Estimating magnitude and frequency of floods for Wisconsin urban streams

Equations for estimating magnitude and frequency of floods for Wisconsin streams with drainage basins containing various amounts of existing or projected urban development were developed by flood-frequency and multiple-regression analyses.

Multiple-regression techniques were used to develop equations for estimating flood frequencies at ungaged urban sites. The flood-frequency equations are based on data from 32 urban gaging stations, including 19 crest-stage gages and 13 rainfall-runoff gaging stations. Significant characteristics in the equations are drainage area and impervious area. Standard errors of estimate for the regression equations ranged from 32%-39%. Separate equations were developed for Milwaukee County. The USGS Distributed Routing Rainfall-Runoff Model-Version II was used to extend records by synthesis for the 13 rainfall-runoff urban stations. (Author 's abstract)