Mono County Community Development Department P.O. Box 347 Planning Division P.O. Box 8 Mammoth Lakes, CA 93546 Bridgeport, CA 93517 (760) 924-1800, fax 924-1801 (760) 932-5420, fax 932-5431 [email protected] www.monocounty.ca.gov March, 2007 UPPER OWENS RIVER BASIN 1. Introduction Watershed approach California watershed programs and Mono County’s involvement What is a watershed assessment? Publicly perceived problems and issues Water quantity Water quality Aquatic habitat Recreation Wildfire Invasive species List of assorted issues Publicly perceived key resources Driving questions Watershed boundaries 2. Descriptive geography Climate Precipitation Snowpack Air temperature Wind Evaporation Topography Geology Soils Upland vegetation Wildfire history and risk Planning / Building / Code Compliance / Environmental / Collaborative Planning Team (CPT) Local Agency Formation Commission (LAFCO) / Local Transportation Commission (LTC) / Regional Planning Advisory Committees (RPACs 3. Riparian areas and wetlands Meadows Wetlands Threats to riparian areas and wetlands Restoration efforts 4. Fish and wildlife Fisheries Exotic aquatic species Terrestrial wildlife 5. Land use and human history Human history Land use Residential Roads Grazing Recreation Airport Off-highway vehicle use Mining Forestry Land ownership and interagency cooperation 6. Descriptive hydrology Runoff generation processes Water balance Streamflow averages and extremes Floods and droughts Baseflow Lakes Groundwater Diversions and storage Water rights, use and management Residential and commercial supply Pasture and golf course irrigation Hydrologic effects of snow management Urban runoff and stormwater management Wastewater treatment and disposal 7. Descriptive geomorphology Channel networks Channel processes Surface erosion Hillslope processes Sediment transport Human influences 2 8. Description of water quality Categories Sediment Minerals Nutrients Metals Organics Toxics Temperature Dissolved oxygen Pathogens Measurements of surface water quality Measurements of groundwater quality Natural sources of constituents Human sources of constituents 9. Known and potential impacts of altered water quantity and quality Water availability for human uses Riparian habitat Aquatic habitat Wetlands Fish and other aquatic species Terrestrial wildlife Discussion of risk 10. Subwatersheds “Hartley Springs Creek” Glass Creek Deadman Creek Upper Owens River Dry Creek O’Harrel Canyon Creek Little Hot Creek Sherwin Creek Laurel Creek Mammoth Creek Hot Creek Convict Creek McGee Creek Hilton Creek Whiskey Creek Crooked Creek Rock Creek Crowley Lake 3 11. Evaluation of problems and issues Potential or suspected influences Water quantity Water quality Potential watershed problems Knowledge and information gaps Summary and simplifications 12. Literature cited INTRODUCTION WATERSHED APPROACH The natural unit for considering most water-related issues and problems is the watershed. A watershed can be defined simply as the land contributing water to a stream or river above some particular point. Natural processes and human activities in a watershed influence the quantity and quality of water that flows to the point of interest. Despite the obvious connections between watersheds and the streams that flow from them, many water problems have been looked at and dealt with in an isolated manner. Many water problems have been treated within the narrow confines of political jurisdictions, property boundaries, technical specialties, or small geographic areas. Many water pollution problems, flood hazards, or water supply issues have been examined only within a short portion of the stream or within the stream channel itself. What happens upstream or upslope has been commonly ignored. The so-called watershed approach attempts to look at the broad picture of an entire watershed and how processes and activities within that watershed affect the water that arrives at the defining point. The watershed approach is a convenient means of considering water problems in a comprehensive manner. This report describes how the 380-square mile watershed influences the quantity and quality of water that flows into the upper Owens River above the Crowley Lake dam. The study area has been called the Long Hydrologic Area (and Subarea) and is watershed #603.1 in the Calwater system of watershed delineation (http://www.ca.nrcs.usda.gov/features/calwater/ and http://cwp.resources.ca.gov). CALIFORNIA WATERSHED PROGRAMS and MONO COUNTY'S INVOLVEMENT Within California, the U.S. Environmental Protection Agency and the state Regional Water Quality Control Boards are the principal agencies charged with minimizing water pollution and maintaining or improving water quality. These entities have been largely successful at