CS(AR)-13/97-98 : Modelling of Vasishta Godavari river mouth using FESWMS-2DH

Abstract

The surface water levels of a river, especially at mouth, are required for planning and managing flood alleviation schemes and river engineering works. In the lower reaches of many rivers, flood plain inundation may result from a very high tide or a very high flood or a combination of both. Also, the extent of landward intrusion of saline water into a river at, mouth, varies with the relative strength of fresh water discharge and the co-oscillating tidal flow resulting from the dynamical interaction of the adjacent coastal waters.

An attempt is made to simulate the flow process over a reach of 10 km in the Vasishta river mouth in the Godavari delta. A finite element surface water modelling system. FESWMS developed by USGS is implemented to model the reach. Since the Godavari at mouth is wide and shallow ,it is expected that the model may simulate the flows reasonably well. Unlike in an estuary hydrodynamics may not be so dominant at the Godavari mouth as it drains an area more than half of deccan plataeu.

The outcome of this two dimensional depth averaged flow modelling study is to simulate the water level and velocity distribution in the study reach for different tide conditions during the flood scenario during which there is lot of variation in river flows.