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Tackling the Climate Challenge

Hot Water Report 1


Welcome to Save Our wild Salmon’s Hot Water Report 2021. During the summer, this weekly report will provide an update on real-time water temperatures in the lower Snake and Columbia river reservoirs via graphs and analyses, a report on the highest weekly water temperature at the forebay/reservoir of each dam, and the status of adult returns for the different salmon and steelhead populations as they make their way back to their natal spawning grounds. We’ll share information from scientists, fishers, guides, advocates, and other experts about the challenges facing the Columbia and Snake rivers - and opportunities we have to restore healthy rivers and to recover abundant fish populations and the many benefits they deliver to the Northwest’s culture, economy, and ecology.

The once-abundant anadromous native fish populations that call the Columbia-Snake River Basin home are struggling to survive primarily due to multiple harmful effects caused by the system of federal dams and their reservoirs. The federal hydro-system creates conditions that harm and kill both juvenile and adult fish, including by elevating water temperatures in the large, stagnant reservoirs, especially in the summer months. As cold water species, these salmon and steelhead begin to suffer harmful effects when water temperatures exceed 68° Fahrenheit. The longer and higher temperatures rise above 68°F, the greater the harm, including disruption in their migration, increased metabolism, increased susceptibility to disease, reduced fecundity or reproductive potential (by reducing egg viability), and in the worst case - death.

These harmful hot water episodes above 68 degrees in the Columbia and Snake Rivers are increasing in duration, frequency, and intensity. Our changing climate is making a very bad situation for the Northwest’s iconic fish worse. Our region and nation must take urgent action to lower these high temperatures - or scientists tell us that we will lose these species forever. Restoring a freely flowing lower Snake River by removing its four federal dams is our best and very likely only option for lowering water temperatures in this 140-mile stretch of river in southeast Washington State. Restoring the Snake River is one essential part of what must be a larger regional strategy to protect and rebuild healthy, abundant salmon and steelhead populations in order to benefit other fish and wildlife populations, including critically endangered Southern Resident orcas, to honor tribal rights, and to ensure prosperous communities across the Northwest.

Will you be on the river this summer? Do you have a story or photo you would like to share? Please send them to Martha Campos

The Hot Water Report is a joint project of the Save Our wild Salmon Coalition, Washington Sierra Club, Columbia Riverkeeper, Idaho Rivers United, National Wildlife Federation, Snake River Waterkeeper, Northwest Steelheaders, Defenders of Wildlife, and Endangered Species Coalition.

II. READING THE DATA - Lower Snake and Columbia River Temperatures

The daily mean temperature at the four reservoir forebays (immediately upstream from the dam) in the lower Snake River (above) and the lower Columbia River (below) for 2021 is represented with solid lines and their 10-year average (2011-2021) temperatures with dashed lines of the same color. The dotted line across the graph represents the 68°F “harm threshold” for adult and juvenile fish. Salmon and steelhead begin to suffer harmful effects when water temperatures exceed 68° Fahrenheit. The longer temperatures remain above 68°F and the higher the temperatures rise above 68°F, the more severe the potential effects, including: increased metabolism, increased susceptibility to disease, reduced fecundity or reproductive potential, and/or death.

Water temperatures remain high - and harmful to salmon and steelhead - in the lower Snake and lower Columbia River reservoirs: On the lower Snake River, the Ice Harbor, Lower Monumental, and Little Goose reservoirs have all peaked over the threshold (68 degrees) this week. The Ice Harbor Dam has consistently maintained mean temperatures above 71°F, and with a high mean temperature of 72.32°F on July 18, 2021. The Lower Monumental Dam had high mean temperatures of 71.06°F on July 17, 2021. This week, the Lower Granite reservoir is the only one with water temperatures below the 68°F threshold. Temperatures in Lower Granite’s reservoir in the summer months are typically slightly cooler than the three downstream reservoirs on the lower Snake because the U.S. Army Corps of Engineers traditionally releases cold water from the Dworshak Dam (just upstream into the Clearwater River) in July and August. However, this year, due to the extreme heatwave in the Pacific Northwest, the Army Corps began to release “43-degree Fahrenheit (6-degree Celsius) water from Dworshak Dam on June 22. These releases are continuing in July and are helping to prevent the water temperature from reaching 68 degrees Fahrenheit in the Lower Granite Dam reservoir near Lewiston (ID) and Clarkston (WA). Despite these cold water releases from Dworshak reservoir this summer, all reservoirs downstream from Lower Granite Dam continue to experience temperatures above 68°F. As long as these four dams remain in place, the benefits of Dworshak’s cold flows are limited and serve only as a short-term solution to cooling water behind Lower Granite Dam. EPA models show that a freely flowing lower Snake would carry these cooler waters all the way downstream to its confluence with the Columbia River near the Tri-Cities (WA) (see Issue 2 for more information).

