information to watershed fairly easily using a hydrological predict the relative risk among the different modeling tool. If you are using a areas and from the different stressors topographical map, you will need to rely on
- 13 - California Watershed Assessment Manual, Chapter 6 August, 2004 the contours of the map to approximate sub- to each other, but ALL can potentially cause watersheds. These divisions create risk stress to aquatic organisms. regions for which risks will be calculated. In some cases, you might identify so many risk Step 4: Evaluate uncertainty and sensitivity regions that it is impractical to work with of the relative rankings. them. In these cases, group small regions It is important to at least qualitatively identify together based on common land uses or uncertainty in your analysis. Refer to sources of stressors. Chapter 4 of the Manual for more details.
Step 2: Adopt a method for evaluating Step 5: Identify next steps. types of land uses, stressors, and habitats. One important ‘next step’ is to identify The relative risk model is based on relative hypotheses that form the basis for future ranks which are assigned to land uses, study and effort. For example, if in the risk stressors, and habitats. The areal extent, or analysis, certain stressors or land uses total acreage for each land use and habitat were identified as high risk, then future types, within each sub-watershed is study should be directed to evaluate the calculated using either a GIS or making risks of these human activities and/or estimates by hand. To evaluate each stressors. For example, in one watershed stressor, initially the values for the in-stream assessment using the RRM, contaminants or riparian conditions in the watershed are in the sediment and the amount of fine compared to benchmarks, those levels sediment in the streambed were found to be above which it is probable that an adverse high-risk stressors. Since there was limited effect will occur. This follows the same data, statistical analysis could not be process described in Ch 5.2 of the Manual. performed and the degree of uncertainty was high. But the assessment was Step 3: Calculate the risk. nonetheless useful because it pointed to The risk calculation involves a comparison those areas which needed further study; it of various land uses (sources of stress) with generated a series of hypotheses which laid each other, as well as comparisons of the basis for future data collection efforts. various stressors and habitats with each other. For example, ranks of 0, 2, or 4 could Possible RRM scenarios be assigned to various land uses/human activities. A rank of zero would be assigned The relative risk model can be used in those if a particular human activity did not occur situations in which little or a lot of data are within the risk region. Alternatively, a rank of available. An example of two different zero would be assigned if the average water conditions illustrates how these analyses temperature fell between the lower and would differ: upper temperature thresholds for the aquatic species of interest. A rank of 4 Scenario 1: No or very little in-stream data might be assigned if the land use available associated with a stressor (such as golf courses which are often heavy users of If your group has very little in-stream data, pesticides) covered large areas of the sub- you can use the RRM to assess the land watershed. The key take-home message uses within the watershed and make a first here is that these ranks are assigned based estimate of what human activities have the on the magnitude of the factor being potential to be associated with observed evaluated. Ranks are used because issues of concern. The RRM will help to diverse factors as concentrations of focus attention on those habitats and sub- chemical contaminants, characteristics of watersheds that are at greatest risk. The the benthic substrate, and amounts of large principle behind this approach is that the woody debris cannot be directly compared greater the areal extent or acreage of land
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An example of ranking a biological stressor
In this example, invasive species have been found in a salmon spawning stream. Predatory bass are present and you wonder to what degree they might contribute to the observed decline in the salmon population. Do the bass prey on the juvenile salmon? Assume you have data on water temperature and have done a bit of seining so you know the approximate distribution, size, and abundance of the two species within the 3 major reaches of the waterway. A ranking system was developed that reflected a various combination of factors such as temperature, abundance and size of bass, and the distribution of salmon in the stream. Using this scheme, ranks were assigned to each of the 3 reaches, to evaluate if and where the bass posed a risk. In this case, statistical analyses would not be valid, but a basic estimate of potential harm produced from this analysis can serve to guide future monitoring efforts. uses that might be the source of stressors human activities on valued ecological will probably pose a greater risk than those systems that are the focus of your with a smaller areal extent. Likewise, the assessment. This method is especially larger the extent of various habitats, the useful when relatively small amounts of data greater the amount of a natural system that are available or when you have a limited is at risk of harm. Land uses with the budget for hiring consultants. It provides a greatest coverage are assigned higher method for making a first-cut estimate of ranks than those with fewer acres. risk to valued resources and can serve as a tool for developing plans and strategies for Scenario 2: Existing or new data has been future work. collected 6.4.4 Southern California Riparian In this circumstance, you will be able to Ecosystem Assessment Method compare data from your watershed on key (SCREAM) stressors/conditions to benchmarks or thresholds that are thought to protect Goals of the Southern California Wetlands aquatic life or whatever valued ecological Recovery Project (WRP) include the components you have identified as identification and recovery of riparian important for your assessment. The wetlands in coastal watersheds. The methods for doing this are discussed in SCWRP team is developing a model detail in the Appendix. Briefly, a rank is (Southern California Riparian Ecosystem assigned to each stressor based the Assessment Method-SCREAM) for relationship between the in-stream/riparian information integration about watershed conditions and the benchmark. Conditions condition to help prioritize places and that appear to exceed values known to actions for wetlands restoration. This model protect aquatic organisms, for example, will may not be suitable for all watersheds in be assigned a moderate or high rank (2, 4, California, but its design should help with or 6 on a scale of 0 - 6) compared to values the design of similar integration of that are at or below the benchmark (0 on a information in other places. SCREAM is a scale of 0 - 6). Using some simple GIS-based tool to assess the ecological calculations, you can group those stressors condition and stressors affecting riparian into high, moderate, or low risk categories. habitat at a landscape scale. The method was developed collaboratively by the WRP, In conclusion, the Relative Risk Model is Southern California Coastal Water one method that can be used to begin to Research Project (SCCWRP), and the gain an understanding of the effects of NOAA Coastal Services Center.
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WRP has identified critical ecological 7) Hydrologic continuity: stream system indicators and used them to develop rules complexity, degree of impoundment, for the decision-support process. These flow restrictions indicators are linked to the recovery 8) Runoff/infiltration: infiltration capacity, objectives. There are five recommended groundwater recharge, and width of quantifiable recovery objectives: natural area 9) Flow augmentation: dry season artificial 1) Maintain existing and increase new discharges and NPDES-permitted daily wetlands and riparian acreage discharges 2) Recover habitat diversity to reflect 10) Regional planning: position in landscape historic distribution and drinking water conservation areas 3) Recover biological structure and 11) Sediment processes: intact sources of function sediment, stream slope, sinuousity, 4) Restore physical processes adjacent floodplain, and impoundments 5) Recover landscape elements of 12) Sources of contamination: persistent ecosystem structure and function. sources of nutrients, pesticides, heavy metals, and organics; contaminated The evaluation of wetland and riparian sediments; and water quality impairment areas will include consideration of both the 13) Factors affecting biogeochemical attributes and condition of the areas cycling: upstream engineered system, themselves and of surrounding and upland streamed hardening, impoundments, areas. The categories of attributes and perennialized flow, adjacent floodplain, metrics include: opportunity for hydrologic connection, sinuousity, riparian vegetative cover, 1) “General” habitat quality: presence of wetland edge-to-area ratio); invasive species, domestic predators, 14) Regional planning: position on habitat diversity, threatened and landscape and soil composition endangered species habitat, and riparian vegetative cover Lists like this may be useful for your 2) Aquatic habitat quality: water quality, watershed assessment as you consider presence of persistent sources of what information to integrate and how to contamination, known contaminated categorize it. The conditions for these sediments, streambed condition, parameters within a watershed are used to presence of adjacent floodplain, assess altered conditions. Although the opportunity for hydrologic connection specifics will vary from one watershed to 3) Fish habitat: fish passage, known another, the general categories being spawning ground evaluated are applicable to most all areas of 4) Bird habitat: bird diversity, known the state. rookery 5) Landscape: connectivity to coastal In the SCREAM model, existing or new GIS wetlands, riparian connectivity and data layers are compiled and organized, extent, surrounding land use, and the information contained in those connectivity between open spaces, layers is used to calculate hydrologic, adjacency to preserved areas, and biogeochemical, and “habitat support” component of a corridor network scores. In SCREAM, all streams in a 6) Channel-floodplain interaction: adjacent watershed are divided into “units of floodplain, opportunity for hydrologic analysis” (UAs) and condition scores are connection, stream profile, streambed calculated for each UA hardness The foundation of SCREAM is a geospatial database (ArcGIS geodatabase) that is
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created using GIS data layers on the condition of the UA. Specific scoring physical, biological, hydrologic, and algorithms and weightings can be user- chemical properties of a watershed. Input modified based on availability and data layers include land use/land cover, confidence of specific data layers. The channel properties (i.e. channelization), output of the model is a GIS coverage in infrastructure (e.g. bridges), locations of which each UA is attributed with overall known pollutant point-source discharges, condition scores, as well as scores for the soil characteristics, topography, and underlying metrics. documented occurrences of sensitive and invasive species. The WRP envisions that the SCREAM tool will be used as part of a comprehensive Once compiled, the model queries the assessment program to evaluate the geospatial database and assigns scores to condition of and stressors affecting series of metrics using a defined set of wetlands and riparian ecosystems in formulas. Metric scores are then integrated southern California. SCREAM also has into component scores, and finally into potential to aid in the prioritization of overall scores for hydrology, recovery activities by identifying riparian biogeochemistry, and habitat, using a series areas with a high functional contribution to of rule based models. Condition scores are the watershed. The results of SCREAM based on an integration of features within a could be used in combination with other specific UA as well as in surrounding or considerations such as feasibility of adjacent areas that may affect the overall restoration and cost to inform decisions
- 17 - California Watershed Assessment Manual, Chapter 6 August, 2004 about restoration priorities. SCREAM is outputs. For example, if you are uncertain intended to be flexible and accessible to a about the magnitude or sign of the variety of user levels. SCREAM could easily coefficient for a model parameter, and the be adapted to other areas of the state by model is relatively sensitive to that adjusting the parameters of the model to parameter, it may be worth taking steps to reflect the appropriate landscape and reduce that uncertainty, e.g., through physiographic conditions of the region. additional research. The more sensitive a model is for a given parameter, the more The diagram above illustrates the 15 factors concerned you should be with the quality identified above that are included in the (accuracy and variability) of the data since “Habitat Support” part of the SCREAM small difference could result in a large model. difference in the model output. If the model is highly sensitive for a parameter, and the 6.4.6 Common Aspects of the Methods quality of the input data for the associated for Data Integration independent variable is poor, it might be worth investing more money or effort into There are a number of common improving the quality of the input data. characteristics that all the methods for data integration share: Sensitivity analysis can be applied to • They utilize a pre-established set of conceptual models as well as to computer- criteria for evaluation of data, thereby intensive quantitative models. If your minimizing subjectivity from the analysis watershed assessment does not involve as much as possible. computer modeling, you can still conduct • They employ a system of ranking of the the same exercise of iteratively leaving out geographical areas, stressors, or certain types of information (e.g., intensive conditions based on an evaluation of the land use) from your conceptual model and altered watershed conditions or seeing how that impacts your condition processes. assessment. You may find that certain • The results of the evaluation can be processes have greater potential impact on used for decision support and the your findings than others. You can then development of a watershed determine whether data quality is high for management plan. the processes that have the greatest impact on your condition assessment. 6.5 Sensitivity Analyses and Developing Future Scenarios Statistics for Sensitivity Analysis
Sensitivity Analysis When doing sensitivity analysis with numeric values, including ranks, be sure to Sensitivity analysis is a technique to test statistically analyze the differences among how sensitive the model “output” or results different treatments. Each treatment is an are to changes in the “input” data. independent model slightly different from Sensitivity analysis involves changing the the others. The point of sensitivity analysis input parameters of a model over a is to assess the magnitude of change in the reasonable range and examining how this model’s product after modifying an input change affects the model outputs. By variable. The greatest sensitivity clarifying how the model outputs respond to corresponds to the greatest difference changes in the inputs, the appropriate level between values in your indicator variable. of confidence in the model becomes clearer. The greater the difference there is in your Information derived from sensitivity analysis indicator variable, the more the system is helps clarify which parameters in the model sensitive to that variable. If the model’s have the greatest influence on the model product is spatial data or a time series, then
- 18 - California Watershed Assessment Manual, Chapter 6 August, 2004 how you compare the original model development will occur and thus assess the product with the alternatives is important. kinds of impacts to be expected. Useful statistical principles and tools are described in the Appendix and on the Although this Manual doesn’t describe many CWAM website (http://cwam.ucdavis.edu). of the ways to develop future scenarios, here are ways of deciding how and whether Developing Future Scenarios to do this type of modeling.
Many models are intended to describe how 1) Consider whether your assessment a system works and can therefore be question or purpose logically leads to valuable for anticipating change and projecting conditions into the future. For predicting the impacts of change in the example, if you are concerned about future. Many watershed groups and impacts of specific land uses, you might decision-makers are interested in the want to model potential impacts of these potential consequences of future actions. uses under climate scenarios that did These actions could be ones they have not occur during your data collection. control over or not. By using different 2) Accurately projecting forward from models and changing assumptions both historical data requires that you be within the models and within the data confident in your knowledge of cycles sources, it is possible to project actions and and trends. Without knowing how potential impacts in the future. For example, watershed parameters change and a county anticipates that under its revised respond to each other, you won’t be general plan 2,500 acres of rural landscape able to construct a model correctly. will be developed in five-acre parcels. 3) Future scenarios are usually developed Although the exact distribution of these to inform policy (e.g., land use, parcels is unknown, the county anticipates regulation, restoration). Therefore, the that development will take place in three description of scenario development and watersheds. Planners could model potential the products should be written and impacts of increased impervious surface presented is such a way as to be development on runoff, potential increases understandable to the intended in sediment production from disturbed audience. areas, and fragmentation of wildlife habitat 4) Because there are likely many by new roads and parcels. In addition, if unknowns, several scenarios should be what attracts people to develop is known developed that reflect variations in the and can be mapped (e.g., proximity to amounts, distributions, or rates of an public lands, proximity to services), then it influential process (e.g., logging). To keep will also be possible to estimate where things simple, one major influence should
Information Integration Checklist
Select a method for data synthesis and integration o Team mental integration o EMDS o RRM o SCREAM o Other appropriate model
If appropriate, use sensitivity analysis to evaluate the model
- 19 - California Watershed Assessment Manual, Chapter 6 August, 2004 be varied at a time. In some ways, this is cumulative effects of forest practices at the similar to sensitivity analysis (see above). National Convention of the Society of American Foresters in Spokane, WA. 6.6 References Harwell, M.A. and J.H. Gentile. 2000. Berg, N.H. K.B. Roby and B.J. McGurk. Environmental Decision-making for Multiple 1996. Cumulative watershed effects: Stressors: Framework, Tools, Case Studies, Applicability of available methodologies to and Prospects. In: Multiple Stressors in the Sierra Nevada. Sierra Nevada Ecological Risk and Impact Assessment: Ecosystem Project: Final Report to Approaches to Risk Estimation. S.A. Congress, Vol. III, Assessments, Ference & J.A. Foran, eds., SETAC Press, Commissioned Reports, and Background Pensacola, FL, pp. 169 - 236. Information. pp. 39-78. Davis: University of California, Centers for Water and Wildland Landis, W.G. and M-H. Yu. 2003. Resources. Ecological Risk Assessment. In: Introduction to Environmental Toxicology, Bunte, K. and L.H. MacDonald. 1996. Scale Lewis Publ., Boca Raton, pp. 359-400. considerations and the detectability of sedimentary cumulative watershed effects. MacDonald, L.H. 2000. Evaluating and Report to the U.S. Forest Service and managing cumulative effects: Process and National Council for Air and Stream constraints. Environmental Management Improvement of the Paper Industry. Fort 26(3): 299-315. Collins: Colorado State University. Menning, K. M., D.C. Erman, K.N. Johnson, Coats, R.N. and T.O. Miller. 1981. and J. Sessions. 1996.Modeling aquatic and Cumulative silvicultural impacts on riparian systems, assessing cumulative watersheds: A hydrologic and regulatory watershed effects, and limiting watershed dilemma. Environmental Management 5(2): disturbance. Sierra Nevada Ecosystem 147-160. Project: Final Report to Congress, Addendum. Pp. 33-51. Davis: University of Dunne, T., J. Agee, S. Beissinger, W. California, Centers for Water and Wildland Dietrich, D. Gray, M. Power, V. Resh, and Resources. K. Rodrigues. 2001. A scientific basis for the prediction of cumulative watershed effects. McGurk, B.J. and D.R. Fong. 1995. Report 46. Berkeley: University of Equivalent roaded area as a measure of California, Wildland Resources Center. cumulative effect of logging. Environmental Management 19(4): 609-621. Gilbert, G.K. 1917. Hydraulic mining debris in the Sierra Nevada. Professional Paper Michael, G.Y. 1991. Environmental data 105. Washington, DC: U.S. Geological bases: design, implementation, and Survey. maintenance. Lewis Publishers, Chelsea MI. 98 pp. Girvetz, E.H. and F.M. Shilling. 2003 Decision support for road system analysis NCWAP methods manual and modification on the Tahoe National (http://www.ncwatershed.ca.gov/pdf/Draft_N Forest. Environmental Management. 32(2): CWAP_Manual.pdf) 218-233. Reid, L.M. 1993. Research and cumulative Harr, R.D. 1989. Cumulative effects of watershed effects. General Technical timber harvest on streamflows. Unpublished Report PSW-141. U.S. Forest Service, paper presented at the technical session on Berkeley, CA.
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Reynolds, K., Cunningham, P., Bednar, L. (and others). 1996. A design framework for a knowledge-based information management system for watershed analysis in the Pacific Northwest U.S. AI Applications. 10: 9-22.
Reynolds, K. 1999. Netweaver for EMDS user guide (version 1.1); a knowledge base development system. Gen. tech. Rep. PNW-GTR-471. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station.
Shenk, T.M. and A.B. Franklin. 2001. Modeling in natural resource management: development, interpretation, and application. Island Press, Wash. D.C. 223 p.
US EPA, 1998, Guidelines for Ecological Risk Assessment, EPA/630/R0-95/002F, Washington, DC
Wiegers, J.K., H.M. Feder, L.S. Mortense, D.G. Shaw, V.J. Wilson, & W.J. Landis. 1998. A regional multiple-stressor rank- based ecological risk assessment for the fjord of Port Valdez, Alaska. Human Ecological Risk Assessment 4: 1125-1173.
