The study uses HEC-RAS to analyse the water surface profiles of Malaprabha river system upto Khanapur for different combinations of discharges through various reaches of the river system. The river system is divided into eleven reaches, and forty one cross sections have been measured and interpolated within these reaches.
Discharge values have been assigned for different reaches according to the ratio of contributing area for each reach. The bridge across the river at Khanapur is reproduced in the modeling system to test its capabilities. Various return period floods have been allowed to pass through the river system to compute the individual water surface profiles.
HEC-RAS developed at the Hydrologic Engineering Centre (HEC), Davis, California supports one-dimensional steady flow water surface profile calculations for a full network of natural and constructed channels. It is an improved Microsoft Windows based version of HEC-2 and is more user friendly because of its better graphics and input data preparation capabilities.
It can also be used to analyze the effect of various obstructions along the river reach such as bridges, culverts, weirs and structures in the flood plains. It is capable of assessing the change in water surface profiles due to channel improvement, levees and ice cover. The program computes water surface profiles from one cross section to the next by solving the one-dimensional energy equation using the standard step method.
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