You are here:
LAPWAI CREEK STUDY, LEWIS AND NEZ PERCE COUNTIES, IDAHO. 1979
Description:
During Water Year 1979, a water quality study was conducted on the Lapwai Creek in Nez Perce and Lewis Counties, Idaho (17060306) to obtain background information on nonpoint source pollution impacts and for effluent limitation development. The study involved approximately bi-monthly monitoring at 4 mainstem stations from the outlet of Winchester Lake to the USGS gaging station 2 miles above the mouth. The parameters covered in the study include temperature, dissolved oxygen, pH, bacteria, oxygen demand, solids, select ions, nutrients, and trace inorganic toxins. Water quality of Lapwai Creek is marginal with frequent bacteria violations, seasonal elevated turbidity and suspended sediment, and consistent trophic nutrient concentrations. Iron and manganese concentrations also exceeded recommended instream criteria during periods of high turbidity and suspended solids. The analysis indicates that the City of Lapwai should reduce or eliminate any domestic wastewater discharge when stream flows are less than 50 times their discharge. Lapwai Creek drainage has been identified as a first priority area in the Idaho Agricultural Pollution Abatement Plan. The major improvement in stream water quality will come from the application of Best Management Practices on agricultural nonpoint sources. Water Quality Summary No. 5. 1980. Department of Health and Welfare, Division of Environment, Boise, ID.