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5 Analyzing Data
This chapter helps you move from raw data, (results of data analyses) into a useful story as described in Chapter 4, to interpretation. about how your watershed evolved into its You might be data rich, but information poor current condition and what that condition is and find yourself staring at a bunch of (see Chapter 6). Your analyses will also numbers that do not yet tell a story (Dates help establish the events and processes 1999). The material presented here and in that contributed to different aspects of your Chapter 6 on information integration will watershed’s condition. assist you in making the assessment more complete and accurate. In moving from raw As you pursue different analytical data to interpretation, you may encounter a procedures, stay focused on your few stumbling blocks along the way. objectives. With so many possible analyses Suggestions to overcome these problems that might be conducted, try to choose only can be found in this chapter. A discussion of those that will help you answer the options for presenting your findings in an fundamental questions posed at the outset easy-to-understand format is reviewed in of your assessment. Chapter 7. The following sections describe a variety of This chapter is not intended to turn you into approaches to exploring and analyzing an expert in statistics. It should provide you typical watershed data sets. When your with a basic understanding of the terms and analysis is finished, consider the outcome: concepts related to the statistical analysis of Do the results make sense? Will other data. This background should help you to people believe and accept the results? If the understand existing statistical analyses of analysis was inconclusive or the uncertainty data from your watershed and to work was too great, reevaluate your procedures effectively with consultants or collaborators and your available data. Quite often, sample who will be conducting new analyses of sizes are just too small to provide definitive watershed data. answers. In such cases, if there is no clear alternative means of analysis, it is perfectly Chapter Outline acceptable to state that you are unsure or that there is a lot of uncertainty in the 5.1 Analysis Overview analysis. It is quite common to have an 5.2 Indices and Standards for Evaluation indefinite outcome from analysis of 5.3 Applying Statistics environmental data sets where tight 5.4 Spatial and Temporal Analysis experimental control is not feasible or cost- 5.5 Factors Complicating Interpretation of effective. Honestly state the limitations of Statistical Analysis the analysis and resulting conclusions. 5.6 Statistical Resources 5.7 References 5.1.1 Revisit Your Original Questions ______and Conceptual Model
When choosing which analyses to perform, 5.1 Analysis Overview think strategically about what you want to get out of the process. Go back to your The analysis portion of your watershed original watershed assessment questions assessment is critical to your effort. The and issues and determine what kinds of careful and thorough analyses of existing answers would be useful. Because you can and new data you generate will support the easily go astray in this phase by pursuing integration and synthesis of all information intriguing, though not necessarily useful,
- 5.1 - California Watershed Assessment Manual, Chapter 5 August, 2004 analyses, you should be very deliberate in choosing which analytical paths to follow. • Do the data and data collection Review the conceptual model. Have the techniques meet quality standards? data you’ve collected supported the • Are the gathered data and information relationships you initially hypothesized? Or, useful for your needs? have the data suggested that certain • Are the data at appropriate scales of relationships you thought existed actually do resolution for your questions? not? If so, you might need to revise the • Do the data contribute toward answering conceptual model. This new version can, in your questions? turn, be used to help focus your data • Do you require new or more data? What analysis. You may find that reviewing the good will it do you? initial questions and conceptual model is • When will you be satisfied? How much beneficial at several stages of your data is enough? compilation and analysis.. • Do all the potential users and detractors of the watershed assessment accept the 5.1.2 General Considerations in Data raw data? Analysis • Do all the stakeholders support the
choice of analysis types? The following principles are common to data • Are you thinking in ranges rather than analysis (Dunne & Leopold 1978; Gordon et single values for the data? al. 1992; Washington Department of Natural Resources, 1997). • Are you making comparisons to natural variability, which requires determining or Common Principles estimating baseline and reference conditions? 1. All the data, information, maps, photos should be in hand before the analysis There are two major aspects of data begins. analysis: 1) comparison of data on your 2. Leave your preconceived conclusions watershed to some reference values or behind. Bias is not acceptable. Let the standards and 2) the statistical treatment of data and information lead to the the data. This chapter will focus on these conclusions. Test hypotheses with data. key issues. 3. Since many data analysis methods are 5.2 Indices and Standards for available, the methods chosen depend Evaluation upon the nature of the available data and the purpose of the investigation. The method(s) for drawing conclusions The purpose of analyzing data is to put the from results should be outlined. information you have about watershed 4. Conclusions in a controlled study can conditions into a framework or context that only be as good as the study design, the will help you answer the questions or accuracy of measurements, and the address the issues that brought the appropriateness of statistical analysis. assessment team together in the first place. 5. There are no “cookbook methods” for One way to create this context is to data analysis. compare the conditions in your watershed to standards that are recognized as supporting With these principles in mind, and with the ‘normal’ hydrological function, ‘healthy’ data collection steps in previous chapters riparian and instream habitat, or water behind you, it’s time to assess how quality that is ‘adequate’ to support aquatic prepared you are for data analysis. The life. Much debate exists on what is meant checklist below can help with this by ‘normal’, ‘healthy’, or ‘adequate’. One assessment. definition of such terms is ‘pre-development’ conditions. For example, hydrological
- 5.2 - California Watershed Assessment Manual, Chapter 5 August, 2004 processes within the watershed are usually between pollutant concentrations and altered by urbanization or commercial environmental effects. They do not reflect activities. Pre-development conditions are a consideration of economic impact or standard to which you can compare the technological feasibility (U.S. EPA, 2002). present hydrological conditions. Another The U.S. EPA categorizes pollutants into definition is the concentration of certain three major categories: priority pollutants, constituents in water that are known to allow non-priority pollutants, and pollutants with survival of aquatic life. The water quality “organoleptic” effects (those that affect measurements collected in your local water’s taste or odor). Priority pollutants stream can be compared to the reference include pesticides, PCBs, and a variety of values known to protect either warm-water anthropogenic chemicals. Non-priority or cold-water aquatic species. Reference pollutants include conventional water quality values are the benchmarks, standards, parameters, such as pH, dissolved oxygen, thresholds against which measurements turbidity, and temperature. Pollutants with and conditions are assessed organoleptic effects are primarily applicable (http://www.fs.fed.us/institute/monitoring/rv_ to drinking water. factsheet.htm). In some cases, the benchmark values are specific to certain The criteria that the U.S. EPA uses for types of stream or regions of the state. aquatic life protection are the same as those Except for drinking water standards, no one contained in the California Regional Water standard can be used for all waterways. In Quality Control Boards’ Water Quality other cases, such values are not available. Goals. Each of the nine Regional Boards Sometimes, comparisons can be made to a prepares a Basin Plan, which designates similar waterway that has been subjected to the beneficial uses of that region’s waters, fewer human impacts, and is therefore in a as well as water quality objectives for a wide more pristine’ condition. Streams such as variety of constituents that will support the this are referred to as ‘reference’ streams. identified beneficial uses. The Water Quality Regardless of the specifics, indices or Goals contain numeric criteria that, for standards can be used to analyze the aquatic life protection, are the same as U.S. meaning of the data you have collected. EPA criteria.
5.2.1 Indices and Standards for Water Each Regional Board’s Basin Plan identifies Quality Analysis beneficial uses of the water, water quality objectives, and a plan for implementation of Background these objectives. Each Basin Plan’s Chapter 3 contains the water quality objectives, The U.S. Environmental Protection Agency including criteria values for conventional (U.S. EPA) has developed a set of water and priority pollutants. Some Regional quality criteria that can be used for Boards attach relevant documents, comparative purposes. These criteria including recommended numerical limits for identify the concentrations of constituents pollutants, to their Basin Plans. The Central and contaminants in water that are thought Valley Regional Board has prepared “A to protect aquatic life. The U.S. EPA’s Compilation of Water Quality Goals,” a staff Water Quality Criteria were developed report that “contains numerical water quality pursuant to Section 304a of the Clean limits from the literature for over 800 Water Act, which required U.S. EPA to chemical constituents and water quality develop and publish criteria for water quality parameters” that accurately reflect the latest scientific (http://www.swrcb.ca.gov/rwqcb5/available_ knowledge for a variety of aquatic species. documents/wq_goals/index.html). The These criteria are based solely on data and companion document Recommended scientific judgment of the relationship Numeric Limits, available at the same URL,
- 5.3 - California Watershed Assessment Manual, Chapter 5 August, 2004 is an Excel spreadsheet containing a list of “conventional” water quality values such as water quality criteria for a wide variety of alkalinity, ammonia, hardness, nitrates, oil conventional and priority pollutants. It is an and grease, and pH. The National excellent reference document and the Oceanographic and Atmospheric criteria can be used for comparison with the Administration (NOAA) publishes an easy- data collected in your local waterway. to-use list of these criteria known as Screening Quick Reference Tables or A number of other water quality standards in SQuiRTS California reflect protection of various other (http://response.restoration.noaa.gov/cpr/se beneficial uses of water. For example, the diment/squirt/squirt.html). SQuiRTS contain Maximum Contaminant Level (MCL) is a benchmarks for both water and sediment drinking water standard based on human quality. health, economic, and technological considerations. Frequently, these standard Two values are identified for each concentrations are higher than those used constituent on the list. The “criteria for aquatic life protection. Public Health maximum concentration,” or CMC, is the Goals (PHGs) for drinking water are another maximum value that is safe for an acute set of standards based solely on the exposure, defined as a one-hour exposure. protection of human health. The “criteria continuous concentration,” or CCC reflects the maximum concentration For the purposes of a watershed for exposure for a 96 hours or longer. CCC assessment, you should compare the data reflects chronic exposure. Both values obtained on the stream(s) in your watershed reflect safe levels of exposure for most with numerical criteria that are protective of aquatic life and were derived from a review aquatic life. You may also be interested in of scientific studies on many different identifying the designated beneficial uses species of aquatic organisms. A more set forth by the local Regional Board and in detailed explanation is contained in the determining which, if any, pollutants are SQuiRTs. impairing those uses. You might find that other water quality constituents might not While most values can be read directly from meet the standards required for a beneficial the tables published by either NOAA or the use. When some watershed groups have U.S. EPA, many values for metals are identified problems like this some have dependent on the hardness of the water. recommended to the Regional Board that a Some metals will form complexes in water total maximum daily load (TMDL) standard that is hard or that has a high mineral for that contaminant be established. content. Therefore, the actual concentration that aquatic animals will be exposed to is Information on Priority Pollutants different than the dissolved concentration typically measured. Most often, aquatic The U.S. EPA Water Quality Criteria organisms will tolerate a greater provides the best source for reference concentration of these metals in hard water values to compare with those data you have and a lower concentration in soft water. The collected in your watershed. Criteria values NOAA and EPA tables contain formulas that have been established for both freshwater permit the user to adjust the criteria value and saltwater. The values are regularly depending on water hardness (see text box updated, with the most recent update on next page). occurring in 2002. See http://www.epa.gov/waterscience/criteria/aql Additionally, SQuiRTS contains the most ife.html. Criteria exist for a large number of easily accessible information on sediment metals, volatile organic compounds, quality criteria. These types of criteria are pesticides, hydrocarbons, and slightly different from the CMC and CCC
- 5.4 - California Watershed Assessment Manual, Chapter 5 August, 2004 values for water. For example, instead of university libraries, but is usually not the acute or chronic criteria values, available online. Using the ASFA database, sediment standards are reported as Effects you can find scientific articles that have Range-Low, Median, or Probable Effects been published on that topic and then check Levels. Effects Range-Low is the lowest 10th out or copy the pertinent articles. percentile contaminant concentration among samples shown to be toxic to In many waterways that support salmonids, aquatic organisms. SQuiRTS contains a excessive suspended and benthic fine detailed explanation of these terms. This sediment are a serious issue. Yet, criteria document also includes graphs that allow values for these endpoints are not readily you to easily determine the criteria value for available. The British Columbia Ministry of metals corrected for hardness. Using these Water, Land, and Air Protection has tables allows you to avoid performing any prepared a review that contains ambient calculations to correct for metals solubility in water quality guidelines for excessive water of varying hardness. sediment that may be useful in certain circumstances. They are posted at: Information on Non-priority Pollutants http://wlapwww.gov.bc.ca/wat/wq/BCguideli nes/turbidity.html#tab1. The US EPA is in Although non-priority pollutants, such as the process of preparing similar guidelines altered temperature or dissolved oxygen are for US waterways, included in the U.S. EPA Water Quality Criteria, EPA frequently refers the reader to The Hazard Quotient other reference material because these values are highly species-dependent. For The ratio of the actual concentration of a example, a warm-water fish in warm water contaminant in your waterway to the might be able to tolerate a dissolved oxygen protective concentration listed in the criteria concentration of 5 ppm, but a cold-water tables is known as the hazard quotient. This fish in cold water could not. Consequently, is a widely used value in environmental to obtain criteria or benchmark values for toxicology. A hazard quotient greater than 1 the species of interest in your watershed, suggests that there is a risk for harm from you will need to gather information from that constituent or contaminant. If it is much other sources. greater than 1, the possibility exists that harm to aquatic life could be significant. If A good place to obtain this information is the hazard quotient is less than 1, it is the Regional Boards’ Basin Plans. For unlikely the contaminant could cause harm. example, the Central Valley Board’s Recommended Numeric Limits document The hazard quotient is a useful, but rough, contains recommended criteria for pH, estimate of whether a contaminant is likely sulfate, total dissolved solids, ammonia, and to be of concern. other conventional water quality parameters. This information is posted at: To summarize the key points regarding the http://www.swrcb.ca.gov/rwqcb5/available_d use of standards to evaluate water quality: ocuments/wq_goals/index.html. If the • Obtain water quality criteria for information you are seeking is not available contaminant of interest in these documents, you may wish to carry • Collect data on the concentration of out a literature search for the constituent of chemicals in your waterway concern and the species of interest. The • Compare contaminant concentrations to best place to perform such a search is standards and criteria. through the Aquatic Sciences and Fisheries Abstracts (AFSA). This database of scientific literature is available at most
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How to Use the Water Quality exposure is continuous, or at regular Criteria: An Example intervals, then it is more likely that adverse effects could result. It might be useful to Water quality criteria reflect consult with a local aquatic biologist (at a concentrations of constituents that university or state department with are generally considered protective of responsibilities for health of aquatic aquatic life. These criteria can be organisms such as the Dept. of Fish & used to compare data from any Game) to get a professional opinion on this individual waterbody to determine or other related issues. whether there is a risk for adverse effects from contaminants. For 5.2.2 Benchmarks for Water Quantity example, copper is a common and Flow contaminant in many California [under construction] creeks and streams. The chronic value (or “chronic continuous 5.2.3 Benchmark Values for Land Cover concentration”, CCC) is 9.0 parts per billion (ppb) or µg/L at a hardness of When trying to evaluate the impacts that 100. Assume a creek in your changes in land cover might have on your watershed has a hardness of 50 and watershed, there are few standards to which the concentration of copper was you can compare your watershed values. measured at 8 ppb. At face value, the Two of these are area of impervious 8 ppb in the water is below the 9.0 surfaces (impacts to hydrology) and the ppb criteria value, so you would fragmentation of habitat by human guess there isn’t cause for concern. infrastructure and activities. However, because the hardness of the water is different than 100, the Impervious surface (IS) refers to areas such original chronic value requires an as roads, driveways, houses, patios, and adjustment. Using the formula any other surface that is no longer provided by both U.S. EPA and permeable to water. As IS increases in a NOAA in the publications cited, the watershed, there are changes in runoff hardness-corrected safe quantity and timing, erosional processes, concentration of copper is actually water quality, and channel condition. These 5.15 ppb. Therefore, the copper effects are reviewed in Chapter 3 of CWAM. concentration in your local creek Watershed performance can be linked to could pose a risk to aquatic life since the percentage of the landscape that is 8 ppb is greater than the adjusted covered by roads and other developed criteria value of 5.15 ppb. areas (i.e. impervious surfaces). Total imperviousness can be calculated for the One issue to keep in mind when using water watershed and/or sub-watersheds. quality criteria data is the length of time the Information on how to estimate impervious aquatic organisms were or might be area is available online at exposed to the contaminants. This question http://www.nemo.uconn.edu/publications/ind is often difficult to answer because the ex.htm#technical. Technical Bulletin #3 answer requires collecting a considerable posted on the NEMO website contains amount of data, an impractical task in many information on calculating imperviousness cases. using a few different methods. Having Use best professional judgment to estimate estimated IS in your watershed, you can the duration of exposure to the contaminant. compare your values to those shown to be If the exposure is for a brief period of time associated with degradation of stream and (minutes or hours) and the concentration is waterways. The benchmarks identified by not great, perhaps little harm will result. If the Center for Watershed Protection are:
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• <10 % impervious cover associated with structures as dams, reservoirs, diversions, minimal impacts in most cases and roads. A rough indication of where • >10% -- <25% associated with these barriers might be is at the intersection moderate impacts of the waterway with the structure as a point • >25% associated with serious-severe (dam) or line (road). For some regions of impacts California, major barriers to salmonid (Schueler, 2000). If your watershed is migration have been mapped. For some located in an urban or urbanizing area, local areas, finer-scale analysis of barriers these values can be used to make rough has been accomplished, including locations, estimates of the degree of potential impacts types, and characteristics of culverts (water- you might encounter. This could be very carrying pipes running under roads). useful for future planning efforts as well. Culverts can pose a significant barrier to migrating fish, effectively fragmenting In rural developed areas, road density is aquatic habitat. To determine if culverts in sometimes simpler to estimate than your waterway are acting as a barrier, impervious cover and can act as a criteria have been established by the Dept. surrogate. It is also useful in estimating Fish and Game. The Culvert Criteria for impacts in forested areas where logging Fish Passage document can be roads pose a risk to rivers and streams. In downloaded at: forested areas, road position on slope, http://www.dfg.ca.gov/nafwb/pubs/2002/culv proximity to streams, and disturbance of ert_criteria.pdf. steep erodible soils all contribute to road impacts to aquatic ecosystems. As road The location of potential physical barriers is density increases, the likelihood of road not the only indicator of fragmentation. For impacts increases example, below a dam and between diversions, there may be miles of a stream Fragmentation of plant communities is an or river where flows are insufficient or important ecological impact of human excessive for supporting certain aquatic activities, as well as a naturally occurring species. In this case, the ecosystem would process. There are various indicators for be effectively fragmented by water this phenomenon, including the extent and management, independently of being near, type of roads in an area, the density of downstream, or upstream of a physical developed parcels, human population structure that acts as a barrier. density, and actual forest cover remaining after logging. You may have data for only 5.2.4 Reference Values for Habitat two of these indicators for your watershed. Characteristics Sometimes one or two fragmentation indicators can stand in for the rest Identifying reference values for habitat (depending what they are), giving you a characteristics is not as straightforward as sense for where fragmentation may be high. for water quality. For any group of plants or The best-case scenario is where you have animals, different habitat characteristics are digital spatial data derived from recent geo- important. No one set of benchmarks is referenced aerial photographs combined useful for more than a handful of species. with remote sensing of vegetation types. Probably the greatest number of benchmark This combination will allow you to determine values for habitat characteristics are the actual edges of patches of particular available for salmonid species. The Oregon plant communities and thus measure Watershed Assessment Manual contains fragmentation directly. benchmarks for salmon spawning streams for percent pools, characteristics of riffles, Human-caused fragmentation of aquatic percent canopy cover, amount of large communities is primarily caused by such woody debris, and number of riparian
- 5.7 - California Watershed Assessment Manual, Chapter 5 August, 2004 conifers for coastal waterways. Some of suitable that habitat characteristic is for these values might be useful for other salmon. Unfortunately, similar curves are locations as well. This data can be found in not available for other species at this time. Appendix IX-A of the Fish and Fish Habitat chapter and is posted at: One additional source of information on http://www.oweb.state.or.us/publications/wa benchmark values for habitat for aquatic _manual99.shtml. This information provides species is the USFWS. In the 1980s, they a rough idea of the conditions that are developed a series of Habitat Suitability favorable for salmon, but are not “hard and Indices (HSI) for numerous terrestrial and fast” numbers. aquatic species. These models “provide an objective quantifiable method of assessing The California Department of Fish and the existing habitat conditions” for many Game has published the California aquatic species (Raleigh et al., 1986). Salmonid Stream Habitat Restoration Conditions in your stream can be compared Manual. It contains desired conditions for using the curves developed by the USFWS. stream habitat that could be used to In effect, these curves are a variant of a develop estimates of benchmarks. The stressor-response curve; they relate a manual is posted at: single variable like temperature or % pools http://www.dfg.ca.gov/nafwb/manual.html. to a suitability value between 0 and 1. The Keep in mind when you use these higher the number, the closer the condition benchmarks that many of them are based in your waterway is to optimal or highly on best professional judgment and have not suitable condition required by a particular undergone a peer-review process. species for that particular habitat Consequently, these values should be used characteristic. The suitability models and as estimates only in your analysis. indices are posted at http://www.wes.army.mil/el/emrrp/emris/emr The North Coast Watershed Assessment ishelp3/list_of_habitat_suitability_index_hsi_ Program (NCWAP) has developed a series models_pac.htm. There are various of reference curves for salmon spawning strengths and weaknesses to using HSIs. A streams along the north coast. Reference review of how these models work, their uses curves show the relationship between a and limitations, is available and worth stressor and the response of an organism, reading (Rand & Newman, 1998). in this case salmon. The values they have identified are probably useful for many 5.2.5 Use of a Reference Site northern California streams, but likely not for southern California where some salmonids In some cases, you can identify a relatively are more tolerant of warmer temperatures. undisturbed watershed in the same general The reference curves developed by region as your watershed. The habitat, NCWAP, based on the best available water quality, hydrological conditions, etc. information, can be used to identify can in effect serve as reference values. The conditions that are ‘fully unsuitable’ to ‘fully conditions within the reference watershed suitable’ for salmon species. The can be used to compare to the conditions in benchmark values are contained in the your watershed. The differences between Appendix on Ecological Management the two can be used to evaluate the degree Decision Support (EMDS) Model, posted at: to which human activities have altered http://ftp.dfg.ca.gov/outgoing/whdab/ncwap/ conditions and processes in your public/watersheds/mattole_river/pdf/Final_M watershed. The main difficulty in using this attole_Synthesis_Rpt_032403_Subbasin_Pr approach for comparisons is that there are ofiles.pdf. By locating the value for habitat few watersheds in the state that have not conditions in your waterway on the been disturbed to one degree or another. In reference curve, you can estimate how addition, it takes some work to determine
