Theme-4-1-Surface runoff modelling of small watersheds.

Abstract

The work reported herein deals with the formjlation of a mathematical model to estimate the surface runoff hydrograph-for a given net-rainfall hyetograph over small watersheds. With the precipitation excess as input into the model, overland flow was computed using the governing physical laws relating to the overland flow. This overland flow has been used as input while solving the stream flow equations (gradually varied unsteady flow equations) to obtain the hydrograph. The stream flow equations were solved by using Finite Element Method (FEM) in space domain and Finite Difference Method (FDM) in the time domain. The model has been applied to a small catchment in the western peninsular India of size 100 square kilometers and the results were compared with the actual observed hydrograph.