| Abstract/Description or Keywords |
Under the terms of the Columbia River Treaty, Canada permitted the U.S. to build the Libby Dam on the Kootenai River (U.S. spelling) in Montana. The dam was completed in 1973 and the reservoir, flooding approximately 70 kilometers into Canada, filled for the first time in 1974. Under the Treaty, operation of Libby Dam was to be coordinated with Canada. Operations of Libby Dam from 1973 through 1992 were managed to optimize power generation and flood control in the two countries. Since construction of Libby Dam, average mean annual peak floods on the Kootenay River, as measured at the Canada-US Border, have decreased by more than a factor of two, while fall and winter mean discharges have increased by a factor of three to four times. Similarly, Kootenay Lake peak water levels have decreased on average by about 2 m. This result is not unexpected as Libby Dam regulates about 70% of the total Kootenay River runoff at the border and about 45% of the total inflow into Kootenay Lake. In 1993, the U.S. Army Corps of Engineers, responding to U.S. regulatory agency concerns, began to operate Libby in a manner designed to benefit downstream sturgeon spawning, with less water released from Libby during the fall and winter and more water released during the spring and summer. This operation resulted in power losses, including additional spill and reduced seasonal value, at downstream Canadian hydropower plants on the Kootenay River system. The Canadian Entity objected to this unilateral operating change. The dispute was set aside with the signing of the Libby Coordination Agreement. In return for Libby Dam operations that meet U.S. regulatory requirements for fish, the Libby Coordination Agreement gives Canada the flexibility to self-compensate for its Kootenay River power value losses. Canada has the option to release water from the Arrow Lakes Reservoir and receive the resulting power generated at U.S. federal plants during periods of high power value. Canada returns the power to the U.S. during times of lower power value, with the value difference being the net compensation to Canada. Under the Libby Coordination Agreement, Canada also obtains some non-power benefits, including more favourable Treaty requirements on Arrow discharges during January, which benefits mountain whitefish spawning, and an option to exercise an Arrow-Libby “storage swap” agreement when beneficial to Canada. This “storage swap” agreement has been used in several years to improve recreational conditions for the communities on Koocanusa Reservoir. Until 2002, Libby Dam operations continued to observe the “Standard Flood Control” regime that had been in place since dam operations began. However, in response to a 2000 Biological Opinion, under the U.S. Endangered Species Act, Libby began operating to an interim alternative flood control procedure referred to as “Variable Flow” or “VARQ”. Libby dam began discharging less water during the fall/winter period and more water during the spring/summer to benefit downstream fish. However, this new flood control operating regime also resulted in slightly higher frequencies of peak water levels on Kootenay Lake and on the Columbia River downstream of Castlegar. In June 2008, the U.S. Entity permanently adopted VARQ Flood Control (FC) for Libby which, while still providing significant energy benefits and flood protection for Canada, does so at a reduced level compared to the terms expected by Canada when it ratified the Columbia River Treaty. The Canadian Entity notified the U.S. that compensation would be required for the reduced levels. The Columbia River Treaty Operating Committee has made some good progress on this issue, but has not yet reached final agreement. Local residents of the Creston Valley have recently expressed concern that implementation of VARQ FC has resulted in increased bank erosion along the Kootenay River, which in turn has impacted diking infrastructure as a significant proportion of the dikes are located immediately adjacent to the river. The Columbia River Treaty Review Team (CRTRT), a branch of the Ministry of Energy, Mines and Natural Gas (MEM), has retained BGC Engineering Inc. (BGC) to evaluate the concerns of the local residents, who are amalgamated into a number of Diking Districts. The proposed scope of work is to investigate whether implementation of VARQ FC has had a significant negative impact on diking infrastructure adjacent to the Kootenay River between the Canada-US border and Kootenay Lake. |
