Publication Summary

This is the supplemental study plan for the Walla Walla River Basin Fecal Coliform Bacteria and pH Total Maximum Daily Load.

The Touchet River has been listed by Washington State under Section 303(d) of the federal Clean Water Act for non-attainment of Washington State fecal coliform bacteria and pH criteria. The U.S. Environmental Protection Agency requires the states to set priorities for cleaning up 303(d) listed waters and to establish a Total Maximum Daily Load (TMDL) water cleanup plan for each. The Touchet River was included in the Walla Walla River TMDL that was conducted in 2002. As a result, additional monitoring for the Touchet River has been recommended (Joy and Swanson, 2005; Joy et al, 2007).

This Supplemental Quality Assurance Project Plan describes additional monitoring that will address:

--Possible inconsistencies in the effectiveness of the Dayton Wastewater Treatment Plant ultraviolet (UV) disinfection levels.

--Possible groundwater nutrient transport from the wastewater lagoon at the Waitsburg Wastewater Treatment Plant to the Touchet River.

--Validation of nutrient levels in the Touchet River upstream and through the city of Dayton.

The study will be conducted by the Washington State Department of Ecology′s Environmental Assessment Program.

Link to EIM data for User Study ID SCTA0001