Though fishing has been excellent on Rainy Lake for walleyes and smallmouth bass, complications from this summer's flooding will prevail long after water along the border has receded to more normal levels.

"More normal'' is the important term, because disputes over operating levels of waters stretching from Crane Lake to the east, to Namakan and Kabetogama lakes along the Minnesota-Ontario border, to Rainy Lake and Lake of the Woods, won't go away soon.

At issue is the "rule curve'' that governs levels and flow from mammoth watersheds along the border. By agreement of the United States and Canada, the curve was changed in 2000, in part to raise levels on Namakan and Kabetogama, and in part to allow the system to operate "in a more natural state.''

At least that was the theory, said Billy Dougherty, whose family operates Rainy Lake Houseboats.

"Since then we've had seven floods in 14 years,'' he said.

Fully operating this summer, Rainy Lake Houseboats and many other businesses and homes nonetheless have suffered considerable dock and other losses.

Much of the water that enters Rainy Lake flows from Namakan Lake over dams at Kettle Falls and Squirrel Falls. Ultimately, the system is controlled at the Fort Frances-International Falls dam.

Due to the late ice-out this spring and record June rains, and limited outflow capacity of the Fort Frances-International Falls dam, Rainy Lake this summer experienced water levels unseen since 1950, even though all 15 of the dam's spill gates were opened June 6.

Levels of the Namakan chain of lakes peaked June 18 at their highest marks since 1968.

Fixing the problem won't be easy. The waters are managed by the International Joint Commission (IJC) of the U.S. and Canada, which is advised by the Water Levels Committee of the International Rainy-Lake of the Woods Watershed Board, which must consider changes to the rule curve.

If the IJC reconsiders the curve — which Dougherty says should be done immediately on an emergency basis — the often-conflicting interests of property owners on the Namakan basin and other waters will be considered along with those on Rainy Lake and beyond. What's more, the surface area of Namakan is smaller than Rainy's, further complicating the issue.

"We need a solution that benefits everyone,'' Dougherty said. "Meanwhile, the fishing's great.''

Dennis Anderson dennis.anderson@startribune.com