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“Statistics should be regarded as a tool, an aid to understanding, but never a replacement for useful thought.” (Haan, 1977) and ensure similarity between the reference for decades to analyze environmental data. and assessment watershed. Further, data Even if you do not plan to use statistics isn’t necessarily available for the reference yourself, it is important that you understand watershed. However, if such data is how these tools work so you can participate available, it can be very useful as part of the in discussions about data analysis. analysis of conditions in your local waterway. • How and when should statistics be applied within a watershed assessment? 5.3 Applying Statistics Any time a watershed assessment includes At this point, you have reviewed your data a quantification of condition (e.g., water and have obtained the appropriate flow), it is appropriate to consider statistics. standards against which to compare data for your watershed. You will now want to • When are statistics NOT necessary? find out if there are significant differences between your environmental measurements There are times when statistics may be and the standards. Alternatively, you may less informative. For example, many want to know how one reach of the stream metrics of geomorphology, surveys of within the watershed compares to another. plants and soils, and descriptions of a As a third alternative, or in addition, you community’s socio-economic status may be may want to measure trends or changes expressed without consideration of over time in conditions in all or part of the statistical analyses. watershed. Statistics are used to make unbiased comparisons like these. • How much statistical rigor is necessary for the purposes of the assessment? “Statistics” is a set of mathematical tools that may help guide the design of data The use of statistics provides much of an collection efforts and assist in summarizing assessment’s rigor. You must decide how and interpreting the data. Statistics are much confidence you want to have in the particularly valuable in describing data quantification of conditions used to inform variability that reflects the inherent variability your decision-making. in natural watershed processes and phenomena. Statistical methods may be • What level of “significance” is used to calculate data significance and the necessary? differences among measurements across time and space. They provide a way to The term “significance” in statistics refers to assess how reliable your conclusions are how likely the conclusion you draw from when drawn from a particular data set (Zar data reflects a real condition, which is 1984). analogous to the confidence you can have in the conclusion being correct. A common This section explains the basic concepts standard in natural sciences is “95% that are important to understand in order to confidence”, which refers to how confident use statistics properly and describes some you are that a conclusion drawn from of the most common statistical tools used in numeric data is correct. watershed assessment. The information presented here is very basic relative to the many texts that natural scientists have used
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Examples of Using Statistics in can be grouped with those of other samples Watershed Assessment and generalized to the larger population. [Under Construction ] Sampling can be either random or directed. Usually random sampling, or its cousin 5.3.1 Terms and Definitions “stratified random sampling”, involves selecting at random a subset for the total Types of data—You will find several main population of the target of analysis. For types of data in your assessment work. example, if you have 100 sub-watersheds in Discriminating among data types is critical your watershed and you want to study for choosing the appropriate data analysis sediment production in the overall tools. “Nominal data” refers to classes, such watershed, you could create a random as soil types, that have names rather than sample by choosing 10 of the sub- numeric values. “Ordinal data” are data that watersheds at random, by literally placing have been ranked or ordered in some way the sub-watershed names in a hat and according to attributes of the data. For picking 10. Stratified random sampling example, stream orders are on an ordinal involves first creating groups of likes (e.g., scale. The stream order numbers sub-watersheds that are geologically- themselves don’t mean anything in a similar) and then selecting randomly from quantitative sense, but they do rank the within each group. This approach ensures a streams according to their relative representative sample from each major contribution to higher order waterways. group in the population. “Interval data” refers to data on a scale that does not have a true zero. Temperature is a Replicates—If you collect two or more good example of this type of data. There are samples from a population of something at constant intervals between degrees of the same time and place and in the same temperature, but there is only an arbitrary way, then you have collected replicate point assigned the value of zero and many samples. Collecting two samples (X1 and intervals below zero. “Ratio data” are similar X2) means that you can calculate the to data on an interval scale, but with an average value ([X1 + X2]/2) but you won’t absolute zero. For example, tree heights are have a measure for how representative the measured on a scale with a constant average value is of the population. If you interval (e.g., meters) and a true zero point. collect three or more replicates, then you can use the values in statistical Population— The term refers to the entire comparisons comparing average values for collection of items that are the focus of each group of samples . concern, such as a particular water quality characteristic. The population of Variance and variability— Nature possess temperature values for a given stream reach natural variation. When you try to describe consists of all of the temperatures that some factor by taking samples, you are occur. It is usually impossible to collect all of taking a partial snapshot of the true quality these values, but it is usually possible to of the thing you are measuring. The sample collect some small fraction of them. values will be different from each other, and the magnitude of the differences will depend Samples and sampling— A sample is a set on what you are measuring and how you of items drawn from the population. measure it. A measure of these differences “Sampling” means collecting a subset of the is the “variance”. For example, if you take population of values. Each sample is multiple water temperature measurements intended to be a representative of the whole in the same spot on a stream one after the population. An individual surveyed by the other using the same thermometer, you will Census Bureau on income and employment get values that are very similar to each information would be a sample, whose data other, and the variance will be low. If you
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12 12 10 10 8 8 6 6 4 4 2 2 0 0 0 20 40 60 80 100 0 20 40 60 80 100
Example of a normal (left figure) and non-normal (right figure) distribution of any data. Arrows represent means for both sets of data. took three samples of benthic measure of statistical significance. This term macroinvertebrates from a single riffle, you means how much confidence you can put in would probably find a wide variation of types the conclusion reached from the calculation and numbers of these animals among (e.g., how water quality has changed over samples, and the variance would be high. time). For example, let’s say that you want Measures of variance are critical for making to know whether measured contaminant comparisons among places in the values in your waterway are “significantly” watershed, over time, and between lower than a water quality standard. You reference and measured parameters. would use a statistical test such as a “t-test” to determine whether or not there was a Distribution—For ratio and interval types of true difference between your measured data, your measurement values will usually values and the standard. How much be spread across a range of possible values difference there was between your values and will be grouped around an average and the standard would determine how value. Measured values for some population confident you were in the significance of the of possible values are distributed in one of difference. two ways: normally or non-normally (see box above). Normal distribution means that 5.3.2 Summarize and Explore the Data most values tend to be near the mean and evenly distributed above and below the Before beginning any formal statistical mean value. Non-normal distribution refers analysis, you should explore the data to there being more values either above or informally. This can be done with descriptive below the mean and clumped differently on statistics. Descriptive statistics can be either side of the mean. A frequency calculated using an Excel spreadsheet and distribution represents graphically the way includes calculating the mean value, the the data varies around the mean. standard deviation (or range of variation), and as well as a frequency distribution if you The concept of normal distribution is have sufficient data points. important because subsequent calculations involving variation will depend on whether The mean of several replicate your distribution of values is normal or not. measurements theoretically represents the population or process that is being Statistical significance—Comparing your measured. For example, if three samples values against some standard (e.g., for are taken for suspended sediment at a water quality) or with each other requires a certain depth near the same time on a given
- 5.11 - California Watershed Assessment Manual, Chapter 5 August, 2004 day, the mean concentration value is the from 15 sites in the watershed in the month “true” value for suspended sediment at that of September, you might plot the data to depth at that time on that day. Means see how similar or different the sites are. should only be calculated for three or more Plotting the data in a frequency distribution samples so that the variation can be gives you a visual picture of the variability in calculated. If you have only two values, then temperature throughout the stream. It helps you can calculate an average, but you won’t to give more meaning to the average. know how well the average represents the “true” value. Variation is a measure for how It is also important to know when not to well the mean represents the population of calculate a mean and standard deviation. values. The higher the variation relative to For example, if you are investigating a the mean, the less likely it is that the mean process that changes over the timeframe value represents that population or process. you examined, such as suspended The standard deviation is a common form sediment concentration during a storm of representing variability around the mean. event. Calculating the mean suspended Both mean and standard deviation are sediment concentration and standard easily calculated in a spreadsheet program deviation for that timeframe will be less such as MS Excel. meaningful than other ways of analyzing the data, such as calculating the total You can calculate means by adding up all suspended sediment load during the whole values and dividing that sum by the number storm event. Deciding whether to calculate of data points used. For example: 2 + 3 + 4 a mean value for a watershed feature = 9; 9/3 = 3. In this example, the means is depends on the questions you have. 3. Overall, descriptive statistics allow you to For example, if you’ve collected water get a better feel for the data. These simple temperature data once a month for 3 years, statistics are sometimes all that is possible you might decide to summarize the data for for the watershed assessment, especially if each month, based on the value you you have a small dataset. collected over the 3 years, by calculating the mean and standard deviation. You can 5.3.3 Perform Statistical Analyses, if then construct a graph or table that reflects Warranted the average temperature each month. Once you have summarized your data, you A frequency distribution plot (shown below) will need to determine if it would be useful to is another way to look at variability of the perform a statistical analysis in order to data. If you collected data on temperature identify significant changes over time, between different places within the watershed, or 5 between your watershed 4 data and reference or benchmark values. 3 2 Here are some questions to review to determine how to 1 proceed: number of site 0 42 44 46 48 50 52 54 58 60 • What statistical tests do you plan to use? temperature • Is the data of sufficient quality to use?
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• Would it be worthwhile to consult with between the sets of values is what you will an ‘expert’ on statistics? be determining with these comparative tests. If your team decides it is appropriate to move forward with a more formal statistical Just as with the calculation of the mean, it is analysis of the data, one of the most also important to know when comparing common analysis methods is a comparison means is appropriate. In a situation of means. Frequently data collected from involving time (last year vs. this year), there different sites, for example, appears to be are many factors that change over long time different; but when you do a formal periods that affect comparisons of statistical comparison, the differences aren’t watershed values between years. So, significant. You may want to compare two although you may find a year-to-year or more collections of values (e.g., for a difference for a particular watershed water quality parameter) across space (e.g., parameter value, the difference diminishes upstream vs. downstream) or time (e.g., last in importance as larger forces change the year vs. this year). You may also want to watershed over the timeframe of several compare your mean for a range of values to years. a standard. To do any of this, you must calculate the variation around each mean To compare means, there are several and use these calculations to compare the comparative statistical tests to choose from. means, or a mean to a standard. The A common one is the Student t-test (see significance of the difference or similarity box below). In this test, you compare one
Student t-test
The following table displays data for two months, October and April, and the output from performing the T-test. In this case, the calculation in Excel provides critical values, so you don’t need to look them up in a book. The critical value is like a benchmark value: if the T- statistic is greater than the critical value, then the difference between means is significant. In this example, the critical t-value is 2.13 while the t-statistic for the actual data is -4.27. Since the absolute value of the t-statistic is greater than the critical value, the difference is significant. The p, or level of significance value, is 0.006. This number implies that there is a 0.6% chance that the mean temperature in October and April are not significantly different from each other.
Temperature Readings by Month October April t-Test: Two-Sample Assuming Equal Variances 13 21 12 18 Oct. April 15 25 Mean 15.67 22.33 20 24 Variance 16.33 14.33 Observations 4 4 Pooled Variance 15.33 Hypothesized Mean Difference 7 df 3 t Stat -4.27 P(T<=t) one-tail 0 .006 t Critical one-tail 2.13 P(T<=t) two-tail 0.013 t Critical two-tail 2.78
- 5.13 - California Watershed Assessment Manual, Chapter 5 August, 2004 set of data with another by comparing their occasionally, on both. means. Your data should be normally • An example of an analysis over a distributed in order to use this test. You will spatial scale is the measurement of get a t value from this test, which you can extent of development (e.g., human compare to standard values from a t-table. If population or parcel density) in your t value is greater than the standard, watershed areas that erode more rapidly then your difference is likely to be than other areas. significant. These calculations can be • An example of analysis over a temporal performed in MS Excel. scale is determining the frequency and regularity of pesticide applications in an There are numerous additional statistical agricultural watershed over a several- tests that can be used to compare means, year period. some of which are listed in the box below. Others are described in the Appendix. For The analysis methods used for things that additional information, it would be best to change over space are different from those consult with someone knowledgeable about used for things changing over time. There is selecting the best statistical tests for the extensive technical literature on how to type of data you have. measure each of these types of changes, depending on what needs to be measured 5.4 Spatial and Temporal Analysis (e.g., analysis of trends over time). This type of analysis is fairly sophisticated so it Watershed assessment requires the would be wise to consult with a consideration of human and natural knowledgeable person to determine if these processes occurring over space (the methods are appropriate for your data and watershed) and time (history). Analyses of to obtain assistance actually performing the these processes are often performed on analysis. One cautionary note is that most either spatial or temporal scales, and analyses involve assumptions about the
Overview Additional Statistical Methods
• ANOVA - Another common and powerful test for comparing among means is the Analysis of Variance (ANOVA). This test gives an F-statistic to compare against standard F- values. Just as with the t-test, if your F-statistic is greater than the standard, then the differences among means are significant. You might want to analyze your data using more complex, multivariate methods. These methods permit you to estimate which factors contribute the most to minimizing variability in the results. In most cases, those factors that reduce variability in the data are usually the most important re: meaningful relationship. • Principals components analysis - One method to determine, for example, which watershed condition out of many might contribute the most toward the change in habitat that you have observed. • Regression analysis – A method for finding the relationship between two factors (e.g., road density and human population density). Regression tests the strength of the relationship or how much one variable depends on another. For example, the relationship between road density and wildlife occurrence could be analyzed with regression analysis. This analysis could be for linear or non-linear relationships. • Correlation – A method for measuring the strength of an association between two factors. Correlation does not imply causation. A strong correlation warrants further investigation to determine causation.
- 5.14 - California Watershed Assessment Manual, Chapter 5 August, 2004 nature of the process being analyzed. In http://cwam.ucdavis.edu. The first column other words, that it is possible to represent a describes the type of analysis; the second process with spatial data. In addition, in the column, the type of data used or needed for past, analysts have employed inappropriate the analysis; the third column, a possible analysis tools, so copying an approach used product; and the fourth column, the relative elsewhere should be done with caution. An difficulty. “Easy” calculations could be example of this would be the use of an performed by someone (including a erosion model developed for agricultural volunteer) with basic skills in ArcGIS or areas in rugged mountainous areas without similar GIS software. “Moderate” analyses modifying the model. could be performed by someone (a GIS technician or scientist with GIS proficiency) 5.4.1 Spatial Analysis with skills in ArcGIS. “Hard” analyses should be performed by a professional GIS Geographic information systems (GIS) were technician with guidance from a natural created to allow calculations for specific scientist. places on the earth. If you have a GIS software program, you can carry out these There are several important principles to calculations. Examples of common keep in mind when carrying out this type of straightforward analyses are densities of analysis objects located within a certain area of the landscape (e.g., abandoned mine density in 1) Not all spatial data are created equal. a sub-watershed), intersection of lines of Spatial data will vary in scale, accuracy, and different types (e.g., roads crossing quality, depending on how and when they streams), and summarizing data for an area were collected. Use care when carrying out (e.g., the number of people in a watershed). calculations using two or more data sets Not all spatial analysis needs to involve a that were created at different scales from computer-based GIS, but that is the focus in each other and vary in their accuracy (i.e., this Manual. how well the data represent the actual landscape). Types of spatial scale calculations 2) Principles of statistics hold for spatial The table below summarizes a sampling of data too, but the methods are not as clear the types of spatial scale calculations that as for other kinds of data. Spatial data are you or your analyst might consider carry similar to water quality and other data in out. Other, more intensive, analyses can be many respects, except that they are geo- found in the Appendix or online at referenced—they are for a specific place. If
Analysis Data source or type Product Difficulty Line density Line data, (e.g., roads and Line density per unit area (e.g., Easy streams) square mile or sub-watershed) Point density Point data (e.g., mines, low- Point density per unit area Easy income schools) Attribute density Numbers of attribute type Attribute density per unit area Moderate (e.g., population per grid cell density) Summarize attribute Sum, mean and other Summarized data for a Moderate data by area (e.g., statistics for attribute particular area (e.g., number of sub-watershed) miles of roads on steep slopes) Contribution of areas Distribution of problem Relative ranking of areas or Hard to downstream sources, driving natural mass calculation of pollutants problems processes, and impacted from contributing areas values
- 5.15 - California Watershed Assessment Manual, Chapter 5 August, 2004 you have a range of measurements for a example, pesticide runoff during storm place, it is possible to calculate the mean events. While short-term data collection is and variance, as well as compare with extremely valuable, interpretation of these another place. data must be consistent with temporal and spatial scales for which the data are 3) Avoid over-interpreting the data. Because collected. GIS programs usually allow you to create pretty maps, there can be a strong For example, data on short-term changes in temptation to enhance or reduce apparent channel morphology are sometimes differences using colors or color intensity in erroneously used as the basis for decisions order to create a certain impression. regarding river behavior. An example of this occurs when conclusions are drawn from 4) Relative differences among areas within surveyed channel cross-sections showing a watershed can be shown using a broad channel aggradation after one storm, a palette of colors (e.g., low = green, high = series of storms, or even after several orange, very high=red). However, if some years. These short-term changes only kind of reference is available for an area reflect the river’s response to watershed near your watershed (e.g., road-stream conditions over the period of measurement, crossing density), you should use it to and may simply represent “blips” in the provide a color or other standard in your longer-term trends and alterations in mapping. This will inform your audience of channel morphology. Thus, when changes the importance of your finding relative to the in the river process being evaluated occur standard. over a longer timeframe than the period of measurement, certain data analyses may 5.4.2 Trends Analysis be misleading, because they represent only a small part of the big picture. A large proportion of your data is likely to be related to time. However, analyzing data 5.4.2.1 Choosing a Timeframe for over time and interpreting it is not a trivial Analysis task. Analyzing trends in some parameter over time is essential to understanding how Choosing the “right” timeframe for analysis things are changing in your watershed1. You is just as critical as choosing the method to may wish to analyze trends over decades in use for analyzing trends. The question you order to get a general idea of how ask determines the timeframe. For example, conditions are generally changing. You may you may want to figure out if certain land also want to figure out how things are uses are having a negative impact on water changing over much shorter timeframes, for quality. From other studies, you might know that the effects are best detected over 1 several years, rather than over several The Journal of Time Series Analysis (JTSA), the abstracted articles of which can be viewed at months. You might also know that to detect http://www.ingenta.com/journals/browse/bpl/jtsa, change, you need both frequent periodic covers the very technical aspects of trends analysis. sampling (e.g., weekly) and measurements In 2003 alone, outside of the JTSA, there were over during storm events. In order to draw any 300 scientific articles on time series analysis in the conclusion about the impacts of land-use on medical, sociology, biology, climate, and manufacturing journals. Many of these articles water quality, you would have to design discussed how to use statistical analyses and models your sampling and analysis with this to explain or discover apparent trends. Conducting timeframe in mind. these analyses and approaching these models requires training in statistical analysis. However, for many analyses of watershed processes, using sturdy There are no strict rules for choosing the statistical tools to analyze how things change over right timeframes. However, there are some time is essential. guidelines you can use.
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1) Based on the questions you have for your The chart below shows an example of cyclic watershed assessment, decide the changes in water temperature in a managed appropriate timeframes for the underlying river in the Sierra Nevada. Temperatures processes. These timeframes will inevitably were measured nine times a year at roughly be closely linked to the sampling regimes even intervals over eight years. The for monitoring data that you are relying on. seasonal cycle in temperature is obvious in this chart. Changes (e.g., in peak water 2) Decide whether you are interested in how temperature) over the eight years shown your watershed is changing over years or are less obvious, even though there seems decades, or whether you are looking for rapid impacts in specific areas from specific sources. 30
3) Initially, separate the “where” (in the 25 )
watershed) part of your questions from the C “how long” (in time units) and “how much” 20 (relative to zero or some standard) parts of
ure (deg. 15 your questions. 10 4) Decide whether you can analyze each of Temperat these parts separately, or whether you need 5 two or more of these parts together (e.g., how much for how long). 0 Year 5) Once you have laid out the concepts for your analyses, decide on a statistical or to be an upward trend. It is also not data analysis method that is appropriate for apparent that the highest temperature has the question. There will not be much point in been captured with a particular sampling performing an analysis that is not event in a given year. This can be seen by appropriate for the questions you have. It looking at the gap between the data points would be better to leave the analysis marked by circles. It is possible that higher undone and identify the topic as unresolved water temperatures occurred in between and in need of more study. measurements.
5.4.2.2 Cycles The graph below shows pH changes over
Many natural processes occur in cycles of intensity. The continuous occurrence and 9.5 maintenance of these cycles is part of how 9.0 things naturally work and can indicate a 8.5 healthy, dynamic system. This cycling 8.0 makes trend analysis very challenging. For 7.5 example, if water temperature, precipitation pH 7.0 intensity, erosion rates, or wildlife 6.5 abundance changes in a positive or 6.0 negative direction, the change may be 5.5 occurring against a background of cycles of 5.0 intensity, frequency, or numbers of the natural parameters of interest.
