D.C. fifth-grader Siraugh Williams spent part of the hot, steamy morning yesterday bent over an Anacostia River mud flat planting wild rice, the swampy muck sucking at his rubber boots "like an animal pulling on your leg."

He loved it. "I want to go back in the mud," he said, "and have a mud fight."

Building enjoyment of the outdoors in young people is one goal of the Anacostia Watershed Society, which runs an educational program that brought the 11-year-old and two dozen other D.C. public school students to an island across from Robert F. Kennedy Memorial Stadium yesterday. Another goal is building back the ruined wetlands of the tidal Anacostia River.

Thousands of acres of wetlands where wild rice once grew were destroyed when the U.S. Army Corps of Engineers channelized the river 75 years ago. Now the Corps of Engineers is among a gaggle of local and federal agencies trying to bring the wetlands back to life. The project involves bureaucratic coordination, high-tech hydrogeology and low-tech grunt work.

The most recent marsh restoration sites on the Anacostia River are clustered around city-owned Kingman and Heritage islands, where more than 50 acres of new wetland have been built with dredged sediment and hundreds of thousands of plants have been tucked into the muck. That work relied on lessons learned from the first marsh restoration project on the Anacostia, a 32-acre wetland constructed a decade ago at Kenilworth Aquatic Gardens.

To the planners' surprise, long-dormant seeds sprang up in dredged sediment at the Kenilworth Marsh, helping to fill in the barren mud flats. But some of the plants were undesirable cattails and phragmites. When newer marshes were built, the hydro-engineers arranged the sediment in a way that would discourage the plants they did not want and encourage the ones they did.

Another problem has been Canada geese, which regard the tender marsh plants as a salad bar. Like suburban pond geese, these birds stay year-round, chowing down. Government officials have taken gentle steps such as fencing to discourage them and are debating stronger measures. Meanwhile, the marshes remain at risk.

"It is not for the faint of heart," John Paul Woodley Jr., assistant secretary of the Army for civil works, said of projects to revive deteriorated urban environments such as the Anacostia River. The Anacostia project, he said, "is the cutting edge of environmental restoration."

Environmental restoration is a growing part of the Corps of Engineers budget and now accounts for $25 million a year, Woodley said. That includes such marquee projects as bringing back the Florida Everglades as well as lesser-known ones that include turning a former drive-in theater parking lot in Rhode Island into a wetland.

Before yesterday's planting fest, schoolchildren and Anacostia Watershed Society volunteers already had installed an acre and a half of wild rice on a mud flat next to Heritage Island, formerly known as Children's Island. The plants are spaced a forearm's length apart, then placed in planting holes that are patted down with mud.

The wild rice plants put in the ground yesterday are Zizania aquatica, a variety that can be found from Florida to Massachusetts. Students in the Watershed Society's Rice Rangers program collect seeds from rice plants in the marsh each fall and nurture them until the plants are about three feet tall. If all goes well, they will grow into a grassy, shoulder-high thicket.

After Siraugh and his classmates from LaSalle Elementary School in Northeast finished their work, teacher Ric Zeller explained to them how their plants would root and hold dirt to prevent erosion. Using the example of a carnation placed in water with food coloring, he described how plants absorb what is in the water around them.

"Those rice plants you planted are sucking up the water," he told them. "They're filtering the water."

At a ceremony yesterday, Benjamin H. Grumbles, acting assistant administrator for water at the U.S. Environmental Protection Agency, presented the Watershed Society's president, Robert H. Boone, with a $100,000 check to fund the Rice Rangers program.

"You're not just planting seeds of rice," he told Boone. "You're planting seeds of hope."