Water resources & erosion control research & reports

We protect and improve water quality by conducting and funding research and complying with permits. Find information on our stormwater research efforts as well as compliance activities required by the Washington State Department of Transportation (WSDOT) Municipal Stormwater Permit and the Construction Stormwater General Permit on this page.


Stormwater Research

Stormwater research projects help identify state-of-the-art, cost effective solutions for designing, constructing, and maintaining stormwater management systems. Visit our Research Reports webpage to find information on past research. We are currently working on two stormwater research projects:

  • Steep Slope Ksat Study - quantify runoff volume loss over roadway embankments as stormwater flows down the slope.
  • CAVFS vs Compost Blanket over a VFS application for BMP runoff treatment effectiveness.

To comply with our Municipal Stormwater Permit, WSDOT also contributes funds to Stormwater Action Monitoring (SAM) for research related to the status and trends of water quality in receiving water bodies.


Municipal Stormwater Permit Reports

Annual Stormwater Report

Read the 2020 Annual Stormwater Report (pdf 1.81 mb) to get an update on WSDOT’s compliance with its municipal stormwater permit from July 1, 2019 to June 30, 2020, our reporting period. This document serves as the annual report required by the WSDOT Municipal Stormwater Permit. Read the 2019 Annual Stormwater Report (pdf 1.56 mb) to get an update on WSDOT's compliance during the previous reporting period.

To request copies of Annual Stormwater Reports from previous years, contact Garrett Starks, Garrett.Starks@wsdot.wa.gov.

Annual Stormwater Monitoring Reports

In 2020, WSDOT submitted two Final Monitoring Reports.

  • The Embankment Hydrology Monitoring Final Report (pdf 1.59 mb) summarizes monitoring activities completed at embankment hydrology monitoring sites from October 1, 2017, through September 30, 2019 (water years 2018-19). 
  • The Compost-Amended Bioswale Monitoring Final Report (pdf 1.46 mb) summarizes WSDOT's study of compost-amended biofiltration swales (CABS) for treatment of stormwater runoff at one eastern Washington and two western Washington maintenance facilities.

In 2019, WSDOT submitted two Monitoring Status Reports.

  • The Embankment Hydrology Monitoring Status Report (pdf 2.18 mb) is an update on WSDOT's status of collecting hydrologic data from roadside embankments to assess infiltration levels, which will help validate our Ksat method for estimating saturated hydraulic conductivity and improve BMP effectiveness.
  • The Compost-Amended Bioswale Monitoring Status Report (pdf 1.75 mb) is an update on WSDOT's status of evaluating compost-amended biofiltration swales (CABS) for treatment of stormwater runoff at one eastern Washington and two western Washington maintenance facilities.

To request copies of Annual Stormwater Monitoring Reports from previous years, contact Brad Archbold, Brad.Archbold@wsdot.wa.gov.

Total Maximum Daily Load (TMDL) Programmatic Implementation Summary Reports

Read these reports to learn about highway discharge locations and potential pollutant sources within each TMDL, as well as how we followed up to address potential pollutant sources identified. To request copies of these reports, contact Elsa Pond, Elsa.Pond@wsdot.wa.gov. Reports are available for the following TMDLs:

  • Bear-Evans Creek
  • Green River
  • Hangman Creek
  • Issaquah Creek Basin
  • Little Bear Creek
  • Newaukum Creek
  • Oakland Bay
  • Palouse River
  • Puyallup River
  • Salmon Creek
  • Snoqualmie River
  • South Fork Palouse
  • Swamp Creek Basin
  • Stillaguamish River
  • Totten/Eld and Skookum Inlets Tributaries
  • Upper Naches River and Cowiche Creek
  • Whatcom Creek Watershed


Construction Stormwater Permit Reports

Monthly Discharge Monitoring Reports (DMRs) – Use Ecology’s Permit and Reporting Information System (PARIS) to find submitted discharge monitoring reports.