5/2/1996 5/2/1997 5/2/1998 5/2/1999 5/2/2000 11/2/1995 11/2/1996 11/2/1997 11/2/1998 11/2/1999 Date
- 5.17 - California Watershed Assessment Manual, Chapter 5 August, 2004 time in the same river, where 10 measurements a year were taken. Although The data analysis and statistical tools there may be sufficient data between 11/95 available usually require experienced and 11/97 to suggest no long-term change technical staff and a high level of in pH outside of seasonal variation, beyond understanding of how natural processes that point the values vary more widely, and work and interact with each other. Summary there is a significant data gap for a year and descriptions for data analysis tools are a half. With this data set, only a crude available online at http://cwam.ucdavis.edu analysis of trends in pH will be possible for and in the Appendix of the Manual. For the period 1995 to 2000. example, the “R Statistical Package” provides a wide variety of statistical (linear These observations point to several and nonlinear modeling, classical statistical considerations to keep in mind when tests, time-series analysis, classification, analyzing trends: 1) depending on sampling clustering, etc.) and graphical techniques. It frequency, certain cycles or trends may be has tools for handling and storing data, a obvious, but others may not be detectable; large collection of intermediate tools for data 2) cycles with wide swings at one time analysis, and graphical facilities for data scale, such as seasonal water temperature, analysis and display either on-screen or on may mask other trends with smaller annual hardcopy. The data analysis and statistical changes, such as gradual warming or tools available usually require fairly expert cooling over many years; 3) data collection technical staff to operate and a high level of should correspond to the questions being understanding of how natural processes asked; and 4) scope of data analysis will be work and interact with each other. limited by the frequency of data collection. Even with these tools, there are many 5.4.2.3 Analytical Tools questions about change at the watershed scale that are beyond the current scope of Analyzing change in watershed condition relevant scientific fields and where sufficient over time requires specialized approaches. high-quality data are not available. When The simplest and most familiar approach is faced with these obstacles, it is best to think to take a measured attribute of the ahead to likely future assessment needs watershed (e.g., peak daily average water and try to figure out how much and what temperature or nutrient load) and see how it kinds of data a future assessor will need. changes over years, assuming data is This means that your consideration of available. More complicated approaches trends analysis may end up usefully include analyzing the change in watershed informing monitoring and research in your process over time, while taking into account watershed the influence of seasons, climate cycles (e.g., El Niño cycles), and gradual climate 5.5 Factors Complicating change. Interpretation of Statistical Analysis
Benchmarks exist for evaluating over time A number of different factors affect the some watershed processes (e.g., infiltration interpretation of data and statistical capacity as related to impervious surface) or analyses. Three that are of particular attributes (e.g., water quality). Although you importance are uncertainty, disagreement may be able to isolate certain watershed among experts, and confounding variables. properties to look at change over time, in Uncertainty is associated with the difficulty reality, these properties are linked to other of knowing and accurately describing processes in the watershed. The truth is complex conditions and processes in nature. that there is no simple way to analyze the This can be due to a variety of factors. changes in most processes of interest. Confounding variables are factors that could
- 5.18 - California Watershed Assessment Manual, Chapter 5 August, 2004 influence the results of the analysis that analyzing uncertainty because the haven’t been taken into account when assessment contains the information and conducting the analysis. Disagreements tools needed to do so. An evaluation of among experts are often associated with uncertainty helps a future decision-maker trying to interpret data in the face of gain a better understanding of the uncertainty. In the following section, these information on which they based their three commonly-encountered problems will decisions. be reviewed and suggestions offered for dealing with the challenges they present. 5.5.1.1 Sources of Uncertainty
5.5.1 Uncertainty In most cases, uncertainty cannot be eliminated, but being aware of the various The term “uncertainty” refers to the ways uncertainty shows up in a watershed probability of an outcome occurring, for assessment will help you realistically which the variation in possible values might analyze how much weight to place on any be known and specific statistical tools can one aspect of your assessment. Examples be used to measure the uncertainty. One of sources of uncertainty include (Warren- statistics text considers “uncertainty to be Hicks & Moore, 1998): synonymous with diversity” (Zar 1984). This example presents one way to think about • The degree of exposure of ecological uncertainty: Say there is a high probability processes to a chemical or a habitat of occurrence of salmon spawning in gravels alteration between one and three inches in diameter • The accuracy and completeness of the that are deeper than 6 inches below the conceptual model, a reflection of our water’s surface. Also say there is a low understanding of watershed processes occurrence of spawning anywhere else. The • The severity of adverse effects diversity of places that salmon spawned • Lack of information or data gaps would be low and the uncertainty about • The appropriateness of the temporal or where salmon spawn would also be low. spatial scale of the assessment • Extrapolation of information from one There is often a great deal of uncertainty species to another or from the laboratory associated with the measurement and to the field. For example, using data on analysis of natural conditions. Some of this toxicity tests from a surrogate test plant uncertainty is associated with the or animal for another species that measurement and analytical approaches resides in the watershed themselves, because we don’t know how to • The ability to differentiate between perfectly sample or represent complex natural variability and human-induced systems. Other uncertainty comes from changes incomplete measurements of the systems • Accuracy or appropriateness of an due to inadequate resource investment, for analytical or statistical test example, or inaccessibility of a location. • Human error Generally, most science and knowledge development aims to reduce uncertainty If the uncertainty is associated with and increase our ability to predict events identifying the range of possible choices, and parameters around us, for which there then more information should be collected is a known or unknown probability. prior to decision-making. However, if
uncertainty is primarily associated with the Watershed assessment is based on making presence of a number of known choices, the most scientifically sound decisions in the then the decision-making process is clearer face of uncertainty. The watershed to the decision maker. For example, if assessment is an excellent place for restoration scientists want to install gravel
- 5.19 - California Watershed Assessment Manual, Chapter 5 August, 2004 beds in a salmon-bearing stream to enhance be more information, but will also be more spawning, but the variation in flows in the data that represent the “true” condition of a river were unknown, then they don’t know watershed process or feature. Uncertainty where to place the gravel bars and how long can be reduced to some degree by the bars would exist before the gravel was performing more analyses and employing transported downstream by river flow more sophisticated methods to analyze conditions. In this case, the uncertainty is information. However, no matter how much associated with the range of possibilities, time and money are spent, it is not possible which the assessment could make clear to remove all uncertainty. when discussing flow conditions Additional examples of uncertainty in watershed Most watershed assessors must decide how assessment can be found in to reduce uncertainty within the limitations of McCammon et al (1998) Framework for their available resources. Here are some Analyzing Hydrologic conditions of suggestions for accomplishing this: Watersheds. • Involve people with diverse backgrounds 5.5.1.2 Measuring Uncertainty in the assessment process—the variety of stakeholder experience and expertise Statistical analysis is one way to measure makes it less likely that the assessment data uncertainty. This is done by placing will overlook some important watershed confidence limits (a measure of how factors, thereby reducing uncertainty in confident you are in the value representing the conceptual model a population of values) around the mean of • Carefully select analytical tests, being the data that represent a specified sure to follow quality control/quality probability or confidence. The limits that assurance protocols. This will help contain a parameter with a probability of reduce uncertainty associated with data 95% are called the 95% confidence limits quality. for the parameter. The wider the upper and • Consider the processes you are lower limits (or interval) of confidence are investigating, being sure to select around the mean, the less certainty that the appropriate temporal and spatial scales. mean represents the population; the This will reduce uncertainty associated narrower the interval, the higher the the question of whether findings reflect certainty. the actual watershed conditions. • Learn as much about the history of the For example, the mean diameter of the watershed as possible to reduce the streambed substrate at Site A is 13.81 mm, chance of attributing changes to human with a 95% confidence interval of 12.74 to activities when they might just be part of 14.87. This interval is quite narrow (< 8% natural variation. from the mean), indicating that there were • Avoid over-interpreting information or probably sufficient samples collected (or the data. If you have only one years’ worth substrate was quite uniform) to have a 95% of water quality data, don’t under- or probability that the actual mean is within over-interpret its significance. Be sure to that narrow range and that the measured identify in your report the uncertainty mean reflects the population mean. associated with the information. • Consider collecting more data if 5.5.1.3 Reducing Uncertainty uncertainty could undermine the work you are trying to do. The main way to reduce uncertainty in your watershed analysis is to increase the richness of the information you have at your disposal for analysis. Ideally, this won’t just
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5.5.2 Disagreements among ‘Experts’ conflict with the Sierra research. You need to check the units and the assumptions Another issue that frequently arises in the when citing sources for interpretation of course of analyzing data is that experts can your data. When there is little research upon interpret the same data differently. which to base a conclusion, be sure to Interpreting the results of your assessment’s qualify any interpretation of your findings. findings could be confounded by Here are some suggestions for what to do contradictions in what experts or the when the perceived experts disagree on the literature says the findings might mean. interpretation of your data: Sometimes the apparent disagreement may 1. Acknowledge the disagreement. (“Ideal be due to differing experiences based on LWD density is not clearly known for 2nd regional variations (e.g., coastal vs. inland, order streams in our watershed, since the Pacific Northwest vs. Southern California), experts seem to disagree.”) as well as differing methods of analysis, 2. Clarify the possible source of the professional specialization, agency disagreement. (“Different assumptions and missions, and other causes. Professional regions were used for previous studies.” or opinions and findings can also change over “Different units and scales were used—feet time, so an article on optimal fish habitat versus miles—and different diameters were from the 1970s might not have the same used to define LWD.”) interpretation as one from 2003. 3. Suggest options for resolving the Disagreements can also be associated with conflicting interpretation, if possible. uncertainty in the data (see 5.5.1). (“Search for existing LWD surveys in 2nd order watersheds in our region that could be If differing conclusions are noted in your compared to our watershed.”) assessment, be sure to clarify why they 4. Offer a range of interpretation (“Our might be different. For example, a fish average of 20 pieces of LWD per 100 habitat survey of ‘Mill Creek’ may have meters is lower than one benchmark of >30, found that the average density of large but higher than one suggesting >15.”), or a woody debris (LWD) is 20 pieces (> 12 in. qualitative conclusion (“Large wood was diameter) per 100 meters of stream. Does extremely scarce in Mill Creek compared to this amount of LWD provide adequate similar streams recently surveyed in the habitat for salmonids or not? The literature region.”) on LWD varies on this criteria, often 5. Make a recommendation that this issue depending on region (coastal, inland, needs to be revisited after more surveys or Sierra), stream order (1st to 5th order), and research have been done in the region. assumptions (e.g., historic condition, logging history). Only a few studies have Another type of “expert disagreement” is the measured LWD in streams of the Sierra difference among the various schools of Nevada, for instance (Kattelmann & professional and practitioner opinion. Embury, 1996). Those limited results Operating in the watershed field are revealed a range from one to 16 pieces per professionals from many disciplines— 100 m (> 6 in. diameter) in small streams. In hydraulic engineers, geologists, contrast, interim LWD objectives for the geomorphologists, fishery biologists, and U.S. Forest Service in California’s North botanists, along with stream restorationists, Coast streams are > 80 pieces per mile (> who might represent a combination of 24 in. diameter) (USFS & BLM 1994). In disciplines and/or unique field experiences. other words, this no one single benchmark Each of these disciplines offers distinct or reference value to which you can refer to. analysis tools, and each tool has its own Professionals in your area might want to strengths and weaknesses. There may be adopt the coastal objectives to your not right vs. wrong tools—the approach watershed—and then they would be in really depends upon which perspective is
- 5.21 - California Watershed Assessment Manual, Chapter 5 August, 2004 being applied to the watershed. Looking at widening due to increased sediment load, all these perspectives and using as many and/or all of the above? Without a carefully tools of analysis as appropriate will controlled study design, determining the contribute to putting together a more precise contribution of these factors will complete picture of the watershed. probably not be possible in your assessment. 5.5.3 Confounding Factors Chapter 6 presents various methods for Sometimes your assessment data and integrating information that may help you to information just do not seem to add up better understand confounding influences in correctly. There is a blip in your temperature your watershed. graph that is not readily explainable. Fish are not being found in obviously good 5.6 Statistical Resources habitat. A mile of stream lacks riparian vegetation for no apparent reason. The following books cover a variety of Whatever the mystery, you cannot easily statistical material and approaches ranging find an answer. from the very basic to the advanced. Their listing does not constitute an endorsement, Detective work might be in order to rather these books represent a selection determine if confounding variables might be you might find useful. contributing to the observations. This challenge can actually be fun and, if Basic successful, very rewarding. Look at the data more closely. Ask others, including Statistics a self-teaching guide. 1997. D.J. specialists and local residents. Historical Koosis. 4th edition. John Wiley and information might help—what used to be in Sons Inc. NY. 278 p. that area? An old dam or millsite? Check Includes descriptions of samples, the museum, ask longtime residents, review populations, means, variance, and old aerial photos. For example, in one comparison among means. sediment study, increased fine sediment was measured in a reach that was not the Statistics with Microsoft Excel. 2001. B.J. lowest gradient and was not below a Dretzke. 2nd edition. Prentice Hall tributary. After asking a longtime resident of Inc. NJ. 257 p. the area, it was discovered that that a 30- Provides guidance for the use of this year-old small diversion dam had been spreadsheet program in conducting removed recently from the site. Apparently, many basic statistical procedures. the sediment previously stored behind the dam was moving downstream in a sediment The cartoon guide to statistics. 1993. L. plug (Sommarstrom et al. 1990). Gonick and W. Smith. HarperCollins Publisher Inc. NY. 230 p. It is not always possible to find an accurate Very basic introduction to statistics explanation. Too many variables may be in a graphical form. interacting, and you may have insufficient data to separate them. The farther Statistics for dummies. 2003. D. Rumsey. downstream you examine and the larger the Wiley Publishing Inc. 355 p. watershed, the more likely “confounding Another very basic introduction with effects” will be found. Is bank erosion in the thorough introductions to the basis lower channel being caused by increased of statistical analysis. flows due to a greater number of impervious surfaces, or lack of riparian vegetation, or upstream channelization, or channel
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Intermediate An introduction to multivariate statistical analysis. 2003. T.W. Anderson. John Statistics and fluvial geomorphology. Wiley & Sons Inc. NJ. 721 p. Clement, P. and Piegay, H. 2003. Basics of multivariate analysis, In: Tools in Fluvial Geomorphology, correspondence analysis, principal G.M. Kondolf and H. Piegay, editors. components analysis, and variate Pp 596-630. distribution.
Using statistics to understand the Advanced environment. Wheater, C.P. and Cook, P.A. 2000. Routledge An introduction to applied geostatistics. Introductions to Environment Series, 1989. E.H. Isaaks & R.M. NY, 245p. Srivastava. Oxford University Press Inc. NY. 561 p. Statistical methods in water resources. Theory based discussion of the Helsel, D.R. and R.M. Hirsch. 2002. basic statistics to use when U.S. Geological Survey Techniques analyzing spatial data. of Water Resources Investigations, Book 4, Ch. A3. Introduction to time series analysis and http://water.usgs.gov/pubs/twri/twri4 forecasting. 2002. P.J. Brockwell & a3/ R.A. Davis. 2nd edition. Springer- Verlag Inc. NY. 434 p. Statistical methods in hydrology. 2002. C. T. Theory based discussion of the Haan. Ames, IA: Iowa State Press. analysis of trends in various 496 p. environmental, economic, and other Standard reference for statistics data. applied to hydrology; good section on time series analysis Nonlinear time series nonparametric and parametric methods. 2003. J. Fan Statistics for environmental science and and Q. Yao. Springer-Verlag Inc. management. 2001. B.F.J. Manly. NY. 551 p. Chapman & Hall. 326 p. Basic statistics, discussion of sampling and monitoring, time series analysis, and spatial analysis.
Analyzing Data Checklist
Choose benchmarks and reference values for comparison to data collected Assess quality, quantity, and scale of data Agree on approach(es) for analysis of data Summarize data using descriptive statistics Apply more sophisticated statistical analysis as appropriate, including spatial and temporal analysis methods Assess uncertainty and confounding factors that might influence the interpretation of the data Consider differences of opinions among experts
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5.7 References Haan, C.T. 2002. Statistical methods in hydrology. Second edition. Iowa State Bedient, P.B. and C. W. Huber. 2002. Press, Ames. IA. 496 p. Hydrology and floodplain analysis. Prentice Hall. 763 p. Helsel, D.R. and L.M. Griffith. 2003. Assess and interpret data. Water Resources Impact Clement, P. and H. Piegay. 2003. 5(5): 25-29. (www.awra.org) Statistics and fluvial geomorphology. In: Tools in Fluvial Geomorphology, (G.M. Helsel, D.R. and R.M. Hirsch. 2002. Kondolf and H. Piegay, eds). John Wiley & Statistical methods in water resources. U.S. Sons. pp. 596-630. Geological Survey Techniques of Water Resources Investigations, Book 4, Ch. A3. Conrad, M. and J. Dvorsky. 2003. Aptos http://water.usgs.gov/pubs/twri/twri4a3/ Creek Watershed Assessment and Enhancement Plan. Coastal Watershed Huff, D. 1954. How to Lie with Statistics. Council and Swanson Hydrology & W.W. Norton & Co., NY. 142 p. Geomorphology. Santa Cruz CA. 82 p. Journal of Time Series Analysis (JTSA). Dates, G. 1999. Moving from data to http://www.ingenta.com/journals/browse/bpl/ information. River Voices 10 (3&4):26-29. jtsa. (http://www.rivernetwork.org) Kattelmann, R. and M. Embury. 1996. Dawes, R.M. 1988. Rational Choice in an Riparian areas and wetlands. In: Sierra Uncertain World. Harcourt Brace Nevada Ecosystem Project: Final report to Jovanovich, Inc. Orlando. 346 p. Congress, Vol. III, Assessments and scientific basis for management options. Dunne, T. and L.B. Leopold. 1978. Water in Centers for Water and Wildland Resources, Environmental Planning. W.H. Freeman, U.C. Davis, p. 225-226. San Francisco. 818 p. Kerr, M. 1995. Using graphs to tell your Forman, R.T.T. 2000. Estimate of the area story. Volunteer Monitor (Spring 1995). affected ecologically by the road system in the United States. Conservation Biology. Langendorf, R. 1995. Presentation graphics. 14(1):31-35. PAS Report No. 453, American Planning Assoc., Chicago. 80 p. Georgetown Divide Resource Conservation District. 2003. South Fork American River Mattole Watershed Council. 1995. Watershed Stewardship Project, Watershed Dynamics of Recovery: a plan to enhance Assessment. p. 99. the Mattole Estuary. Petrolia, CA.
Gilbert, R.O. 1987. Statistical Methods for McCammon, B., J. Rector, and K. Gebhardt. Environmental Pollution Monitoring. Van 1998. A framework for analyzing the Nostrand Reinhold. NY. 320 p. hydrologic condition of watersheds. Denver: Bureau of Land Management and USDA- Gordon, N.D., T.A. McMahon, and B.L. Forest Service. Finlayson. 1992. Stream Hydrology: An Introduction for Ecologists. John Wiley & Michael, G.Y. 1991. Environmental Data Sons, NY. 526 p. Bases: Design, Implementation, and Maintenance. Lewis Publishers, Chelsea MI. 98 p.
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National Research Council. 1986. RCD and US Fish and Wildlife Service. Etna Ecological Knowledge and Environmental CA. 160 p. Problem-Solving: Concepts and Case Studies. National Academy Press. Wash. Tufte, E.R. 1983. The visual display of D.C., 388 p. quantitative information. Graphics Press, Chelsire, CT. 197 p. National Research Council. 1999. New Strategies for America’s Watersheds. Tufte, E.R. 1990. Envisioning information. Committee on Watershed Management. Graphics Press, Chelsire, CT. 126 p. National Academy Press. Wash. D.C., 311 p. Tufte, E.R. 1997. Visual explanations: images and quantities, evidence and North Coast Watershed Assessment narrative. Graphics Press, Chelsire, CT. 156 Program (NCWAP). 2003. Gualala River p. [1-800-822-2454] Watershed Assessment. Gualala Assessment and Support Team, Calif. U.S. Environmental Protection Agency Resources Agency and CalEPA, (EPA). Ecotox database. Sacramento. 367 p. plus appendices. www.epa.gov/ecotox.
Rand, G.M. and Newman, J.R. 1998. The U.S. EPA. 2000. Water quality criteria for applicabaility of habitat evaluation the protection of aquatic life. methodologies in ecological risk www.epa.gov/waterscience/criteria/aqlife.ht assessment. Human Ecol. Risk Assmt. 4: ml 905-929. Walters, C. 1986. Adaptive management of Raliegh, R.F., W.J. Miller, & P.C. Nelson, renewable resources. Macmillan Publishing 1986. Habitat suitability index models and Co., NY. 374 p. instream flow suitability curves: chinook salmon. USFWS Biol Report 82 (10.122) Washington Dept. of Natural Resources. pp.64. 1997. Watershed analysis manual. Forest Practices Board. Version 4.0. Olympia WA. Schueler, T. 2000. The Importance of Impeviousness. In: The Practice of Watershed Professional’s Network (WPN). Watershed Protection (T.R. Schueler & H.K. 1999. Oregon Watershed Assessment Holland, eds.) Center for Watershed Manual. Prepared for the Governor’s Protection, Ellicott City, MD. pp. 7-18. Watershed Enhancement Board. Salem, OR. Shenk, T.M. and A.B. Franklin (ed.). 2001. Modeling in Natural Resource Management: Wheater, C.P. and P.A. Cook. 2000. Using Development, Interpretation, and Statistics to Understand the Environment. Application. Island Press, Washington, D.C., Routledge Introductions to Environment 223 p. Series, NY, 245p.
