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[Portal ID #1962]

Department of Ecology
Committees, Boards, and Workgroups

Structural Stormwater Controls Stakeholder Process

The Phase I Municipal Stormwater Permit includes a program requirement for Structural Stormwater Controls (SSC), which requires Permittees to prevent or reduce impacts to waters of the state caused by discharges from the MS4s. The SSC program is intended to address impacts not adequately controlled by other required actions of the permit. The permit describes 11 eligible project types that can be implemented to meet the SSC program requirement. Information on the SSC requirement and project types is in Appendix 12 of the Phase I permit. For the first time, the 2019-2024 Phase I permit requires permittees to meet a minimum level of effort in implementing their SSC programs. This permit requirement is an issue in the recent appeal of the Phase I and II permits.


We are taking a stepwise approach to the stakeholder process to inform the SSC program requirement for the 2024-2029 permit. We will begin by conducting a review of available scientific information about the relative environmental benefits of SSC project types. When the permit appeal process is complete, Ecology will convene a stakeholder group to take up the policy issues around this requirement. The stakeholder group will use the scientific information to review the structure and method for measuring the level of effort by permittees implementing SSC programs. We are confident this process can be completed in time to inform the 2024 permit requirements.  You can read a more detailed scope of work here

Contact Emma Trewhitt at emma.trewhitt@ecy.wa.gov with any questions.

Upcoming Events

TAC Meeting #3- TBD, Early 2021

Past Events

TAC Meeting #2- 

TAC Meeting #1- 5/19/2020

Agenda and meeting minutes

Stormwater Work Group- Effectiveness Subgroup Meeting 12/9

The effectiveness study subgroup is open to all Phase I Permittees that are interested in participating (as well as other stakeholders). This group designed the research questions and determined the RFP process and oversaw project selection.

Agenda for the 12/9/2019 Meeting 



 File NameFile SizeDescriptionCategoryDate Added
Nov 21 SSC webinar.notes.pptx 3.6 MB Introduction to the SSC Process
Introduction to the SSC Process
Presentations 11/25/19 10:06 AM

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