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Stormwater Action Monitoring - Effectiveness studies

SAM's effectiveness studies measure the stormwater management actions in Western Washington and communicate useful findings on what works and what doesn't work.

Topics for studies are determined by the Stormwater Work Group.

Topics for the 2013-2018 permit cycle are:

  • Low Impact Development (LIDs)
  • Retrofits
  • Source control
  • Operation and maintenance
  • Public education/behavior change
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What are we learning?

Stormwater Action Monitoring (SAM) has eleven effectiveness studies under contract so far during the 2013-2018 permit cycle. SAM effectiveness projects can occur at site or regional scales and the results can be used across jurisdictions. The first SAM Findings Symposium was June 1, 2017. 

Completed SAM effectiveness studies list

Business Inspection Stormwater Source Control Effectiveness Study
Coho Toxicity Prevention by Bioretention

What projects are underway?

The following studies are active and more information is available on the linked webpages. Five active SAM studies focus on hydrologic and treatment performance of Low Impact Development (LID) best management practices (BMPs). 

What is the process for new projects to get started?

SWG defines the process for SAM to solicit more studies. A second solicitation round began in May 2016, and the top 10 study proposals were voted on by permittees following an April 2017 workshop. 

SWG recommendations in June 2017 were to fund five of the new effectiveness studies, and continue to revise the scope of work on two remaining studies. As these studies are contracted, they will appear on this website.

Permit option 2 & 3 effectiveness monitoring 

Option 2

The City of Tacoma opted out of the pooled-fund SAM program, requiring a large study for stormwater management in their jurisdiction. The City of Tacoma will continue outfall monitoring in the Thea Foss and Wheeler-Osgood Waterways.

Option 3

The City of Seattle and Clark County opted to partially contribute to the pooled-fund SAM effectiveness studies and conduct their own study.

  • Seattle Public Utilities is conducting a street sweeping effectiveness study to quantify the direct effects of street sweeping on stormwater quality using a before/after-control/impact (BACI) study design. QAPP coming soon!

  • Clark County plans to continue monitoring the effectiveness of permeable pavement and maintenance impacts to the BMPs performance.