Publication Summary

The purpose of this Willapa River temperature TMDL is to characterize the water temperature in the basin and to establish load and wasteload allocations for the heat sources to meet water quality standards for surface water temperature. Studies to evaluate 303(d) listings for dissolved oxygen and fecal coliform were initiated in the Willapa River watershed in 1998. Water temperature is the only remaining 303(d) listed water quality parameter in the study area and will be addressed during this study.

This document is a Quality Assurance Project Plan for the following study:

The Willapa River drains into Willapa Bay, located in Pacific County in southwestern Washington State. Ecology′s assessment of the Willapa River watershed identified the system as a high priority for development of a temperature Total Maximum Daily Load (TMDL).

The purpose of this Willapa River temperature TMDL is to characterize the water temperature in the basin and to establish load and wasteload allocations for the heat sources to meet water quality standards for surface water temperature. Studies to evaluate 303(d) listings for dissolved oxygen and fecal coliform were initiated in the Willapa River watershed in 1998. Water temperature is the only remaining 303(d) listed water quality parameter in the study area and will be addressed during this study.

The study area has two segments that are listed for not meeting water quality criteria for temperature. Temperature problems in the basin are likely not limited to the two segments reported on the 303(d) list; therefore, this study concentrates not only on the temperature concerns of the listed segments but those in the entire study area as well. Pickett (2000) and Weyerhaeuser (1994) documented temperatures in excess of 18?C in additional segments throughout the basin.

Link to EIM data for User Study ID ASTO0004