Glossary of terms

Zimmer, David W.; 1983 (August); Phosphorus Loading and Bacterial Contamination of Cascade Reservoir, Boise Project, Idaho; Boise Project Power and Modification Study; USDOI, Bureau of Reclamation, Pacific Northwest Region, Boise, Idaho; 143p.

Study of the water quality of Cascade Reservoir as related to phosphorus loading and bacterial contamination to define existing and potential problems as described in previous studies by the BOR (Bureau of Reclamation; 1975; Payette River Basil) Water Quality Study, Part 2, Cascade Reservoir Area; USDOI, Bureau of ReclaniatiOl 7, Pacific Northwest Region, Boise, Idaho), and Idaho Department of Health and Welfare (Clark, William H.; Wroten, Jon W.; 1975; Water Quality Status Report: Cascade Reservoir, Valley County, Idaho; Water Quality Series No. -70; Idaho Department of Health and Welfare, Division of Environmel7t, Boise, Idaho; 46p -appendix). Recommends action by regulatory agencies which may avoid or alleviate the identified problems. Specific objectives include the compilation of an annual phosphorus budget, determination of bacterial contamination in the reservoir and adjacent shallow -round water, and examination of strategies for limiting nutrient and bacterial contamination of the reservoir. Annual phosphorus budget (as total phosphorus) was determined to be 27,83 5 kg for water year 198 1. Bacterial contamination of the reservoir was found to exceed standards in the Lake Fork and Gold Fork arms, and near Sugar Loaf Island, probably due to inadequately treated sewage from recreational homesites and livestock grazing along the shoreline. Bacterial contamination of ground water was identified in all but one shallow ground water sample, most probably resulting from the sources listed above, in areas where the water table is within a few feet of the ground surface. Findings/conclusions show 87% of the total phosphorus load for 1981 was from non-point sources (>50% from agricultural and grazing lands), point source loading (McCall Treatment' Ponds) accounts for an additional 6%, and precipitation deposition accounts for 7%. Annual phosphorus loading for 1981 was calculated to be only 69% of the "average year" phosphorus load estimated by the EPA (Environmental Protection Agency; 1977; Report oil Cascade Reservoir, Valley County, Idaho, EPA Region X; Working Paper No. 777; National Eutrophication Survey, National Environmental Research Center, Corvallis, Oregon). A recommendation is made for a prevention of further increase in phosphorus loading rather than a reduction in the (then) current rates of deposition.