Sommarstrom, S., Kellogg, E., and J. Zar, J.H. 1984. Biostatistical analysis. 2nd Kellogg. 1990. Scott River basin granitic edition. Prentice Hall, NJ sediment study. Prepared for the Siskiyou
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8 Using the Watershed Assessment for Decision-Making
One of the most important uses of a conditions regarded as detrimental or watershed assessment is to support degraded in the assessment. Information watershed-scale decisions that protect or from the assessment contributes directly to restore watershed function. This is probably the plan by providing the knowledge on one of the most difficult as well. Watershed which to base the proposed actions. In a assessments and watershed planning are recent study of watershed groups, the use the cornerstone for effective human action of watershed plans was one of the few at the watershed-scale, but only if the factors that had a high correlation with findings and proposed actions are potential positive environmental outcomes implemented and the response of the (Huntington & Sommarstrom 2000). watershed monitored (Naiman, 1992; Reimold, 1998). This chapter expands on In general, a watershed plan consists of an chapter 2 and describes different ways that overall vision or set of goals for the a completed watershed assessment can be watershed, a series of steps needed to used to support watershed-scale decisions. achieve those goals, and detailed Restoration planning, water quality consideration of how to implement those regulation, land-use planning, water steps. The plan should also include management, watershed planning, prioritization of the goals and actions, floodplain management, and monitoring are optimization of the sequence of actions for all activities where watershed assessment greatest efficiency and effectiveness, and can be useful. means of monitoring the implementation and results of the actions. However, Chapter Outline “effective plans can range in size and content from simple documents of only a 8.1 Watershed Planning few pages to multi-volume comprehensive 8.2 Restoration Planning and Projects reports” (Born & Genskow 2001). 8.3 Land-Use Planning 8.4 Public Lands Management Actions typically found in watershed plans 8.5 Water Management include: 8.6 Floodplain Management • public awareness and education 8.7 Regulation programs 8.8 Voluntary Private Lands • agency coordination mechanisms Management • proposals for changes in land use via 8.9 Monitoring Programs incentives, regulations, zoning, and 8.10 References conservation easements ______• aquatic and riparian habitat restoration • proposals for changes in water, 8.1 Watershed Planning vegetation, and waste management • best management practices to minimize Watershed plans are the logical follow-up to soil loss and water-borne transport of watershed assessments. Plans take the waste materials and pollutants information developed during the • structural changes in drainage systems, assessment and design a program of storm water conveyances, bridges, solutions to address the fundamental needs dams, and diversions. and problems identified in the assessment. A watershed plan consists of a series of Information contained in your watershed proposed actions that seek to improve any assessment should be helpful for designing
- 1 - California Watershed Assessment Manual, Chapter 8 August, 2004 each action. Each proposed action should • funds available relate to at least one objective or goal of the • opportunities for partnerships watershed assessment, and contain • return on funds to be invested - “most information about: bang for the buck” • basis in assessment findings, • time and other non-financial resources • alternatives, • ability to get the action done • responsible parties, partners and • early successes motivate more action assistants, • some actions rely on other actions for • public education and involvement, success • time schedules, • preventative actions versus remedial • costs, ones • opportunities for funding, • ability to measure progress or success • resources needed, with performance indicators • potential impediments, • potential jurisdictional conflicts and 8.1.1 Develop a Successful Plan cooperation, • steps for implementation, and A useful assessment provides an evaluation • measures of success. of how well a watershed is working and how it got that way. It does not necessarily give a ‘Good’ planning processes lead to better direction, which requires decisions. Here we recommendations for action (Born & are now, but where do we want to go with Genskow 2001), so be careful about these helpful new findings about our jumping into developing a “Wish List” of watershed? Planning is a process that proposed projects and actions. It is enables you to determine where you want to tempting, and sometimes watershed groups go, how and when you’re going to get there, need to have some relatively easy projects and who is going to do what. under their belts first in order to garner First, however, you need to clearly define public interest to sustain a longer planning why a plan is needed. People will not process (see “Action” type of planning in the participate in the planning process or accept table of concepts of schools of planning). the final plan unless they understand the need for the plan and the decisions to be Your list of actions will likely exceed more made (Saul & Faast 1993). An assessment than you can possibly accomplish in a 2-5 can usually make this explanation easier by year period, or your ability to find the identifying what needs to be improved in the immediate funding to help implement. To watershed. The assumption (explicit or help set priorities for the proposed actions, implicit) is that people will want to follow considering the following (Conservation through with working on the findings of the Technology Information Center, 1994 and assessment through a plan and its others): implementation. Do not always assume, • watershed assessment findings of though, that a good assessment will critical causes of problems automatically lead to a publicly-supported plan.
“A key question underlying all watershed planning is: What is an effective process to relate science, policy, and public participation? Watershed planning demands integrative thinking and a coordinated approach. Perhaps the greatest contemporary concern is to provide meaningful public involvement in the process, because experience has shown that top-down planning can create a variety of implementation barriers grounded in the lack of public involvement at key points in the planning process.”
~ National Research Council (1999)
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As emphasized in Chapter 2, the process A successful plan must be able. It your group uses with your watershed must be: community will be critical in developing the • Understandable understanding and support for your plan as • Supportable well as your assessment. Who makes the • Implement-able decisions about what goes into the plan is • Adaptable another key factor toward developing a sound strategy. The assessment process entails some decision-making, but the 8.1.2 Choose a Type of Planning planning process involves much more. Decisions have to be made on the best How to approach planning for watersheds strategy, and priorities have to be set. will necessarily involve the different Opinions and values become more concepts or “schools of planning” that have involved, and trade-offs have to be made. evolved in the U.S. Each concept carries its The primarily objective assessment process own set of expectations as well as strengths becomes transformed into an essentially and weaknesses. There is no ideal form of subjective planning process. Science planning for all cases. Today watershed informs those decisions through the plans could be one or all of these types, assessment, but choices still are made. Not depending on your needs and preferred everyone can necessarily be satisfied, choice. though consensus should still be sought. Planning must “be seen as part of a process Planning expertise can often be lacking in that strives to create a watershed community-based watershed planning community” (National Research Council, efforts, as it is not usually a discipline 1999). associated with watershed efforts. One suggestion is to work with your local county With a credible assessment and plan having and city planners to help improve your own strong stakeholder support, successful watershed planning process and product implementation should be able to follow – (Huntington & Sommarstrom 2000). pending funding, permitting, and other needs, of course. If monitoring and other Remember that the key is the process - evaluations later indicate that the plan “the process by which people of different needs to be changed, then the planning vantage points come together, learn each process should readily provide for adapting others’ languages, and begin to forge a the plan’s content and approach as needed. common language to describe what they want to achieve with their rivers, streams, and surrounding lands” (Environment Now & Southern California Wetlands Recovery Project, 2002). What Helps Create Good Planning Decisions?
Your planning process will entail many decisions. Researchers have found that five key factors seem to distinguish successful decision-making processes (i.e., decisions that will be implemented) from the rest: 1. Builds trust 2. Builds understanding 3. Incorporates value differences 4. Provides opportunities for joint fact-finding 5. Provides incentives for collaboration and cooperation
Source: Wondolleck (1988) in: Saul & Faast (1993)
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Concepts or ‘Schools’ of Planning Type of Planning Description Planning Strengths Planning Weaknesses Comprehensive Sytematic, step-by-step Can recognize the High costs; too broad and setting of goals and interrelationships of many not site-specific enough; low objectives for a number issues and disciplines; implementation rates; often of related mgt. needs, emphasis on science and entails a top-down process, evaluation of data collection; logical so little public support; may alternatives, adoption of process is appealing; create illusion of scientific implementation used by many federal objectivity; planning is not a measures; also called agencies; needs strong rational science but an art; “rational planning” laws to implement. Incremental Developed and Results oriented with Actions may not address implemented gradually focus on what can be some of larger, more difficult over time through a done; the public guides issues; plans may proceed bargaining process; and makes the plan; without adequate science & Focus is on specific small-scale solutions knowledge; implementation problems or issues & reduce risks; adopted may or may not be short-term results, now as “adaptive coordinated; continual which over time management”; little steps interaction required with address the larger help map future steps clients for implementation problems. Consensus Involves as many Implementation rates high Process can be lengthy and stakeholders in an area due to political buy-in; can perceived as too “time- as possible; all players be successful in resolving consuming”; plan may be a treated as equals; difficult issues; helps package of diverse benefits implementation based communities build and to satisfy partners but not on negotiated political learn; good strategy for focused and integrated; very agreement. attracting diversified difficult individuals can derail funding sources the process. Advocacy Citizens organize to Can be politically Technical content of plan advocate a position or empowering if coalition or may be professional but action; plan used to consensus is developed; may not be representative of strategically show can help with community broader community; may alternative approach to building across formerly lack integration with other a more traditional one. disparate groups; can disciplines; polarization may break political impasse result if consensus not reached from advocacy. Action Initiated by citizen Builds public awareness Small action projects may or groups, districts, and for the difficult Big Picture may not correctly apply agencies to make needs and watershed- science or restoration something visible and wide approaches; confers methodologies; plans may positive happen on the credibility on planning not develop enough ground in order to build process; can develop integration, coordination, or public support and credibility for government expertise; monitoring may interest; a form of programs or expertise; be lacking. incremental planning. helps develop new community leadership (based on Riley 1998)
8.1.3 Set Direction: Goals & Objectives these plan terms are used sloppily or interchangeably and unclear expectations Your plan should be based on the direction can result. Purported “plans” with no stated set by a hierarchy of consistent goals and goals or objectives and only a list of objectives. Following your group’s setting of recommendations do not give any measure broad goals and specific objectives comes for evaluating success in the direction you the details of your proposed strategy, which desire for your watershed. includes tasks, activities, or actions. The latter can get more and more detailed within the outline of your hierarchy. Too often,
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Some helpful hints for reviewing and revising watershed plans are: • Have a yearly informal “here’s where we are” session to update folks on plan implementation. • Ask people to evaluate your planning process so you can do better next time. • Issue periodic “report cards” to the public on plan implementation and monitoring results to keep them informed and to “give dignity to the plan”. • Ask yourselves, “Do we still need to do this action?”; “Has our vision changed?”; “What else can we do?”; “What has been successful, and why?”; “What has not worked, and why?” • Celebrate your successes! You’ve accomplished several tasks, you’ve achieved an objective, or you’ve made significant progress towards your goal. Feel good about your progress!
Sources: Saul and Faast (1993); Conservation Technology Information Center (1994)
The table in the box below provides As the Washington Guide to Watershed practical definitions for the terms most Planning and Management states, “A commonly applied to a plan’s structure. watershed plan does not need to offer all the answers. Instead, it can lay out a long- While your Goal statements can be long- term process towards finding answers and term and somewhat lofty, your Objective improving solutions…” Plan to be statements should be more achievable adaptable! (Conservation Technology Information Center, 1994). Examples of such Through experience, monitoring results, and Objectives include: “Reduce sediment to other continuing assessments, your group improve habitat for trout” or “Incorporate will evolve a greater understanding of what watershed protection into county and city implementation actions work and do not General Plans and Specific Area Plans”. work in your watershed. Restoration and Each goal will likely have more than one ecosystem management are still in the objective, and each objective may have experimental stages, and feedback is more than one strategy, which may have necessary for their progress. New more than one task/action. One way to check if your draft statements for each of Defining the Hierarchy of Plan Terms these terms make sense is to read them from the bottom up (tasks-strategy- Term Definition objective-goal). Goal Broad statement of intent, direction, and 8.1.4 Revising & Updating Plans purpose. Objective Specific, clear statement Plans should be viewed as “living that describes desired condition for a specific documents” that are assumed to change as area, activity, or species. needed, and not remain fixed to gather dust. May be qualitative or Dog-eared pages of plans are a good sign quantitative. that they are being used frequently. But Strategy Explicit description of even well-used plans still need regular what will be done to review, updates, and revisions. This cyclical achieve objectives. evaluation and opportunity for adjustment is Task / Specific step, practice, a form of adaptive management, which is Action or procedure to get the encouraged by the scientific community but job done, usually not widely practiced (Born & Genskow organized sequentially 2001). with timelines and assignments. (Saul & Faast 1993)
- 5 - California Watershed Assessment Manual, Chapter 8 August, 2004 challenges, such as rapidly increasing prioritized conclusions in the form of development in a rural sub-watershed or a realistic priorities for achievable "next recently discovered pollutant or invasive steps" for managing the subbasin's fish species, may stimulate your group to go and wildlife populations. back to the drawing boards and develop (http://www.nwcouncil.org/library/isrp/isr new strategies. Watersheds - and their p2004-4.htm) social and political community - are dynamic systems with changing needs. Economic 8.1.5.2 Water Quality Emphasis Plans cycles may affect the availability of partners and funding sources to share costs of your Watershed-based plans are encouraged by plan’s implementation. With stakeholders both the EPA and SWRCB for various water and other key decision-makers changing quality-related programs, such as the over time, plans will also need to reflect Nonpoint Source (NPS), storm water continually evolving priorities and management, and TMDL programs. practicalities. Expectations for federally-funded or required watershed management plans are 8.1.5 Examples of Watershed Plans described under EPA’s Section 205(j) and Section 319 grant programs. Polluted runoff 8.1.5.1 Subbasin Plans is also being addressed through the State and Regional Boards’ Watershed In the huge Columbia River Basin, the Management Initiative (WMI), which Northwest Power and Conservation Council promotes “integrated planning” with local (NPCC) called in 2000 for the development stakeholder groups. of approximately 60 subbasin plans that are to guide implementation of its Columbia A well-developed example is the Santa Basin Fish and Wildlife Program. The Clara Basin Watershed Management management plans were to help the Council Initiative (WMI) (http://www.scbwmi.org). prioritize projects for a limited amount of This collaborative effort has prepared a funding, through identification of past and three-volume Watershed Management Plan, ongoing work (the inventory) and an composed of a Watershed Characteristics assessment of habitat conditions and Report, a Watershed Assessment Report, factors that limit fish and wildlife production,. and a Watershed Action Plan. Water quality A “Technical Guide for Subbasin Planners” is the primary focus, but other watershed was prepared to assist those developing a values and uses are also incorporated. subbasin plan (http://www.nwcouncil.org/). Urban runoff management triggered by The NPCC's Independent Scientific Review municipal storm water permitting helped Panel (ISRP) reviews each draft plan to initiate much of the San Diego watershed determine if it meets the Council’s planning efforts expectations for completeness and scientific (http://www.projectcleanwater.org/html/ws_e soundness (e.g., the Program’s Scientific fforts.html). Some of these urban runoff Principles). In particular, the Panel is plans appear to have meshed or integrated concerned that subbasin plans address: with other watershed issues, some have • the need to adequately use available not. As a means of complying with a information, regulatory program, these watershed plans • the need to clearly link the Assessment, and their implementation need to maintain the Inventory, and the analysis of their focus on water quality compliance. information in these two documents to the resulting Management Plan, and • the need to carry the planning process to scientifically justified, integrated, and
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8.1.5.3 Coastal Watershed Plans in-progress watershed plans. The Santa Monica Bay, part of the National Estuary The State Coastal Conservancy encourages Program, region had 4 completed the development of watershed plans watershed plans, supported by over 80 through financial and technical assistance to studies. Water pollution and recreation local groups and has prepared a short concerns initially jump-started these Watershed Planning Guide outlining a step- collaborative restoration planning efforts, by-step sequence of actions during the such as in the Malibu and Topanga Creek process to achieve a watershed plan. While watersheds. acknowledging that every watershed will have a unique planning process, the Guide 8.2 Restoration Planning and Projects seeks to highlight the steps that are common to most planning efforts as well as Restoration efforts are frequently an the stumbling blocks: “It should be modified important part of a watershed plan or they as much as necessary to fit the particular can be undertaken independently of a plan circumstances of your watershed.” Since as an application of a watershed the Conservancy funds many projects, it assessment. California is the home to sees the plans as a means of identifying multiple state- and federally-funded and prioritizing coastal restoration projects. restoration programs that have evolved from A variety of watershed efforts have used the diverse legislative mandates, ballot assistance of the Conservancy to prepare initiatives, and citizen-sponsored programs. their plans The term “restoration” offers a sense of (http://www.coastalconservancy.ca.gov). purpose, of restoring something that has These plans include, but are not limited to, been lost, and has developed a popular the watersheds of: Tomales Bay, Pescadero following throughout the state. We seek to Marsh, Aptos Creek, Morro Bay, Calleguas “restore” many natural features within the Creek / Mugu Lagoon, Arroyo Seco, and watershed: fisheries, wetlands, streams, San Luis Rey River. water quality, ecosystems, and habitat, among others. In coastal Southern California, there are “many different patterns to get watershed Restoration plans and projects need a solid planning underway”, rather than a single scientific underpinning to be successful. A rational sequence of events (Environment recent study by the State found, “Absence Now & Southern California Wetlands of useful watershed assessments and plans Recovery Project, 2002). A snapshot at the can result in restoration projects that don’t end of 2002 revealed that watershed address priority problems and their causes” management planning was “still in its (California Resources Agency & State infancy” in the five-county region, but many Water Resources Control Board, 2002). new efforts were underway. Of 20 Agencies are concerned that projects may completed plans, most were for partial be scattered, unfocused on achieving watersheds and a number focused on the watershed management objectives and, same region (e.g., Santa Monica Bay and therefore, inefficiently using state grant Los Angeles River). Los Angeles County funding. was the most productive for completed or “Watershed-scale restoration should begin with an understanding of watershed structure and function and of how human activities affect and shape watershed health.” (Williams, Wood & Dombeck 1997)
“To achieve long-term success, aquatic ecosystem restoration should address the causes and not just the symptoms of ecological disturbance.” (NRC 1992, p. 55)
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An Example of a Fluvial Restoration Strategy
The Goal of fluvial restoration in _____ Watershed is to restore the river or stream to dynamic equilibrium. [The assumption is that dynamic equilibrium of the physical system establishes a dynamic equilibrium in the biological components.] The Objectives under this broad goal are to: 1. Restore the natural sediment and water regime. [‘Regime’ refers to at least two time scales: the daily-to-seasonal variation in water and sediment loads, and the annual-to- decadal patterns of floods and droughts.] 2. Restore the natural channel geometry, if restoration of the water and sediment regime alone does not. 3. Restore the natural riparian plant community, which becomes a functioning part of the channel geometry and floodplain/ riparian hydrology. [This step is necessary only if the plant community does not restore itself upon achievement of objectives 1 and 2. 4. Restore native aquatic plants and animals, if they do not recolonize on their own.
Source: National Research Council (1992) pp. 206-207.
• Provide basis for a Restoration Plan, The analysis contained in a watershed including goals and objectives. assessment lays the very foundation for • Help identify types of restoration successful restoration projects. The methods needed to address the problem analysis made as part of the assessment causes. serves to explain, based on the best • Locate the priority sub-watersheds, available information, the likely causes of stream reaches, or other areas within the alterations within the watershed that led the watershed for restoration projects, to the need for the restoration activities. based on the above. More specifically, the analysis in the • Identify priority restoration projects, assessment can help to: based on the above • Provide baseline and reference data, with which to compare restoration The California Department of Fish and progress or success. Game’s California Salmonid Stream Habitat • Help understand the patterns of water Restoration Manual recommends that a and sediment transport that create and ‘preliminary watershed assessment’ be maintain the natural morphology of the done to get the “big picture” about present channel and its associated floodplain. and potential fish production in a stream • Provide information for aquatic system before beginning field surveys and restoration, including descriptions of designing projects. However, the upslope connections to the riparian and expectation is more of a watershed waterway “overview” rather than a full assessment as • Help identify the causes and not just the described in this Manual. The concept still symptoms of problems needing advocated is that restoration efforts need to correction. address how the watershed works and what • Reveal restoration opportunities, key processes and conditions have been including getting beyond preconceived altered, before prescribing the remedies. perceptions about problems and solutions. It is the physical and biological processes • Coordinate with other stakeholders in operating in the watershed are the developing a common understanding of mechanisms that govern the watershed’s how the watershed behaves condition. Working with the natural
- 8 - California Watershed Assessment Manual, Chapter 8 August, 2004 processes in your restoration strategy will department staff, planning commissioners, improve your chances of success. Some or city council members who make players tend to be more interested in the decisions about land uses. Usually, people project phase than the assessment or in these positions are civic-minded planning phase, and they might not have individuals with no special knowledge of been aware or interested in your watersheds and how land uses influences assessment process. Their enthusiasm the hydrological cycle as well as other might also get ahead of them. Do a reality potential impacts on waterways. The check with everyone on previous restoration information generated by a watershed assumptions and project ideas now that the assessment and plan could be invaluable to assessment is completed. local decision-makers.
