Hurricane Katrina proved America is paying a high price for its loss of wetlands, scientists say, and activists are pressing for restoration of swamps and marshes to prevent new catastrophes.

In a speech on the Senate floor last February, Sen. Mary Landrieu warned lawmakers that disappearing wetlands along the coast of her native Louisiana - vanishing at the rate of 25 square miles a year - would ultimately result in "more severe and frequent flooding than ever before" and cost in the billions of dollars.

"With the loss of barrier islands and wetlands over the next 50 years, New Orleans will lose its wetland buffer that now protects it from many effects of flooding," she said. ""Hurricanes will pose the greatest threat, since New Orleans sits on a sloping continental shelf that makes it extremely vulnerable to storm surges."

Landrieu's words proved eerily prescient. Less than eight months later, Katrina hit the region with Category 5 fury, inundating New Orleans and causing billions of dollars in damages.

Katrina hit the New Orleans region with such force that ruin likely would have resulted regardless. But scientists are almost unanimous in their assessment that vanishing wetlands are having a deleterious impact, creating hazardous conditions that could have been mitigated by their continued existence.

Too often, environmentalists say, communities are draining swamps and marshes to allow for commercial and residential development.

"Disappearing wetlands increase the risk of flooding, threaten the survival of migrating birds and endangered species and diminish the environment for outdoor lovers and sportsmen," said Eric Schaeffer, director of the Environmental Integrity Project, a Washington-based interest group.

The U.S. Fish and Wildlife Service maintains that wetlands "function as natural sponges that trap and slowly release surface water, rain, snowmelt, groundwater and flood waters."

"Trees, root mats, and other wetland vegetation also slow the speed of flood waters and distribute them more slowly over the floodplain," the service said in a statement. "This combined water storage and braking action lowers flood heights and reduces erosion. Wetlands within and downstream of urban areas are particularly valuable, counteracting the greatly increased rate and volume of surface-water runoff from pavement and buildings. The holding capacity of wetlands helps control floods and prevents water logging of crops."

Despite their value and even though protections are offered under the Clean Water Act of 1972, wetlands are disappearing at an alarming rate. The wildlife service notes that 220 million acres of wetlands existed in the lower 48 states in colonial America. That total has declined to about 100 million acres.

From the mid-1950s to the mid-1970s, the lower 48 lost an average of 458,000 acres of wetland each year. Between the mid-1970s to the mid-1980s, the loss rate dropped to about 290,000 acres annually. Today, the annual loss rate is somewhere between 70,000 and 110,000 acres.

In the spring of 2004, President Bush pledged his administration to a no-net-loss policy and went so far as to commit to annual gains in wetlands habitat. Critics assert he has not honored that pledge and that the Army Corps of Engineers, a key federal agency charged with protecting wetlands, is engaging in practices that are destroying thousands of acres.

In a report issued last month, the Environmental Integrity Project said the Army Corps has opened more than 11,000 acres of wetlands in 15 states for development since the spring of 2004. Among the enterprises who benefited was a Wal-Mart shopping center in Texas, a titanium sand mine in Georgia, a peat bog mine in Florida and a highway project in North Dakota.

"This administration is not very good at keeping promises made to the American people," said Joan Mulhern, senior legislative counsel for the environmental group Earthjustice. "The president and his appointees promised not to change the Clean Water Act's rules, but they are shirking that responsibility by just ignoring those rules. In turn, they are breaking the promise of the Clean Water Act, which is to protect all of the nation's waters, to make them safe for drinking water, for swimming and fishing. This cannot be done when the Corps leaves waters out of the law's scope."

James Connaughton, chairman of the White House Council on Environmental Quality, defended the administration's record, saying a report released by the council in April shows the administration is on target to "restore, preserve and protect at least three million acres of wetlands over the next five years.'' The effort was enhanced, he said, by $40 billion in conservation funding in the 2002 Farm Bill and reauthorization of the North American Wetlands Conservation Act.

The administration is looking to develop public-private partnerships to meet its goals.

"Working collaboratively has proven remarkably effective in improving and sustaining America's wetlands," Connaughton said.

However, in two separate reports released last month, the Government Accountability Office found the Army Corps has failed to determine whether developers were offering proper justification for building in wetlands before issuing permits. It also accused the agency of failing to explain why it is not assuming jurisdiction over disputes rising from wetlands development.

"These reports show that the Corps is failing to ensure that Clean Water Act regulations are applied to their full extent and is providing no rationale for its failure to protect many wetlands," said Jim Murphy, water resources counsel for the National Wildlife Federation. "And if this isn't troubling enough, the Corps is making little effort to ensure that permitted impacts to wetlands are mitigated. This all adds up to wetlands losses that are not being accounted for."

The Army Corps officially accepted the criticisms contained in the reports and said it is developing policies to address the problems.