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Mitigating Warming and Preserving Cold Water Refuges in the Columbia River
The confluence of the Deschutes and Columbia Rivers, with a plume of cold water from the Deschutes visible.
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ew tasks are as challenging as conserving endangered or threatened species. Such conservation often requires balancing many diverse and competing factors to preserve the species and their habitat while also allowing for the appropriate use of natural resources. John Palmer is part of a team at the region 10 office of the U.S. Environmental Protection Agency (EPA) that is working to achieve such a balance on the Columbia River by finding ways to preserve the cold water refuges that are important to migratory fish while ensuring dam operators and irrigators can still operate as well. In this interview, Mr. Palmer tells Hydro Leader about the EPA’s efforts, why cold water refuges are so vital for the future of salmon and other fish, and the role of collaboration with dam operators in conservation. Hydro Leader: Please tell us about your background and how you came to be in your current position.
36 | HYDRO LEADER | April 2021
John Palmer: Cold water refuges are areas of water that are colder than the mainstem river—the Columbia, in this case. We generally find that where cold tributaries come into the Columbia River, there are areas of cooler water in which migrating fish can hold out in to avoid the warmer water of the mainstem. Where a tributary comes into the river, it creates a plume of cold water. The fish use the plume and the lower mile or so of the tributary itself as a refuge. The Columbia is hottest from mid-July to mid-September. When the river’s temperature exceeds 20°C (68°F), salmon and steelhead start using these refuges. The main fish that use these refuges are steelhead, which migrate up the Columbia River during the peak temperatures in the summer, and fall Chinook, which are Chinook salmon that start migrating up the Columbia River in August. We started this project because of the State of Oregon’s water quality standard, which stipulated that the Columbia River needed to have a sufficient number of cool water refuges distributed along the river to allow salmon and hydroleadermagazine.com
PHOTOS COURTESY OF THE EPA.
John Palmer: I’m a senior policy advisor for the water division at the EPA region 10 office in Seattle. I’ve been here for a little over 20 years. I work to ensure that our programs comply with the Endangered Species Act (ESA), and I work on a variety of special projects within the office.
Hydro Leader: Tell us about cold water refuges on the Columbia River and how they help migratory fish.
