Get the facts about Deschutes River fish reintroduction

As co-owners of the Pelton Round Butte hydroelectric project - an important source of emissions-free energy - the Confederated Tribes of Warm Springs and PGE pay close attention to what’s happening on the Deschutes River and in the surrounding basin.

Here are answers to some common questions about our work – ones we’ve heard, and the ones we’re actively asking and studying. The information is based on robust and high-quality scientific data, as well as traditional ecological knowledge from generations of Tribal experience.

Download get the facts or go deeper in the data .

1. What is the Deschutes fish reintroduction program?

From the 1950s to 2010, dams on the Deschutes River blocked the migration of ocean-going salmon and steelhead (anadromous fish). In 2005, when the Pelton Round Butte hydropower project was relicensed, PGE and the Confederated Tribes of Warm Springs (CTWS) began an ambitious effort to change that, alongside many partners in the Deschutes River Basin. The reintroduction program is a long-term project to restore anadromous fish runs to a fully reconnected Deschutes River Basin. Our strategies are always evolving, guided by the latest science and best practices from peer programs.

2. Is the reintroduction program a success?

We are seeing progress, and the science suggests we’re on the right track.

• Our biologists monitor multiple sites and collect data year-round to help us understand how several variables affect water quality and fish survival over time. Together with our regulators and other experts in Central Oregon, we evaluate our progress and make thoughtful course corrections when the science supports them – an approach known as “adaptive management.”

• For example, we now generate power at night during peak fish migration to attract salmon and steelhead toward our collection facilities when they’re most active. We installed a net that guides fish toward the collection area and a stress relief pond to allow fish more time to recover after handling. We’ve begun releasing excess hatchery broodstock upstream of the project to help jumpstart spawning – a common strategy employed by other reintroduction programs. These changes have all shown positive results, and we expect to see more over time.

• Anadromous fish life cycles last four to eight years. This means it may take several years for us to see the results of our most recent changes. When it comes to high-quality science, patience is essential.

3. How do the Tribes and PGE manage water quality, including water temperature, in the Deschutes?

The Selective Water Withdrawal (SWW) facility is the centerpiece of the Pelton Round Butte Project’s Fish Passage Plan and is an effective tool for water quality management downstream of the project.

• The SWW works by creating attractant currents in the surface of Lake Billy Chinook, guiding in juvenile fish and enabling their transport downstream.

• By mixing water from both the surface and depths of the reservoir, the SWW reduces the project’s effect on temperature in the Lower Deschutes. The water blend released downstream targets what temperatures would be like without the dams’ presence, restoring natural seasonal patterns. What comes out now matches what goes in, thanks to the SWW.

• These patterns aid juvenile fish growth, particularly for fall Chinook, and preserve cold water – a limited resource – for when fish need it most.

4. Does the SWW affect energy production or revenue?

No. The SWW’s only function is to correct issues with water temperature and fish passage. If the science were to suggest a better way to operate the facility, PGE and the Tribes would work with our regulators to adopt those new procedures. Learn more .

5. Why not release cold water from the depths of Lake Billy Chinook year-round?

Cooler water from the depths of Lake Billy Chinook is a finite resource that can be depleted if released too early in the year. If we do that – as we did before the SWW was constructed – we will cause the river to be unnaturally warm in the late summer and early fall, when migrating fish need cool water the most.

• To create more natural and more optimal conditions for fish, we add the available cold water to our blend strategically, to closely match “without-project temperatures” for as much of the year as possible – the temperatures we would expect the river to be without the dams' presence.

• This approach is supported by guidance from the Environmental Protection Agency, which identified cooler temperatures in August and September as a priority for fish.

• Even on the hottest days, water released from the project rarely, if ever, exceeds 62 Fahrenheit.

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6. Some groups have advocated for a water management protocol that involves pulling more water from the bottom of the reservoir at night. Have PGE and CTWS considered this proposal?

Yes. Several years ago, it became clear we needed a better understanding of water quality dynamics in the Deschutes River Basin to continue making informed decisions. To address this need, we contracted outside researchers to conduct a comprehensive water quality study, which involved more than two years of field data collection, scenario modeling and robust analysis.

