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cyanobacteria, water quality, Moses Lake, algae


Moses Lake is a shallow, hypereutrophic lake in Grant County, Washington (Carroll and Cusimano, 2001), with a surface area of 6,800 acres (27.5 km2 ), total volume of 130,000 acre-ft (160.4 × 106 m3), average depth of 19 ft. (5.8 m), and maximum depth of 38 ft. (11.6 m; Dion, et al., 1976). The lake is situated adjacent to the city of Moses Lake and drains into Crab Creek, a tributary of Columbia River. The lake is a popular recreational destination for fishing, boating, swimming, and camping.

Moses Lake develops nuisance blooms of cyanobacteria during the summer and fall. The blooms often form unsightly mats that decompose on the shores creating unpleasant odors, and can be a public health threat if toxin-forming species are abundant. During the summer of 2017, the Institute for Watershed Studies (IWS) was contracted to provide information about the relative densities of cyanobacteria and other algae in Moses Lake. This report includes a summary of the IWS analysis methods, tables containing the algal counts, and and appendix containing digital images of the algal taxa identified during this project.




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