On the lower Columbia River, current reservoir temperatures are above the 10-year averages for this time of the year, and all reservoirs registered temperatures above 69°F. On July 19, 2021, The Dalles Dam had the highest mean temperature of 71.96°F. From July 17 to July 20, the John Day Dam had the second highest mean temperature of 71.60°F.

A note on the lower Snake River Water Temperature Graph: The mean water temperature data from these reports comes from the USGS Current Conditions for Washington State and the 10-year average water temperature data comes from the Fish Passage Center. USGS began recording water temperatures at Ice Harbor and Lower Monumental on June 16, 2021, Little Goose on June 19, 2021, and Lower Granite on June 18, 2021. Although we are not able to compare spring water temperatures to summer water temperatures, we can see June temperatures rising above the 10-year average and all water temperatures in the lower Snake River are above 60°F.


On the lower Snake River this week, the reservoir behind Ice Harbor Dam registered the highest temperature at 73.22°F - significantly above the level that coldwater fish require. Lower Monumental Dam had the second highest temperature at 71.42°F.

On the lower Columbia River, all reservoirs registered high temperatures above 69°F for multiple days. The Dalles Dam had the highest temperature this week at 72.32°F, followed closely by the John Day Dam with a high temperature of 71.96°F.

Temperature data included in these reports come from the USGS Current Conditions for Washington State and the Fish Passage Center. Graphs and tables were assembled by SOS Staff.

IV. Columbia-Snake fish need help! Salmon and fishing groups, State of Oregon and Nez Perce Tribe call on court to help critically endangered salmon and steelhead.

gavelOn July 16, 2021, Earthjustice representing the National Wildlife Federation, American Rivers, Idaho Rivers United, Institute for Fisheries Resources, NW Energy Coalition, Northwest Sportfishing Industry Association, Pacific Coast Federation of Fishermen’s Associations, Sierra Club, Columbia Riverkeeper, Idaho Conservation League, and Fly Fishers International as plaintiffs, requested a motion for a preliminary injunction against the U.S. Army Corps of Engineers to address violations of the Endangered Species Act.1 The plaintiffs are asking the U.S. District Court in Portland to order the federal dam agencies to implment specific changes (i.e. "injunctive relief") to how the dams are managed and operated starting in 2022 in order to “reduce irreparable harm to, and increase the survival of, Endangered Species Act-listed salmon and steelhead in the Columbia and Snake Rivers.”1

This latest round of litigation is challenging the Trump Administration’s 2020 Record of Decision for Columbia River dam operations and the U.S. Army Corps of Engineers’ reliance on the 2020 Biological Opinion (Federal Salmon Plan) for the Federal Columbia River Power System.1 The State of Oregon has also filed a similar motion for injunctive relief and with the support of the Nez Perce Tribe.2

To “reduce irreparable harm” to salmon and steelhead, the plaintiffs are asking the Court to require the Army Corps of Engineers to:

  1. increase spring spill for 24 hours per day to the maximum level that meets but does not exceed state water quality standards at the dams on the lower Columbia and lower Snake Rivers, beginning in 2022;
  2. restore summer spill at all eight dams to the levels set in prior BiOps (or federal salmon plans)  through August 31st, beginning in 2022;
  3. provide continuous 24-hour spill from September 1 to the beginning of the following spring spill season at all eight projects through the operation of at least one spillway weir or other surface passage route, beginning in 2022;
  4. operate the four lower Snake River reservoirs at lower levels, (also known as "drawdown" or minimum operating pool elevations) from March 1 through August 31, beginning in 2022; and,
  5. develop and submit to the Court by September 1, 2022, an implementation plan to operate the four lower Columbia River reservoirs (above McNary, John Day, The Dalles, and Bonneville dams) at their minimum operating pool elevations from March 1 through June 15, beginning in 2023.”1

