2.The Area Served
The area served by the Chehalis Basin Fisheries Task Force encompasses the entire Chehalis River watershed; the second largest river system in the state of Washington. This basin includes 90% of Grays Harbor, 30% of Mason, 55% of Thurston, 50% of Lewis, and small parts of Pacific, Jefferson, Cowlitz, and Wahkiakum Counties; encompassing 1,694,951 acres. This region consists of two major and a number of minor, independent drainages and 1,391 rivers and streams containing 3,353 linear stream miles. The Hoquiam and Humptulips Rivers, plus several smaller systems, enter Grays Harbor from the north; the Chehalis River from the east; and the Johns and Elks Rivers, along with a number of smaller drainages, from the south.
The Chehalis Basin, Water Resource Inventory Areas (WRIA) 22 and 23, is one of the larger river basins in the state of Washington. It is bound on the west by the Pacific Ocean, on the east by the Deschutes River Basin, on the north by the Olympic Mountains, and on the south by the Willapa Hills and Cowlitz River Basin.
Elevations vary from sea level at Grays Harbor, to 5,054 feet in the Olympic National Forest.
The Chehalis Basin encompasses 2,520 square miles and drains 2,660 square miles.
The Chehalis River system flows through three distinct eco-regions; Cascade (including the Olympic Mountains), Puget Lowland, and Coast Range before emptying into Grays Harbor near Aberdeen.
The Chehalis Basin encompasses large portions of Grays Harbor, Lewis, and Thurston counties, and lesser parts of Mason, Pacific, Cowlitz, Wahkiakum, and Jefferson counties.
The mainstem and South Fork Chehalis drain areas west and south of the City of Chehalis. Two major tributaries in mid-basin, the Newaukum and Skookumchuck Rivers, have their headwaters in the foothills of the Cascade Range. Another mid-basin tributary, the Black River, originates in Black Lake.