Assessing the Effects of Climate Change on Precipitation and Flood Damage in Wisconsin

Abstract

Studies on the effects of anthropogenic climate change have found that the magnitude and frequency of intense precipitation events are expected to increase over the next century for the midwestern United States. The goal of this study was to use statistically downscaled and debiased precipitation projections for the state of Wisconsin derived from 14 general circulation models (GCMs) to assess the projected precipitation changes for the mid–21st century in a way that is relevant to water-resource decision making. The authors analyzed metrics that are relevant to storm-water design, such as the 100-year, 24-h quantile, and the authors also evaluated the changes in a risk-assessment context using idealized damage functions that translate precipitation depths into economic damages. The results of our design-metric analysis show that the 100-year, 24-h quantiles for Wisconsin are projected to have significant but modest increases of approximately 11% over the next 50 years. Our risk assessment shows that the largest percent changes in risk for Wisconsin are projected to be in the northeast portion of the state. Both of these analyses will be used as part of the Wisconsin Initiative on Climate Change Impacts (WICCI) to develop climate-change adaptation strategies for communities throughout the state.