In summary, conservation and fishing plaintiffs seek increased spill starting next spring (2022) to help endangered salmon and steelhead populations navigate the federal dams and reservoirs in the lower Columbia and Snake rivers.2 Spill sends water and fish over the tops of dams - rather than through power turbines or dam bypass systems that increase fish mortality. Years of scientific study demonstrate that spill increases the survival of out-migrating juvenile fish, reduces mortality, and leads to increased adult returns in the years that follow.

Similarly, restoring spill during the entire summer migration season will help to “preserve as much of the diversity of summer migrating juveniles as possible, limit harm to them, and increase their resilience in the future.”1 The voluntary spill from September 1 to the beginning of the following spring spill season will support the migration of late and early juveniles and serve benefits to Endangered Species Act-listed adult steelhead in the Columbia and Snake River basins that otherwise experienced harm by the limited spill.1

The plaintiffs also seek “drawdown” (lowered reservoir levels) to help speed fish migration through reservoirs with hot water temperatures. Science confirms that lowering reservoir levels “increases the speed with which water moves through the reservoirs.”1 A faster current reduces the amount of time required for juvenile salmon to pass through the reservoirs and can also reduce water temperatures in these reservoirs to some extent, and increases the survival rates for endangered juvenile salmon and steelhead.1 The faster juvenile salmon and steelhead pass through a reservoir, the greater the chance to avoid predators like bass and pikeminnow, whose populations have increased significantly due to the large warm, stagnant waters created by the dams.

For Snake River fish that must pass through eight dams and reservoirs to get to and from the ocean, spill and the lowered reservoir levels has the potential to significantly increase survival rates. As we have seen, temporary and short-term solutions like the release of “43-degree Fahrenheit (6-degree Celsius) water at Dworshak Dam” has helped to prevent the water temperature from reaching 68 degrees Fahrenheit and higher. Specifically, this week, we have seen consistent temperatures of 66°F - 67°F at the Lower Granite Dam’s reservoir.

Unfortunately, despite the release of cool waters from the Dworshak reservoir, harmful water temperatures have reached the Columbia and Snake Basin, with high water temperatures of 73.04°F at the Little Goose reservoir on June 27th and a high temperature of 72.32°F at the Ice Harbor reservoir on July 10th. This week, on July 18th, the fish experienced another high temperature at the Ice Harbor reservoir of 73.22°F, which hot water temperatures severely impacts the survivability of these fish. Each year, approximately 50-70 percent of young Snake River fish are killed in the dams and reservoirs en route to the Pacific Ocean.

Spill and reservoir drawdown are two methods that help aid the migration of endangered salmon and steelhead and increase their survival in the near-term. However, the best available science strongly supports lower Snake River dam removal as necessary to protect these populations from extinction and restore them to abundance. The plaintiffs view the requested injunction as “an emergency stop-gap measure and not enough alone to prevent extinction.”2 A reservoir-free lower Snake River will deliver considerably cooler waters, restored spawning and rearing and migrating habitats - and big benefits to migrating juvenile and adult salmon and steelhead populations that will lead to increased survival and reproductive success.

1. NWF’s Motion For A Preliminary Injunction And Memorandum In Support: National Wildlife Federation, Et Al. v. National Marine Fisheries Service, Et Al.
2. Earthjustice: With Snake River Salmon Facing Deadly Heatwave, Conservation & Fishing Groups Seek More Spill from Dams to Aid Fish (July, 16, 2021)


 Martha Bio picMartha Campos is the Hot Water Report Coordinator with Save Our wild Salmon this summer while she resides on Kizh/Tongva ancestral lands in California. Martha holds a BA from the University of California, Davis in Native American Studies (and two minors: Environmental Policy, Analysis, and Planning and Climate Science and Policy) and is a queer, non-binary person of color with ancestral roots in Mexico.

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