A range of management scenarios encompassing the “night blend” were modeled in the study, allowing us to assess the feasibility, potential benefits and potential drawbacks of changing operations at the SWW. The scenario analysis, along with additional evaluation by the Pelton Round Butte Fish Committee , found that the blend would likely result in reduced water quality in the Lower Deschutes River and warmer water temperatures in the fall when fish need cool water most. Based on this evaluation and the best available science, the Fish Committee did not recommend adopting the blend.

7. Why not use the SWW and the dams to insulate the lower Deschutes River from the conditions of the upper Deschutes Basin?

It’s all one river. As stewards of this area since time immemorial, the Confederated Tribes of Warm Springs know how important it is to manage the Deschutes as an interconnected system – not as separate pieces. The SWW helps us restore a more natural, more connected ecosystem.

• The condition of the Lower Deschutes River is, in many ways, a direct reflection of water quality in the upper basin tributaries and reservoir, especially with regard to flows, temperature and nutrients.

• Our license requires that we operate our project as “run of the river,” which means that flows entering Lake Billy Chinook are roughly the same as our output at the ReRegulating Dam. The SWW allows us to do the same for water temperature, creating a blend of surface and bottom water that more closely matches what downstream temperatures would be like naturally, without the project.

• This means that improving water quality in the Deschutes will require basin-wide strategies . This approach will ultimately benefit all communities – both human and wildlife – upstream and down.

8. What water quality standards apply to the Pelton Round Butte project?

The Pelton Round Butte Project complies with the current standards set by the State of Oregon and the CTWS Water Control Board. When there are differences between the two sets of standards, we comply with the most stringent of the two. The details for how we comply with these standards are described in two active 401 water quality certificates and our Water Quality Monitoring and Management Plan

• The Oregon Department of Environmental Quality (DEQ) develops water quality standards to support recreation, drinking water, agriculture, industry, the needs of fish and other aquatic species, and other uses. Because there are salmon and steelhead species downstream of the Pelton Round Butte project year-round, we are held to some of the strictest year-round standards for temperature and dissolved oxygen.

• The Environmental Protection Agency (EPA) requires states to review and revise water quality standards on a regular basis. Changes to state standards are made through a state-wide rulemaking process conducted by DEQ that includes opportunity for public comment and requires EPA approval.

• The CTWS Water Control Board was formed in 1975 by the Tribes' Water Code – one of the oldest of its kind in the nation. Composed of Tribal members, the Board oversees the allocation and control of the Tribes' water resources and administers the Tribes' water quality standards program. This includes exercising delegated authority under the federal Clean Water Act and issuing Section 401 Water Quality Certifications for applications for federal licenses or permits. In any updates to the Tribes' water quality standards, the Board follows a public engagement process consistent with EPA’s requirements.

9. Are dams, like the Pelton Round Butte hydropower project, good or bad for the environment?

• While all methods of generating electricity have some impact on the environment, hydropower is one of Oregon’s cleanest options because it produces no greenhouse gas emissions. The Pelton Round Butte project is also nationally recognized for its exceptional environmental practices.

• Hydropower offers a consistent, reliable and low-cost source of clean electricity. As Oregon works to achieve its climate targets, projects like Pelton Round Butte play a key role.

• Pelton Round Butte generates nearly 500 MW of clean electricity. It is the largest, most productive hydropower system located entirely within the state of Oregon.

• Climate change is one of the biggest threats facing fish today. Scientists have documented rising river temperatures, altered ocean conditions and reduced habitat. While there’s no doubt that dams can create challenges for fish, they continue to be a critical tool in the larger fight against climate change.

• Of the 2,500 hydropower projects in the U.S., only 200 are certified by the Low Impact Hydropower Institute (LIHI) for their environmental excellence. Pelton Round Butte was first LIHI certified in 2007 and was recertified in 2023, affirming that we’re generating power in a way that respects Oregon’s aquatic, terrestrial, cultural and recreation resources.

Have more questions? Check out “Inside Reintroduction ” for additional FAQ and data citations.

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