Publication Summary

The Washington State Department of Ecology conducted a two-year wet season fecal coliform study of the Black River in Thurston and Grays Harbor Counties during the winters of 1991-92 and 1992-93. The intent of the study was to establish a nonpoint source loading capacity for fecal coliform bacteria, recommend load allocations for control of sources throughout the basin, and identify specific problem areas for follow-up action or study. Three of the major tributaries (Waddell, Beaver, and Mima Creeks) were sampled to determine inputs from subdrainages.

The Washington State Department of Ecology conducted a two-year wet season fecal coliform study of the Black River in Thurston and Grays Harbor Counties during the winters of 1991-92 and 1992-93. The intent of the study was to establish a nonpoint source loading capacity for fecal coliform bacteria, recommend load allocations for control of sources throughout the basin, and identify specific problem areas for follow-up action or study. Three of the major tributaries (Waddell, Beaver, and Mima Creeks) were sampled to determine inputs from subdrainages.

Study findings indicated nine of the 11 mainstem sites violated at least one of the two water quality criteria for fecal coliform. A mass balance model was developed in order to evaluate critical condition loads and estimate pollutant reductions needed to achieve compliance with the fecal coliform standard. Seven of the 10 mainstem Black River segments established in this survey will require load reductions to meet proposed bacteria load allocations. Beaver Creek had the highest fecal coliform counts in the basin, with water quality standards being exceeded throughout both years. Recommendations are included to pursue corrective actions for control of nonpoint source problem areas.

Link to EIM data for User Study ID RCOO0001