Moving from watershed condition evaluation California planning law requires that - your assessment - into identifying the landowners and local planning agencies appropriate restoration measures often engage in the formulation of zoning and involves another set of skills and parcel-specific land use plans to guide the approaches. Applied science and development of residential, commercial, and technologies tend to become more industrial areas. The most common way of important, such as engineering, surveying, doing this is through the general plan contracting, heavy equipment, and resource process, where a municipality or county management skills. Experience with what planning agency decides which areas in the works and doesn’t work with certain jurisdiction should fall under which zone restoration techniques, especially in your type and what proportions of land uses area, becomes of critical importance. Some would be appropriate. agencies, consultants, landowners, and citizen organizations may have a wealth of There are very few instances where experience with certain methods – be sure watershed assessments have been used to ask around. Use the same collaborative explicitly to aid decision-making in land-use process applied to your assessment, but planning, although information contained in now bring in those people with the applied an assessment could be very useful for restoration skills. This difference in needed planning purposes. Orange County has expertise is one of the reasons that project conducted many watershed assessments recommendations within the watershed through cooperative arrangements with the assessment product can appear naïve or Army Corps of Engineers (ACE). These impractical when evaluated later by assessments are associated with restoration practitioners (Riley 1998). restoration goals and programs and are not explicitly intended to support land-use 8.3 Land Use Planning decision-making. However, they contain information relevant for land-use decisions Watershed assessments are intimately tied and could be used in that fashion. to land use planning. The relationship between land use and watershed conditions Some of the information frequently and processes has been described in detail contained in a watershed assessment that in this Manual. However, this relationship is could be used to support land use planning not always appreciated by local planning include:
Land use planning is the process by which public agencies, mostly local governments, determine the intensity and geographical arrangements of various land uses in a community Fulton, 1999
- 9 - California Watershed Assessment Manual, Chapter 8 August, 2004 o Data on surface and ground hydrology the area of impervious surfaces and under natural and modified conditions other land use modifications o Stream bank stability and channel characteristics which are influenced by
Watershed-related References in the State’s General Plan Guidelines [Office of Planning & Research; http://www.opr.ca.gov]
Watershed Based flood protection , p. 12 Safety Element Cities and counties should identify risks from natural hazards which extend across jurisdictional boundaries, then use any available data from watershed-based floodplain management, mapped earthquake faults, or high fire hazard areas as planning tools to address any significant issues. Each local planning agency carries a responsibility to coordinate its general plan with regional planning efforts as much as possible.
Relationships Among Elements and Issues, p. 37 General plan elements and issues interrelate functionally. For example, consideration given to the vegetation which supports an endangered wildlife species in the conservation element also involves analyzing topography, weather, fire hazards, availability of water, and density of development in several other elements. Thus, the preparation of a general plan must be approached on multiple levels and from an interdisciplinary point of view.
Ideas for Data and Analysis, Open-Space, p. 38 The following consists of topics which should be considered during the preparation of the general plan and, if relevant, included in a land use element. These subjects are based upon a close reading of the statutes and case law. When the information collected for the land use element overlaps that needed for other elements, the related element has been noted in parenthesis. Delineate the boundaries of watersheds, aquifer re-charge areas, floodplains, and the depth of groundwater basins (diagrams) (CO, OS, S) Delineate the boundaries and description of unique water resources (e.g., saltwater and freshwater marshes, wetlands, riparian corridors, wild rivers and streams, lakes). (CO)
Conservation Element The conservation element may also cover the following optional issues: Protection of watersheds; Water, p. 56-7 Inventory water resources, including rivers, lakes, streams, bays, estuaries, reservoirs, ground water basins (aquifers), and watersheds (Map) (LU, OS) Identify the boundaries of watersheds, aquifer recharge areas, and groundwater basins (including depths) (Map) LU, OS) - Assess local and regional water supply and the related plans of special districts and other agencies - Analyze the existing land use and zoning within said boundaries and the approximate intensity of water consumption Map the boundaries and describe unique water resources (e.g., salt water and fresh water marshes and wild rivers) (LU, OS) Assess the current and future quality of various bodies of water, water courses, and groundwater (LU, OS) Inventory existing and future water supply sources for domestic, commercial, industrial, and agricultural uses (LU, OS) Assess existing and projected demands upon water supply sources, in conjunction with water suppliers (LU, OS) - Including: agricultural, commercial, residential, industrial, and public use Assess the adequacy of existing and future water supply sources, in conjunction with water suppliers. (LU, OS)
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Watershed-related Citations in the General Plan Guidelines [Office of Planning & Research] cont’d.
Map riparian vegetation (LU, OS) Assess the use of water bodies for recreation purposes (LU, OS) Forests, p. 62 Inventory forest resources including a comprehensive analysis of conservation needs for forests, woodlands and the interrelationship they have with watersheds (Map) (LU, OS) - Describe the type, location, amount, and ownership of forests with a value for commercial timber production, wildlife protection, recreation, watershed protection, aesthetics, and other purposes Fisheries, p. 62 Identify water bodies and watersheds that must be protected or rehabilitated to promote continued recreational and commercial fishing – including key fish spawning areas Evaluate water quality, temperature, and sources of contaminates Identify physical barriers (man-caused or natural) to fish populations within the watershed, then propose alternatives and set priorities
Open-Space Element, Background, p. 68 The following topics are to be addressed, to the extent that they are locally relevant: Open-space for the preservation of natural resources including, but not limited to: Areas required for ecologic and other scientific study; rivers, streams, bays and estuaries; and, coastal beaches, lake shores, banks of rivers and streams, and watersheds; Open-space for public health and safety including, but not limited to: Areas that require special management or regulation because of hazardous or special conditions such as earthquake fault zones, unstable soil areas, flood-plains, watersheds, areas presenting high fire risks, areas required for the protection of water quality and water reservoirs and areas required for the protection and enhancement of air quality. Identify watersheds and key areas for the protection of water quality and reservoirs (map) (CO) Safety Element, p. 77 Flood Hazard - A comprehensive approach should include mapping floodplains…, and floodplain management policies (which may include both structural and non-structural approaches to flood control using a multi-objective watershed approach). Flooding is often a regional problem that crosses multiple jurisdictional boundaries. Slope instability and the associated risk of mudslides and landslides • Identify areas that are landslide-prone by using, among other sources, Division of Mines and Geology’s seismic hazard zone maps, landslide hazard identification maps, watershed maps, and geology for planning maps, and landslide features maps produced by the U.S. Geological Survey (map) (OS)
[General Plan Elements: LU=Land Use; OS=Open Space; CO=Conservation; S=Safety ] o Existing and potential future surface and for residential, commercial, or industrial ground water quality under different land development and general or specific uses of use and development scenarios. lands within a county outside developed o Biological diversity and status of aquatic areas1General plan “elements” (e.g., land and riparian species of plants and animals 1. These plans are required by Govt. Code 65300 et seq. and are implemented through 8.3.1 General Plans policy narratives, zoning ordinances and maps (Gov’t. Code 65850 et seq.), and Municipal and county general plans govern subdivision maps and regulations (Gov’t. the development of land annexed by a city Code 66410 et seq.; Fulton, 1999).
- 11 - California Watershed Assessment Manual, Chapter 8 August, 2004 use, circulation, open space; see chapter feasible (e.g., restoring natural processes or 3.10) are used to detail the planned growth features). The three classes of regulations and consequences of the growth. Because are: a general plan must be analyzed for its potential impacts to the environment • Both the federal and California (California Environmental Quality Act), there Endangered Species Acts require that is a nexus between the plan and watershed populations and habitats of listed assessment. CEQA requires that the ‘best species be protected from take available information’ be used to evaluate (destruction of habitat or individuals), or potential impacts of a general plan or a if take is planned, that it be mitigated. specific project. Many times, the best For aquatic, wetlands, vernal pool, and available information can be found in riparian species this would seem to watershed assessments. For example, the require a watershed perspective for land use element must show the location, general planning as developed areas distribution, and intensity of development will have direct and indirect impacts on and particular elements (e.g., wastewater aquatic natural processes, wildlife, and treatment facilities) allowed under the plan. plants. Watershed assessments can This is usually done using a map, which inform these decisions by showing the along with zoning and parcel maps can linkages between existing and proposed make the general plan process a very land-use decisions in the general plan tangible part of watershed assessment and and downstream habitat and vice-versa. Frequently, consultants hired to populations of listed species. perform CEQA assessments rely on incomplete databases or field assessments • The federal Clean Water Act and the of limited scope. The information in a state Porter-Cologne Act require that watershed assessment could be an state regulators analyze and consider invaluable source of data and analysis of for permitting any activity that may conditions. cause harm (e.g., pollution) to California waterways and wetlands. There are three locations in the state where Watershed assessments can inform state law requires the consideration of these decisions by showing the linkages natural resource protection at a “pseudo- between existing and proposed land-use watershed scale“ when developing general decisions in the general plan and plans. These are the Lake Tahoe basin, the downstream habitat, water quality, California coastline, and the Sacramento channel conditions, and natural and San Joaquin Rivers Delta. In all other processes (e.g., flooding). parts of the state, there is nothing (see “Improving our Bay-Delta Estuary approximating a requirement to consider Through Local Plans and Programs: A watershed processes when developing Guidebook for City and County plans. Governments (Association of Bay Area Governments, Oakland, CA), 1995, 21 Three classes of regulations require that the pp.) effects of harmful actions be mitigated, though rarely is this requirement • The federal National Environmental accompanied by performance measures for Policy Act and the California the evaluation of effectiveness. A watershed Environmental Quality Act require that assessment approach could be used in plans such as general plans be conjunction with wildlife and habitat analyzed for potential impacts to human assessments to expose the environmental and natural environments. Alternative costs and benefits of actions proposed in a plans must be put forward by the lead general plan, or that were not considered planning agency, based in part on public
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input, that show different ways to measurable until full general plan build-out achieve the plan’s objectives and the at the river basin scale. Matching scales of potential impacts from each alternative. assessment or monitoring activity is critical The lead agency must, theoretically, in the use of this approach in informing choose the least environmentally general planning. damaging and feasible alternative. Watershed assessment can list the 8.3.2 Ordinances various natural and human features (e.g., streams and roads) and processes Municipal or county ordinances govern (e.g., agriculture and fire) that are certain uses of public and private property important in watersheds and sub- and their environmental impacts. These are watersheds within the general planning binding and enforceable at that scale and area. It can describe the overall and tied to local problems and governance localized condition, make linkages styles. For example, a rural county with a between human activities and condition, natural fire ecology may be very proactive in and serve as a major type of enforcing vegetation control immediately environmental assessment against around structures, whereas an urban county which to judge proposed actions. or municipality may be very active about dumping into storm drains. Information In all of the above cases, data contained in contained in watershed assessments can a watershed assessment can aide local also be useful to local decisions makers in municipalities in meeting these crafting local ordinances that might impact requirements. Frequently, the analysis the health and conditions of waterways. In performed by local government is particular, data on the conditions of local incomplete and omits important information waterways and the links to local land uses, related to protecting waterways. The data could be used to highlight the impacts of and analyses contained in an assessment local policies on watershed health. The can play an important role in informing local development of ordinances dealing with decisions-makers of this important flooding and floodplains, stormwater run-off, information. In cases where general plans subdivision landscaping and design, roads are being adopted, community watershed and grading, and stream buffers or setbacks groups should bring their analysis to the all could benefit from knowledge and attention of local planning commissions and analyses typically contained in a watershed city councils to ensure that all requirements assessment. can be evaluated with the best available and most complete set of information Examples of these ordinances are:
When considering informing general • Subdivision & zoning ordinances planning with snapshot or continuing Data from your watershed assessment watershed assessment work, scale is an combined with information on important quality to keep in mind. A fine- watershed-friendly ordinances could be grained assessment is needed to judge the a powerful tool in the hands of local land impacts of parcel and subdivision scales of use planners. Information on model development activities. A coarse-grained ordinances, design guidelines, and other watershed-wide assessment is not an relevant guidance for local officials is adequate substitute for this. Similarly, the available online from the Center for right time frame for analyzing and modeling Watershed Protection potential impacts is needed. Changes in (http:www.cwp.org), the Low Impact watershed functions and outputs may be Development Center immediate, substantial, and long-lasting at (http://ww.lowimpactdevelopment.org) the sub-watershed scale and not
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and the NEMO Project (http://www.nemo.uconn.edu). • Landscaping and water conservation ordinances can regulate the rate of • Flooding and floodplain development pesticide application and irrigation in ordinances are a useful way for local order to reduce the input of chemicals governments to reduce damage from and excessive water into streams. flooding. Guidance from the State on the Pesticides can cause direct mortality of development of general plans to aquatic biota, excessive nutrients can minimize flooding can be combined with cause potentially harmful algae blooms, data your assessment has produced to and summer irrigation in arid areas can identify the need for sound development upset the ecology of seasonally dry planning. The state’s guidance is streams in the arid West. The state of posted at: Vermont and the cities of Sebastopol http://www.fpm.water.ca.gov/generalpla (CA), Buffalo (NY), and Burlington (VT) n.html. limit the application of pesticides to residential and forestry landscapes to • Stormwater runoff and dumping into reduce impacts to human and storm drains are a commonly- ecosystem health. If pesticides and recognized problems in urban settings,. excessive nutrients from fertilizer Because developed areas have highly applications are a problem in your impervious surfaces (e.g., roads and waterways, then municipal ordinances parking lots), water will not percolate restricting these chemicals could be naturally into the ground over large appropriate. Water quality analysis and areas. Stormwater not only frequently the condition of aquatic communities contains contaminants that is harmful to described in your watershed aquatic life, but the increased volume assessment could inform local associated with reduced percolation is government officials about the damaging to streams. Chemicals tend to development of landscaping ordinances. collect on impervious surfaces and attached to dust and dirt particles. • Riparian ordinance When it rains, especially with the first [under construction] rain of the rainy season, these chemicals can be washed into local 8.4 Public Lands Management streams. Similarly, illegal dumping of chemicals into industrial, commercial, On federally-managed lands, watershed and stormwater drains can be an assessments are usually termed watershed occasional but major input to streams. analyses. Some people believe the term Municipal and county ordinances can “analysis” implies more detail at a finer regulate the flow of water and chemicals spatial scale than typical “assessments”, but from urbanized areas. If excessive “analysis” is the usual term used by the storm flows and diffuse or localized Forest Service and Bureau of Land chemical inputs are disrupting your Management for their process. waterways, then storm water and dumping ordinances could help. Water These watershed analyses on federal lands quality analysis, impacts to aquatic became institutionalized during the biota, diversion of surface water from development of the Northwest Forest Plan natural percolation areas, and timing (FEMAT 1993, USDA-Forest Service 1994). and volumes of flow of storm water Among the recommendations of the described in your watershed Northwest Forest Plan was an aquatic assessment can help determine if this conservation strategy intended to improve type of ordinance might be helpful. stream conditions for anadromous fish. A
- 14 - California Watershed Assessment Manual, Chapter 8 August, 2004 major part of this strategy was an 3) Description of current conditions assessment process that became known as 4) Description of reference conditions watershed analysis. Although it was initially 5) Synthesis and interpretation of designed to focus on riparian issues, federal information watershed analysis was soon recognized to 6) Recommendations (usually including be useful for evaluating a broad range of desired future conditions and potential issues throughout a watershed (Grant strategies for moving the landscape 1994). During the 1990s, watershed toward those conditions) analysis evolved as a tool for describing watershed attributes, issues, and The resulting report of a federal watershed capabilities that would form the basis of analysis usually includes: future land management on National 1) Description of the watershed including Forests and Bureau of Land Management its natural and cultural features properties (Reid, et al. 1994). 2) Description of the beneficial uses and values associated with the watershed Individual National Forests and some BLM and, when supporting data allow, offices have been conducting watershed statements about compliance with water analyses for the past decade using the quality standards protocol outlined by USDA-Forest Service 3) Description of the distribution, type, and (1995). In the federal context, watershed relative importance of environmental analysis is a tool for description and processes assessment of watershed processes and 4) Description of the watershed’s present ecological conditions. It is based on condition relative to its associated processes, ecosystem components, and values and uses locations, but not on projects or proposals 5) Maps of interim and potential riparian as is typical of other Forest Service planning reserves processes. Watershed analysis on federal 6) Description of the mechanisms by which lands is not designed to produce a decision environmental changes have occurred document and is not subject to the National and description of specific land-use Environmental Policy Act. Instead, the activities in generating change information generated from a watershed 7) Description of likely future analysis can be used to inform and guide environmental conditions in the the projects that eventually implement a watershed, including discussion of forest plan. trends and potential effects of past activities The basic parts of watershed analysis as 8) Interpretations and management described in the Federal Guide to recommendations Watershed Analysis (USDA-Forest Service 1995) include the following: The usual scale Much of the federal guide covers various of analysis is for watersheds of 20 to 200 analysis methods for describing key mi2. A particular watershed is selected for processes and conditions and their possible analysis on the basis of regional interests, causes. These topics include fire history, controversies, and opportunities for existing and potential vegetation, roads, management. Public input is sought to mass movements, surface erosion, channel identify critical issues, locate contributing erosion, sediment yield, streamflow information, and provide reality checks. The characteristics, runoff generation, stream federal approach includes the following temperature, channel conditions, aquatic steps: and terrestrial habitat, and water supply. 1) Characterization of the watershed Descriptions of these methods include 2) Identification of issues and key generic goals, data needs, assumptions, questions products, and procedures at both a cursory
- 15 - California Watershed Assessment Manual, Chapter 8 August, 2004 level and a more quantitative level Plans of the National Forests of the Sierra depending on the needs of a study (USDA- Nevada includes a major component of Forest Service 1995). Another related set watershed analyses, but few had been of procedures that focus on watershed completed to date within the Sierra Nevada. hydrology is found in the publication, A Web sites for most of the National Forests Framework for Analyzing the Hydrologic include the completed reports as well as Condition of Watersheds (McCammon, et progress of ongoing efforts. al. 1998). Perhaps the most comprehensive If your watershed includes some National watershed analysis completed to date on Forest land, looking at the approaches and federal land in California and Nevada was techniques of the federal guide is certainly for the Lake Tahoe Basin (USDA-Forest worthwhile. The “analytic modules” will Service 2000). The national significance provide some guidance for a variety of and public visibility of the Lake Tahoe Basin measurements and analyses that may be allowed an investment of about $2 million in appropriate for your situation. Just decide this assessment. The document is a good on your objectives first and see if any of the source of ideas and approaches to federal procedures would help meet those watershed assessment, even if your budget objectives, rather than charging into a is on a somewhat smaller scale. measurement program just because the Forest Service finds it useful. You can take advantage of watershed analyses done by the National Forest in Within the National Forests of California, a your region for a variety of background variety of watershed analyses have been material relevant to your own watershed conducted. In general, the forests in the assessment. Check the web site of your northern part of the state that were part of local National Forest for completed the Northwest Forest Plan have had a more watershed analyses. They may be found active (and better funded) watershed under resource management, watersheds, analysis program. This program has been or publication or by using the web site’s driven by northern spotted owl and salmon search engine. Alternatively, call the nearest issues. The Shasta-Trinity National Forest ranger district or supervisor’s office and ask has produced more than a dozen watershed about watershed analyses that have been analyses. Other forests are still working on completed or are in progress. The basic their first analysis. The quality and level of descriptions of climate, hydrology, detail of the initial round of watershed vegetation, management, and disturbance analyses is quite inconsistent, depending on history may be directly applicable to your the issues and local support for a particular watershed if the analysis area is close analysis. Many of the watershed analyses enough or may provide some good leads for have had their scope expanded somewhat pursuing information about your watershed. by also incorporating guidance from the We recommend that you use Forest Service Region 5 (California) guide to ecosystem watershed analyses as information sources management (Manley et al. 1995). and not as templates or models for your Reduction of the risk of catastrophic assessment. Your fundamental goals and wildfires through management of fuels is the driving issues are likely to be quite different primary focus of many of the recent than the motivations behind the federal watershed analyses. At least one analysis analyses. has incorporated hydroelectric project re- licensing as the principal issue. The ultimate 8.5 Water Management utility of the wide range of watershed analyses is yet to be determined. The Sierra A consideration of watershed conditions is Nevada Framework for revising the Forest part of an integrated water management
- 16 - California Watershed Assessment Manual, Chapter 8 August, 2004 plan. In previous eras, water management • Integrated Regional Water was viewed primarily from an engineering Management Planning Act of 2002 perspective – how to deliver and dispose of (Water Code sections 10530-10537) water. More recently, however, the was created by SB 1672 (Costa). This structure and function of the overall act’s implementation is to lead to the watershed is considered as another development of integrated regional important factor in water management. water management plans, as a means Integrated water management has the of “maximizing the quality and quantity potential to go beyond watershed of water available to meet the state’s management which focuses on conditions in water needs by providing a framework the waterway and the processes that for local agencies to integrate programs influence them. Science-based integrated and projects that protect and enhance water management considers the best way regional water supplies.” A "regional to develop/retrofit infrastructure in water management group" is defined as coordination with land use planning and “three or more local public agencies, at protection of the aquatic ecosystem. The least two of which have statutory term “best way” reflects the development of authority over water supply.” a plan that includes the wise use of water, Groundwater management and grant- the environmental sound disposal of funded projects are also to be tied into stormwater and wastewater, land use plans, such plans (section 10753.7) and ecosystem protection and restoration. To address all these issues successfully • The Integrated Water Management involvement of critical stakeholders is Program (IWMP) (sections 79560-63) essential. Watershed assessments can was created by Proposition 50 as a provide an important source of grant program operated by two state information and analysis that is required agencies: the Department of Water for the development of an integrated Resources (DWR) and the State Water water management plan. Resources Control Board (SWRCB). It requires that eligible projects are In 1998, the Washington State legislature consistent with an adopted integrated passed the Watershed Planning Act to set a regional water management plan, or framework for addressing the State’s water such a plan is in progress. Such a plan resource issues… When lawmakers passed under the DWR grant program is to the Act, they stated that the primary address, at a minimum: water-related purpose of the statute was "…to develop a objectives and conflicts in the more thorough and cooperative method watersheds of the region, including: 1) of determining the current water water supply, 2) groundwater situation in each water resource management, 3) ecosystem restoration, inventory area of the state and to provide and 4) water quality. local citizens with the maximum possible input concerning their goals and The details and coordination of these new objectives…". This statement identifies the programs are being worked out by the purpose and issues associated with water departments and the California Watershed management. To manage water, issues of Council, a state-supported collaborative surface and groundwater water supply and partnership effort quality need to be evaluated. (http://cwp.resources.ca.gov/cwc_about.htm l). Under the SWRCB program, the In 2002, several acts were passed in integrated plan must be designed “to California that were aimed at achieving improve regional water supply reliability, similar goals as Washington state. The water recycling, water conservation, water statutes added to the Water Code are: quality improvement, storm water capture
- 17 - California Watershed Assessment Manual, Chapter 8 August, 2004 and management, flood management, A well-developed watershed assessment recreation and access, wetlands has a number of important uses for water enhancement and creation, and management (Washington Department of environmental and habitat protection and Energy, 1998): improvement.” • Identifying the water supply and In addition to contributing to sounder land demands within the watershed, use planning, a watershed plan and the • Analyzing the relationship between assessment on which it is based, can also surface water and ground water, inform the integrated water management • Analyzing the connection between water effort. The analysis of the effects of human quality and water quantity, activities on watershed components and • Integrating short-term and long-range processes needs to be integrated into a water planning, water management plan. The impacts of • Addressing and integrating water water conveyance and discharge must be quantity, quality, and habitat needs, evaluated in this plan as well. This analysis • Providing part of the information that is usually part of watershed assessments and crucial to making water-right decisions. therefore, has direct relevance and use in • Providing information the facilitates water management plans. decisions that protect and enhance the aquatic ecosystem. Integrated water management might include some or all of the following: The following section reviews some of the • Balancing water use with water supply key components of an integrated water • Connecting water supply protection with management plan and identifies how watershed management. information generated in a watershed • Utilizing low impact development assessment is useful for decision-making 2 methods to improved groundwater around each of these issues. recharge, reduced stormwater volume, and protection and enhancement of 8.5.1. Water Supply instream habitat • Integrating land use planning with water A key part of a water management plan is management and ecosystem protection identifying and planning for water supply. • Coordinating water supply infrastructure Interestingly, the first watershed and planning among water agencies assessments in California were conducted within a region to evaluate potential for water resources • Affecting inter-basin water transfer and development. Thorough field studies were delivery decisions, and/or conducted early in the 20th century to • Linking regional water availability with evaluate whether different watersheds had future land use development the capability to serve as a reliable water • Balancing viewpoints of diverse societal source for San Francisco (Freeman, 1912) interests into decisions about water and Sacramento (Hyde, et al., 1916). These resource allocation. studies included detailed descriptions of watershed conditions.
