Department of Ecology News Release - June 10, 2019

Lake Osoyoos water levels on the rise

Responding to drought conditions in the Okanogan Valley

Zosel Dam at Oroville on June 10
OROVILLE  –  Water levels in Osoyoos Lake are rising as the Washington State Department of Ecology works to respond to declared drought across the region.

Extreme low flows forecast in the Okanagan and Similkameen rivers threaten the ability of local irrigators to use water from the river later in the summer. In conditions such as this year, the lake can provide some limited backup going into the summer.

Lake levels are managed at Zosel Dam in Oroville under orders of control mandated by the International Joint Commission (IJC). The joint commission recently approved recommendations that Ecology operate Zosel Dam
now through Sept. 15, 2019, according to drought-condition rules included in the those orders.

“Filling the Lake will occur immediately,” said Al Josephy with Ecology’s water resources program. “It will probably take til about June 20 to bring the lake up about a half a foot higher than usual. Although storage capacities in Lake Osoyoos are limited an extra half foot of water will give us 3,000 acre-feet of water to help maybe even into September.”
The Department started filling operations, in anticipation of a favorable ruling from the IJC, during the week of June 3. Ecology and the local operator will endeavor to keep the lake at that level until mid-August at which point residents can expect the lake to slowly decline to 911 feet or lower by mid-September.

Drought operation authorization by the IJC allows Ecology to fill the lake a half a foot higher than usual, from 912 feet to 912.5. It also allows Ecology to draw the lake down to 910.5 later in the summer, below the usual operating summer minimum of 911.

More information is available on Ecology’s website. More information on the drought at

Contact information

Joye Redfield-Wilder
Communications manager
Twitter: EcyCentral