In a way, they are.

A little more than a year ago, this thriving marshland was an ordinary soybean field on the banks of the Mississippi River. McGinnis, a wildlife biologist, supervised its transformation into 1,200 acres of wet prairie, restoring an ecosystem that virtually disappeared a century ago.

"There are people here in the Midwest who have never seen water like this," McGinnis said. "My father's father probably never saw water this clear."

All the more remarkable is that the wetlands project is the work of the Army Corps of Engineers, better known for draining swamps than building them.

"The corps always thought of water resource development as development - you know, industrial development," said McGinnis, a 13-year corps veteran. "It was rape and pillage, cram a project into the land without regard for its long-term effects."

But a fundamentally different corps - an increasingly "green" organization - built the Riverlands Demonstration Project near the confluence of the Mississippi and Missouri Rivers, about 20 miles north of St. Louis.

"The corps has gotten religion now, and in good faith is trying to do a better job," said Steve Moyer, a lobbyist for the National Wildlife Federation.

The corps is touting its new mission to protect the environment. And it is doing so first with a confession that its past practices damaged sensitive ecosystems, and second with the claim that only the corps has the engineering expertise to correct the problems it created.

The corps' $9.4 billion budget next year includes more than $1 billion devoted to environmental projects, ranging from hazardous-waste cleanups at military bases to creation of wetlands.

The budget also includes reworking some corps projects that are notorious for the environmental damage they caused: increasing water flow into the dying Florida Everglades, restoring wildlife areas along the Tennessee-Tombigbee Waterway and rebuilding fish habitat along the Columbia River.

"It is we engineers who hold most of the keys to the solutions of the world's environmental problems," Lt. Gen. Henry J. Hatch, the commander of the corps, told the American Society of Civil Engineers last fall.

"We have a common concern with environmentalists: the health of our planet and the health and prosperity of our people," he said.

The corps has gone so far in some regions that its enforcement of wetlands regulations has created a backlash among private property owners, farmers and developers.

"They are very much going overboard," said Larry Mitchell, assistant director of the American Agricultural Movement in Washington, whose members complain that the corps has blocked them from building dikes and drainage systems to protect their fields.

The corps' metamorphosis demonstrates how much environmentalism has entered the mainstream.

But the transformation is also rooted in pragmatism. With the Defense Department curtailing construction projects, the corps faces massive budget cuts and needs to find other work for its 42,000 civilian employees.

Moreover, the corps acknowledges that it is running out of the mammoth civilian projects that have been its bread and butter since the 1930s. Few rivers remain that the corps has not dammed, dredged or channelized.

Corps officials say the agency has been quietly evolving during the last decade as younger, more environmentally aware engineers, who are known in-house as the "bird and bunny" types, replaced traditionalists, known as the "dam-it, ditch-it and dredge-it" engineers.

But environmentalists say the changes are profound since President Bush came into office. In his first State of the Union address, in 1989, Bush declared a national goal of "no net loss of wetlands."

Assistant Army Secretary Robert W. Page and Hatch - who began his four-year hitch as head of the corps in 1988 - have since issued a stream of directives underscoring the corps' environmental mission.

"The whistle has blown and the army has wheeled," said Hope Babcock, legislative director of the National Audubon Society. "And now it's marching off in another direction."

Hatch's message is that the corps, throughout its history, has altered its mission to be "relevant" to popular concerns. When the public wanted to control floods and improve navigation on the nation's rivers, the corps built massive lock and dam systems.

The time has come for the mission to change. "Nation building no longer automatically means large construction and maintenance operations," Hatch said last fall.

The corps' new environmental ethic is being carried out with varying degrees of enthusiasm in the agency's 38 district offices, as the agency undergoes an internal shakeup that frequently pits the new-generation engineers against the old.

"Some of the grayheads are still sitting around," said William H. Dieffenbach, assistant environmental administrator for the Missouri Conservation Department, who added that he had butted heads frequently with the eight corps districts whose jurisdictions overlap his state. "They take some changing and convincing."

Col. James E. Corbin, the district commander in St. Louis who is regarded as one of the more environmentally enlightened commanders, said it was only a matter of time before the changes became more widely accepted by his staff.

"It's not right or fair for you or me to walk out there, turn the world upside down and expect them to understand immediately what the change is," said Corbin, who assumed command in St. Louis two years ago.

One of Corbin's primary duties in the district, which regulates the Mississippi River basin between Hannibal, Mo., and Cairo, Ill., was supervising construction of Lock and Dam 26, a $980 million navigation project on the Mississippi River.

As part of that project, the corps bought 1,200 acres of farmland that became saturated by the dam's impounded water.

The corps' real estate office wanted to lease the land to farmers. But Corbin went along with McGinnis' idea to build the Riverlands Demonstration Project.

"I said to hell with the real estate brokers, let's go create an environmental demonstration area," Corbin said. "It's a unique place for it, sitting right there by the largest structure in the Mississippi River."

McGinnis and his staff designed a wetland prairie. Corps equipment operators sculpted the land into a mosaic of ponds, swamps and islands where the water level can be controlled with a system of valves.

The corps planted 7,000 pounds of prairie grass seed, plus other native weeds and flowers. Once the plants came up - plus hundreds of other species that were lying dormant - waterfowl and shore birds arrived in droves. The corps even introduced a pair of endangered peregrine falcons into the plot.

In order to plan and complete the project in less than two years, Corbin and McGinnis stretched the corps' rules. They wanted public nature trails through the area. But footpaths are "recreational activities," which regulations say must be financed with matching private funds. So McGinnis instead called the paths "fire trails" - and the corps paid.

"For basically $500,000, we took a 1,200-acre area and got it well on the way to being what it was 200 years ago," said Corbin. They maneuvered the money from the budget for the lock and dam construction.

McGinnis is unabashed about his intention - he wants the demonstration to become a model for the new corps. "It's a marketing chip for Gen. Hatch," he said.

So far, the project has won over a few converts to the corps.

"For years the St. Louis corps district was known as the environmentally worst district in the nation," said Jim Bensman, a Sierra Club official in Alton, Ill.

But Bensman was so impressed by the Riverlands project that he immediately removed the bumper sticker that had festooned his car for years - "Damn the corps, not rivers."