Road Services - Stormwater Best Management Practices (BMP) sites

Project overview: We were trying to find effective, cost-efficient ways to treat stormwater in roadside ditches. This study was conducted to test an in-line ditch BMP that, if effective, could potentially be widely used by jurisdictions trying to minimize the impacts of stormwater runoff on surface water bodies and groundwater aquifers. This 2008-2011 study was made possible, in part, through funding from the Washington State Department of Ecology.

Timing: 2011 Water Year beginning October 2010 and ending October 2011.

Location: Southwest shoulder of S.E. Petrovitsky Road between house #17201 and #17235 and near S.E. 192nd Drive.

Drainage basin: Low density rural residential properties (zoned RA-5) and City of Seattle’s Lake Youngs Watershed on the southwest side of S.E. Petrovitsky Road; collects runoff from adjacent properties and the paved roadway; the ditch flow drains southeast to Shady Lake.

Traffic: Relatively high [average daily traffic volume (ADTV) of approximately 17,000 vehicles].

BMP type: Water quality.

BMP description: Compost filter socks secured inside of a modified rock check dam (treatment cell). Coarse compost met Washington State Department of Transportation (WSDOT) specification for use in stormwater treatment projects. Six water quality treatment BMPs were installed in a section of ditch approximately 300 feet in length. See the BMP engineering design for more information.

Monitoring and equipment: Learn about the monitoring practices and equipment used at the project sites.

Project photos:

Looking northwest at the upstream monitoring station at Project 192. (Enlarged view, 63KB .jpg)

Looking southeast from above the downstream monitoring station at Project 192. (Enlarged view, 67KB .jpg)

Have questions?

For more information about this project, please contact:

Information from the Road Services Division's website is available to people with disabilities in alternate formats upon request by calling 206-263-6482 or 711 for the TTY relay service.

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