Surface Runoff and Streambank Erosion
Total Page：16
File Type：pdf, Size：1020Kb
Load more
Recommended publications
-
Geomorphic Classification of Rivers
9.36 Geomorphic Classification of Rivers JM Buffington, U.S. Forest Service, Boise, ID, USA DR Montgomery, University of Washington, Seattle, WA, USA Published by Elsevier Inc. 9.36.1 Introduction 730 9.36.2 Purpose of Classification 730 9.36.3 Types of Channel Classification 731 9.36.3.1 Stream Order 731 9.36.3.2 Process Domains 732 9.36.3.3 Channel Pattern 732 9.36.3.4 Channel–Floodplain Interactions 735 9.36.3.5 Bed Material and Mobility 737 9.36.3.6 Channel Units 739 9.36.3.7 Hierarchical Classifications 739 9.36.3.8 Statistical Classifications 745 9.36.4 Use and Compatibility of Channel Classifications 745 9.36.5 The Rise and Fall of Classifications: Why Are Some Channel Classifications More Used Than Others? 747 9.36.6 Future Needs and Directions 753 9.36.6.1 Standardization and Sample Size 753 9.36.6.2 Remote Sensing 754 9.36.7 Conclusion 755 Acknowledgements 756 References 756 Appendix 762 9.36.1 Introduction 9.36.2 Purpose of Classification Over the last several decades, environmental legislation and a A basic tenet in geomorphology is that ‘form implies process.’As growing awareness of historical human disturbance to rivers such, numerous geomorphic classifications have been de- worldwide (Schumm, 1977; Collins et al., 2003; Surian and veloped for landscapes (Davis, 1899), hillslopes (Varnes, 1958), Rinaldi, 2003; Nilsson et al., 2005; Chin, 2006; Walter and and rivers (Section 9.36.3). The form–process paradigm is a Merritts, 2008) have fostered unprecedented collaboration potentially powerful tool for conducting quantitative geo- among scientists, land managers, and stakeholders to better morphic investigations. -
Flood Hazard of Dunedin's Urban Streams
Flood hazard of Dunedin’s urban streams Review of Dunedin City District Plan: Natural Hazards Otago Regional Council Private Bag 1954, Dunedin 9054 70 Stafford Street, Dunedin 9016 Phone 03 474 0827 Fax 03 479 0015 Freephone 0800 474 082 www.orc.govt.nz © Copyright for this publication is held by the Otago Regional Council. This publication may be reproduced in whole or in part, provided the source is fully and clearly acknowledged. ISBN: 978-0-478-37680-7 Published June 2014 Prepared by: Michael Goldsmith, Manager Natural Hazards Jacob Williams, Natural Hazards Analyst Jean-Luc Payan, Investigations Engineer Hank Stocker (GeoSolve Ltd) Cover image: Lower reaches of the Water of Leith, May 1923 Flood hazard of Dunedin’s urban streams i Contents 1. Introduction ..................................................................................................................... 1 1.1 Overview ............................................................................................................... 1 1.2 Scope .................................................................................................................... 1 2. Describing the flood hazard of Dunedin’s urban streams .................................................. 4 2.1 Characteristics of flood events ............................................................................... 4 2.2 Floodplain mapping ............................................................................................... 4 2.3 Other hazards ...................................................................................................... -
Prp Stream Bank Restoration What You Need to Know
PRP STREAM BANK RESTORATION WHAT YOU NEED TO KNOW JOHNNA ZONA Streams Streams form a continuous system of pools, riffles, bars and curves to absorb the energy of the flow They are rarely perfectly straight. Water naturally meanders from one side of a channel to the other, and soil, sand and gravel are washed away from the areas where the current is fastest and deposited where the water moves more slowly Adjustments a stream makes creates a balance between the amount of water flowing in the channel, the amount of sediment it is transporting through the channel, and the changing slope and size of the channel https://www.youtube.com/watch?v=HDjcT8-xsXk Fish and Wildlife Habitat Values of Streams A healthy aquatic population in a stream depends on a variety of suitable habitats, adequate food supply and clean water dFish an organism need a mixture of habitats such as fast flowing riffles, deep pools and cool water, rocks, snags and overhanging vegetation Streamside vegetation is important as it provides a food supply, shade to cool the water and cover for roosting, resting/nesting and protection Stream Blockages Debris jams, log, tires, construction materials and things like shopping carts can cause streambank erosion by deflecting flows off of banks. Municipalities and homeowners can help remove the obstructions and reduce potential bank erosion problems and increase the capacity of the stream channel to carry flows without over topping Stream Blockages fRemoval o debris from a channel should be done without altering the stream or banks, including vegetation. If it can be removed from the side by “picking” it out without entering the stream, a permit is not required. -
