Scientific Basis Behind Reform of Wetlands Law Is Challenged

A panel of eminent scientists and experts on wetlands Tuesday challenged many scientific assumptions at the core of a proposal in Congress to overhaul the nation’s wetlands protection law.

The conclusions by a panel of the National Academy of Sciences are expected to play a prominent role during a debate over wetlands protection this week in the House as lawmakers prepare to vote on a bill to revamp the federal Clean Water Act.

The long-awaited study by a 17-member committee of the academy’s National Research Council reaffirmed that defining a wetland should be made “more efficient, more uniform, more credible . . . and more accurate in a technical and scientific sense.”

But the study, which was commissioned by Congress, also questioned the scientific credibility of holding such a definition to a strict single criterion, such as a specific number of days in which surface land is flooded.

Such a definition is at the heart of the bill before the House that would rewrite much of the Clean Water Act. It would require land to have 21 days of consecutive surface water during the growing season to be protected as wetland.

The Environmental Protection Agency and the Assn. of State Wetland Managers estimate such a criterion--as well as other provisions in the legislation--would reduce America’s protected wetlands by 50% to 80%.

Wetlands, which are areas that lie between being dry land and permanently under water, play a crucial role in providing habitat for wildlife, filtering polluted water and absorbing floodwaters.

Much of the debate over wetlands has revolved around definition.

The academy’s study said that surface water should not be the defining factor. “Specific hydrologic conditions . . . should not be held as a strict requirement for identification and delineation of all wetlands,” said the scientists in the study released Tuesday.