Beginning in 2011, funds from King County’s Surface Water Management (SWM) fees have been used to conduct routine water quality monitoring in portions of the County that are included in the Snohomish River drainage, or Water Resources Inventory Area 7 (WRIA 7). Objectives of this program are focused on quantifying long-term water quality trends that might help inform the management of stormwater, salmon recovery efforts, land use regulation, and an increasingly variable climate. This effort expands on the existing ongoing King County Routine Streams Monitoring Program that has historically been centered in WRIAs 8 (Greater Lake Washington) and 9 (Green River/Vashon). The newly established WRIA 7 Routine Streams Monitoring program consists of twelve sampling sites that are distributed throughout the watershed on tributary streams and mainstem rivers that drain a variety of land covers. This report presents results from the first three years of this ongoing monitoring effort in WRIA 7.

The first three years of monitoring data collected through this program (2011-2013) suggest that water quality conditions in WRIA 7 are currently mostly of low concern, although a few subbasins are of moderate concern. Water quality in these subbasins appears to be challenged primarily by temperature, fecal coliform bacteria, dissolved oxygen, and nutrients. Specifically, 6 of the 12 sampling locations drain systems that consistently exhibit good water quality and are considered to be of "low concern" according to WQI criteria. These stations include Cherry Creek, Griffin Creek, Harris Creek, the Snoqualmie River at Duvall, Tolt River, and the Skykomish River. Four of the sites have WQI scores that straddle the threshold between "low concern" and "moderate concern." These locations are the Middle Fork Snoqualmie River, North Fork Snoqualmie River, the Raging River, and the South Fork Snoqualmie River. Finally, two of the sites drain watersheds that so far, have exhibited consistent water quality problems and are considered to be of "moderate concern" according to their WQI scores. These include Ames Creek and Patterson Creek, which both have repeated high temperatures, low DO, and high bacteria concentrations.