Department of Ecology News Release - January 14, 2013


U.S., Canada, Washington State agree to new cross-border lake operations

OLYMPIA – U.S. and Canadian authorities have reached an agreement with the state of Washington to renew and update joint operations of Osoyoos Lake, which straddles the two countries at Oroville, Wash. The Washington State Department of Ecology (Ecology) owns and operates Zosel Dam, which controls lake levels and trans-border flows downstream from the outlet of Osoyoos Lake on the Okanogan River.

In signing the agreement, Washington Gov. Chris Gregoire accepted the conditions and recommendations negotiated over the past several years between the International Joint Commission (IJC), Canada and United States. The agreement updates and renews orders established in 1982 to jointly manage lake levels for irrigation, flood control, drought and recreation. The agreement was due to expire Feb. 22, 2013.

New joint operations reflect seven years of study and public input and recommendations by the International Osoyoos Lake Board of Control, established by the IJC in 1946 to ensure compliance and supervise cross-border operations of lake levels during both wet and dry years.

Gregoire said the work to update cross-border lake operations enables the state to continue to partner with British Columbia to operate and maintain the lake for the mutual benefit of homeowners, agriculture, tourism, fisheries and all concerned.

During normal years the lake elevation is held between a maximum elevation of 911.5 feet and a minimum elevation of 909.0 feet. However, under the new orders, during a drought year water may be stored to lake elevation as high as 912.5 feet, a reduction of one-half foot from the 1987 Order. Zosel Dam effectively controls the elevation of Osoyoos Lake except during periods of high snowmelt runoff when natural conditions often force the lake above elevation 913.0 feet.

The six-member International Osoyoos Lake Board of Control holds an annual meeting and reports to the International Joint Commission each fall. Monthly reports of daily lake levels and flows are kept by the board to document compliance with agreement orders.

More information about the agreement can be found online.


Media Contact: Joye Redfield-Wilder, 509-575-2610,

Osoyoos Lake International Water Control Structure - Zosel Dam (

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