Publication Summary

This is the study plan for the Skagit-Samish Watershed Intensive Surface Water Sampling for Pesticides in Salmonid-Bearing Streams.

The Washington State Department of Ecology (Ecology) has conducted a surface water monitoring program for pesticides in salmonid habitat since 2003. This program has included weekly monitoring at 16 sites in five index watersheds statewide: Thornton Creek, Longfellow Creek, Lower Yakima River, Wenatchee River, and Entiat River.

In 2008, the National Oceanic and Atmospheric Administration National Marine Fisheries Service (NOAA-Fisheries) released a biological opinion for three organophosphate pesticides: chlorpyrifos, diazinon, and malathion. The biological opinion recommended seven consecutive days of monitoring in at least three seven-day events during the typical pesticide application season. In Washington, this usually occurs from March through September.

The current 2009 study will incorporate daily monitoring during a seven-day period into the weekly monitoring program to evaluate comparability of the results generated from these sampling frequencies. Sampling will be conducted at four sites in the Skagit River delta which is an important salmonid-rearing area in Puget Sound. In addition to conventional water sampling on a weekly and daily basis, a new continuous sampling technique will be evaluated using Continuous Low-Level Aquatic Monitor (CLAM) devices.

Understanding short-term variability of pesticides in surface waters will assist the Washington State Department of Agriculture, U.S. Environmental Protection Agency, and NOAA-Fisheries in evaluating pesticide risks to salmonids.

Each study conducted by Ecology must have an approved Quality Assurance Project Plan. The plan describes the objectives of the study and the procedures to be followed to achieve those objectives. After completion of the study, a final report describing the study results will be posted to the Internet.

Link to EIM data for User Study ID DSAR0005