The International Joint Commission (IJC) announced on Thursday, January 31 that it has issued an Order of Approval renewing the State of Washington’s authority to operate Zosel Dam and making minor modifications in how water levels on Osoyoos Lake will be managed. The dam, located in Oroville, Washington is subject to international jurisdiction because it regulates the outflow from Osoyoos Lake, and backs water across the border into British Columbia.
“Thanks to the active participation in the process by watershed residents and input from the State and Province, the IJC was able to thoroughly vet the issues affecting both countries before revising this Order,” said Commissioner Lyall Knott of the IJC.
“As we move forward, we will continue to engage stakeholders in the watershed, and keep them advised of the reservoir operations and water levels. Cooperation is an ongoing process,” commented IJC Commissioner Rich Moy.
The current Orders for Zosel Dam were scheduled to expire in February and April 2013. The renewal process began in 2000 with the scoping of issues related to water levels, future water supplies and water quality in order to develop a plan of study. A number of these issues had been raised at the annual public meetings of the International Osoyoos Lake Board of Control (the Board), which was appointed by the IJC to oversee implementation of its Orders. The IJC launched eight studies in 2006 and these were completed in 2011. Stakeholders also held in-depth discussions of watershed issues at the Osoyoos Lake Water Science Forums held in September 2007 and September 2011.
In a June 2012 report to the IJC, the Board concluded that the current Orders have adequately facilitated control of water levels in Osoyoos Lake, to the extent possible, primarily for the benefit of agriculture, tourism, municipal interests, and fisheries protection. The board recommended only minor modifications to the rule curve that sets Osoyoos Lake upper and lower target water levels for different times of the year. The previous rule curve had specified that the lake be maintained within a half-foot range (911.0 to 911.5 feet) from April through October during normal conditions, but be allowed to rise to 913.0 feet during drought years. The board recommended that the maximum elevation be reduced to 912.5 feet with the flexibility to regulate within a two-foot range every year, thereby eliminating the need for drought declarations. The rule curve recommended in the board’s June 2012 report also provides for a more gradual transition in water levels during the spring and fall.
The IJC held public hearings in Oroville, Washington and Osoyoos, British Columbia on July 24 and 25, 2012, respectively, and met with the Osoyoos Indian Band on July 25, 2012. Several shoreline residents in Canada voiced the view that a sustained maximum lake level of 912.5 feet would be too high because of concerns about flooding, erosion, riparian habitat, endangered species and navigation. The IJC Commissioners heard these concerns and, after due consideration and consultation with the board, made adjustments to the rule curve recommended by the board in their June 2012 Report. The Commissioners decided that the rule curve would include a one foot-range with a 912-foot maximum in the summer under normal conditions, and a two-foot range with a 912.5-foot maximum during drought years. Commissioners also heard comments about the need to protect spawning habitat and maintain flows to sustain migratory runs of salmon and steelheads. The more gradual seasonal transition under the new rule curve is expected to provide improved river conditions for fish below the dam. The new Order also specifies that during a drought year, as determined by the board, the operation of the dam to raise the elevation of Osoyoos Lake is to be conducted in a manner considering fisheries interests.
The International Joint Commission (IJC) was established under the Boundary Waters Treaty of 1909 to help Canada and the United States prevent and resolve disputes over the waters they share. One of the IJC’s main responsibilities is to approve projects that affect the natural water levels and flows on the other side of the international boundary. The IJC may impose conditions on the design and operation of such projects to protect all interests that may be affected. Zosel Dam is one of 15 dams approved by the IJC in five transboundary basins. The IJC issued its first Order of Approval for Zosel Dam and Osoyoos Lake in 1946. Zosel Dam was replaced in 1988 and since that time the new dam and Osoyoos Lake levels have been managed under IJC Orders of Approval issued in 1982 and 1985. The previous Orders were set to expire on February 22, 2013 and April 20, 2013, respectively. The new Order does not contain an expiration date, however, in response to public comment, the Commission decided, in collaboration with its Board, that the new Order is subject to review no later than 25 years following its adoption, or as otherwise determined by the Commission.