Water Levels Committee Release: Rainy Peaking, Namakan Declining
International Falls, MN, Fort Frances, ON — The level of Rainy Lake is close to peaking at its highest level since 1950. At the Fort Frances-International Falls dam, all fifteen spill gates have been open since June 6, and the overflow weir that spans the center of the dam began passing water last week for the first time since 1950. Although the dam has been fully opened, record high rainfall in June in Minnesota led to inflow to Rainy Lake that far exceeded the outflow capacity of the dam. As a result, Rainy Lake continued to rise throughout the month. The high water levels have caused significant damage in communities, for individual property owners, and for busineses on both sides of the border. Emergency declarations have occurred in several communities with coordinated efforts at sandbagging and other protective measures being carried out over the last few weeks by various levels of government and volunteers.
Along the Namakan chain of lakes the peak level occurred on June 18, the highest level since 1968. Many properties and businesses have been contending with flooding in this area as well. Particularly hard hit have been the lakes upstream of Namakan Lake such as Crane Lake which rose several inches higher than the main body of Namakan.
Since June 18, the level has been declining, but Namakan Lake remains 15 cm (6 in) above the emergency level defined by the International Joint Commission (IJC), known as the All Gates Open level, while Crane Lake is 25 cm (10 in) above this level. The All Gates Open level is nearly a foot higher than the top of the Rule Curve band, the target lake level range defined by the IJC for this reservoir. The dams at Squirrel Falls and Kettle Falls, the principal outlets of Namakan Lake, have been fully opened since May 16. These dams are now providing slightly more than half of the flow entering Rainy Lake, although at the peak of the inflow to Rainy Lake the dams at Namakan Lake provided roughly one-third of the flow.
Over the past week, the International Rainy-Lake of the Woods Watershed Board has received a number of inquiries as to whether there will be action taken to reduce flow out of Namakan Lake to help the level of Rainy Lake decline faster. The option of a flow reduction out of Namakan Lake requires serious consideration, as it would involve increasing risk to one area to reduce it in another. The Water Levels Committee of the International Rainy-Lake of the Woods Watershed Board, which advises the IJC on emergency conditions within Rainy River watershed, is reviewing possible options, but would like to advise the public of the facts considered in such a decision.
The surface area of Namakan Lake is much smaller than that of Rainy Lake. As a result, for every inch that would be saved on Rainy Lake by holding back water in Namakan Lake, the level of Namakan Lake would be nearly 4 inches higher.
While Namakan Lake has been declining, water is leaving the lake only slightly faster than it is flowing in. Reducing flow now would postpone the decline below the All Gates Open emergency level at a time when the Namakan chain of lakes is still at the second highest level since 1968 (2002 was slightly higher than the current level). While the short-term forecast is favorable, there is still the risk that the rest of July could see wet weather. Reducing flow from Namakan Lake now would place interests in this basin at significant additional risk for a small benefit to Rainy Lake.
If the level of Namakan Lake declines below the All Gates Open emergency level as expected later in July, the Water Levels Committee will be reviewing whether to recommend to the IJC to reduce Namakan Lake outflow until Rainy Lake has also declined below its emergency level.
The IJC has no authority over dams in the watershed other than those at the outlets of Namakan Lake and Rainy Lake. However, the Water Levels Committee has been working closely with operators of smaller upstream dams, including the Ontario Ministry of Natural Resources (OMNR), to determine if there is any capacity to store water safely without compromising upstream interests. OMNR has stated that its primary concern is to ensure that their dam structures are not compromised by high water levels. Since water levels remain high throughout the basin, no flow reductions are currently planned at smaller control structures. Along the Seine River system, some small flow reductions have occurred over the past couple of weeks.
The Water Levels Committee suggests that waterfront property owners and users of the system keep themselves updated on basin conditions as forecasts may change significantly through the month. Up-to-date information can be found by following the International Rainy-Lake of the Woods Watershed Board’s page on the IJC website, www.ijc.org or by calling 800-661-5922.