FACT SHEET - Libby Dam

Published Oct. 31, 2019

Libby Dam is a vital component in the region’s ability to provide environmental sustainability, national energy independence, protection of public safety and infrastructure, and economic well-being.  The construction and operation of Libby Dam was authorized by Congress as part of the Columbia River Treaty in 1964, and is the only U.S. dam among the four storage dams constructed in the headwaters of the Columbia River system under the Treaty, making it the only Corps-operated facility in the nation to have both upstream and downstream international impacts.  When the Treaty was originally drafted in the 1960s, it was designed to optimize hydropower production and coordinate flood risk management as its two primary benefits. Since that time, the region has come to increasingly recognize and value the importance of the Basin’s ecosystem. 

The Treaty is now under review (as required) - with 50 years having passed since it was signed by the U.S. and Canada - and a draft recommendation by the U.S. Entity was developed with input from sovereigns and stakeholders through an extensive, multi-year process in collaboration with the Sovereign Review Team, comprised of designated representatives of the states of Washington, Oregon, Idaho and Montana, 10 federal agencies, and 15 Native American Tribes.  Equally critical to the Treaty Review and development of the draft recommendation has been the extensive involvement and input of the region’s stakeholders.  Libby Dam has been a focal point for stakeholders of all levels during the Treaty Review process. 


Libby Dam spans the Kootenai River 17 miles upstream from the town of Libby in the heart of northwestern Montana.  The Corps began construction of Libby Dam in 1966 and completed the structure in 1972, with the first commercial power coming on-line on August 29, 1975.  By March 1976, three more units were put on-line, and the fifth unit was finished in 1984.  While the main purpose of Libby Dam is flood risk management (to control the devastating floods of the Kootenai River and to provide 5.8 million acre feet of storage), the dam and reservoir also serve the multiple purposes of hydropower, recreation, navigation, and environmental stewardship.  Frequently, the needs of each of these project purposes conflict with one another, which requires careful balancing to ensure that as many needs as possible are met.

Libby Dam is a straight-axis, concrete, gravity structure solidly anchored in bedrock. It was constructed with 7.6 million tons of concrete and holds back the water of the Kootenai River with its own massive weight.  The dam is 422 feet tall and 3,055 feet long. The Kootenai River is the third largest tributary to the Federal Columbia River Power System, contributing almost 20 percent of the total water in the lower Columbia.  Libby Dam backs up the Kootenai River to form Lake Koocanusa, extending 90 miles upstream, making it the seventh largest reservoir in the United States.  Forty-two miles of Lake Koocanusa are in British Columbia, Canada.

Water from Lake Koocanusa passes through 17 Federal Columbia River Power System (FCRPS) dams prior to reaching the Pacific Ocean, of which Libby Dam is the first. Because Libby Dam is the first dam in the system, it is used to store water for use during peak power needs, as well as water for use during spring for sturgeon spawning, and during summer and fall for anadromous fish migration downstream in the mainstem of the Columbia River.

Libby Dam operations must take into account two Biological Opinions for endangered species (Columbia River salmon and steelhead and Kootenai River white sturgeon and bull trout). Libby Dam also provides funding and management direction for Murray Springs Fish Hatchery near Eureka, Montana. The Corps provides funding to Montana Fish, Wildlife & Parks to manage the hatchery, which rears and stocks trout into Lake Koocanusa and many other lakes in the area.

Lake Koocanusa and the Kootenai River offer abundant recreational opportunities in both Canada and the United States. The reservoir has several private marinas and many public boat ramps. Fishing and water sports are popular year-around activities. The Kootenai River has the reputation of being a blue ribbon fishery for rainbow trout, and there are several    private    outfitters    who    depend    on    the    river    for    their    livelihood.

Libby Dam is also known for other recreational opportunities, including camping, wildlife viewing, picnicking and boating, and the ever-popular interpretive tour of the dam. While Libby Dam's project lands have a smaller footprint in acreage compared to some, we boast an innovative and forward-looking interpretive and recreational program that is well-rounded and serves an average of 175,000 visitors per year.  Libby Dam leads local tourism efforts through connections to regional tourism - increasing collateral value and boosting the local economy through multiple pioneering partnerships - which enriches all mission and program areas at Libby Dam.  We lead the nation in educating the rest of the Corps about leveraging those partnerships in innovative ways.

Libby Dam Benefits

Power production and revenue: 

  • Megawatt-Hours generated by Libby Dam vary by water year.  In Fiscal Year 2019 Libby Dam generated – 161,51,000 mwhs with an estimated market value of up to $57,322,000 (using historical monthly market prices.)
  • Recreation economic benefits to local economy: camping, fishing, public education and safety.
  • Libby Dam provides personnel for three flood teams that cover all the drainages in Montana, west of the Continental Divide and Northern Idaho.
  • The Murray Springs hatchery (owned by USACE) produces triploid (sterile) Gerrard rainbow trout for the reservoir; sexually sterile fish do not reproduce, and thus divert that energy into growth. The target Gerrard rainbow trout fishery in Koocanusa is considered a “trophy fishery” due to the potential maximum sizes attained by these fish – 10 to 25 pounds.
  • 95,593 fish were stocked in this year from this hatchery.

    Visitation - In fiscal year 2019 Libby Dam hosted 185,000 visitors.