Average water temperature: This week, the Bonneville, The Dalles, and John Day dams’ reservoirs had a high average temperature of 71.42°F.

DISCUSSION OF DATA:

The states of Oregon and Washington have recognized that the lower Columbia and Snake river reservoirs are major sources of heat pollution (hot water pollution). Water temperatures are actively reaching between 69°F - 71°F across the lower Snake and Columbia rivers.

The harmful and lethal impacts to salmon and steelhead as they experience water temperatures of 69°F - 71°F include reduced available oxygen; increased susceptibility to parasites, predators, and disease; altered growth and development for juvenile salmon; growth of harmful fungus on salmon; slowed or arrested migration for salmon and steelhead.

Salmon and steelhead mortality rates increase significantly with the number of dams and reservoirs they encounter during their migration. In the Columbia-Snake Basin, the construction of the federal hydro system has profoundly degraded fish habitat and is the primary source of mortality for salmon and steelhead.

Fishery managers have reported historically low 2026 adult returns for sockeye, Spring Chinook, and steelhead returning to the Columbia and Snake rivers, with numerous fishery closures and emergency intervention measures. Recently, the Fish Passage Center (FPC) released their weekly report of current salmon and steelhead runs, outlining these historically low numbers. We’ll learn more as this year’s return continues into the fall.

ATTEMPTS TO COOL THE RIVER

Each summer, the US Army Corps of Engineers seeks to partially mitigate hot water in the four lower Snake River reservoirs by releasing cold water stored behind the Dworshak Dam—a strategy that was developed in the early 2000s in collaboration with federal, state, Tribal fish managers, and the Army Corps. These cold waters flow from the Clearwater River (a tributary to the lower Snake River) into the Lower Granite Reservoir.

The cold water releases are timed to aid salmon migration. “Above about 68 degrees, they start showing signs of stress, migration delay, and, if temperatures go higher, mortality can start to occur,” stated Chris Peery, Corps of Engineers fish biologist, in a news release. However, there is a limited amount of cold water that can be released from Dworshak, says Peery. This often means less cold water to help Endangered Species Act-listed Snake River fall Chinook and steelhead migrate upriver later in the year.

With a free-flowing lower Snake River, the great benefit of these cold water releases from Dworshak will help keep temperatures suitable for fish all the way downstream to the confluence of the Snake and Columbia rivers near the Tri-Cities, WA, during the summer and fall. Restoring the lower Snake River will significantly reduce mainstem water temperatures on a long-term basis, and remains an essential action to prevent extinction of the Northwest’s native fish.

Dams Full of Hot Water, BPA Full of Hot Air: Debunking the misinformation blocking real solutions for energy and salmon

Toxic algae outbreaks in the lower Snake River © Ecoflight

Bonneville Power Administration (BPA) and some public utilities in the Northwest are spending absurd amounts of money to distort facts about the status of endangered salmon and steelhead, mislead the public about the reason for rising energy costs, and deny the limitations of lower Snake River hydropower operations. For three decades, BPA and public utilities have resisted developing collaborative and durable solutions to protect salmon, modernize our region’s power system, and ensure a reliable, affordable energy future.

In this Hot Water Report, we’ll address common misinformation BPA and utilities claim and share solutions for our region’s needs for energy development and salmon recovery.

What are BPA's legal responsibilities? BPA, a federal agency that sells Columbia Basin hydropower, is required by law to provide reliable and affordable electricity for its customers. BPA is also required by law under the Northwest Power Act to protect and mitigate harm to our environment, including endangered salmon and steelhead populations. These days, BPA is failing at both, and using legally required salmon protection efforts as a distraction from its bad decisions and rising energy costs.

How much energy do the lower Snake River dams generate? The lower Snake River dams have provided, on average, roughly 700 megawatts (aMW) of energy each year. This average energy output of these dams is just over 2% of the entire Northwest regional power system.

These four dams are a very small part of BPA’s broader electricity portfolio, which includes power from 31 federal hydroelectric projects, the Columbia Generating Station (a non-federal nuclear plant), and several small non-federal power plants.

Lower Snake River hydropower is declining: Lower Snake River hydropower is dependent on the water available in any given year—how much water flows in the river is based on the available snowpack. The lower Snake River dams are “run-of-river,” which means they do not store appreciable amounts of water. Therefore, they only generate electricity when water is available flowing down the river. Climate change is affecting air temperatures, precipitation, snowpack, and wind patterns in the Northwest and, in turn, increasing land and river heat waves, droughts, and variations in river-flow patterns. This is limiting the power, capacity, and value of these dams.

Can lower Snake River hydropower alone keep the lights on during extreme weather events across the region? The lower Snake River dams are very limited in their ability to increase energy output in response to extreme weather events.

The lower Snake River dams produce significantly less power at the times when the region needs it the most—for heating in the winter and cooling in the summer. They produce the most power from March to June, when the rest of the energy system is also generating significant output—often in excess of customer demand.

What is driving increased energy rates? Our region is facing real energy affordability and reliability challenges today. BPA and many public utilities in the region are falsely blaming salmon recovery programs (which BPA is legally required to do!) for the rise in energy rates.

