Kootenay Lake is at a very low level for this time of year, according to the International Kootenay Lake Board of Control.
“Based on preliminary data from the Kootenay Lake at Queens Bay Water Survey of Canada (WSC) gauging station, the lake water level on Aug. 1 is the second lowest for that date since 1976,” said Joel Trubilowicz, Canadian co-chair of the International Kootenay Lake Board of Control (IKLBC).
The lowest lake level on Aug. 1 was in 2021. Trubilowicz said the period from 1976-2023 is the comparison period because Libby Dam in Montana, which influences water inflow and levels at Kootenay Lake, was completed in 1975.
The IKLBC does not have water volume commitments to the U.S., Trubilowicz explained. The 1938 Kootenay Lake Order primarily directs the maximum allowable lake elevation throughout the year with no directions on minimum levels.
“Therefore, the (current) drought conditions have not impacted the Kootenay Lake Order of Approval,” he said.
Although inflows to Kootenay Lake peaked on May 17, the lake reached its 2024 peak elevation of 1,745.67 feet (532.08 metres) on June 4 at Queens Bay.
“The level peak was close to the 1976-2023 average; however, it occurred about a week earlier than usual,” noted Martin Suchy, IKLBC Canadian secretary.
Despite the earlier peak, IKLBC Kootenay Lake operations have complied with the International Joint Commission’s (IJC) 1938 Order of Approval throughout the spring and into summer. The lake level peak occurred in early June and then decreased to current levels.
“During the freshet, lake releases were limited by the natural constriction at Grohman Narrows,” said Suchy.
He said that based on the 1938 Order of Approval Kootenay Lake levels will be kept below 1,743.32 feet until Aug. 31, while control of the lake level will fluctuate between Corra Linn Dam and Grohman Narrows.
That will change Sept. 1, when the upper limit for the Kootenay Lake level will increase to 1,745.32 feet.
The commencement of the spring rise on Kootenay Lake (April 16) was the earliest it has occurred in seven years, and two weeks earlier than 2023. The early entry was attributed to sustained higher temperatures at higher elevations.
The proclamation stated that the maximum allowable level of Kootenay Lake will now be calculated based on the “lowering formula defined in the Order until the lake returns to an elevation of 1,743.32 feet as measured at Nelson … on the recession limb of the snowmelt hydrograph (sometime in the summer).”
Kootenay Lake at Queen’s Bay reached its minimum daily average elevation of 1,739.22 feet (530.11 meters) for the year on April 13-14.
The International Kootenay Lake Board of Control oversees the operation of Corra Linn Dam to manage water levels in Kootenay Lake, while FortisBC is the dam’s owner/operator.
