Allows the curve number to be calculated for the SCS runoff method.
As different options are selected from the drop down lists, the appropriate curve number is selected. Clicking OK will select the currently displayed curve number.
Curve Numbers are calculated by looking up the values in the tables 2-2a to 2-2d in document TR-55.pdf, authored by Natural Resources Conservation Service (NRCS). TR-55 is a widely used approach to hydrology in the US.