The Upper and Lower Chehalis Watershed, also known as WRIAs 22 and 23, are jointly defined as that area that drains to the Chehalis River, but also includes the Humptulips River drainage. The WRIAs are located in Southwest Washington, covering a large portion of Grays Harbor County, as well as portions of Lewis, Mason, Pacific, and Thurston counties. Although legally divided into two WRIAs they are managed as a single drainage basin.
The Chehalis River’s major tributaries are the Skookumchuck, Satsop, and Wynoochee rivers. The watershed includes various other tributary streams such as the Newaukum and Wishkah rivers.
Existing water rights
Water rights have been issued in the Chehalis Watershed for over 100 years, and as a result most water in the watershed is already legally spoken for or “appropriated.”
Instream flow rule
Instream flow rules are an element of water and river management that help maintain healthy ecosystems that support fish, communities, and economies. WRIAs 22 and 23 have an Instream Flow Rule adopted to preserve the uses and values of individual rivers and streams within the watershed.
In 2018, the Legislature passed a streamflow restoration law in response to the Hirst decision. The law helps improve streamflows to levels necessary to support robust, healthy, and sustainable native fish populations while providing water for homes in rural Washington. It directs 15 local planning groups, including one in WRIAs 22 & 23, to develop watershed plans that offset impacts from new domestic permit-exempt wells and achieve a net ecological benefit within the watershed.
Find more information about water availability in WRIAs 22 and 23 including acquiring water, finding existing water rights and learning more about instream flow rules in our Water Availability Focus Sheet linked below: