We’ve Proved That We Can’t Conquer the River : Floods: Advocates of better zoning and building laws have new arguments against the dam-and-levee crowd.

When John McPhee wrote about how our society responds to floods in his 1989 book, “The Control of Nature,” he chose as his examples the Mississippi River Valley and the Los Angeles area. Both areas have large populations at risk, and both vividly illustrate the problems of protecting people by relying exclusively on technology to control massive floods.

Perhaps the only positive aspect of the long-running disaster in the Mississippi Valley is the hope that it will rekindle moves to adopt a rational flood-management policy for the nation. For many years , the United States has substituted flood control for flood management.

On one side of the debate are advocates of non-engineered approaches that discourage occupancy of flood-prone areas; on the other are those who favor structural solutions such as big dams and levees. For decades the advocates of structural flood control have won the debate hands down, supported by the Congressional pork-barrel system and federal spending. As early as 1937, a high-level government committee found that “attention has been centered too much upon control of destructive flood waters, or upon protection against them by physical works, and too little upon control of the occupation and use of valley bottoms which are natural floodways.”

By the early 1970s, this policy had clearly failed. Huge increases in spending on structural flood control were accompanied by larger and larger increases in flood damages. In the memorable 1973 flood, the Mississippi rose higher than ever before, even though there was less volume of water in the river than in previous floods. New levees had isolated the river from the flood plain, preventing the storage of floodwaters and constricting the flow to a narrow channel. When the levees failed under the increased water pressure, inundation was sudden and unexpected. Whole communities had been built on the flood plain; believing that the levees would protect them, they had taken no steps, such as building raised structures, to protect themselves.

Experiences like the 1973 flood, in combination with the growing strength of the environmental movement, led to significant new initiatives in national policy. By 1981 there was a national flood-insurance program that encouraged flood-plain zoning; construction of pork-barrel flood-control projects virtually ended when local communities were required to pay 25% of the cost.

Just at that moment, when changing attitudes in flood management were taking hold, a new Administration, antagonistic to the idea of national planning, reversed course. It abolished the Water Resources Council, which had been a major force in advancing flood-management policy. In California, Proposition 13 gutted flood control districts’ budgets, stifling new approaches in flood-hazard management.

In the last 12 years, as flood damages have continued to mount, new ideas have arisen that substantially alter the way we look at not only floods, but also rivers. It is not just property damage and environmental regulations that are pushing us in a new direction, but a more positive view of rivers and creeks as assets to their communities. There is a growing constituency for restoring and managing rivers, exemplified by the widespread support in Los Angeles for groups like Friends of Los Angeles River.

A type of flood management that is compatible with restoring and protecting rivers is emerging. Such an approach has as it primary goal the reduction of hazards to lives and property. The control of floods is not a goal in itself, but one of several possible tools. In other words, what we should care about most is not whether a river has been tamed but whether the risk of floodwater coming through our front doors has been reduced to acceptable levels. But in the absence of clear national leadership, flood-control agencies are already advocating that broken levees along the Mississippi be rebuilt, at great cost and in a way that virtually ensures failure in the next big flood.

It is possible to imagine a city that understands the value and power of its rivers, where creeks are no longer regarded merely as concrete-lined storm sewers but as the centerpieces of parkways and open spaces, as well as storers and absorbers of floodwater; where parking lots are landscaped so that they remove street pollutants and percolate runoff, and where the Los Angeles River is a river again and a symbol of the city’s ability to remake itself, instead of a threatening stage set for movies like “Terminator 2.”