Canada and the U.S. were facing two major challenges in the Columbia Basin after the Second World War.
First, the Columbia River was causing periodic and sometimes devastating flooding. Second, an upswing in the economy and population increased the need for additional energy sources.
In response to these challenges, Canada and the U.S. decided to investigate if water could be stored in the upper Columbia Basin for the benefit of both countries. After years of study, investigations, and negotiation the Columbia River Treaty was signed by the U.S. and Canada on January 17, 1961. Instruments of ratification covering the Treaty and Protocol were exchanged on September 16, 1964.
The Treaty was developed to provide for cooperative measures for : hydropower and flood risk management, which will make other benefits possible as well.
Under the treaty, Canada agreed to build three storage dams Keenleyside, Duncan and Mica - in the Canadian Columbia Basin. It also provided permission for the U.S. to build Libby Dam in the U.S. with its reservoir reaching into British Columbia.