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Yakima River Delta, Washington - Investing in science to improve fisheries

On the Yakima River in Washington, the USACE Walla Walla District is gathering information on temperature and flow in order to help guide water management for salmonids. Water quality conditions in the Yakima River Delta have made the confluence of the Yakima and Columbia Rivers a barrier to salmon migration.

A 2012 aerial photo of the Yakima River Delta where it meets the Columbia River. Water quality conditions have made the delta a bottleneck for salmon that are migrating up and down the river.

Confluence of the Yakima and Columbia Rivers - An aerial photo shows the Yakima River flowing to the right and joining the Columbia River at the northern tip and southern edge of Bateman Island. Water quality in this delta area can be a barrier for migrating salmonids (USACE photo).
The west side of Bateman Island in the Columbia is marked by slower currents and stagnant, slack water conditions.

Bateman Island, Columbia River - Flows along the west side of Bateman Island are characterized by slow water velocities and warm water temperatures in the summer months (USACE photo).
SRP helped the USACE Walla Walla District deploy sensors to collect data on water temperature and water quality.

Water Quality Monitoring - Sensors suspended under floats were deployed to collect water temperature and water quality data (USACE photo).
At the Yakima River Delta, summer temperature data collected with support from SRP shows the difference between the Columbia, which averages 67-70 degrees, and the Yakima River Delta, which can approach 90 degrees.

Water Temperatures - Summer water temperature data show differences between the Columbia, which averages 67 to 70 degrees, and the Yakima River Delta, which can approach 90 degrees Fahrenheit.

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The Yakima River drains the west side of Washington’s Cascade Mountains, flowing eastward to its confluence with the Columbia. The Yakima is heavily regulated, primarily for water supply and irrigation.

The Yakima joins the Columbia River in the pool of Lake Wallula, a run-of-river reservoir created by McNary Dam, which is 42 miles downstream on the mainstem of the Columbia. McNary Dam is part of the Federal Columbia River Power System, an integrated system of dams and reservoirs that is managed to meet a suite of congressionally authorized purposes, including hydropower production and flood risk management.

Fisheries experts have identified the Yakima Delta as a crucial link in a salmon migration that extends from the Pacific Ocean all the way to the upper reaches of the Columbia River watershed. Water quality conditions in the Yakima River Delta, especially high water temperatures and low dissolved oxygen, can make the Yakima Delta a seasonal barrier to salmonids like sockeye and summer and fall chinook.   Read More

  • USACE Walla Walla District
  • Washington Department of Fish and Wildlife
  • Mid-Columbia Fisheries Enhancement Group
  • U.S. Bureau of Reclamation
  • Conservation Districts
  • Washington Audubon Society
  • City of Richland, Washington
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