The Ambient Water Quality Monitoring Program
Chemical and Physical Water Quality Monitoring
Beginning in 1994, the County started routine monthly sampling of surface waters, in conformance with an approved quality assurance project plan to identify trends in temperature, dissolved oxygen, conductivity, pH, turbidity, total suspended solids, total phosphorus, total nitrogen, fecal coliform bacteria, copper, lead and zinc. Results of data gathered from 1994 – 2000 are summarized in the 2000 State of Water Report.
From 2000-2009 monitoring remained largely unchanged, with the exception of rotating sampling stations to address data gaps. Trends analysis was conducted on Snohomish County, Stillaguamish Tribe and Washington State Department of Ecology data for Stillaguamish basin sites data ranging from 1994-2006. Results are found in section 2.3.2 of the State of the Stilly Report.
All Snohomish County sampling locations and monthly monitoring data from 1994 - 2009 may be viewed or downloaded through the Surface Water Online Database.
In 2007, the Washington State Department of Ecology issued Snohomish County a Phase I Municipal Stormwater Permit for Western Washington. The permit requires the County to takes actions which reduce discharges of pollutants to the storm drainage system.
Actions, required by Appendix 2 of the permit, include implementation of a water quality monitoring program to address surface waters determined by Ecology to be polluted beyond state standards for fecal coliform bacteria. Resources needed to implement a fecal coliform bacteria trends and source identification monitoring program led the County to design a monitoring program focused on bacteria. The fecal coliform trends and source identification monitoring program, which began January, 2010 is designed to:
asssess whether or not affected water bodies and/or stormwater discharges are meeting state water quality standards for fecal coliform bacteria,
reasonably characterize the receiving waters or waste stream,
estimate changes in bacterial levels in Swamp Creek as a result of stormwater inputs through receiving water monitoring coupled with flow duration or comparable analysis, and
identify sources of bacterial pollution.
The Quality Assurance Project Plan which describes the monitoring program can be downloaded here:
Snohomish County Surface Water Fecal Coliform Bacteria Trends and Source Identification Monitoring Program
Appendix A. NPDES Permit Identified TMDL Coverage Areas
All water quality data gathered under the fecal coliform trends and source identification monitoring program is being loaded to the Washington State Department of Ecology EIM Database. You will find a program description and data through the study name Snohomish County Surface Water Management Fecal Coliform Bacteria TMDL Monitoring. Long term water quality data from 1994-2009 is not loaded to the Department of Ecology database, but can still be found at Surface Water Online Database.