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Project overview

Green River stormwater retrofit project area map - smallerThis project estimated the amount and cost of stormwater infrastructure that would be needed in the Duwamish River Watershed, or Water Resource Inventory Area (WRIA) 9, to improve stream flow and water quality to levels comparable to those found under fully forested conditions. The study accounted for existing stormwater infrastructure, anticipated population growth, and climate change impacts. Cost estimates for constructing stormwater retrofits throughout the Puget Sound basin were also derived via extrapolation of results. The project was funded by a grant from the USEPA, with match from King County, University of Washington, and the cities of Auburn, Covington, and Seatac. For more information, review the detailed work plan (Acrobat PDF).

Project documents

Documents are provided in Adobe Acrobat format.

Project management documents

Project Management Team Meeting, June 5, 2014

Project Management Team Meeting, January 16, 2014

Project Management Team Meeting, Dec. 4, 2013

Project Management Team Meeting, Sep. 19, 2013

Project Management Team Meeting, June 5, 2013

Project Management Team Meeting, March 6, 2013

Project Management Team Meeting, Dec. 13, 2012

Project Management Team Meeting, Sept. 13, 2012

Project Management Team Meeting, June 5, 2012

Project Management Team Meeting, March 22, 2012

Meeting minutes, WRIA 9 Retrofit Project Management Team, December 8, 2011 (254 Kb)

Project Management Team meeting summary, May 19, 2011 (252 Kb)

Project documents

Salish Sea Conference, May 2014

Workshop documents

Stakeholder Workshop #4, February 27, 2014

Stakeholder Workshop #3, April 25, 2013

Workshop presentations, January 26, 2012

Project workshop summary, April, 2011 (391 Kb)

Project workshop attendees, April 2011 (59 Kb)

Technical documents

Wright Masters Thesis Modeling Hydrologic Response of Urban Watersheds to Restoration (external link)

Existing Flow Control Facilities in WRIA 9 (298 KB)

Climate Change Impacts on Stormwater Management (1.1 MB)

Population Growth, New and Re-development, and Stormwater Management by 2040 (4.4 MB)

Final SUSTAIN Stormwater Infrastructure Modeling Report (2.6 MB)

WRIA 9 Stormwater Retrofit Plan Needs and Cost Assessment and Project Summary Report (2.5 MB)

Final SUSTAIN Model Pilot Study (5.5 Mb)

Final Flow and Water Quality Indicators and Targets (593 Kb)

Watershed Model Development for Water Resource Inventory Area (WRIA) 9 Stormwater Retrofit Planning Project (7.8 Mb)
August 2013

Data Report for Field Data Collection for the Development of a Stormwater Retrofit Plan for Water Resources Inventory Area (WRIA) 9 (19 Mb)

Amended Existing Data Review For the Development of a Stormwater Retrofit Plan for Water Resource Inventory Area (WRIA) 9: Historical Flow, Total Suspended Solids, and Turbidity Data, December 2011 (12.4 Mb)

Status Report, Development of Flow and Water Quality Targets, January 5, 2012 (283 Kb)

Hydrologic Indicators (511 Kb)
Rankings, illustrative graphs and definitions of candidate hydrologic criteria.

Project data collection map (3.5 Mb)
Existing and proposed gage locations within the project area.

SUSTAIN - System for Urban Stormwater Treatment and Analysis INtegration (2.1 Mb)
Descriptive illustration for an ArcGIS-based modeling application designed to help select and strategically place Best Management Practices (BMPs) and Low Impact Development (LID) techniques in urban watersheds.

Water quality indicators (2.4 Mb)
Land use and cover map, graphs and summary of water quality indicators in the project area.

HSPF watershed modeling (2.8 Mb)
Visual description of hydrologic model inputs and products.

Development of Flow and Water Quality Indicators (187 Kb)
April, 2011 status report by Dr. Richard Horner, University of Washington.

Quality Assurance Project Plan (QAPP) for Field Data Collection for the Development of a Stormwater Retrofit Plan for Water Resource Inventory Area (WRIA) 9 (956 Kb)
This plan describes the activities associated with field data collection for developing a Stormwater Retrofit Plan for Water Resource Inventory Area (WRIA) # 9 in King County, Washington. It describes the strategy and methods the project will use to ensure that the project is being managed, developed, and deployed in a sound, reasonable way; and that the project's deliverables are of acceptable quality before they are delivered to the project's clients.

Grant documents

Partner agencies, study area map, objectives and schedule (4.5 Mb)Poster summarizes the who, what, where and why for the Stormwater Retrofit Planning Project for WRIA 9 (Green River).

Project overview (36 Kb)
The steps planned for this project.

Project Work Plan for developing the Stormwater Retrofit Plan for Water Resource Inventory Area (WRIA) 9 (141 Kb)
This plan outlines the project’s purpose; existing conditions; and summary of tasks, participants, components, budget, schedule, location, including approach, anticipated outcomes, deliverables, and products.

For more information about the Stormwater Retrofit Project, please contact Jim Simmonds, Project Manager, Science and Technical Support Section.