Monitor water levels and flows

International Rainy Lake of the Woods Watershed Board monitors water levels and flows on the Rainy River, Rainy Lake and Namakan chain of lakes.

Water Levels Committee ensures that the operation of the dams follow the Orders of the International Joint Commission.  The current Order consists of a rule curve band for Rainy Lake and one for the Namakan chain of lakes, with minimum releases in times of low inflows and all gates open levels in times of high inflows.

The rule curves provide an upper and lower limit for the water elevation in the reservoir at any day of the year, lower in the winter and higher in the summer.  

In times of extremely low inflow for that time of year, the water level may go below the rule curve; however a minimum release comes into effect to ensure there’s sufficient water downstream.  In times of extremely high inflows for that time of year, water levels may go above the rule curve because the outlet capacity is unable to release as much water as is coming into the reservoir, even with all gates fully open.

The Water Levels Committee maintains a list of people whom it notifies in cases of drastic outflow changes and has a fish spawning protocol to protect the desiccation of eggs from lowering outflows.

A provision of the 2000 Consolidated Orders called for the evaluation of the rule curves after 15 years which means that the Watershed Board and the International Joint Commission have sponsored some two dozen studies to evaluate the performance of various economic and ecological indicators under the latest two sets of rule curves.  The earlier set dates from 1970.  The Rainy and Namakan Lakes Rule Curve Review Study Board reported on their evaluation in May 2017, the IJC subsequently issued a March 2018 Order and an official Compilation of the Order in September of 2018.

The 2018 Order states:

Whearas after careful consideration the Commission is confident that the adoption of the rule curves contained in this Order will result in broad ecological benefits, and that the new inclusion of an alternative rule curve for Rainy Lake for high flood risk years will help to reduce flood peaks. Combined with further operational guidance for the Water Levels Committee, more flexibility for the Water Levels Committee in targeting levels within the rule curves, continued and improved engagement with Métis, Tribes, and First Nations, and the exploration of adaptive management, the rule curves will help to ensure that the boundary waters of the Rainy River basin are well managed for years to come.

Operational Guidelines were prepared as part of the International Rainy and Namakan Lakes Rule Curves Study Board’s final report to the Commission. The intent of guidelines is to summarize best practices and considerations for managing water levels throughout the year within the established rule curves, when conditions allow. The Water Levels Committee may therefore amend these Guidelines as new information becomes available, including input from resource agencies, the public, stakeholders, and indigenous communities. 

Please submit and comments to the Water Levels Committee under the contact us tab.