It's been called a slow-growing monster: a huge lake that has steadily expanded over the past 20 years, swallowing up thousands of acres and at least two towns in its rising waters.

Devils Lake keeps getting larger because it has no natural river or stream to carry away excess rain and snowmelt. Now it has climbed within 6 feet of overflowing, raising fears that some downstream communities could be washed away if the water level isn't reduced.

"It's a slow-moving torture," said 72-year-old Joe Belford, a lifelong resident of Devils Lake and a county commissioner who spends most of his time seeking a way to control the flooding and money to pay for it.

No other place in America has faced such a dilemma.

"We're unfortunately or fortunately - I don't know what it is - pretty unique," said Dick Johnson, mayor of Devils Lake, which has nearly 7,000 residents. The flooding "doesn't have the immediate impact that a hurricane or typhoon might have, but it's devastating."

Since the water began rising in the 1990s, more than 400 homes around the lake have been relocated or destroyed.

The lake, about 160 miles northwest of Fargo, is the largest freshwater body in North Dakota, with an estimated shoreline of at least 1,000 miles. It's up to 75 feet deep and has attracted tourists from across the nation with excellent fishing and other recreational activities.

But local people and politicians fret that the lake is a catastrophic flood waiting to be released in their direction.

In the tiny town of Minnewaukan, the lake was once 8 miles away. Today it is lapping at the community from three sides, and residents are begging for help.

"This is tearing people apart," said Minnewaukan Mayor Trish McQuoid, fighting back tears. Proposals include moving the entire town to higher ground.

By the end of 2010, the federal government will have spent more than $1 billion to ease the threat, buying property, building dikes and making other improvements. It also costs $330,000 a month to power pumps to take 1 inch off the lake.

All of those measures are considered temporary. The solution - and its cost - are not known.

"The issue of stopping the flooding and trying to get water out of that lake is complicated," said Sen. Byron Dorgan, a North Dakota Democrat. "If it weren't complicated, it would have been solved long ago."