YAKIMA – Additional water will be held back at Zosel Dam on Lake Osoyoos now that a drought has been declared in the region by a joint international board, according to the state Department of Ecology, which owns the dam in Oroville.
Earlier this month, the International Osoyoos Lake Board of Control (IJC), made up of American and Canadian interests formally declared a drought for 2010 for the Okanagan Valley in British Columbia, Canada. The declaration affects the regulation of the lake, which straddles the border with B.C. and Washington State, as well as downstream flows in the Okanogan River below Zosel Dam.
Drought is declared in the region when one of three conditions is met. In this case, drought has been declared because the predicted flow in the Similkameen River is less than one million acre-feet between April and July. As of April 7, the National Weather Service predicts flows will be at 865,000 acre-feet this year, triggering a drought declaration.
In accordance with the IJC’s approval, the lake level will be increased to 912.5 feet elevation over the months of April and May. That is one foot higher than normal.
“This increase in lake level, which occurs as a normal operation during declared droughts, is meant to hold more water in anticipation of needs lower down in the Okanogan later in the summer,” explained Al
Josephy, with Ecology’s water resources program in Olympia. “Flows in the Okanogan River below Zosel Dam will be somewhat constrained during that fill period. As the spring melt has not begun in earnest, dam operators do not expect the impact on flows in the river to be greatly affected.”
The current regulations are consistent with how the dam has been operated over the past nearly quarter century. In fact, drought has been declared 12 times in the past 24 years. Any interested persons are encouraged to call Ecology in Olympia, with their questions. Contact Al Josephy at (360) 407-6456.
More information is available at the International Osoyoos Lake Board of Control website: http://www.ijc.org/conseil_board/osoyoos/en/osoyoos_home_accueil.htm.