Quick Facts

What is an estuary?

Estuaries are found where a river meets the sea. Bays, sounds, and other types of partly enclosed water bodies are all estuaries. In an estuary, freshwater from the river and salt water from the sea mix together. The ocean tide also affects estuary waters. Watch this video produced by the Association of National Estuary Partnerships to learn more about estuaries and why they matter for humans and wildlife.

Where is the Columbia River estuary?

The estuary is between Oregon and Washington along the Pacific Coast. The tidal influence of the ocean extends from the coast upriver 146 miles to Bonneville Dam.

Where does the Columbia River start?

British Columbia, Canada.

How long is the Columbia River?

1,243 miles.

How many U.S. states drain water to the Columbia River?

Seven: Large portions of Idaho, Oregon and Washington and smaller portions of Nevada, Montana, Utah and Wyoming.

Is the Columbia River estuary salty?

Not very. The flow of freshwater pushing out towards the ocean is usually stronger than the ocean currents pushing salty water upriver. Still, salt can be measured in the Columbia River to about 30 miles upriver from the coast.

What animals live in or near the river?

Several hundred species visit the region or call it home. See the full list here.

Why is the Columbia River estuary important for salmon?

Young migrating salmon stay in the estuary for several weeks to several months adjusting to saltwater on their way to the ocean. They also stay in the estuary as adults on their way back from the ocean to readjust to freshwater.