Surface Water Monitoring Program

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Ambient Monitoring for Pesticides In Washington State Surface Water


The Washington State Department of Agriculture (WSDA) has been conducting annual monitoring to evaluate pesticide concentrations in surface waters since 2003. Collecting data on the fate and transport of pesticides used in Washington State allows WSDA, the pesticide user community, U.S. EPA, NOAA Fisheries, U.S. Fish and Wildlife Service, and others to:

  • Develop effective mitigation strategies to minimize offsite movement
  • Identify opportunities for increased education and outreach to the user community
  • Recommend best management practices
  • Make informed management decisions that protect Endangered Species Act listed species (including salmon)
  • Refine exposure estimates and model assumptions that are routinely used to estimate risk in risk assessments
  • Support the continued uses of valuable pest management tools for agriculture
Field sampling is conducted at salmonid-bearing streams in selected watersheds from March through October by staff from the Natural Resources Assessment Section. Samples at site visits are analyzed for an extensive list of insecticides, herbicides, fungicides, breakdown products, and even some pesticides that have been used historically but are no longer registered. Data is also gathered for total suspended solids, pH, dissolved oxygen, conductivity, continuous streamflow, continuous air temperature, and continuous water temperature at all site visits.


Assessment of Herbicides in Surface Water in the Hoh River Watershed Report

Assessment of Herbicides in Surface Water in the Hoh River Watershed Report.

2017 Ambient Monitoring Fact Sheets


The surface water monitoring for pesticides online webmap displays the boundaries and locations for all of the monitoring sites from 2003 through 2017 and calendar style tables showing pesticide data from each site through 2016.

Surface Water Monitoring web map thumbnail and link


Surface Water Monitoring Program QAPP Addendum 7 [PDF 204 KB]

Surface Water Monitoring Program Initial QAPP [PDF 1654 KB]

Please visit the NRAS publications page to view additional supporting information.