North Dakota says it has a solution to the lake's spread and wants to divert water ultimately to a river in Canada. But that $25 million plan has caused an uproar across the border, where Canadian politicians worry the water will bring pollution that will harm a valuable fishery.

North Dakota has built a system -- set to go into operation on July 1 -- of pumps, pipes and canals to take water from land-locked Devils Lake to the nearby Sheyenne River with the goal of stabilizing the lake at current levels.

The Sheyenne will carry the water south to the Red River near Fargo, North Dakota, joining the Red as it courses north up the Minnesota state line and then over the Canadian border.

In Canada, the Red drains into Manitoba's Lake Winnipeg, the world's 10th largest freshwater lake. Canadian politicians have been scrambling to stop the plan because they believe the water will threaten Lake Winnipeg's commercial fishery, worth C$25 million ($20 million) a year.

Although its water quality has not been extensively studied, critics say landlocked Devils Lake has especially high concentrations of pollutants because runoff from farms and populated areas accumulates there.

But Belford, the North Dakota county official, said the area's excellent fishing was proof Canadians are overreacting.

"If (the lake) had all of the bad things that (Canadians) say were in it, people wouldn't want to come here" to fish, he said.

REPERCUSSIONS FOR CANADA

But across the border about 280 miles (450 km) northeast of Devils Lake, fisherman Bruce Benson fumes about the project as he untangles his nets in preparation for the 100-day fishing season on Lake Winnipeg.

"We've got enough problems on the lake," said Benson, a fourth-generation fisherman and one of about 1,000 who make a living catching pickerel -- what Americans call walleye -- and other species.

Each season, he must replace at least one net because it gets so gummed up with algae that it can no longer be used. The algae -- whose growth is spurred by phosphorus in fertilizers carried by groundwater draining into the lake -- kills fish.

About 6,600 tonnes of phosphorus a year from fertilizer used on farms and city lawns across the Canadian prairies, North Dakota and Minnesota ends up in Lake Winnipeg.

The Manitoba government estimates the Devils Lake outlet could dump another 20 tonnes of phosphorus into Lake Winnipeg each year, along with salts, other pollutants, foreign fish and parasites.

The Americans "don't understand the repercussions of some of their actions," Benson said.

What bothers Benson most is North Dakota's refusal to have its project reviewed by the International Joint Commission, an independent binational agency set up to resolve cross-border water disputes.

But North Dakotans say the commission could take years to do its work, and they can't afford to wait.

By the end of 2004, state and federal governments had spent $400 million moving 500 homes and buildings and repairing roads and bridges as the lake swelled to 136,000 acres (55,000 hectares), more than three times its 1993 size.

Belford said he fears the wet weather, which has raised the lake's water levels by 26 feet (8 m) since 1993, could continue, forcing more people to move and ruin more farmland.

North Dakota started building its $25 million outlet in late 2003 after balking at a US Army Corps of Engineers proposal that was more than seven times the cost, said state water engineer Dale Frink.

But Frink said the Army Corps' environmental studies showed an outlet would be safe.