Lake level dips to lowest on record: board of control
By Timothy Schafer Local Journalism Initiative Reporter
Kootenay Lake is at its lowest level in almost 50 years.
The International Kootenay Lake Board of Control (IKLBC) revealed that on Aug. 19 the lake water level — as measured at Nelson and Queen’s Bay — was the lowest recorded in the 1976-to-present comparison period.
Kootenay Lake at Nelson was at 1,741.91 feet (530.93 metres) and further up the lake at Queen’s Bay Water Survey of Canada (WSC) gauging station it was 1,742.39 ft. (531.08 m.). The calendar year peak at Queen’s Bay was on June 4 at 1,745.67 ft. (532.08 m.), which is below normal at the 29th historical percentile, said Katryna Slimmon, Canadian secretary to the IKLBC.
“Due to low snowfall throughout the winter of 2023/2024, Kootenay Lake water levels are very low for this time of year,” she said, adding that lake level operations remained in compliance with the International Joint Commission’s (IJC) 1938 Order of Approval.
The 1976-2023 comparison period is used 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. The 1938 Kootenay Lake Order primarily directs the maximum allowable lake elevation throughout the year with no directions on minimum levels.
Delving a little further back, the total volume of water that entered Kootenay Lake during the April 1 through July 31 runoff period was the fifth-lowest volume observed between 1999-2024 (in-flow data provided by Fortis BC has only been available since 1999).
Kootenay Lake’s compliance with the 1938 Order is not impacted by drought conditions, said Slimmon.
“The 1938 Order of Approval for Kootenay Lake sets allowed maximum lake elevations throughout the year. There are no lower elevation bounds,” she said.
After the mountain snowmelt dwindles in the late spring, Kootenay Lake is required to be lowered until it reaches 1,743.32 ft. (531.36 m.) at the Nelson gauge. After that point, Kootenay Lake levels — measured at Nelson — must be kept below 1,743.32 ft. until Aug. 31.
The commencement of the spring rise on Kootenay Lake (April 16) in 2024 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.
Kootenay Lake at Queen’s Bay reached its minimum daily average elevation of 1,739.22 ft. (530.11 m.) for the year on April 13-14.
In Control
The International Kootenay Lake Board of Control oversees the operation of Corra Linn Dam to manage water levels in Kootenay Lake, while Fortis BC is the dam’s owner/operator.
The web-based Kootenay Lake visualization tool is available for people to investigate Kootenay Lake conditions in dry, normal and wet years. That link is here.
Information on the IJC 1938 Order of Approval for Kootenay Lake can be found here (the lowering formula is referenced on page four in item 2, part 6).
Real-time Kootenay Lake levels can be found at the FortisBC website.