Stream Restoration, a Natural Channel Design
Stream Restoration Prep8AICI by the North Carolina Stream Restonltlon Institute and North Carolina Sea Grant INC STATE UNIVERSITY I North Carolina State University and North Carolina A&T State University commit themselves to positive action to secure equal opportunity regardless of race, color, creed, national origin, religion, sex, age or disability. In addition, the two Universities welcome all persons without regard to sexual orientation. Contents Introduction to Fluvial Processes 1 Stream Assessment and Survey Procedures 2 Rosgen Stream-Classification Systems/ Channel Assessment and Validation Procedures 3 Bankfull Verification and Gage Station Analyses 4 Priority Options for Restoring Incised Streams 5 Reference Reach Survey 6 Design Procedures 7 Structures 8 Vegetation Stabilization and Riparian-Buffer Re-establishment 9 Erosion and Sediment-Control Plan 10 Flood Studies 11 Restoration Evaluation and Monitoring 12 References and Resources 13 Appendices Preface Streams and rivers serve many purposes, including water supply, The authors would like to thank the following people for reviewing wildlife habitat, energy generation, transportation and recreation. the document: A stream is a dynamic, complex system that includes not only Micky Clemmons the active channel but also the floodplain and the vegetation Rockie English, Ph.D. along its edges. A natural stream system remains stable while Chris Estes transporting a wide range of flows and sediment produced in its Angela Jessup, P.E. watershed, maintaining a state of "dynamic equilibrium." When Joseph Mickey changes to the channel, floodplain, vegetation, flow or sediment David Penrose supply significantly affect this equilibrium, the stream may Todd St. John become unstable and start adjusting toward a new equilibrium state. -
Documentation and Analysis of Flash Flood Prone Streams and Subwatershed Basins in Pulaski County, Virginia
DOCUMENTATION AND ANALYSIS OF FLASH FLOOD PRONE STREAMS AND SUBWATERSHED BASINS IN PULASKI COUNTY, VIRGINIA Prepared by Anthony Phillips Department of Geography Virginia Polytechnic Institute & State University Report Distributed August 10, 2009 Prepared for National Oceanic and Atmospheric Administration - National Weather Service Blacksburg, Virginia & Office of the Emergency Manager Pulaski County, Virginia The research on which this report is based was financed by Virginia Tech through the McNair Scholars Summer Research Program. ABSTRACT Flash flooding is the number one weather-related killer in the United States. With so many deaths related to this type of severe weather, additional detailed information about local streams and creeks could help forecasters issue more accurate and precise warnings, which could help save lives. Using GIS software, streams within twenty-five feet of a roadway in Pulaski County, Virginia were identified and selected to be surveyed. Field work at each survey point involved taking measurements to determine the required stream level rise necessary to cause flooding along any nearby roadway(s). Additionally, digital pictures were taken to document the environment upstream and downstream at each survey point. This information has been color- coded, mapped, and overlaid in Google Earth for quick access on computers at the National Weather Service Office in Blacksburg, Virginia. It has also been compiled into an operational handbook and DVD for use at the NWS. iii ACKNOWLEDGMENTS The author would like to thank -
Flash Flood PREPAREDNESS
Flash Flood PREPAREDNESS Flash floods occur within a few minutes or Before a flood occurs. hours of excessive rainfall, a dam or levee failure or a sudden release of water held by an Find out if you live in a flood prone area. ice jam. Flash floods can roll boulders, tear out You can check with your local building trees, destroy buildings and bridges. Flash department to see the flood maps for your floods can also trigger catastrophic mudslides. municipality. Flash floods are the #1 weather related killer If you are in a flood zone - purchase in the United States. sufficient flood insurance. Flood losses are not covered under normal National Weather Service . homeowner’s insurance. Staying current with forecasts from the Learn how your community would alert you National Weather Service can be an important if a flood was occurring or predicted. part of flood preparedness. Individuals can purchase a NOAA weather radio to directly Pre-assemble flood-fighting supplies like hear the forecasts, advisories, watches and/or plastic sheeting, lumber, sandbags. warnings. Some NOAA weather radios can alarm when there is a serious/dangerous Have check valves installed in building weather condition. These radios are available sewer traps to prevent flood waters from at many stores. backing up in sewer drains. The following terms may be used by the As a last resort have large corks or National Weather service: stoppers to plug showers, tubs or basins from water rising up through the pipes. A Flash Flood or Flood Watch means that flash flooding or flooding is possible within the Maintain a disaster supply kit at home. -
