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Thornton Creek Watershed Reports

Thornton Creek Watershed Characterization Report

The Thornton Creek Watershed Characterization Report, completed in 2000, contains background information on the watershed, historical accounts, maps and scientific data. This report was the most comprehensive effort at its time to document the character of the Thornton Creek Watershed and provided the foundation for the Thornton Creek Watershed Action Plan (see the State of the Waters Report  volume 1 (pdf) for information dated through 2007). This report was prepared by the Thornton Creek Watershed Management Committee, in collaboration with Seattle Public Utilities and funded by a Washington state Department of Ecology loan.

Thornton Creek Watershed Action Agenda

The Thornton Creek Watershed Action Agenda is a draft 2001 plan that includes actions to restore the Thornton Creek ecosystem for the welfare of fish, wildlife and people, improve the quality of life in the watershed, and prevent further degradation of Thornton creek watershed as population and development increases. The Action Agenda was developed by the Thornton Creek Watershed Management Committee, consisting of a group of citizens from the Thornton Creek Watershed and local agency representatives from Seattle and Shoreline. It was funded with a loan from the Washington State Department of Ecology.

Action Agendas

Draft Action Plan

Microbial Trace Study

Fecal coliform bacteria concentrations in Thornton Creek and at Matthews Beach (Lake Washington) exceed the state water quality standard and pose a potential threat to public health.

Investigation of Bacteria Sources in the Thornton Creek Watershed Seattle, Washington (pdf) - June 2013, confirmed that high counts of E.coli bacteria are entering North Seattle’s Thornton Creek and that there is a human component to these bacteria. This study identifies localized areas that appear to have higher amounts of bacteria entering the stream. SPU stormwater investigators are continuing to locate sources of bacteria entering the creek, and will be using the study results to direct their summer 2013 source tracing work.

In 2005, Seattle Public Utilities hired Herrera Environmental Consultants to conduct a microbial source tracking (MST) study (pdf) to determine potential sources of the bacteria in Thornton Creek and at Matthews Beach, and to evaluate the relative contribution of Thornton Creek to the contamination observed at Matthews Beach.