reducing water pollution that starts at a known point, such as a sewer outfall from a city or a waste pipe from a factory. As these so-called point sources have been brought under control, the agencies found that pollution from broader areas of land was still degrading water quality. Sediment from dirt roads and bare construction sites, pesticide runoff from farms, nutrients and bacteria from 4 livestock operations, chemicals and oil residues from urban streets are all examples of so-called non-point-source water pollution. The agencies concerned with limiting water pollution have adopted the watershed approach to studying and controlling non-point-source pollution. In 1997, the Governor's office directed state agencies that deal with natural resources (e.g., State Water Resources Control Board and Regional Water Quality Control Boards, Department of Fish and Game, Department of Conservation, and Department of Forestry and Fire Protection) to coordinate activities on a watershed basis. In March 2000, California voters passed Proposition 13, the Costa-Machado Water Act, which included substantial grant funding for local watershed management activities. In early 2001, Mono County in cooperation with the Mono County Collaborative Planning Team responded to a request for proposals from the State Water Resources Control Board by submitting two proposals to develop watershed assessments and plans. Both proposals were successful, and scopes of work were developed and eventually approved in 2004. Work began on these projects in January 2005. WHAT IS A WATERSHED ASSESSMENT? The California Watershed Assessment Manual (Shilling, et al., 2004) defines a watershed assessment as "a process for analyzing a watershed's current conditions and the likely causes of these conditions." This manual lists the usual components of a watershed assessment as: • a question or set of questions about watershed condition that puts boundaries on the assessment; • a collection of relevant information about human and natural processes at the watershed scale; • the identification of gaps in knowledge; • the combination of information about various processes to reflect the integrated nature of watersheds; • analysis and synthesis of the information regarding the watershed's condition drawn from data collections, often at various geographic scales; • a description of how the analysis can assist with decision making in the watershed; • a design for the collection of future monitoring data; and • a strategy to evaluate future data and communicate that information via a status-and- trends analysis. 5 The fundamental concept is to describe any known problems concerning water quantity and quality and attempt to connect those problems with conditions, processes, and activities within the watershed. Such linkages between problems and potential causes can provide the basis for subsequent planning and management that attempt to address the identified problems. PUBLICLY PERCEIVED PROBLEMS AND ISSUES The upper Owens River watershed (aka Crowley Lake watershed or Long Hydrologic unit) was classified as a Category 1 watershed and a priority during the California Unified Watershed Assessment under the Clean Water Action Plan in 1998. The Category 1 classification was described as "candidates for increased restoration activities due to impaired water quality or other impaired natural resource goals with emphasis on aquatic systems." The upper Owens River received the priority ranking with respect to high value, high risk, and high opportunity. WATER QUANTITY The primary water issue within the upper Owens River watershed is supplying water for the town of Mammoth Lakes without adversely affecting aquatic habitat in Mammoth Creek or water quantity and/or temperature at the Hot Creek hatchery springs. This water supply concern has been a persistent problem since the 1970s and becomes more acute with the town's growth. WATER QUALITY Many of the constituents of concern (such as phosphorus, arsenic, and mercury) in the area's water are naturally occurring products of the local geology. Although the presence of such substances may limit the use of the water, natural geochemical processes are not readily addressed by watershed management practices. Sediment has been increased above natural levels by some human activities within the watershed. Minimizing disturbance of riparian areas could significantly reduce sediment loading to the watershed's streams. Water temperatures in some stream reaches during summer are greater than what would occur with greater shading by riparian vegetation. AQUATIC HABITAT The condition of aquatic habitat in Mammoth Creek and Hot Creek has been a matter of public concern since the 1970s when the amount of water diverted from Mammoth Creek for