CHARACTERISTICS OF RECENTLY RESTORED WETLANDS IN THE PRAIRIE POTHOLE REGION

Between 1987 and 1991, 1892 prairie potholes were restored in northern Iowa, southern Minnesota, and southeastern South Dakota by state and federal agencies, most as part of the Conservation Reserve Program. Th e total area covered by these restored wetlands is approximately 2714 ha. Most restorations are small (less than 4 ha) wetlands with a seaso nal hydrologic regime. Wetlands with an ephemeral/temporary water regi me are under-represented compared to their pre-drainage extent. Inform ation on basin morphometry, hydrology, and vegetation-zone development was collected on 62 wetlands restored in 1988. Earthen dams are insta lled on most (73%) restorations in the region, increasing the full poo l volume but not the mean depth of the basin. Overall, restored wetlan ds have basin morphometries that are comparable to those of similarly sized natural wetlands. About 60% of the basins had their predicted hy drology or held water longer than predicted. Nevertheless, about 20% o f the projects that we examined were hydrologic failures and either ne ver flooded or had significant structural problems. Most restored wetl ands had developed emergent and submersed aquatic vegetation zones, bu t only a few had developed wet prairie and sedge meadow vegetation zon es.