Changes will be coming to the Okanagan/Okanogan and Similkameen Basins in Canada and the United States due to extreme drought conditions.
The International Joint Commission (IJC) has approved a temporary variance to how Osoyoos Lake levels are managed this summer to hold more water than usual.
Zosel Dam will hold lake levels within specified limits under drought conditions in the IJC Order for Osoyoos Lake, and the variance will be in effect until Nov. 1, or until water supply and weather conditions improve.
The temporary limit will allow levels to range between 910.5 and 912.5 feet, which is an extra foot and a half above and below the normal summer level range. The plan will see a gradual increase to Osoyoos Lake levels over the next few weeks towards the new temporary upper limit of 912.5 feet.
"The additional stored water will help to augment late summer water supplies and support downstream flows in the Okanogan River, which is crucial for endangered fish and other aquatic species," the International Osoyoos Lake Board of Control (IOLBC) stated.
The Washington State Department of Ecology operates the dam under the authority of the IJC, which involves equal representation from both countries. The variance will allow the department to be more flexible when operating Osoyoos Lake levels.
Osoyoos Lake serves as a source of water for fish, wildlife, irrigation and summer recreation in both Canada and the United States, and the need for lake level variance comes from the usual water and weather conditions in the Okanagan and Similkameen basis earlier this year.
"While conditions for a drought year haven't been officially met this year due to proactive water management in the Okanagan Basin, low winter snow pack, coupled with early snow-melt due to warm temperatures, have heightened water supply concerns for the late summer months in the basin," the IOLBC stated.
Okanagan Lake peaked on June 1 and is being drawn down, leading to less water flowing into Osoyoos Lake. The Similkameen sub-basin is also experiencing reduced water flows at only 47 per cent of normal for this time of year.
The provincial government has deemed the basin to be at Drought Level 2 and Washington State has declared a drought emergency for Okanogon Country, as both sides of the boarder experience the effects of the drought.