Severe Weather Safety Guide Flash Flooding
What causes River Flooding? Stay informed! • Persistent storms over the same area for long Listen to NOAA Weather Radio, local radio or Severe periods of time. television for the latest weather and river forecasts. • Combined rainfall and snowmelt • Ice jams Weather • Releases from man made lakes • Excessive rain from tropical systems making Safety landfall. How does the NWS issue To check out the latest river forecast information Guide and current stages on our area rivers, visit: Flood/Flash Flood Warnings? http://weather.gov/pah/ahps Flash Check out the National Weather Service Paducah website for the latest information at Flooding weather.gov/paducah Call for the latest forecast from the National Weather Service’s Weather Information Now number: Paducah, KY: 270-744-6331 Evansville, IN: 812-425-5549 National Weather Service forecasters rely on a A reference guide from your network of almost 10,000 gages to monitor the National Oceanic & Atmospheric Administration height of rivers and streams across the Nation. National Weather Service National Weather Service This gage data is only one of many different 8250 Kentucky Highway 3520 Paducah, Kentucky sources for data. Forecasters use data from the Doppler Radar, surface weather observations, West Paducah, KY 42086 snow melt/cover information and many other 270-744-6440 different data sources in order to monitor the threat for flooding. FLOODS KILL MORE PEOPLE FACT: Almost half of all flash flood Flooding PER YEAR THAN ANY OTHER fatalities occur in vehicles. WEATHER PHENOMENAN. fatalities occur in vehicles. Safety • As little as 6 inches of water may cause you to lose What are Flash Floods ? control of your vehicle. -
Stream Erosion
STREAM EROSION Erosion is an ongoing process on all bodies of water, especially moving water. Both natural and human- caused factors affect the amount of erosion a stream may experience. Natural factors include the gradient (or steepness) of the streambed since that affects the speed of the flow of water. Rainfall and snowmelt affect the amount of water in a stream as well as the speed of the flow. Human factors include run-off from farm fields and parking lots and water releases from dams that increase the amount of water flowing in streams. Removal of trees and shrubs from stream banks and deadfall from within the stream makes them more susceptible to erosion and increases stream flow. When there is too much erosion in a stream or on lands that drain into a stream, there is an increase in silting, a serious problem that affects our drinking water and the plants and creatures that live there. Serious problems are also caused by flash floods, when a river or stream is carrying a far greater than normal amount of water. Flash floods damage streams because they tear up stream banks and bottoms and move silt downstream and into lakes and ponds and slow spots in a stream. Causes of flash floods can be natural, human-made or a combination of both. Our experiments will examine three variables that affect water flow in a stream and test for their effect on erosion: slope (gradient) of the streambed, total amount of water flowing in a streambed (discharge), and pulses (spikes) in water. -
Classifying Rivers - Three Stages of River Development
Classifying Rivers - Three Stages of River Development River Characteristics - Sediment Transport - River Velocity - Terminology The illustrations below represent the 3 general classifications into which rivers are placed according to specific characteristics. These categories are: Youthful, Mature and Old Age. A Rejuvenated River, one with a gradient that is raised by the earth's movement, can be an old age river that returns to a Youthful State, and which repeats the cycle of stages once again. A brief overview of each stage of river development begins after the images. A list of pertinent vocabulary appears at the bottom of this document. You may wish to consult it so that you will be aware of terminology used in the descriptive text that follows. Characteristics found in the 3 Stages of River Development: L. Immoor 2006 Geoteach.com 1 Youthful River: Perhaps the most dynamic of all rivers is a Youthful River. Rafters seeking an exciting ride will surely gravitate towards a young river for their recreational thrills. Characteristically youthful rivers are found at higher elevations, in mountainous areas, where the slope of the land is steeper. Water that flows over such a landscape will flow very fast. Youthful rivers can be a tributary of a larger and older river, hundreds of miles away and, in fact, they may be close to the headwaters (the beginning) of that larger river. Upon observation of a Youthful River, here is what one might see: 1. The river flowing down a steep gradient (slope). 2. The channel is deeper than it is wide and V-shaped due to downcutting rather than lateral (side-to-side) erosion. -
