The Snake River plays a vital role in providing electricity to Idaho Power’s 590,000-plus customers throughout southern Idaho and eastern Oregon. A healthy Snake River also benefits all other users — irrigators, fishery managers, wildlife and people who enjoy the river for boating, fishing and other recreational uses.
Idaho Power is committed to preserving the Snake River’s ability to provide clean water and clean power to our region for future generations. As part of that commitment, Idaho Power has proposed the Snake River Stewardship Program (SRSP), a long-term project to address the causes of elevated water temperatures and other water quality concerns.
Why is Idaho Power proposing the Snake River Stewardship Program?
Idaho Power has applied for a new long-term federal license to operate the Hells Canyon Complex (HCC) – Brownlee, Oxbow and Hells Canyon dams. These dams are an essential part of our hydroelectric system, which generates clean, affordable electricity for our customers.
One requirement is to address the temperature of water flowing out of Hells Canyon Dam. In the summer, water temperatures rise as the Snake River flows through southern Idaho before reaching Brownlee Reservoir. During a brief period in the fall, water leaving the HCC is warmer than the standard for protecting Snake River Fall Chinook spawning. Because the causes of elevated water temperatures are best addressed through watershed restoration, Idaho Power has proposed the SRSP as part of the relicensing process.
What is the Snake River Stewardship Program?
The SRSP is a watershed-scale restoration program primarily targeting the Snake River and its tributaries between Swan Falls and Hells Canyon dams.
The two components of the program are:
- In-stream projects, that include the creation of floodplains and wetlands, designed to reduce water surface area, increase water velocity, and increase channel depths. This will reduce the surface area exposed to heating, decrease aquatic algae and plant production, and improve fish and wildlife habitat.
- Restoring native vegetation along key tributaries of the Snake River. This will shade sections of these waterways, provide more diverse fish and wildlife habitat, and help prevent sediment and pollutants from entering the water.
The SRSP has been included in the Clean Water Act Section 401 Water Quality Certifications (certifications) issued by the Idaho and Oregon Departments of Environmental Quality in 2019. The certifications are available online at the Idaho and Oregon DEQ websites.
What has Idaho Power done to date?
- Construction of the Bayha Island Research Project was completed in November 2016. This project was designed to narrow and deepen a section of the Snake River channel by creating approximately 7.5 acres of floodplain adjacent to Bayha and Wright islands (map), increasing water velocity and decreasing heating by reducing the surface area. The constructed floodplain, excavated channel, and planted riparian vegetation have successfully weathered high flows and improved aquatic and terrestrial habitat.
- Idaho Power has planted approximately 20 acres of riparian vegetation along the Powder River, Weiser River, and Little Weiser River as part of the tributary component of the SRSP.
- Idaho Power is planning to construct the Rippee Island Research Project in summer/fall 2021. The project will create approximately 16.5 acres of floodplain and excavate the adjacent river channel to improve water flow and quality. This project will build on lessons learned from the Bayha Island Research Project. Rippee Island is located between the Walter’s Ferry and Bernard’s Ferry boat ramps (map).
What is Idaho Power planning for the future?
Idaho Power will fully implement the SRSP once we receive a license from the Federal Energy Regulatory Commission. We will continue to monitor and maintain research projects for the life of the program and license.