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USGS Washington Water Science Center
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WA261 - Classification of Washington Lakes with Reconnaissance Data - Completed FY1983
Problem - Washington has more than 7,800 lakes, ponds, and reservoirs, many of which provide exceptional recreational benefits to both residents and visitors, and which supply water for agricultural, industrial, and municipal purposes. As more demands are placed on these lakes, their basins, or their shorelines, problems of nutrient enrichment and/or water-quality deterioration become more likely. Previous cooperative studies by the U.S. Geological Survey (USGS) and State Department of Ecology have resulted in the collection of physical, chemical, and biological data from about 775 lakes statewide.
Objectives - To provide basic data on the physical, cultural, and water-quality characteristics of an additional 55 lakes statewide; classify the trophic level of these lakes; re-sample 75 lakes previously studied that have had major land-use changes within their drainage basins to determine if the land-use changes have caused water-quality changes; and classify, according to trophic level, those lakes for which adequate data exist, utilizing the techniques of Bortleson (1978) and Carlson (1977).
Approach - Lakes not previously studied will be selected based on size, proximity to urban areas, and degree of public use. Priority will be given to lakes close to urban areas. Bathymetric maps will be prepared and area, volume, maximum depth, mean depth, shoreline length, shoreline configuration, development of volume, and bottom slope will be calculated. Lakes previously studied will be selected by contacting regional planners regarding recent lake-use changes and by comparing pre-development phosphorus concentrations to concentrations as measured in recent studies. Water-quality and biological sampling will be conducted by float-equipped helicopter. The data collected will be used to classify the lakes using a method developed by Bortleson in a previous investigation (WRI 77-94).
WA136 - Hydrology of Lakes - Completed FY1978
Problem - Despite the widely recognized importance of lakes as an economic and aesthetic resource, the basic understanding of eutrophication and how lakes function in the hydrologic system is meager. As the State's growth and population increase, there are ever-increasing demands placed on the lake environment, creating inevitable hydrologic and water-quality problems. In order to detect any present or anticipated impairment it is important that existing conditions in Washington's lakes be investigated and defined.
Objectives - The purpose of this study is to obtain and analyze physical, chemical, and biological data on the lakes of Washington. The information gained on lake systems will serve as a basis for water management decisions and studies of future problems, help delineate current or developing water problems, and assist in selecting lake-restoration techniques.
Approach - About 20 to 25 lakes are selected each year for determination of profiles of water temperature, dissolved oxygen and specific conductance. Also secchi disc depths, water-quality samples, lake-water levels and lake inflows and outflows are measured on selected lakes; phytoplankton samples are collected and analyzed for total biomass and plant pigments, along with identification of dominant algal genera. In addition, measurements of macrophyte growth are made, land use and lake origin are investigated, and 73 morphometric parameters are measured from bathymetric maps of each lake.
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