Publication Summary

Stream conditions and potential or existing uses were surveyed both above and below the College Place Wastewater Treatment Plant on Garrison Creek in south-eastern Washington. Observations of existing beneficial uses of Garrison Creek, including human, aquatic life, and wildlife uses, were made using water column, sediment, biological, and aquatic habitat surveys during the period of September 16-19, 1996. Anecdotal information on existing and potential uses for other seasons and in other reaches of Garrison Creek, as well as historic uses, was collected by using a survey questionnaire which was sent to individuals knowledgeable about the creek and water uses.

Stream conditions and potential or existing uses were surveyed both above and below the College Place Wastewater Treatment Plant on Garrison Creek in south-eastern Washington. Observations of existing beneficial uses of Garrison Creek, including human, aquatic life, and wildlife uses, were made using water column, sediment, biological, and aquatic habitat surveys during the period of September 16-19, 1996. Anecdotal information on existing and potential uses for other seasons and in other reaches of Garrison Creek, as well as historic uses, was collected by using a survey questionnaire which was sent to individuals knowledgeable about the creek and water uses.

An intensive field survey sampled water column characteristics and sediment characteristics for insecticides, herbicides, metals, nutrients, temperature, coliform bacteria and other chemical parameters with both grab samples and continuous in-situ instrumentation. The biological community, both fish and benthic invertebrates, were quantitatively assessed to estimate densities and species compositions within Garrison Creek. Tissue samples from fish were also obtained to analyze the deposition of pesticides and herbicides.

Results indicated that most beneficial uses within Garrison Creek, a Class A waterbody, were either non-supported or partially supported, based on the Washington State Water Quality Standards. Biological communities were extremely depressed below the WWTP and several water quality parameters including nutrients and ammonia were highly elevated. However, throughout the creek, temperature and fecal coliform bacteria were found at very high levels and did not meet state standards.