Water Quality Improvement Projects
Chehalis River Basin
The Chehalis River Basin (Basin) is located in western Washington State between the Deschutes River Basin
the east, the Cowlitz River Basin to the south, the Willapa Hills to the
southwest, and the Olympic National Forest to the north. The Basin includes parts of Lewis,
Thurston, Pacific, Grays Harbor, and Mason
The Basin is the second largest river basin in the state (the
largest is the Columbia River Basin), with a total drainage area
of the Basin is 2,660 square miles.
The majority land use within the Basin is forestry, including
private commercial forest lands as well as publicly-owned forest
lands in the Olympic National Forest, Capitol State Forest, and
Mt. Baker-Snoqualmie National Forest. A variety of crop and
livestock agricultural land uses constitute approximately 8% of
the basin and are also a significant economic driver. Commercial
and recreational shellfish harvesting is also important to the
Grays Harbor area.
The Confederated Tribes of the Chehalis Reservation is somewhat centrally
located in the Chehalis River watershed, near the town of Rochester. The
Quinault Indian Nation has treaty rights to protect their usual and accustomed areas within the Basin,
while their reservation is contained within Jefferson County along the
The four major population centers: Chehalis, Centralia, Aberdeen, and Hoquiam
depend on groundwater and surface waters of the basin for the largest portion of
their municipal and industrial supplies. The Port of Grays Harbor is located in
Aberdeen. Shellfish harvesting depends on receiving good water quality from the
Chehalis River and other tributaries directly to the harbor. Port activity
relies on annual dredging by the Army Corps of Engineers to maintain the
navigation channel and turning basin in Grays Harbor.
The resident and anadromous fish resources are of national, local, and
international economic significance. Significant anadromous fish species include
fall and spring Chinook, Coho, Steelhead Trout, Chum, and Bull trout. Sport,
tribal, and commercial fishing are important to the economy of the Basin.
The Quinault Indian Nation and the Washington Department of Fish and
Wildlife are co-managers of the salmon fishery in this basin. There are many
state and private fish hatcheries throughout the basin to support
recreational, commercial, and tribal fisheries.
Water quality issues
Development is concentrated in areas close to important streams and
rivers, mostly along state and federal highway corridors. Past community
development decisions have adversely impacted water quantity and water quality.
Forestland management practices also strongly affect water flow and quality in
the Basin. Currently there are no listed threatened or endangered salmon
populations in water resource inventory areas (WRIAs) 22 and 23, but continued
actions to improve salmon habitat and water quality are needed to keep it that
way in light of increasing levels
of direct anthropogenic impacts. Pollution from most all land types (urban, rural,
agricultural, forestland, commercial, industrial) is documented in many Chehalis
watershed studies by various
dissolved oxygen, higher water temperatures, and bacteria levels are
primary water quality concerns.
Total Maximum Daily Load (TMDL) reports have been approved by the U.S.
Environmental Protection Agency (EPA) for bacteria, temperature, dissolved
oxygen, and dioxin. Please see the Project Information table for specific information
about each TMDL project.
What is being done
Various organizations are helping to protect and enhance
salmon habitat and improve water quality. A local discussion and water resource planning group called the
Chehalis Basin Partnership (CBP) helped develop plans for water quality
improvement. Ecology collaborates with the CBP
and other watershed stakeholders to improve water quality and reduce non-point
sources of pollution, as well as regulating point sources of pollution through
National Pollutant Discharge Elimination System (NPDES) permits.
Ecology is also engaged with the
Recovery Lead Entity in this watershed. Salmon recovery projects
can be more than just correcting or removing fish passage barriers. They can
also improve instream and riparian habitat that helps improve water quality.
By working together with local stakeholders, the CBP, and salmon recovery
groups we approach water quality problems holistically, with multiple
perspectives and expertise, to ensure that investments of public money are
well spent on solutions that are good for water quality, people, and salmon.
Contact us for more information
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