By Sean Henahan, Access Excellence

CORVALLIS, Ore. (5/22/96)- The rapid destruction of wetland areas around Portland, Ore. may be a harbinger of ecological impacts to come in other fast growing urban areas across the nation, experts say.

A study by Oregon State University investigators revealed that about 40 percent of the wetlands in the Portland metropolitan area have disappeared during a recent 10 year period, even as protective regulations were in place. The massive survey effort entailed visits to each of 233 previously identified wetland sites.

The study showed:

• Of the 233 wetland sites, 92 were gone outright, in new uses ranging from houses to farms, businesses and parking lots.

• Of the 92 wetlands that disappeared, all but 11 were of the "dry-end," seasonal type without permanent water.

• Of the 92 wetlands lost, 67 had been destroyed by one type or another of human activity, not as a result of natural processes.

• Of the 141 wetlands that remained, at least one fourth were severely degraded, suffering impacts such as ditches, grazing, noise and litter.The losses were primarily in "seasonal" wetlands, or small marshy areas that are sometimes wet and sometimes not. Most were destroyed by human activities but some were apparent victims of drought.

"Some of these losses may have resulted from ignorance, the filling in of land that simply wasn't wet enough to be recognized as a wetland," said Mary Kentula, a wetland ecologist with Oregon State University and the Environmental Protection Agency laboratory in Corvallis.

But the study of problems in Portland, Kentula said, may become a microcosm of similar issues facing many other cities across the U.S. It highlights the need for better monitoring, more stringent protection methods, and anticipation and planning for the changes that will occur with development, she said.

The usual suspects - residential growth, highway construction, industrial expansion and other commerce - accounted for a majority of the losses, the research found.

"The Willamette Valley has a lot of the dry-end wetlands, but the amount of this loss was still surprisingly high," Kentula said. "It's clear that some of these sites are not being protected by regulation."

That's a major concern, Kentula said, because many people still do not appreciate the ecological significance of all types of wetlands, including the drier ones. Seasonally-dry, urban wetlands may have unique characteristics and harbor some important plant and animal species.

The cumulative loss of these small wetlands could have major impacts on water quality protection, wildlife habitat, flood attenuation and storage.

Compensatory mitigation efforts have sometimes sought to "replace" wetland losses by constructing similar systems elsewhere. More than 50 percent of all such permits issues in Oregon have been for the Portland area.

But often, scientists have found that a complex, seasonal marsh was replaced by an open pond with quite different plant and animal species.

It may be useful, the study concluded, for land use planners to lead the regulatory process, rather than just respond after the fact to requests for development and building permits.

"Roads are a key," Kentula said. "Plans can tell us where future roads will be built and development will closely follow. It may be possible to anticipate that process and buy, or otherwise protect some of this land before it becomes prohibitively expensive as a result of development pressures."

Restrictions in some areas may allow more flexibility in the use of other wetland areas and still provide for growth, Kentula said. This is exactly what the city of Eugene, Ore., is doing with some its wetland development plans, she said, and such approaches may form a useful model for other U.S. cities in the future.

The OSU study appeared in the professional journal Wetlands.

Related information on the Internet

Sierra Club Wetlands Guide

Econet Resource Center

National Estuary Home Page