Columbia River Treaty

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The Columbia River Treaty is an international agreement between Canada and the United States of America (U.S.) on the development and operation of the upper Columbia River basin. The Treaty was initially signed in January 1961, however further negotiations completed in 1964 resulted in a Protocol to the Treaty, and an agreement between the Canadian federal government and the province of British Columbia that clarified certain rights and obligations. With these clarifications, the Treaty was ratified and implemented on September 16, 1964.

The Mica Dam was required under the Treaty, and was completed in 1973. An underground powerhouse was added 5 years later.

The Duncan Dam was required under the Treaty, and was completed in 1967. It has no powerhouse and remains a pure storage project.

Under the terms of the agreement, Canada was required to provide 19.12 km³ (15.5 million acre-feet (Maf)) of usable reservoir storage behind three large dams. This was accomplished with 1.73 km³ (1.4 Maf) provided by Duncan Dam (1967), 8.76 km³ (7.1 Maf) provided by Arrow Dam (1968) [subsequently renamed the Hugh Keenleyside Dam], and 8.63 km³ (7.0 Maf) provided by Mica Dam (1973). The latter dam, however, was built higher than required by the Treaty, and provides a total of 14.80 km³ (12 Maf) including 6.17 km³ (5.0) Maf of Non Treaty Storage space. The operation of the three Canadian Treaty projects provides flood protection and enables increased power generation at downstream hydroelectric projects in Canada and the U.S. As payment for this storage operation, the Treaty requires the U.S. to deliver to Canada one-half of the increase in U.S. downstream power benefits as estimated five years in advance (the Canadian Entitlement). During the August 2006 through July 2007 operating year, this delivery will comprise 488.5 average annual megawatts of power (4,279 GWh) to British Columbia, shaped hourly at peak rates up to 1244 MW, with slight reductions (1.9%) for transmission losses.

The Hugh Keenleyside Dam (left) was required under the Treaty, and was completed in 1968. The Arrow Lakes Generating Station (right) was added in 2002.

The Treaty also allowed the U.S. to build the Libby Dam on the Kootenai River in Montana which provides a further 6.14 km³ (4.98 Maf) of active storage in the Koocanusa reservoir. Although the name sounds like it might be of aboriginal origins, it is actually a concatenation of the first three letters from Kootenai / Kootenay, Canada and USA, and was the winning entry in a contest to name the reservoir. Water behind the Libby dam floods back 42 miles into Canada, while the water released from the dam returns to Canada just upstream of Kootenay Lake. Libby is operated for power, flood control, and other benefits at-site and downstream in both Canada and the United States.

There was initial controversy over the Columbia River Treaty when British Columbia refused to give consent to ratify it on the grounds that while the province would be committed to building the three major dams within its borders, it would have no assurance of a purchaser for the Canadian Entitlement which was surplus to the province's needs at the time. The final ratification came in 1964 when a consortium of utilities in the United States agreed to pay C$274.8 million dollars to purchase the Canadian Entitlement for a period of 30 years from the scheduled completion date of each of the Canadian projects. In addition, the Treaty required the U.S. to pay C$69.6 million for 50% of the estimated U.S. flood control benefits to 2024, to be paid in portions as each dam was completed. In the absence of other developments, the planned annual flood control operation will convert to "Called Upon" flood control provisions when the flood control purchase expires in 2024.

With the exception of the Mica Dam, which was designed and constructed with a powerhouse, the Canadian Treaty projects were initially built for the sole purpose of regulating water flow. In 2002, however, a joint venture between the Columbia Power Corporation and the Columbia Basin Trust constructed the 185 MW Arrow Lakes Hydro project in parallel with the Keenleyside Dam near Castlegar, British Columbia, 35 years after the storage dam was originally completed. The Duncan Dam remains a pure storage project, and has no at-site power generation facilities.

Additional controversy surrounded the flooding caused by the filling of the four Treaty reservoirs. In particular the filling of the Arrow Lakes reservoir and the Koocanusa reservoir flooded fertile farm land, inundated many ancient Native archælogical sites and artifacts, and displaced a large number of long term residents. The Columbia Basin Trust was established, in part, to address the long term socio-ecomonic impacts in British Columbia that resulted from this flooding.

The Treaty has no specified termination date, but either Canada or the United States can terminate the Treaty any time after 16 September 2024, provided a minimum ten years written notice is provided. Certain terms of the Treaty continue for the life of the projects, however, including Called Upon flood control provisions, Libby coordination obligations and Kootenay River diversion rights.