Watersheds are significant for two primary reasons: water availability and preventing water pollution.
Water flows through a watershed and into large bodies of water, reservoirs or into groundwater. Not enough water flowing through can mean drought conditions. Too much water can mean flooding. As the water flows through, it can pick-up pollutants, which then can accumulate at the watershed's endpoint.
At Ecology we work to ensure plenty of high-quality water for Washington's people, aquatic species, and ecological systems.
The Chehalis Basin is a 2,700 square-mile river drainage system located in Southwest Washington along the Chehalis River and its tributaries.
It is the second-largest river basin in Washington, flowing from the Willapa Hills and the hills east of Chehalis and Centralia, past the Capitol State Forest and Olympic Mountains into Grays Harbor.
The Columbia Basin is vast, including the southeastern portion of the Canadian province of British Columbia, most of the U.S. states of Idaho, Oregon, and Washington, and smaller parts of Montana, Nevada, Utah, and Wyoming. It covers 258,000 square miles total. The Columbia River marks the border between Washington and Oregon, and pours more water into the Pacific Ocean than any other river in North or South America.
In Washington the Columbia basin includes several significant river valleys:
Puget Sound is both an extensive 1,000 square mile body of water – a complex estuarine system of interconnected marine waterways and basins – and a densely populated region including the cities of Bellingham, Everett, Seattle, Tacoma, and Olympia. Pollution and acidification are our primary concerns.
The Spokane River and its tributaries generally flows westward from its source at the outlet of Lake Coeur d’Alene in Idaho. The river drains an area of about 6,640 square miles; approximately one-third is in Washington, with the remainder of the watershed in Idaho.
Our collaborative efforts help us identify ways to improve the rivers and lake health so that people can continue to use the watershed for recreation, fish habitat, hydropower, and wastewater management.