Computer Simulation of Storm Water Runoff

A computer program has been developed that eliminates most of the intuition or experience required in calculating stormwater runoff by the classical rational method. The program gives an approximate solution of the partial differential flow equation over the area. The area considered is divided into a grid of squares with the elevation and soil condition (flow coefficient, initial surface retention, infiltration rate) tabulated for each grid element; often all these may be considered constant except elevation. Typical rainfall data are entered, and the program gives the runoff into drainage lines as a function of time. Depth of water standing in the area is also computed. Copies of the program are available to those interested.