In River Battle, Some View Levees as Most Dangerous Enemy : Environment: Critics charge that the flood barriers have helped create the disaster in some areas.

It is perhaps the ultimate irony of the disastrous floods that have swept the Midwest: While the nation’s $25-billion system of levees, walls and other flood-control structures have proved to be the salvation of many communities, it is possible that those same feats of engineering may have aggravated the natural disaster in other areas.

Of course, monster rains are the primary culprit behind the floods. But the rivers, deprived of their ability to spill out over low-lying flood plains, are surging upward and flowing faster against the strictures of their man-made levees. When they overflow, the result can be more cataclysmic than it otherwise might have been.

“People have created the flood problem,” said Bill Dieffenbach, assistant chairman of the Missouri Department of Conservation’s planning division. “We have spent billions on flood control, but it doesn’t work with these kinds of floods. And we’ve had four or five of these in the last 40 or 50 years.”

Even before the Mississippi River floodwaters have begun to recede, a debate is rising over whether and how to rebuild the flood-control system. There are already calls for constructing more and higher levees, but some say that is the wrong answer.

“A number of environmental groups are rising up at this point and saying: ‘The rivers are totally over-engineered here, and it’s time to make a change,’ ” said Kevin Coyle of the Washington-based environmental group American Rivers.

“The worst mistake we can make is to repeat the mistakes of the past,” said Roger Pryor, executive director of the Missouri Coalition for the Environment, an organization that was founded to fight the development of a St. Louis levee in 1969.

The U.S. Army Corps of Engineers, which has built and maintained the levee system for more than a century, contends that the system has worked remarkably well in all but the most dire emergencies.

Gary Dyhouse, a Corps of Engineers hydrologist, said every flood unleashes new criticism of the levee system.

“I don’t think there’s enough stressed about what federal flood protection does,” he said. “I think folks around here who think levees are bad don’t have a concept about how flooding has been controlled.”

The Corps of Engineers claims credit for preventing more than $200 billion in flood damage since 1937. Indeed, but for its 52-foot flood wall, St. Louis would be under water now, said spokesman Scott Saunders. By Dyhouse’s estimate, the levees upstream added only two or three feet to the depth of the floodwaters.

Yet the Corps of Engineers agreed that this flood may spark some new thinking.

“We have the opportunity to make decisions in favor of preserving the ecological and cultural value of the nation’s flood plains and flood-prone areas,” Brig. Gen. Stanley G. Genega, the Corps of Engineers director, wrote in a letter this week to USA Today.

“Locating homes, businesses and industry out of harm’s way is the most practical, common-sense approach to avoiding flood loss, as is limiting development in flood-prone areas to parks, greenways, recreation areas, wildlife habitat and other uses not susceptible to flood damages,” he added.

The federal government first entered the business of managing rivers in 1879, when it created the Mississippi River Commission and focused its efforts on building levees. But it was not until 1927 that Congress, inspired by a disastrous flood in the region, agreed to begin work on a far more extensive systems of dams and locks.

In the intervening 65 years, billions of dollars have been spent on work by the Corps of Engineers, which has constructed an extraordinarily complex system of dams, levees, dikes, retaining walls and locks in the Mississippi River basin, which drains 35 states and covers 1.25 million square miles--41% of the continental United States.

The better part of the work was concentrated in the Lower Mississippi Valley, where the Mississippi River runs deep and wide, taking the combined flows of the Missouri and Ohio rivers as they pour in.

The Corps of Engineers estimates its $8-billion effort in that area has saved $145 billion in property over the years.

The projects throughout the basin have allowed cities and farms to grow and prosper, but it is clear there has been a downside to what man conspired with nature to deliver.

To see the effects that development has had on the severity of floods, St. Louis University geology professor C.B. Belt Jr. compared two floods--one in 1908 and the other in 1973--caused by rains of similar intensity.

He concluded that they were alike in virtually every respect--except that the 1973 flood rose about eight feet higher. The cause, Belt concluded, was the 65 years worth of engineering.

“The system, in disequilibrium, fluctuates wildly,” he wrote in the journal Science, in effect making “big floods out of moderate ones.”

Admittedly, under no circumstances would the current flood have been a moderate one. Actuaries say this type of disaster occurs once in 200 years. But that is little consolation, statistically speaking.

“The problem is, next year they could get another 200-year flood, and the next year get a 200-year flood, and then not have one for another 600 years,” Coyle said.

He and other environmentalists concede that levees will always be needed to protect people and property in flood-prone areas.

But the environmentalists urge that, wherever possible, the river be reunited with its flood plain, and that levees be moved farther from the river’s edge.

They are also arguing that communities, rather than open farmland, be given priority in the levee-reconstruction projects that will be launched after the flood.

Instead of trying to prevent farms from flooding, they say, the government should anticipate that it will happen from time to time and compensate the owners for their crop losses when it does.

There is also some sentiment that people who choose to live in unsafe areas should not expect the government to come to their rescue when nature inevitably flexes its muscle.

“I think there is a saner course here,” said Annie Hoagland, an Illinois environmental activist. “I think we have to decide what places we want to hold the line at. I don’t think we can hold the line at the whole river.”