Wetlands help control flooding by acting as holding areas for excess water when rivers flood (heir banks. The floodwater stored in wetlands then drains slowly back into the rivers, providing a steady flow of water throughout the year. Wetlands also serve as groundwater recharging areas. One of their most important roles is to help cleanse and purify water runoff, even water that is polluted. They do this by acting as a sink, a reservoir capable of trapping and holding pollutants in the flooded soil. Other pollutants, such as nitrogen from fertil­izer runoff, are absorbed by wetland plants.

Freshwater wetlands produce many commer­cially important products including wild rice, blackberries, cranberries, blueberries, and peat moss. They are also sites of fishing, hunting, boat­ing, photography, and nature study.

Wetlands are increasingly threatened by agri­culture, pollution, engineering (such as dams), and urbanization. In the United States, wetland area, have been steadily shrinking by an estimated 81,000 to 162,000 hectares (200,000 to 4ClW acres) per year. In the contiguous 48 states, of the more than 81 million hectares (200 million acres) of wetlands that originally existed, only 38 million hectares (95 million acres) remain. Most of the loss since the 1950s has been the result of farmers' con­verting wetlands to cropland. Urban and suburban development, dredging, and mining account for most of the remainder of the loss.

The loss of wetlands is legislatively controlled by a section of the 1972 Clean Water Act (cur­rently up for renewal); this legislation does a rea­sonably good job of protecting coastal wetlands, but a poor job of protecting inland wetlands, which g what most wetlands are. The Emergency Wetlands Resources Act of 1986 authorizes the U.S. Fish and Wildlife Service to design and acquire critically important wetlands.

The Service is making an inventory and map of wetlands in the United States. The inventory is scheduled to he completed by 1998.

Currently, the United States is attempting to prevent any new net loss of wetlands. This means that development of wetlands will be allowed only if a corresponding amount of previously converted wetlands is restored. The policy is complicated by two factors: (1) confusion and dissent about the definition of wetlands (which was not spelled out in the Clean Water Act) and (2) the question of who owns wetlands. In 1989 a team of government scientists developed a comprehensive, scientifically correct definition of wetlands. It provoked an outcry from farmers and real estate developers, who perceived it as a threat to their property values. Largely in response to their criticisms, the Bush administration narrowed the definition of wetlands in 1991, removing marginal wetlands that arc not as wet as swamps or marshes. This nar­rower definition excludes approximately one-third of the wetlands in the United States from pro­tection.

The federal government owns less than 5 per­cent of wetlands in the United States; the remain­ing 95 percent is privately owned. This means that private citizens control whether wetlands arc pro­tected and preserved or developed and destroyed. Because of the traditional rights of private land-ownership in the United States, landowners resent the federal government's telling them what they may or may not do with their lands. It is therefore important that private landowners become informed of the environmental importance of wet­lands and the critical need to maintain them. Al­though some private owners do recognize the value of wetlands and voluntarily protect them, others don't. The federal government is examining pro­posals such as tax incentives and the outright pur­chase of wetlands to encourage their conserva­tion.

In 1990 Congress passed the Food, Agriculture, Conservation, and Trade Act (a new version of the Food Security Act of 1985). One of the provisions of this act is the establishment of the Wetlands Reserve Program, which seeks to restore, in a five-,'ear period, 405,000 hectares (1 million acres) of privately owned freshwater wetlands that have pre­viously been drained and converted to cropland. However, the Wetlands Reserve Program is funded annually by Congress and is therefore subject to budget cuts.