North Dakota officials say they are not surprised at Manitoba's plans to sue over an outlet to ease Devils Lake flooding, and they still plan to move ahead with the project.

"We can't sit around on the basis that (Manitoba) may bring a legal challenge," Gov. John Hoeven said on Tuesday.

Manitoba officials say the outlet will threaten the environment on both sides of the border.

"We are ready. That lawsuit will be triggered when our lawyers tell us is the most appropriate time," Premier Gary Doer told reporters in Winnipeg.

"We will definitely challenge this project in two venues," he said. "One is the courts and two is the … International Joint Commission."

The commission referees water disputes between the United States and Canada. It has three members from each nation.

Canada already has asked the IJC to step into the debate over a proposed federal outlet project. North Dakota officials say they doubt the federal outlet will ever be built because of its $186 million cost, and they are moving forward with a $28 million state outlet.

Canadian officials have opposed both projects because Devils Lake floodwaters eventually would flow into the Red River and then north across the border. They fear the introduction of biota, or foreign aquatic species, into their waters.

North Dakota officials dispute those claims, saying the outlet is environmentally sound.

"(Canadian officials) have to do what they have to do," said Bruce Engelhardt, an engineer with the state Water Commission. "They haven't filed a suit, let alone proven anything at this point. We're still moving ahead."

Manitoba officials say a legal challenge could be based on their claim that the outlet violates a century-old agreement known as the Boundary Waters Treaty, which prevents either Canada or the United States from actions that would pollute the other's waters.

U.S. Secretary of State Colin Powell, in a January letter to the Army Corps of Engineers, said officials concluded that Devils Lake has no problem species that do not already exist in downstream waterways.

Construction on the 13-mile outlet channel, which began last year, is to be finished later this year. The Water Commission has said the goal is to start draining water from the lake by the spring of 2005.

Manitoba has been fighting the outlet project through diplomatic means for years. Doer said time is running out, with North Dakota preparing to begin the next phase of construction by the end of the month.

"I think we're dealing with absolute American politics to move some dirt before the November elections in North Dakota," he said. "I think it's regrettable if we do not, as Canada, stand up to this short-term political action."

Hoeven disputed the claim.

"The only politics we're dealing with is the fact that (Canadian officials) have played politics with our water projects … for years," he said. "This is about solving the water problem in Devils Lake, and about doing it right."

Devils Lake has risen about two dozen feet over the past decade because of prolonged wet weather in the basin, causing hundreds of millions of dollars in damage.

Manitoba is not alone in its opposition to an outlet. Minnesota also objects, and a group of property owners downstream on the Sheyenne River also has threatened a lawsuit to stop construction.