In the United States, the numbers of humans living on floodplains seem recently to have increased, and so probably have the annual costs of flood damage. This is despite expenditures of many millions of dollars on flood-control devices in the United States alone.

The means which we use to control or contain excessive water-energy are the dam, channel, levee, sea-wall, and floodplain management. Logic and evidence, although incomplete, seem to argue against employing only structures; indeed there now seems good reason to think that structures should rarely be employed for flood-control. The case against relying solely on a structural strategy to abate floods rests on four main arguments: it is often counter-productive in that it encourages human occupation of the floodplain, thus introducing the elements of future disaster that may be more serious than if nothing had been done; it causes severe and unnecessary losses of resources; it discourages the economic use of land; and it is not cost-effective.

Floodplain management, keeping the floodplain generally free from flood-control structures, is the only method which is effective in the long run. If it is planned adequately, its life is not as dependent on maintenance and upstream activity as are the structural alternatives. Moreover floodplains, when left undeveloped, are ideal and highly productive for a wide range of conservation and allied uses—including farming, parklands, open spaces, and habitats for wildlife.