The tool is not designed to allow the user to specify the elevations of the slices.You could work around it by running first the tool for 1 slice to get EAV at the bottom and at the top and then edit the DEM so that the minimum elevation is always an integer as follows:1. Run the ZonalStatistics tool to create a raster with minimum elevation in each zone (i.e. drainage area).2. Compute a grid = int(ZonalMinGrid)+ + 13. Use the Con tool in Spatial Analyst and replace in your input dem the cells that are strictly less than int(zonalmin) + 1 with int(zonalmin), so that the lowest elevation in each zone is an integer.4.Run the Drainage Area Characterization tool using that modified DEM and set the slice increment to 1ft.Christine DartiguenaveEsri Water Resources Team