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Stormwater Action Monitoring — source identification

SAM's source control studies are focused on learning which actions by permittees and businesses in Western Washington are key to preventing illicit discharges. We are also gaining a better understanding of how to detect sources of pollution to stormwater. 
Source identification logo with a water outfall pipe

What are we learning?

Stormwater Action Monitoring (SAM) completed one source identification study during the 2013-2018 permit cycle and three more projects are under contract development. SAM source identification projects results can be used across jurisdictions. 

Completed SAM source identification studies

Illicit discharge detection and elimination (IDDE) incidents are recorded by Western Washington municipal stormwater permittees in many formats.  The first SAM source identification project compiled the IDDE incidents reported to Ecology from 2014 into a dataset of almost 3,000 incidents. This represents a first step in capturing the breadth and scale of incident investigation work.

Key findings

  • A wide variety of methods are used by permittees to report IDDE efforts to Ecology, requiring a significant effort to compile and learn about local efforts, resource needs, and common solutions. Standardization of reporting is recommended; for example, by spreadsheet.
  • Municipal stormwater staff invest a substantial amount of time investigating and addressing potential incidents. Response is quick, usually within 1-3 days.
  • The most common stormwater problems were:
    • Petroleum hydrocarbons and other vehicle fluids – often from accidents
    • Sediment from construction sites
    • Chemicals from industrial activities
    • Sewage from illicit connections
  • Most incidents were reported to local governments via hotlines or citizen calls. A significant number of incidents investigated were not illicit discharges, but allowable discharges. Permittees will continue to spend time and effort on such calls.
In 2016-17 the Stormwater Work Group's Source Identification Subgroup revised for consideration by Ecology's permit managers, the illicit discharge detection and elimination (IDDE) tracking form.  This revision should help standardize data collection for the next permit cycle.

Upcoming source identification projects

The following study proposals are undergoing contracting with Ecology and the final Scopes of Work will be posted here once contracted.  Also, once we finish contracting, more information about each individual project will be available.