TR(BR)-13/96-97 : Single column hydrologic simulation using SHE model

Abstract

The SHE is a physically based distributed model and it provides a useful setup for understanding importance of evaporation data and soil parameters. In this study, single column hydrologic simulations have been carried out for examining the sensitivity of this model to pan evaporation data of the various stations as well as increase in conductivity of unsaturated zone, reduction in the value of exponent appearing in the Averjanov's formula and reduction in the values of moisture content at wilting point and residual water content has been studied for a single grid of 2 km x 2 km size of river Narmada. It is observed that simulated runoff and actual evapotranspiration are somewhat sensitive to the choice of the various pan evaporation measurement stations. However, depth to ground water table does not show any significant variations when the pan evaporation data of the different stations are used.

Increase in the value of conductivity of unsaturated zone leads to increase in actual evapotranspiration and decrease in runoff. Reduction in value of the exponent appearing in Averjanov's formula which is used in the SHE model decreases the simulated runoff and increases actual evapotranspiration significantly. Reduction in the values of water content at wilting point and residual water content of soil also reduces runoff and significantly increases actual evapotranspiration. Also, it is observed that the ground water table depletes considerably particularly during the dry periods for these cases.