Canada and the U.S. were facing two major challenges in the Columbia Basin after the Second World War.

First, the "untamed" Columbia River was causing periodic and sometimes devastating flooding.

Second, an upswing in the economy and population increased the need for additional energy sources.

To solve these challenges, water needed to be stored in the upper Columbia Basin. The Columbia River Treaty was signed by the U.S. and Canada on January 17, 1961. It was ratified by the U.S. in 1961 and by Canada in 1964. Instruments of ratification covering the Treaty and Protocol were exchanged on September 16, 1964.

The Treaty’s two purposes are to coordinate flood control, and optimize electrical energy production in the Columbia River Basin in the United States and Canada.

Under the treaty, Canada agreed to build three storage dams Keenleyside, Duncan and Mica - in the Canadian Columbia Basin. A fourth dam, Libby Dam, was built in the U.S., with its reservoir reaching into British Columbia.

The Columbia River Treaty has a long history of creating benefits for the U.S. and Canada including provisions for flood control and hydropower.

Benefits
Benefits to the U.S. and Canada derived from the Columbia River Treaty include:

The Columbia River basin in Canada provides about 50 per cent of the total hydroelectric power produced in British Columbia .

• Communities in both Canada and the U.S. are now better protected from extreme floods.
• The U.S. optimized operations to realize benefits of Canadian floodwater storage and Canada received income in exchange.
• British Columbia used its income to construct the dams.
• Additional water storage led to the subsequent development of hydropower generation.
• Increase in short-term employment opportunities to support building and operation of the dams and hydropower projects.
• Low-cost electricity primarily to areas of high consumption like the Lower Mainland.

Flood Control
Treaty provisions for flood control include

• 8.45 million acre-feet (Maf) at Arrow, Duncan, and Mica assured for 60 years.
• Additional 7 Maf of treaty storage and 5 Maf of non-treaty storage available for "on call" purchase.
• $64,400,000 cash payment made to Canada by the U.S. Government.

Hydropower
Treaty provisions for hydropower include

• 15.5 million acre-feet of Canadian storage operated for optimum power generation downstream in both Canada and the U.S.
• Canada receives 1/2 of the expected increase in downstream power generation in the U.S.
• Actual operation does not affect power benefits
• Downstream benefits from Libby remain in the country where they are generated
• The hydroelectric operating plans provide flexibility for optimum power generation in both countries.