The most significant reasons for rising costs today are:

1. 1. Extreme weather and wildfire mitigation programs
   2. Overdue updates and backlog of repairs to our region’s transmission system—the vital network of power lines and related infrastructure used to deliver electricity to our communities, homes and businesses.
   3. Rising electricity demand.
   4. Steadily rising natural gas prices.
   5. Integration of new wind and solar projects into often outdated energy infrastructure.

Our region urgently needs to address these issues collaboratively to meet future energy demand and maintain a reliable and affordable energy system. Salmon, steelhead, and native fish recovery programs are not to blame. Driving salmon to extinction will not make Northwest power any more affordable or reliable, though it would indescribably diminish our region and nation while breaking longstanding promises with Tribal Nations.

SOLUTIONS:

Nimiipuu Energy © Mezia Creative Media

What can BPA and utilities do to support energy affordability and increased demand for energy in the Northwest? A healthy future for our region must include both affordable, clean energy and thriving salmon and steelhead. We urge BPA and the utility industry to focus on meaningful solutions and support a regionally developed comprehensive plan—the Columbia Basin Restoration Initiative, a collaborative effort led by state and Tribal leaders—that restores salmon and other native fish populations to healthy and abundant levels, ensures a clean energy future, supports local and regional economic resilience, and honors commitments to Tribal Nations. This is our best way forward.

Solutions backed by energy experts include:

Replacing the lower Snake River dams is an energy resiliency approach. The energy services of these four dams are replaceable with affordable, clean, and reliable alternatives:

A portfolio of clean energy alternatives will help modernize our energy infrastructure, improve reliability, and invest in our communities: BPA should modernize its energy services and support the full range of customer-side and grid-connected clean resources—energy efficiency, demand response, wind, solar, battery storage, and transmission—to ensure reliability during winter and late summer demand peaks.

By modernizing our energy system (transmission system), we can better connect clean energy generation and meet energy demands. Experts are urging BPA to take a more nimble, efficient, and community-oriented approach to address the massive backlog of pending requests for transmission service so affordable clean energy projects can reliably connect to the grid and meet our growing needs.

A study by Headwaters Economic found that renewable energy projects, such as wind and solar facilities, can also generate tax revenue for local governments and lease payments for landowners in communities that choose to host them. Community-owned or cooperative energy projects, such as solar and wind, are one way communities can participate directly in an energy transition.

Investing in diverse renewable energy saves money: Studies have shown that replacing the lower Snake River dams' hydropower with the clean energy sources that we need today is feasible and cost-effective. Replacing this hydropower with a mixed renewable energy portfolio would generate power at times when the region needs it most, resulting in $69- $131 million per year of energy value above and beyond what the lower Snake River dams provide for the same time period.

Cost of renewable power continues to decrease: The cost of building clean, renewable power (wind/solar/battery) has declined steadily in recent years, leading to the development of thousands of megawatts of new renewable power and battery storage. Recent requests for proposals (RFPs) from investor-owned utilities for development of clean energy resources have drawn responses providing three to five times the amount of power requested by the utilities. We have more clean energy resources available to replace the energy generated by the lower Snake River dams.

BPA should avoid joining Markets+, a deeply flawed energy trading system: If BPA and utilities are really concerned about affordability, they would be transparent about the cost of BPA’s recent decision to join the wrong energy market—Markets+. Despite analyses by BPA and other experts and letters from the Northwest Congressional Delegation outlining the substantial harm and costs to the entire region, BPA continues to ignore these impacts on regional families and businesses and move in the wrong direction.

• It is forecasted that Markets+ will increase regional electricity costs by more than $4 billion in the coming decade. BPA has other, far better options. Right now, it should (i) remain part of the Western Energy Imbalance Market and (ii) reconsider its decision and instead join a larger western market, the Extended Day Ahead Market, which is larger and more diverse and offers access to many more renewable energy options that would greatly diversify our energy system and further increase reliability. Read more here.

Our Northwest energy system is in serious need of upgrades, investments, further diversification and ever-cleaner energy sources. Now is the time for BPA and utilities to play a positive leadership role in our region and uphold their obligations to our environment, salmon, tribal treaties, and all utility customers and energy consumers across the Northwest.

We look forward to working together to protect and recover our salmon while also scaling up to meet our rapidly increasing energy demands with additional non-hydropower energy sources and modernize our grid with clean, affordable options.

READ PAST ISSUES OF THE HOT WATER REPORT

The Hot Water Report is a project of: Save Our wild Salmon Coalition, Association of Northwest Steelheaders, Columbia Riverkeeper, Earthjustice, Idaho Conservation League, Idaho Rivers United, National Wildlife Federation, Northwest Sportfishing Industry Association, Orca Network, Pacific Rivers, Sierra Club, and Snake River Waterkeeper.

Data Sources: The 2026 water temperature data for the lower Snake River and lower Columbia River presented in the Hot Water Report are collected from the USGS, and the Columbia River DART program by Columbia Basin Research, University of Washington, with data courtesy of the U.S. Army Corps of Engineers (USACE). These data temperatures are provisional. The 10-year average water temperature data is courtesy of the Fish Passage Center and Columbia River DART program. Water temperature data is provisional. Graphs and tables are assembled by SOS Staff.