A tricky mix: Managing water in northern Lakes

Fifteen years ago, engineers with the International Joint Commission made big changes in how they regulate water levels on some of Minnesota's largest border lakes.

The commission has hired Bemidji State University economist Patrick Welle to calculate the economic impact those changes had on property and livelihoods.

Here's how the system works:

The Rainy, Kabetogama and chain of Namakan lakes are reservoir lakes connected by three dams. The commission tries to match their rise and fall to the water levels of natural lakes in the region. Engineers open and close portions of the dams to hit scheduled water levels in a rule curve.

But Mother Nature can throw a different kind of curve into the system because the watershed that feeds the lakes is massive. Rain and snow melt flows from the Namakan Chain, which includes Kabetogama, into Rainy Lake, west to the Rainy River and ultimately on to Lake of the Woods.

All of the water is regulated at two spots. Two dams built on each side of an island at Kettle and Squirrel Falls is at the east end of Rainy Lake. The other is a hydroelectric dam where the lake feeds the Rainy River between Fort Frances, Ontario and International Falls. As the water flows into the Rainy River, it spins eight Canadian turbines and seven generators on the U.S. side, which power the Boise paper mill.

When timber baron Edward Wellington Backus built the hydroelectric dam in 1905, providing power for industry was its only purpose. At the time, water levels were largely unregulated so dam operators kept water pouring through the generators at basically the same rate whether the lake was flooding or getting too low.

The lake levels fluctuated until the IJC took over water regulation in 1949. There are still floods, but the primary goal of the reservoir dams today is to keep the lake system away from flood stage, according to Matt DeWolfe, an engineering adviser to the International Lake of the Woods Watershed Board. However, engineers have to balance flood avoidance with the water levels resorts need for recreational use.

Since the IJC implemented its new water management plan in 2000, Rainy Lake has been hit with seven years of floods and high water. DeWolfe said that's largely due to more rain and heavier snowfall dumping more water into the huge basin that feeds the lakes.