Department of Ecology News Release - March 8, 2021

Public input sought on environmental review for new Duwamish–Green river watershed plan

The Green River, which runs through Kanaskat-Palmer State Park, originates in the Cascade Range and becomes the Duwamish River near Tukwila.

Credit: Kayla Magers, CELP.


A new plan for the Duwamish-Green watershed lays out priorities to protect and improve fish habitat, while also ensuring sufficient water is available for rural residents. The plan, developed by a local coalition of governments and groups, is part of a statewide effort to protect streamflows and improve habitat. The Washington Department of Ecology has completed an environmental review of the plan, and is seeking public comment on the review through April 8.

The Duwamish-Green watershed, also known as Water Resource Inventory Area (WRIA) 9, comprises most of southern King County. It is one of 15 watersheds identified in a streamflow restoration law that requires a watershed plan or plan update. Ecology evaluates each plan before making a decision on whether or not to adopt it.

Ecology issued a determination of non-significance under the State Environmental Policy Act (SEPA) for the plan, and is asking for public review to the determination and Environmental Checklist to identify missing or incorrect information, whether additional studies are needed and other information that could help Ecology improve the environmental analysis.

The WRIA 9 watershed plan forecasts the number of new permit-exempt wells between 2018 and 2038, and their potential impacts on streamflows. The plan recommends projects and actions such as buying water rights, recharging aquifers and improving aquatic habitat that, if completed, will offset the impact of additional wells and provide a net ecological benefit to the watershed.

The streamflow restoration law helps improve streamflows to levels necessary to support healthy and sustainable native fish populations, while also providing water for homes in rural communities. Seven watersheds have completed plans or rules, and planning groups in seven other watersheds (WRIAs 7, 8, 10, 12, 13, 14, and 15) are finalizing their plans. More information is available on the Streamflow Restoration webpage.

Contact information

Keeley Belva
Water Resources Communications
Mugdha Flores
Water Resources Communications