ABSTRACT
The Hydrologic Engineering Center – River Analysis System (HEC-RAS) is one of the most famous software for hydraulic engineering modeling in river systems. One of the key capabilities of this program is floodway modeling which is based on an iterative process and good engineering judgments. The iterative process should be implemented in such a way that the water surface elevation does not exceed a designated height (1.0 feet) which is also called a surcharge. In order to keep this restriction, steady-state modeling based on a 100-year flood (base flood) is implemented in HEC-RAS and then multiple profiles based on surcharges are created. This procedure can be done using encroachment analysis in HEC-RAS. The graphical visualization of input and output data in HEC-RAS and also GIS mapping tools provide a simple and useful floodway modeling process.