st However, in the 21 century, a primary use 2 Low impact development methods utilize for information from watershed swales, rain gardens, pervious pavement, assessments related to water supply landscaped bioretention structures, and other projects will be in identifying alternatives for integrated management practices to reduce operation of existing or proposed projects. imperviousness and the production of Such information can be used to identify stormwater.
- 18 - California Watershed Assessment Manual, Chapter 8 August, 2004 opportunities for alternative management of Washington State, the legislature wanted facilities to serve new uses not recognized water rights decisions to be influenced by a during initial project design and good watershed assessment and plan. construction. A recent example is the July 2000 settlement agreement on the 8.5.1.1 Drinking Water Source operation of Pacific Gas and Electric Assessment and Protection Program Company’s hydropower facilities on the (DWSAP) Mokelumne River. Detailed evaluations of natural hydrology and system operation Watershed assessment can provide useful contributed to the settlement agreement and information for drinking water source relicensing of the project (McGurk and protection efforts. Protecting sources of Paulson, 2000). About 30 hydroelectric drinking water is the purpose of the federal projects in California will go through the and state Drinking Water Source relicensing process during this decade. Assessment and Protection Program Proposals for “re-operation” of these and (DWSAP). The initial part of this effort is the other water projects will require much of the Source Water Assessment Program basic hydrologic and operational hydraulic (SWAP), which is where watershed information that might be contained in a assessments become directly relevant. watershed assessment. However, the data Each of California’s 15,000 active public and analysis needs related to these projects water systems must delineate the and proposals for different management will boundaries of the area around their drinking usually be far more detailed than in a typical water source(s) through which contaminants watershed assessment. might move and reach that drinking water supply. They next must inventory “possible Watershed assessment data useful for contaminating activities” (PCAs) that might water supply management lead to the release of microbiological or chemical contaminants within that • Surface and ground water - present and delineated area. This inventory allows for a available in the watershed determination of the water source’s • Surface and ground water - use, by type vulnerability to contamination. After the (agriculture, municipal, etc.) assessment and vulnerability analysis are • Water rights summary, by source completed, the water source protection (ground, surface) approaches, including protection zones, are • Water storage, by source (natural, identified. Local protection programs are artificial) enacted voluntarily, while the assessments • Streamflow (max /min / mean acre-feet are mandatory. per year) • Land use summary, by Type & % cover For surface water sources, the watershed • Vegetation cover, by Type & % cover boundaries above the point of diversion for drinking water use delineate the logical • Impervious surface area, % cover assessment area. Previously, a “watershed
sanitary survey” of the drinking water Water information developed in a watershed source(s) was required at least every five assessment can also help local land use years, but the vulnerability ranking was not agencies in their decision-making. a component. For ground water sources, Connecting water supply availability to land the source areas and protection zones are use planning was required in recent state delineated based on “readily available legislation (e.g., SB 610 and SB 221 in hydrogeologic information on ground water 2001). While focused on large development flow, recharge and discharge, and other approvals, the new laws demand an information deemed appropriate by the assessment of the water supply situation. In State” (California Department of Health
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Services, 1999). This ground water portion 8.5.1.3 Water Quality Considerations of the DWSAP also serves as the State’s wellhead protection program. Watershed assessments can be very useful in management of water quality by providing 8.5.1.2 Groundwater Management basic information about the various factors Planning that affect the constituents of water. A comprehensive watershed assessment Your watershed assessment may also be should include information about: able to contribute to a groundwater • the climate and hydrology of the management plan that is independent or watershed that will determine the water part of an integrated water management availability during different seasons and plan, by improving an existing one or at different places in the watershed and helping to create a new one. A California the consequent capacity for dilution of groundwater law, Assembly Bill 3030 (Water introduced materials; Code section 10750-10756), provides a • the geochemistry of parent material and systematic procedure for an existing local soils that will determine natural agency to develop a groundwater contributions of dissolved constituents; management plan. This section of the code • soil properties, terrain features, provides such an agency with the powers of vegetative cover, land use, and climatic a water replenishment district to raise factors that control potential for revenue to pay for facilities to manage the sediment production; basin (extraction, recharge, conveyance, • hydraulic and geomorphic properties of quality). About 150 water agencies have channels that influence sediment developed groundwater management plans transport; in accordance with AB 3030, which then • riparian vegetation properties that allows them to qualify for certain state influence energy input to streams and grants and loans for groundwater consequent water temperature; management (posted at: • known and suspected sources of http://www.groundwater.water.ca.gov). pollution (both point and non-point); past Public water systems that have performed measurements of water quality evaluations under AB 3030 requirements parameters; and may satisfy all or part of the DWSAP (see • changes in watershed conditions over 8.4.1.3). time.
In developing groundwater management These types of information will provide the plans, one important consideration is the general context of water quality and allow effects of these plans on the conditions in identification of problems that should be the waterway. For example, depletion of addressed. While some polluters will the groundwater could cause perennial voluntarily reduce their sources of streams to become ephemeral. Springs contamination once these problems are that historically have fed a river might no brought to their attention through the longer do so if groundwater supplies are information of the watershed assessment, over-utilized. Information from your some form of regulation is often necessary. watershed assessment might lend insight A detailed watershed assessment may into the potential impacts of groundwater incorporate modeling results from models management plans on the aquatic such as the EPA’s Better Assessment ecosystem. Science Integrating Point and Nonpoint Sources (BASINS) and Stormwater Management Model (SWMM). Such models can aid in identifying sources and factors
- 20 - California Watershed Assessment Manual, Chapter 8 August, 2004 subject to control and estimate the include both structural and non-structural effectiveness of various controls and approaches to flood control using a multi- practices on downstream water quality. objective watershed approach). Flooding is often a regional problem that crosses Considerations of water quality issues is an multiple jurisdictional boundaries. Policies essential part of any integrated water should be developed cooperatively with management plan. Data and analysis from a local, state, and federal agencies, including watershed assessment can make significant special districts, to create feasible solutions, contributions to the understanding of water Guidelines for the preparation of an optional quality conditions and the stressors in the floodplain management element are watershed that pose a risk to maintaining provided in Appendix C. high water quality and meeting the http://www.fpm.water.ca.gov/generalplan.ht beneficial uses of the waterways. ml. The Department of Water Resources’ Division of Flood Management can provide 8.6 Floodplain Management floodplain management and flood control information, including floodplain maps, Another aspect of integrated water where available. management is floodplain management. Planners need to consider how the In addition, the state Cobey-Alquist management of water produced by large Floodplain Management Act encourages rain events fits into the overall water local governments to plan, adopt, and management plans. City and County enforce floodplain management regulations general plans must evaluate flood hazards through an ordinance or other means(Water and develop strategies for floodplain Code §8400, et seq.). Where a federal flood management, as noted in the OPR General control project report has been issued which Plan Guidelines: designates floodway boundaries, the “Cities and counties should identify risks Department of Water Resources or the from natural hazards which extend State Reclamation Board will not across jurisdictional boundaries, then appropriate money in support of the project use any available data from watershed- unless the applicable agency has enacted based floodplain management…as floodplain regulations. Those regulations planning tools to address any significant must provide that: (1) Construction of issues. Each local planning agency structures in the floodway which may carries a responsibility to coordinate its endanger life or significantly reduce its general plan with regional planning carrying capacity shall be prohibited; (2) efforts as much as possible. “ (p. 77) Development will be allowed within the “restrictive zone” between the floodway and The safety element must also identify flood the limits of the floodplain as long as human hazard areas and establish policies which life and the carrying capacity of the will avoid unreasonable flood risks. A floodplain are protected. comprehensive approach should include mapping floodplains, establishing general As a result of the above, local government policies to keep intensive new development and special districts can be both a out of floodplains or to mitigate and protect contributor to and user of your watershed against flood impacts if development is to assessment where it addresses flooding be located in such areas, minimizing and floodplains. impacts on existing development where possible, establishing policies regarding capital improvements or acquisitions necessary to ensure flood protection, and floodplain management policies (which may
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8.6.1 Floodplain Processes and interval associated with specific magnitude Ecology floods—otherwise stated, the occurrence of a high magnitude flood may increase the In our channel-centric view of rivers, the discharge of the design flood, such as the floodplain is often a neglected component of 100-year event commonly used for the fluvial system. This view has been floodplain management. prevalent historically in developed areas of California, where attempts to convey flood Floodplain riparian ecosystems are flows within existing channels are common. sustained by the very disturbances that our There are several problems with this past floodplain management efforts often try approach: to eliminate: flooding and erosion. In California, as in most of the developed 1) Prior to development, natural alluvial world, over 90% of riparian ecosystems channels evolved to accommodate the have been lost. Agricultural and urban dominant discharge, or bank full flow (flows development often extends all the way to with a range of recurrence intervals of about the top of the channel bank, leaving only a 1 to 5 years) while higher magnitude floods single line of trees. In creeks where cattle inundated the adjacent floodplain riparian or other livestock graze, vegetation may be zone on average every few years. The completely absent. In order to minimize current assumption that the channel itself, flood and erosion hazards, and to sustain or without its floodplain, can convey a full restore floodplain ecosystems, floodplain range of flood flows is unrealistic, and has management should: led to considerable flood hazards. Moreover, the hazard worsens • Accommodate physical processes, or incrementally with increases in watershed the “natural disturbances” that create development that reduce infiltration and and maintain processes and functions of increase runoff and peak discharges floodplain ecosystems (flooding, channel migration, avulsion, overbank 2) Floodplain development has led to a flow, sediment erosion and deposition); situation where there is often no riparian • Expect and accommodate change in the buffer between the top of the channel bank relation between the river channel and and the adjacent development. In this floodplain boundary (e.g. erosion, case, attempts are made to prevent the deposition, and migration); natural processes of bank erosion and • Preserve longitudinal and lateral channel migration, processes integral to the connectivity between the channel and storage and transfer of sediment within a floodplain (e.g. dam releases to fluvial system, as well as to vegetation maintain geomorphic processes, succession. Levees and bank protection vegetation succession, overbank flow, are employed to prevent geomorphic and fish use of floodplain areas); processes acting between channels and • Preserve flood storage function of their floodplains, thus creating static river floodplain; morphology. Such attempts to arrest • Preserve floodplain riparian zone as a erosion, and in some cases sediment buffer between developed areas and the deposition, has led to extensive fluvial system. channelization efforts throughout California 8.6.2 A watershed approach to 3) Relatively short hydrologic records are floodplain management used in statistical methods to predict future flood magnitudes and recurrence intervals. A watershed approach to reduce flood However, high magnitude floods change the hazards must consider cumulative effects of flood statistics, and lower the recurrence
- 22 - California Watershed Assessment Manual, Chapter 8 August, 2004 past and proposed floodplain changes. The • City of San Jose / Santa Clara County – most successful approach to minimize flood Guadalupe River watershed hazards it to minimize floodplain [http://www.scbwmi.org] development, and to instead preserve the • City of East Palo Alto – San natural flood storage capacity of the Francisquito Creek watershed floodplain. Flood hazard reduction and floodplain management is encouraged by 8.7 Regulation many, including the California Department of Water Resources (DWR; Regulations influence water quality, land http://www.fpm.water.ca.gov) and the uses, resources extraction (e.g., timber) and professional, non-profit educational integrated planning. Federal, state and local organization, the Floodplain Management regulations define the environment in which Association (FMA; all of the issues are considered. There are http://www.floodplain.org). Flooding often many state and local regulatory processes crosses multiple jurisdictional boundaries for where watershed assessment and ownerships and responsibilities: county, management are either required or are city, special district (water, flood control, useful tools to achieve regulatory goals. community services, etc.), state, federal, and tribal. 8.7.1. Water Quality Regulation
A watershed assessment that evaluates The federal Clean Water Act and the state upslope-downstream hydrologic effects and Porter-Cologne Act are the two primarily causes of alterations can provide a very water quality statutes (see box below). useful tool for floodplain management. These acts prescribe that permits be issued Downstream communities will likely have to regulate the release of contaminants into more interest in a watershed assessment waterways and that reports are prepared to addressing flooding and floodplain issues evaluate the conditions and status of than upstream ones, often driven by recent waterways, among other requirements. or continuous experience with damaging Before discussing how information from floods. Urbanizing areas tend to discover your watershed assessment might be useful that previous “flood control” channels and in this regulatory context, the following reservoirs, as well as road culverts, are not section reviews basic background sized to withstand the flood peaks (“peak information discharge”) estimated when the watershed was more rural, with less paved and 8.7.1.1. Major categories of water covered (impervious) surfaces. pollution
Some examples of downstream California Water pollution is grouped into two major communities (and their watershed) actively categories – point source and nonpoint working with partnerships on watershed source (NPS). Point source pollution is assessments and plans with floodplain defined as anything that is regulated by the management and flood protection as a National Pollution Discharge Elimination major focus include: System (NPDES) and generally comes out • City of Newport Beach – San Diego of the end of a pipe. This includes most Creek watershed urban stormwater run-off, which, now in • City of Santa Cruz – San Lorenzo Creek large part is regulated through NPDES watershed Storm Water programs. Although urban • City of Napa – Napa River watershed runoff is collected from a large geographical • Marine Corps Base Camp Pendleton – area, it is regulated by NPDES, and is Santa Margarita River watershed generally released into a waterway via a pipe so is considered a point source. NPS
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State statutes that affect water quality There are two key laws that regulate water quality in California
Name of Law Key provisions Clean Water Act (federal, • Regulations to meet the goal of zero discharge of 1972) pollutants. • Includes sections on water standards (303) and TMDLs (303d); assessment of water quality (305b); nonpoint source management (319); NPDES permits (402), and wetlands (404). Porter-Cologne (state, • Established the State Water Resources Control Board 1990) and 9 Regional Boards to control water rights and water quality in California. • Empowers the regional boards to prepare water quality control plans (Basin Plans) to ensure that beneficial uses of water are being met and actions are taken to control point and nonpoint source pollution. • Authorizes the Boards. to issue NPDES permits under the federal CWA pollution includes all other sources of reduce pollutant runoff to waterways. A pollution, including run off from agriculture, watershed assessment can still be very rural areas, most abandoned mines, and useful in this setting as one aspect of the forested areas. In particular, data and conditional waiver is to understand analysis from a watershed assessment watershed conditions for a given planning could provide useful information in the area. development of non point source pollution regulations. 8.7.1.2 Point Source Pollution Regulation In reality, almost all NPS pollution is really point source pollution because Point sources may have a wide-range of contaminants and other disruptors of potential impacts, from minor to being watershed function originate from points on drivers of waterway function. Stormwater the landscape. Typically, however, the term permits are given to local municipalities for point source pollution is applied only to point source discharges under the National focused human activities that discharge Pollutant Discharge Elimination System contaminants or modify physical or chemical (NPDES) and are called NPDES permits. qualities of a waterway (e.g., an industrial These permits contain a list of criteria that operation). cities and counties must comply with As a watershed assessor, you will find that regarding stormwater effluent. Large cities there is a gray area between permit- fall under the Phase I permits and are regulated and unregulated pollution that can required to monitor waterways. Monitoring be associated with a type of land-use. For data collected in the course of preparing a example, agricultural operations in the watershed assessment could be very Central Valley have been given a valuable for those involved in overseeing conditional waiver by the state for the compliance with the permits (e.g., Regional pollutants originating from agricultural lands Water Quality Control Boards). Within the in the Valley. In exchange, the growers Public Works or Utilities departments of monitor water quality at the sub-basin level each Phase I city, a “Stormwater Quality” and employ “best management practices” to division oversees monitoring of selected
- 24 - California Watershed Assessment Manual, Chapter 8 August, 2004 waterways for a variety of conventional and and summarized in a way that is useful toxic water quality constituents to comply for future permits. with their permit. Data from a watershed assessment could aid the effort to prioritize 3) Types of pollution that are covered by pollutant monitoring. This prioritization permits include those listed in Chapter process involves identifying key locations 3.6 (e.g., organic compounds, metals, for monitoring and key constituents that are high temperature). Contaminants may most toxic and most prevalent. Data have their effects in isolation from each generated as part of an assessment could other, but often they have their negative identify stream reaches where particular impacts in concert. This is where pollutants were problematic. Additionally, watershed assessment, which is by the assessment will contain an analysis of definition integrative, can have a the impacts of contaminants, sediment, and valuable role in decision-making. For total water volume on habitat conditions. example, future land-use decisions These impacts need to be evaluated during could impact the volume and the permitting process and would be useful composition of municipal waste to the staff at the Regional Boards. discharge, the timing and volume of managed storm-water runoff, and Watershed assessments should at least suppress natural processes. When include the location of point sources and existing conditions and impacts are estimated discharge of pollutants, or other compounded with future possible effects on watershed function. These points scenarios, then the combined impacts sources may have a wide range of potential can be assessed. impacts, from minor to being drivers of waterway function. Assessment of 4) Ultimately, the regulatory agency, the watershed function can also inform future State Water Resources Control Board, permitting of point source discharge. If must accept the finding of a negative waterways within a watershed are already impact to deny a pollution discharge impacted by point or non-point sources of permit, or accept a finding of no net pollution, the future permitted discharges impact to allow a permit. There is not would be inadvisable. always a clear role for watershed groups in this process, though local agencies There are various ways that you can deal may be able to bring forward watershed with point source information: assessment information to the decision- making process. 1) Point source dischargers and the state regulatory agency must monitor the 8.7.1.3 Non-Point Source Pollution pollution originating from the permitted Regulation facility and also the potential impacts of the pollution. This information is an The problem of non-point source pollution important local source of information for has contributed to the widespread the water quality part of your application of watershed assessment and assessment. management. Widely distributed and occasional appearance of water pollution 2) Information about single point sources, across a watershed is a product of the or a combination of point and non-point combination of the natural environment and sources of pollution can be combined to human actions. It is possible in some cases give an assessment of existing impacts. to attribute responsibility for NPS pollution This combined impact should be to individual actions, land uses, or parcels. assessed for ecosystem and other impacts and the information presented
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Non-point source pollution enters http://www.krisweb.com/biblio/garcia_usepa waterways at non-specific places as a _regix_1998_finaltmdl.pdf). consequence of the movement of water across the landscape. When the beneficial TMDLs can consider and allocate loads uses of the waterbodies are impaired as a (amounts) for contaminants originating from consequence of this pollution, total both non-point and point sources. Natural maximum daily loads (TMDLs) can be loads are calculated and are often established to reduce the contaminant(s). considered the background for a particular TMDLs have been established in waterways substance (e.g., sediment or nutrients). for pesticides, nutrients, sediment, and TMDL reports describe the data analysis other types of contaminants. and modeling used to determine likely or actual sources of pollutants and eventually The TMDL process is a framework of “waste load allocations”, or the amount of assessing a watershed, but with a water pollution each polluter or area may quality emphasis. Each TMDL has five contribute to the waterway. general objectives, quite similar to the watershed assessment process described There are no fixed protocols for the in this Manual: determination and allocations of pollutant loads under individual TMDLs. Like 1. To assess the condition of a waterbody, watershed assessments, they are tailored to and determine/confirm cause(s) / the watershed and the sources of pollution. source(s) of pollutant; The San Diego Creek TMDL used the 2. To quantify the sources of the pollutant; proportion of sub-watersheds in different 3. To determine how much of a particular land use categories and measurements or pollutant a waterbody can handle and estimates of loads originating from land-use still meet desired conditions; types to determine loads for each pollutant 4. To identify whether and how much the in each sub-watershed. different sources need to be reduced in order to support desired conditions; Watershed assessment approaches are 5. To develop a plan which, when more general than TMDL calculations and implemented, will restore waterbody might provide more detail about natural health. processes and human activities in the same sub-watersheds. This additional detail would TMDLs are determined by state agencies help the TMDL process and potentially for pollutants impacting specific waterways. inform the implementation of the waste load For example, in the Newport Bay watershed allocation and reduction. (Southern California), San Diego Creek has a TMDL established by the US-EPA for 1) TMDLs being carried out in watersheds organic and inorganic pollutants originating with assessments or similar analyses from residential, commercial, industrial, and should explicitly take into account the agricultural lands (see box below). The watershed characteristics and Garcia River has a TMDL for sediment processes described in the assessment. (posted at:
A TMDL identifies the maximum amount of a pollutant that may be discharged to a water body without causing exceedences of water quality standards and impairment of the uses made of these waters. The federal Clean Water Act requires development of TMDLs for polluted waters to assist in identifying pollutant control needs and opportunities. (Total Maximum Daily Loads For Toxic Pollutants San Diego Creek and Newport Bay, California; US- EPA, Region 9, 2002) http://www.epa.gov/region09/water/tmdl/nbay/summary0602.pdf
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2) Watershed assessments should 3) Cumulative effects of past, proposed, describe historic, present, and likely and future activities are also best future conditions, which is all useful measured at several scales, from the information for determining a TMDL. sub-watershed to watershed. Smaller watersheds may respond more quickly 3) Watershed management plans based and to fewer actions than larger on watershed assessments in TMDL watersheds as well as in different ways. watersheds should take into account the source calculations and waste load 4) Effects of the proposed actions and allocations in the TMDL when describing cumulative effects should be analyzed management recommendations. over appropriate time scales for the processes in question. For example, if 8.7.2 Timber Harvest Plans the logging will impact shade on upland slopes, what will the change in Developing and implementation of timber subsurface water temperature be and harvest plans (THPs) are required by the how will that change affect the Board of Forestry under the California immediate stream reach? At another Forest Practices Act. It is the intention of the scale: how will the combined actions state that these THPs not result in non-point change natural disturbance processes source pollution to the state’s waterways. and population dynamics on the Watershed assessment can provide several landscape and in the waterways of the types of information for THP development: larger watershed over decades?
