GULFPORT, Ill. — The rising Mississippi River broke through a levee Tuesday, forcing authorities to rescue about a half-dozen people by helicopter, boat and four-wheeler as floodwaters moved south into Illinois and Missouri.

But even as the water jeopardized scores of additional homes and businesses, officials said the damage could have been worse if the federal government had not taken steps to clear flood-prone land after historic floods in 1993.

On Tuesday, the flooding halted car travel over two bridges linking Illinois and Iowa and threatened to cover areas near tiny Gulfport with 10 feet of water.

"I'm not going back after this one," 83-year-old Lois Russell said as she watched water surround her house near Gulfport. It was the third time she had fled her home because of flooding since 1965.

"It was a good place to raise my seven kids," she said, crying. "I know I haven't lost anything that feels important because I have a big family."

The area was inundated after a levee broke near Gulfport. The details of the rescues were unclear because of discrepancies in the numbers of people involved and the circumstances described by state and local officials. But authorities agreed that boats, helicopters and an all-terrain vehicle were involved in the efforts.

Preliminary estimates were that the flooding has caused more than $1.5 billion in damage in Iowa, and that figure will undoubtedly rise as the high water moves downstream.

Still, officials said the cost would have been even higher if the federal government had not purchased low-lying land after the 1993 deluge, which caused $12 billion in damage.

Since then, the government bought out more than 9,000 homeowners, turning much of the land into parks and undeveloped areas that can be allowed to flood with less risk. The Federal Emergency Management Agency has moved or flood-proofed about 30,000 properties.

The effort required whole communities to be moved, such as Rhineland, Mo., and Valmeyer, Ill.

In Iowa, FEMA spent $1.6 million to buy out residents of Elkport, population 80, and then knock down the village's remaining buildings. Some residents moved to Garber, Elkport's twin city across the Turkey River, but others abandoned the area.

"There's nothing there in Elkport anymore," said Helen Jennings of Garber. "They built new houses in different places."

Some of those who stayed are paying a price.

The federal government bought about a quarter of the homes in Chelsea, Iowa, after the 1993 floods, but most of the 300 residents stayed. At least 10 homes are now inundated by the Iowa River to their first floors.