Data from 15 wetland study sites, supplemented by data from reconnaissance visits to 219 additional wetlands, were used to describe the hydrologic characteristics of Wisconsin wetlands and to suggest a simple hydrologic classification system. Wisconsin's wetlands OCCUf in depressions and on slopes. They may be in contact with ground water or totally surface-water supported. Hydrologically, wetlands may be classed as surface-water depression, surface-water slope, ground-water depression, or ground-water slope wetlands. Precipitation comprises more than half of the inflow to all but the ground-water slope wetlands, where ground water may provide as much as 90 percent of the inflow. Flood peaks may be as much as 80 percent lower in basins with much wetland area than in similar basins with little or no wetland area. Ground-water recharge appears to be less in basins with much wetland area than in basins with little or no wetland area. Wetlands retain sediment, and sediment loads in streams draining basins with much wetland area may be 90 percent lower than those in streams draining basins with little or no wetland area.
