This section describes the computational methodologies employed by Studio Express. It is highly recommended that you review the computational methods and equations used so that you will better understand the output and results. It is not the intention of this section to provide the basis of the theories used or to demonstrate how they were derived. But rather provide the actual equations and methods employed by the software.


The program uses only widely accepted methods within the industry. Namely HEC-22, Soil Conservation Service, SCS/NRCS and the Rational method. This section will provide a summary of the concepts used but it is not intended to be all-encompassing. Below is a list of publications which provide details on the methods used.

TR-20: Computer Program Manual 1992
TR-55: Urban Hydrology For Small Watersheds.
A Guide To Hydrologic Analysis Using SCS Methods, Richard McCuen
HEC No. 12; FHA; Drainage of Highway Pavements
HEC No. 22; FHA; Urban Drainage Design Manual, 3rd edition.
Hydrology for Engineers; Linsley, Kohler & Paulhus
NEH-4: Hydrology; Section 4, National Engineering Handbook
Urban Storm Drainage Management; Sheaffer, Wright, Taggart & Wright
Handbook of Hydraulics, Brater, King, Lindell, Wei