Traditionally, the Iowa Department of Transportation has used the Iowa Runoff Chart and single-variable regional-regression equations (RREs) from a U.S. Geological Survey report (published in 1987) as the primary methods to estimate annual exceedance-p
Eash, David A. daeash@usgs.gov. Comparisons of estimates of annual exceedance-probability discharges for small drainage basins in Iowa, based on data through water year 2013. 2015-01-01.