The superintendent of the boot camp, John W. McCorkle, is a 6-foot 5-inch Vietnam veteran who dresses in black, rarely takes off his sunglasses and shouts at inmates when they forget to call him sir. It is all part of the four-month paramilitary boot camp training, which the inmates, who have all been convicted of nonviolent felonies, have chosen over prison. But the superintendent cried openly over the levee.

"I told them, 'You're a man; you can cry anytime you want to,' " he said. "I always knew boot camp kids work hard. But they amazed me. They were throwing sandbags and smiling, and I asked them, 'What are you smiling for?' They answered back: 'We're saving lives, sir!' "

He sent the first 50 boot camp inmates to Niota on July 2. The town was desperate for help to fill sandbags and pile them along the levee. "We went there with a purpose," said Dean Ramirez, 20, from Chicago's South Side. "We were there to save the town." First Look at the Mississippi

Most had never seen a levee before. Mr. Yance said that until boot camp he had only made one trip outside of Chicago, to Springfield with his eighth-grade class. He had never seen the Mississippi. "When I got close to it, you know what I did?" he said. "I dipped my hands in it, and ran it over my face. I didn't know when I'd ever get the chance to do that again."

The boot camp inmates threw sandbags from 8 A.M. until dark, for nine days straight, stopping only to eat and to sleep at a nearby work camp. "They got our respect when they showed us how hard they worked," said Mrs. Farr, who has three sons, 22 to 28 years old. "They were so young. I just kept thinking, 'They could've been mine.' "

And the inmates in turn began to think that the town could have been theirs. "At first it was just work," Mr. Ramirez said. "But then I started caring. I said, 'Let's stack these right.' "

On the levee, inmates worked shoulder to shoulder with the men and women of Niota.

"They brought us Pepsi," said Allen Church, who graduated from the boot camp on July 14 and is living in a half-way house in Peoria because he does not want to go back to Chicago. "They let us sit down in the shade and drink from their water hose. They were just nice people. That's what made you want to do more. When you saw the looks on their faces -- all they cared was that you were there."