1) The physical and biological setting for 8.7.3 Federal and State Endangered THP activities should be described at Species Acts several watershed scales. For example, the impacts of logging and grading Both the Federal and California Endangered under a THP will be most apparent at Species Acts (FESA and CESA, the smallest sub-watershed scale. It is respectively) require that federal and/or most valuable to collect data at this fine state agencies consider and regulate the scale on many watershed processes in impacts of land and water use actions on order to provide an appropriate imperiled plant and wildlife species and their description of the natural environment. habitats. For certain species, e.g., salmon, However, some impacts of the project these impacts are often considered at the may work their way downstream into the watershed scale in order to include stream and river system meaning that landscape impacts on waterways. Many processes should be measured there as watershed assessments have been done well. because of the presence in the watershed of endangered or threatened species. 2) Different geographic scales will be appropriate for different potential Watershed assessments can be used to impacts (Ziemer, 2000). For example, inform decisions for managing impacts to road crossings may change stream endangered species in the following ways: channel properties for only a few hundred meters up and down stream of 1) Identify potential and actual impacts to the crossing. In contrast, skid trails and endangered species that may originate from road cuts may contribute excess single or multiple sources that are best sediment, nutrients, and surface water measured at the watershed scale. to downstream channels for many miles. 2) Identify the spatial and temporal scales at which potential and actual impacts should be measured within the watershed.
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3) Use the conceptual model approach from County, where landowners obtained a the assessment planning stage (see CALFED grant to remove a non-functioning chapters 2 and 6) to identify human and earthen dam which had prevented migration other actions and processes that influence of anadramous fish. Landowners such as the well-being of endangered species. this group could benefit from the data and 4) Give relative weights to the human and analysis contained in a watershed natural influences on endangered species assessment. habitats and populations. Use these relative weights to prioritize the influences for Regional information on geology, climate, remedial action. soil productivity, erosion risk, land 5) Describe protection or restoration capability, and vegetation may be useful for strategies that could be implemented at the operations of some farmers and ranchers or watershed scale for the benefit of for planning construction and other endangered species or their habitats. development. These general types of 6) Identify data and knowledge gaps information would be necessary for specific to the species and their habitats environmental analysis of development that are needed prior to making decisions proposals. Watershed information could that are based on knowledge of ecosystem also be useful in complying with regulations and population dynamics. and as background in applications for grants from state and federal agencies for soil 8.8 Voluntary Private Lands conservation and habitat restoration Management projects.
In general, most landowners have intimate Watershed assessments should be helpful knowledge of their property, so it is unlikely to owners of forest-land in scheduling of that a watershed assessment will tell them logging, road construction, and road much that they don’t already know about maintenance to minimize impacts on general condition. Scientific aspects of the streams. Information from watershed assessment may be more revealing to assessments should also assist in them. Perhaps the principal benefit of a complying with California’s Forest Practice watershed assessment to a private Rules and preparing Timber Harvest Plans, landowner is setting the context of their Sustained Yield Plans, or Non-industrial property within the entire watershed. For Timber Management Plans. Watershed some people, this perspective will be of assessments probably have the greatest interest and benefit and may lead to direct applicability to evaluating cumulative alterations in management practices. For watershed effects as required for Timber others, a watershed perspective and Harvest Plans. If the Board of Forestry associated information will not affect their adopts the recommendations of the established way of doing business. A University of California Committee on watershed assessment may contain Cumulative Watershed Effects (Dunne, et substantial resources such as aerial al. 2001), then watershed assessments photographs, satellite imagery, and GIS could become an integral part of planning layers of their land and adjoining properties for forest operations. that an individual may not have ready access to. These types of information may 8.9 Monitoring Programs be of value to some owners in their planning and decision making. Monitoring is an important part of adaptive management and the implementation of Some landowners have partnered with watershed plans, restoration programs, neighbors to restore a waterway. One regulation, and land and water use example is Murphy’s Creek in San Joaquin decisions. Monitoring is closely tied to
- 28 - California Watershed Assessment Manual, Chapter 8 August, 2004 watershed assessment. The results of information gap. For example, if there are monitoring should be useful to assessment particular land-uses of concern distributed and assessment in turn should be used to throughout your watershed (e.g., roads), design and implement monitoring programs. then you should monitor enough of them closely to statistically determine whether or Two important ways that watershed not an impact is occurring, as well as the assessment can inform monitoring program extent of the impact throughout sub- design and implementation are: 1) by watersheds. exposing gaps in knowledge and data about watershed conditions and 2) by showing 2) The temporal scale and resolution of your geographically areas that are at risk or have program is as important as the spatial actual impacts from human activities. resolution. If your data gaps are related to storm event impacts (e.g., large movements Knowledge and Data Gaps of sediment or contaminants), then monitoring should occur intensively during Part of your watershed assessment should and after storms and for several storms. involve identifying gaps in information about Between storms, you would want to systems in your watershed and deficiencies determine non-storm related impacts in in knowledge about how the systems work order to provide a “baseline” against which (see chapter 2.5.2). These gaps should be to compare storm impacts. Frequency of separated into these two major categories, sampling is a critical issue here as it both data and knowledge, and a monitoring and determines whether or not you can tell research program recommended to address something about individual events, changes deficiencies. Obviously implementation of during a water-year, and/or trends over the program will depend on factors beyond decades. the control of the assessment project. In addition, not all data and knowledge gaps Knowledge gaps can be readily filled, even by the most advanced watershed groups. However, it Data gaps are different from knowledge will help your own, or someone else’s, gaps. Knowledge gaps refer to things you future understanding of the watershed if you don’t know about a system or thing you are go through this exercise. interested in. To address gaps in your knowledge about how your watershed is Data gaps working, changing over time, or responding to stress from human activities, you may Monitoring is conducted to find out how a need to implement monitoring that is system works or is changing over time. The basically research. An example of a term is typically applied to water quality knowledge gap is the contribution of monitoring programs, but you could just as nutrients to waterways from different land easily use it to refer to wildlife or ground use and cover types. Addressing this water monitoring. There are a wide variety knowledge gap would demand collecting of things you could conceivably monitor in data about nutrients upstream, adjacent to, response to findings in your watershed downstream, and in sub-surface water for assessment. Here are some things to keep each land use or cover type of interest. The in mind: data would need to be collected over a reasonable time and space resolution and 1) The spatial scale and resolution of your for long enough to establish any trends. monitoring program (e.g., location and Along the way you might fill data gaps (e.g., distribution of monitoring sites) should be nutrient concentration in a certain determined by the nature of your waterway), but the knowledge gap filling monitoring/assessment question or the occurs when you find statistically-significant
- 29 - California Watershed Assessment Manual, Chapter 8 August, 2004 relationships between land-uses and where the gaps occur. Pencil in possible nutrient conditions under a range of climate ways that things might work and use this and other conditions. This obviously exercise to come up with targeted questions requires specialized analytical skills that you for future monitoring or research. may or may not find in your current assessment team or watershed group. 8.10 References
Here are some things to keep in mind when Association of Bay Area Governments. designing programs to address knowledge 1995. Improving our Bay-Delta Estuary gaps: Through Local Plans and Programs: A Guidebook for City and County 1) Differentiate between data gaps and Governments. Oakland, CA. 21 pp. knowledge gaps. Data gaps require the http://www.abag.org collection of information about a system about which you already have some Born, S.M. and K.D. Genskow. 2001. knowledge. Knowledge gaps occur where Toward understanding new watershed you may or may not have data, you just initiatives. A report from the Madison aren’t sure how processes and things are Watershed Workshop (July 20-21, 2000). interacting with each other, or occurring Univ. of Wisconsin Cooperative Extension over space and time. Service and Trout Unlimited. Madison, WI. 23 p. (www.tu.org). 2) Approach knowledge gaps in the same way you went after conceptual modeling California Coastal Conservancy. Watershed (Chapter 2). Think of how a system might Planning Guide. Prepared by Kate work based on your knowledge of how Goodnight. 17 p. similar systems work. Draw or describe a (http://www.coastalconservancy.ca.gov/Publ conceptual model of the system including ications/ws_planning_guide.pdf)
Using the Assessment in Decision- California Dept. of Fish and Game (CDFG). Making Checklist 1998. California Salmonid Stream Habitat Restoration Manual. 3rd edition. Consider the following potential uses for your Sacramento. assessment: http://www.dfg.ca.gov/nafwb/manual.html
Watershed planning California Department of Health Services Restoration Projects (CDHS). 1999. Drinking Water Source Assessment and Protection Program. Integrated Water Management Projects Division of Drinking Water and o Water Supply Projects Environmental Management. Sacramento. o Drinking Water Protection Efforts o Groundwater Management Planning California Office of Planning and Research o Water Quality Protection (OPR). General Plan Guidelines. o Floodplain Management Sacramento. Regulations relating to: o Water quality California Resources Agency (CRA) and o Timber harvesting State Water Resources Control Board o Federal and state endangered (SWRCB). 2002. Addressing the Need to species Protect California’s Watersheds: Working o Local land-use planning with Local Partnerships. Report to the Voluntary Private Lands Management Legislature. Sacramento. 80 p.
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Conservation Technology Information who should pay? J. Amer. Water Res. Center (CTIC). 1994. Putting together a Assoc. 35(3): 527-534. watershed management plan: a guide for watershed partnerships. 16 p. Know Your Huntington, C.W. and S. Sommarstrom. Watershed (KYW) Program. 2000. An evaluation of selected watershed http://ctic.purdue.edu/KYW/KYW.html councils in the Pacific Northwest and Northern California. Prepared for Trout Dunne, T., J. Agee, S. Beissinger, W. Unlimited and Pacific Rivers Council. Dietrich, D. Gray, M. Power, V. Resh, and Portland, OR. (www.pacrivers.org) K. Rodrigues. 2001. A scientific basis for the prediction of cumulative watershed effects. Hyde, C.G., G.H. Wilhelm, and F.C. Miller. Report 46. Berkeley: University of 1916. A report upon possible sources of California, Wildland Resources Center. water supply for the city of Sacramento, California. Sacramento: City Commission. Environment Now and Southern California Wetlands Recovery Project. 2002. Manley, P. N., G. E. Brogan, C. Cook, M. E. Watershed management plan Flores, D. G. Fuller, S. Husari, T. M. characterization report for coastal southern Jimerson, L. M. Lux, M. E. McCain, J. A. California. Prepared for State Water Rose, G. Schmitt, J. C. Schuyler, and M. J. Resources Control Board. Los Angeles, CA. Skinner. 1995. Sustaining ecosystems: a 28 p. conceptual framework. Publication R5-EM- 01. Vallejo, CA: USDA Forest Service, FEMAT (Forest Ecosystem Management Pacific Southwest Region. Assessment Team). 1993. Forest Ecosystem management: An ecological, McCammon, B., J. Rector, and K. Gebhardt. economic, and social assessment. Portland: 1998. A framework for analyzing the USDA-Forest Service. hydrologic condition of watersheds. Denver: Bureau of Land Management and USDA- Federal Energy Regulatory Commission. Forest Service. 1994. Draft environmental impact statement and report, proposed Clavey River project, McGurk, B.J. and B. Paulson. 2001. Tuolumne County, California. FERC/EIS- Mokelumne River hydroelectric project 0074D. Washington, DC: Federal Energy relicensing: Collaborative process integrates Regulatory Commission. multiple resource concerns. Proceedings of the Eighth Biennial Watershed Management Freeman, J.R., 1912. On the proposed use Council Conference, R.N. Coats and M.P. of a portion of the Hetch Hetchy, Eleanor Carlson, eds. pp.13-22. Water Resources and Cherry Valleys. San Francisco: Board Center Report 101. Riverside: University of of Supervisors. California.
Fulton, W. 1999. Guide to California Mitchell, B. (editor). 19990. Integrated planning. 2nd ed. Solano Press Books. 373 Water Management: International pp. Experiences and Perspectives. Belhaven Press, London, United Kingdom. Grant, G.E. 1994. Watershed analysis – a retrospective. Watershed Management Naiman R.J. and 8 others (1992). Council Newsletter 6(2):1, 16-17. Fundamental elements of ecologically healthy watersheds in the Pacific Northwest Grigg, N.S. 1999. Integrated water coastal ecoregion. In: “Watershed resources management: who should lead, management: balancing sustainability and environmental change. Ed. R.J. Naiman
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National Association of Counties (NACo). USDA-Forest Service. 1994. Record of http://www.naco.org/pubs.catalog/index.cfm decision: Amendments to Forest Service • “Leadership in Watershed Management: and Bureau of Land Management planning The County Role” (1999). 86 p. documents within the range of the northern • “Restoring Community Wetlands and spotted owl. Washington, DC: USDA-Forest Watersheds” (1999) Service. • “Protecting Wetlands, Managing Watersheds…Local Government Case USDA-Forest Service. 1995. Ecosystem Studies” (1999) analysis at the watershed scale – The “Watershed Management and Sustainable federal guide for watershed analysis. Development in Coastal Counties” (1996) http://www.or.blm.gov/ForestPlan/Watershe d/ National Research Council. 1992. Restoration of Aquatic Ecosystems: USDA-Forest Service. 1999. Roads Science, Technology, and Public Policy. analysis: informing decisions about National Academy Press, Washington, D.C., managing the national forest transportation 552 p. system. Misc. Rep. FS-643. USD Agriculture Forest Service, Washington DC, National Research Council (NRC). 1999. 222 pp. New strategies for America’s watersheds. National Academy of Sciences. Wash. D.C. USDA 2001. Forest roads: a synthesis of pp. 232-267. scientific information. Page 120 in H. Gucinski, M. J. Furniss, R. R. Ziemer, and Reid, L.M., R.R. Ziemer, and M.J. Furniss. M. H. Brookes. Eds, General Technical 1994. Watershed analysis in the federal Report PNW- GTR-509. USD Agriculture arena. Watershed Management Council Forest Service, Washington, DC. Newsletter 6(2):6-11. USDA-Forest Service. 2000. Lake Tahoe Reimold, R.J. (ed) 1998. Watershed Basin watershed assessment. General management: practice, policies, and Technical Report, GTR-PSW-175 and 176. coordination. McGraw-Hill, NY. 391 p. Albany, CA: Pacific Southwest Research Station. Riley, Ann L. 1998. Restoring Streams in Cities: A Guide for Planners, Policymakers, Washington Department of Ecology (DOE). and Citizens. Island Press, Covelo CA. 423 1998. Guide to Watershed Planning and p. Management. Olympia WA. http://www.ecy.wa.gov/biblio/99106.html Saul, S. and T. Faast. 1993. Natural Amendments Resource Planning Survival Guide. U.S. (http://www.ecy.wa.gov/biblio/0206005.html) Fish & Wildlife Service and Oregon Dept. of Natural Resources. Portland, OR. 24 p. Williams, J.E., Wood, C.A., and M.P. Dombeck, editors. 1997. Watershed Santa Clara Basin Watershed Management Restoration: Principles and Practices. Initiative. 2003. Watershed Action Plan. American Fisheries Society, Bethesda, //www.scbwmi.org/ Maryland. 561 p.
State Water Resources Control Board. World Meteorological 2001. Watershed Management Initiative Organization/UNESCO. 1991. Water Overview. 4 p. resources assessment: Progress in the http://www.swrcb.ca.gov/watershed/index.ht Implementation of the Mar del Plata Action ml Plan and a Strategy for the 1990s. 64 p.
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Geneva: World Meteorological Organization.
Ziemer, Robert R. 2004. Scale considerations for linking hillslopes to aquatic habitats. Pages 22-32, in: Hermann Gucinski, Cynthia Miner, and Becky Bittner (eds.) Proceedings: Views from the ridge: Considerations for planning at the landscape scale. General Technical Report PNW-GTR-596. Portland, OR: U.S. Dept. of Agriculture, Forest Service, Pacific Northwest Research Station. 133 p.
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