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Chehalis River Basin Area Projects
Water Quality Improvement Projects
Chehalis River Basin
Area
Introduction
The Chehalis River Basin (Basin) is located in western Washington State. It lies between the Deschutes River Basin on
the east, the Cowlitz River Basin on the south, the Willapa Hills on the
west, and the Olympic Range on the north. The Basin includes parts of Lewis;
Thurston; Cowlitz; Pacific; Grays Harbor; Mason; Jefferson; and Wahkiakum
counties.
The Chehalis River Basin is the second largest river basin in the state. (The largest is the Columbia River Basin.) The total drainage area
of the Chehalis River Basin is 2,660 square miles, of which approximately 85
percent is forestlands.
Land use within the Basin is mostly forest, interspersed
with agricultural
and residential areas. Forestlands, which constitute approximately 77 percent of
the upper Basin and 91 percent of the lower Basin are generally located on the upland areas with scattered
amounts on bottomlands. Most forested acres are corporation-owned, with the
remainder being privately or government-owned (Capitol State Forest, Mt.
Baker-Snoqualmie National Forest and Olympic National Forest). Intensive
agriculture and irrigation occur mostly in the low-lying valleys along the
Chehalis River and its tributaries. Commercial farms in the basin are following
national trends of increased acreage and reduced numbers. Primary use of
agricultural land is crop production (133,000 acres). Pasture comprises 1.8
percent, or 31,000 acres, of the Basin.
The four major population centers: Chehalis, Centralia, Aberdeen, and
Hoquiam, depend on surface waters of the basin for the largest portion of their
municipal and industrial supplies. The principal industrial use of water
is to manufacture wood, pulp, and paper products. Aberdeen’s industrial
water system supplies most of this water from the Wynoochee River, with the
remainder from Lake Aberdeen.
The resident and anadromous fish resources are of national, local, and
international economic significance. Sport, tribal, and commercial fishing are
important to the economy of the Chehalis Basin.
Water quality issues
Development is concentrated in areas close to important Basin streams and
rivers. This can have adverse impacts on water quantity and water quality.
Forestland management practices also strongly affect water flow and quality in
the Chehalis basin. Pollution from most all land types (urban, rural,
agricultural, forestland, commercial, industrial) is documented in many Chehalis
watershed studies by various
organizations. Low
dissolved oxygen, higher water temperatures, and bacteria levels are
primary pollution concerns.
Why this matters
Oxygen dissolved in healthy water is vital for fish and aquatic
life “breathe” to survive. Fecal coliform can make people sick and cause the closure of shellfish harvesting
beds. Water temperature influences what types of organisms can live in a
water body. Threatened and endangered salmon need cold, clean water to survive.
What is being done
Various organizations are helping to protect and enhance the riparian
corridor. A local discussion and water resource planning group called the Chehalis
Basin Partnership (CBP) helped develop the plans for water quality improvement. They
serve as a focal point for coordinating implementation of
local elements of the implementation plans. A water quality committee of the CBP advises
about priorities for conducting a comprehensive water quality
monitoring plan throughout the basin.
To track changes in water quality
conditions since the TMDL studies were done, about 100 sites
were sampled at least once per month. Sampling was conducted
primarily by the Confederated Tribes of the Chehalis Indian Reservation, with
administrative support from Grays Harbor Community College and financial
support from Ecology.
Project information
Contact us for more information
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