2023 Spring Rise Declaration
The International Kootenay Lake Board of Control, after consultation with FortisBC on Corra Linn Dam operations, has determined that “the commencement of the spring rise” for purposes defined in the 1938 International Joint Commission Order on Kootenay Lake occurred at 00:00 PDT on April 30, 2023.
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, British Columbia. Reaching this threshold will mark the end of the freshet period for the Kootenay Lake basin.
The declaration comes at a relatively later date than usual in the history of the board, two days later than in 2022. Cooler-than-normal temperatures have prevailed since February 2023, keeping lake inflow below normal and snowpacks from melting.
At the time of declaration, the level of Kootenay Lake at Queens Bay, B.C., was 1739.20 feet (530.11 meters). Kootenay Lake inflow was 24,300 cubic feet per second and is forecast to continue increasing for the next month. For reference, Kootenay Lake at Queens Bay reached its minimum daily average elevation of 1,739.06 feet (530.07 meters) for the year on April 26-27, 2023 (Figure 1).
Figure 1: 2023 Kootenay Lake levels at Queens Bay (green) and Nelson (orange), lake outflow control by Corra Linn (pink) or Grohman Narrows (purple), and the International Joint Commission 1938 Order of Approval Rule Curve for 2022 (red).
Please monitor the board website for further hydrologic updates. A news release detailing the freshet conditions will be posted in the coming months following the freshet peak. Real-time Kootenay Lake levels can be found at the FortisBC website.
Information on the IJC 1938 Order of Approval for Kootenay Lake can be found here; the lowering formula is referenced on page 4 in item 2, part 6.
For questions regarding the spring rise declaration, please contact Canadian Board Secretary Martin Suchy at Martin.Suchy@ec.gc.ca or US Board Secretary Sonja Michelsen at Sonja.M.Michelsen@usace.army.mil.