Restoring Streams in an Urbanizing World
Freshwater Biology (2007) 52, 738–751 doi:10.1111/j.1365-2427.2006.01718.x Restoring streams in an urbanizing world EMILY S. BERNHARDT* AND MARGARET A. PALMER† *Department of Biology, Duke University, Durham, NC, U.S.A. †Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, Solomons, MD, U.S.A. SUMMARY 1. The world’s population is increasingly urban, and streams and rivers, as the low lying points of the landscape, are especially sensitive to and profoundly impacted by the changes associated with urbanization and suburbanization of catchments. 2. River restoration is an increasingly popular management strategy for improving the physical and ecological conditions of degraded urban streams. In urban catchments, management activities as diverse as stormwater management, bank stabilisation, channel reconfiguration and riparian replanting may be described as river restoration projects. 3. Restoration in urban streams is both more expensive and more difficult than restoration in less densely populated catchments. High property values and finely subdivided land and dense human infrastructure (e.g. roads, sewer lines) limit the spatial extent of urban river restoration options, while stormwaters and the associated sediment and pollutant loads may limit the potential for restoration projects to reverse degradation. 4. To be effective, urban stream restoration efforts must be integrated within broader catchment management strategies. A key scientific and management challenge is to establish criteria for determining when the design options for urban river restoration are so constrained that a return towards reference or pre-urbanization conditions is not realistic or feasible and when river restoration presents a viable and effective strategy for improving the ecological condition of these degraded ecosystems. -
Drainage Patterns
Drainage Patterns Over time, a stream system achieves a particular drainage pattern to its network of stream channels and tributaries as determined by local geologic factors. Drainage patterns or nets are classified on the basis of their form and texture. Their shape or pattern develops in response to the local topography and Figure 1 Aerial photo illustrating subsurface geology. Drainage channels develop where surface dendritic pattern in Gila County, AZ. runoff is enhanced and earth materials provide the least Courtesy USGS resistance to erosion. The texture is governed by soil infiltration, and the volume of water available in a given period of time to enter the surface. If the soil has only a moderate infiltration capacity and a small amount of precipitation strikes the surface over a given period of time, the water will likely soak in rather than evaporate away. If a large amount of water strikes the surface then more water will evaporate, soaks into the surface, or ponds on level ground. On sloping surfaces this excess water will runoff. Fewer drainage channels will develop where the surface is flat and the soil infiltration is high because the water will soak into the surface. The fewer number of channels, the coarser will be the drainage pattern. Dendritic drainage pattern A dendritic drainage pattern is the most common form and looks like the branching pattern of tree roots. It develops in regions underlain by homogeneous material. That is, the subsurface geology has a similar resistance to weathering so there is no apparent control over the direction the tributaries take. -
Stream Visual Assessment Manual
U.S. Fish & Wildlife Service Stream Visual Assessment Manual Cane River, credit USFWS/Gary Peeples U.S. Fish & Wildlife Service Conasauga River, credit USFWS Table of Contents Introduction ..............................................................................................................................1 What is a Stream? .............................................................................................................1 What Makes a Stream “Healthy”? .................................................................................1 Pollution Types and How Pollutants are Harmful ........................................................1 What is a “Reach”? ...........................................................................................................1 Using This Protocol..................................................................................................................2 Reach Identification ..........................................................................................................2 Context for Use of this Guide .................................................................................................2 Assessment ........................................................................................................................3 Scoring Details ..................................................................................................................4 Channel Conditions ...........................................................................................................4