Lake Billy Chinook, Oregon

About 10-12 million years ago, alternating layers of stream sediments, volcanic debris, and basaltic lava flowed from the Cascade Mountain Range into a huge basin in this area. Named the “Deschutes Formation,” these exposed layers of material were capped by the lava flows from Cascade volcanoes three million years ago. Known as “rimrock basalt,” the cap is easily seen high atop the steep cliffs of the canyons. Subsequent periods of dramatic water erosion and volcanic activity have formed the awe-inspiring canyons and vertical cliffs seen today.

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Lake Billy Chinook has existed since 1964 when Portland General Electric constructed the Round Butte Dam causing the Crooked River, the Deschutes River, and the Metolius Rivers to form the reservoir. The lake was named for Billy Chinook, a well known Wasco Indian scout from the Warm Springs region who traveled with explorer John Fremont in 1843. The lake has also been nicknamed “Three Rivers” due to the three rivers that form it.

PGE operated the Round Butte Dam Hydroelectric Project until 1999 when it entered into an agreement with The Confederated Tribes of Warm Springs to co-manage the facilities. The project generates approximately 800,000 megawatts of electricity per year for residents in the Portland metropolitan area as well as locally.

Surrounded by mostly public lands, Lake Billy Chinook includes 72 miles of shoreline and a surface area of 4,000 acres. Its deepest point is 400 feet at Round Butte Dam itself. The reservoir stays full, or within one foot of full, from June 15 – September 15.

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Location: 7.5 miles west / southwest of Madras and 9 miles from Deschutes River entry into the reservoir

Dam Type: Rock filled with an impervious central core of compacted earth

Height: 440 feet above river bed

Length: 1,382

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