Estimating flood magnitude and frequency for unregulated streams in Wisconsin

First posted January 24, 2023 For additional information, contact: Director, Upper Midwest Water Science Center U.S. Geological Survey1 Gifford Pinchot Drive Madison, WI 53726Contact Pubs Warehouse Flood frequency characteristics and estimated flood discharges for the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, 0.2-percent annual exceedance probabilities were computed at 299 streamgaged locations in Wisconsin. The State was divided into four regions using a cluster analysis to produce which are homogeneous with respect physical basin characteristics. Regression equations relating within each region developed can be used estimate ungaged Basin included final regression include drainage area, saturated hydraulic conductivity, percent forest, herbaceous upland, open water, maximum 24-hour precipitation 10-year recurrence interval. standard error of prediction ranges between 40 71 percent, pseudo coefficient determination 0.8 0.95. Nonmonotonic trends peak flow time series southwest part producing bias some discharge estimates streamgages shorter (less than 20 years) periods record. This increases uncertainty this region.