RUNOFF ESTIMATES USING ANALYTICAL MATHEMATICAL MODEL

Abstract

Estimation of daily runoff from a natural catchment is essentially required for planning,, manage-ment and evaluation of water resources. The behaviour of a natural catchment is predominantly non-linear in nature. Direct runoff hydrograph from a watershed is simulated using a mathematical model instead of the traditional unit hydrograph approach. Simulation of such watershed through linear tho3r•ies would not theoretically in accordance with the requirements of the problems. Considerable studies have been made so far to understand the rainfall-runoff process by adopting simulation techniques. In the present study, an attempt has been made to adopt a non-linear mathematical model to estimate daily runoff from a watershed from the available rainfall data as the main input to the model. The B etson model is taken as the basis of this study. The B etson model simulate the following two processes s Soil moisture accounting which is done by Antecedent Precipitation Index (API) Method; and the surface runoff wherein the relationship between surface runoff volume, moisture deficit parameter and rainfall depth is determined.