Review of Order for Corra Linn Dam

Reviewing the Kootenay Lake Order of Approval 

The International Kootenay Lake Board of Control (IKLBC) is reviewing the International Joint Commission's (IJC) 1938 Order of Approval for the Corra Linn Dam, the binding instrument that governs how water is stored on Kootenay Lake and sets the seasonal "rule curve" of maximum lake elevations.  

The IJC was established under the 1909 Boundary Waters Treaty between Canada and the United States, and its involvement here reflects the transboundary nature of the lake: Kootenay Lake levels can create backwater effects that extend upstream into the Kootenai River valley in Idaho, affecting agricultural lands, drainage, and groundwater. The Order is now almost 90 years old and was written for a much simpler system; one that predates upstream facilities such as Duncan and Libby Dams, the parallel Kootenay Canal Plant, modern flood-risk management, today's understanding of climate impacts on hydrology, the importance of ecosystem functions, and Indigenous rights and engagement. 

Scope and Objectives 

This first phase of the review is the development of a Plan of Study. It does not decide whether the Order should change; rather, its purpose is to identify the studies, analyses, engagement, and decision-support information the board and the IJC will need before they can determine whether the 1938 Order should be retained, revised, supplemented, or modernized. A central question is whether the existing rule curve provides enough flexibility for present and future conditions, while keeping flood-risk management and public safety as core constraints. 

How the Plan of Study Was Prepared 

In September 2025, the IKLBC engaged a consultant to lead development of the Plan of Study. The consultant and Board gathered information from more than 250 technical reports and records, and through extensive engagement including: 

Proposed Studies 

The Plan of Study recommends first establishing a Technical Working Group to define and translate concepts into consistent, model-ready scenarios (such as flexible spring drawdown, conditional spring exceedance, fall/spring water-level management for West Arm shore-spawning kokanee, earlier spring-rise timing, managed high-water ecological operations, and flood-risk override safeguards). The Plan of Study then proposes conducting a series of studies, to investigate topics such as flood-damage and risk management; Grohman Narrows dredging; agricultural impacts; shore-spawning kokanee; wetlands restoration; hydropower generation and capacity; regulatory and ratepayer implications; downstream aquatic habitat; and compensation methods for Kootenai Flats agricultural producers. The studies will be sequenced so they can build on the evidence previously developed, and all will be evaluated using hydrologic and operations models. 

Where Things Stand 

In May 2026, Mountain Station Consultants prepared a draft Plan of Study for preliminary Board evaluation. The Board discussed the preliminary findings at its annual in-person meeting on June 2, 2026, and presented them to the public in Nelson (June 2) and Bonners Ferry (June 3). Feedback from the Board is is now being incorporated into the next revision. 

Next Steps