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Trade-off at Carmel River
Even an ecologically sensitive development can sometimes damage existing wetlands. Can a man-made replacement wetland make up for what was lost?
By Lisa Owens Viani

When Congress passed the Clean Water Act in 1972, one of its intentions was to stop the rampant building over and filling in of wetlands taking place throughout the country. In 1989, President George Bush Sr. stated that a goal of his administration was “no net loss,” a priority that was implemented into agreements among the agencies responsible for regulating wetlands. One way—at least theoretically—of ensuring no net loss is something called wetland “mitigation,” meaning that new, “replacement” wetlands are created under the permit a developer receives to fill an existing wetland to make room for a building, a golf course, or a parking lot.

Image Courtesy Wetlands Research Associates, Inc.

But according to a recent report by the National Research Council, wetlands are still being destroyed without appropriate—or any—mitigation. When mitigation does take place, it isn’t always performed according to the conditions of the permits, says Paul Jones, wetland expert with the U.S. Environmental Protection Agency’s Region 9 in San Francisco. And though mitigation wetlands are supposed to be monitored carefully for several years after they are built, regulatory agencies frequently don’t follow up the way they should, due to staffing shortages, budget cuts, and extraordinary workloads. “We devote 90 percent of our attention to permit issues,” says Jones, referring to regulatory agencies in general. But once the permit is issued, the wetland is often not looked at, he says, and developers are left to their own devices.

When mitigation does happen, how successful is it? Can a wetland really be re-created? Replacement wetlands are supposed to replicate the functions and habitat values of the wetlands that were lost, says Jones, but California wetlands are especially tricky because of the state’s diverse wetland types and topography. Often, he says, created wetlands replace neither the functional values nor the acreage of the original wetlands that were destroyed. These are crucial because, overall, the state is estimated to have lost 91 percent of its pre-European-settlement wetlands. Seasonal wetlands in particular have suffered.

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