Valuation of wetland benefits at the local level will result in a failure to account for the benefits to other users outside the area for flood control, water quality, habitat, and so on. Hey and Philippi (1995) estimated that in order to reduce seasonal flooding and improve water quality in the Upper Mississippi River basin, it would be sufficient to restore 3 percent of the watershed to wetland (approximately 5.38 million hectares). Restoration of wetlands in the Upper Mississippi watershed,