rainfall runoff process of Kharkai Basin.

Abstract: Hydrological modeling is a commonly used tool to estimate the basin’s hydrological response to precipitation. To compute runoff volume, peak runoff rate, base flow, loss rate, various hydrologic as well as hydrodynamic models are used. Rainfall runoff model is such a model which is used to simulate the rainfall- runoff process in a basin. This model is also very effectively used for flood forecasting and flood plain mapping, which is a natural demolishing phenomenon of high importance. Estimation of rainfall-runoff and flood is a difficult task due to influence of different factors. So far, different models have been proposed and used effectively to analyse such phenomena. In view of the above, the present study has been conducted in the basin of Kharkai River (Eastern India) in Jharkhand and Odisha State using Hydrologic Engineering Centre Hydrologic modeling system (HEC-HMS) model. In this study HEC-HMS hydrological model has been used to simulate the flow in the hydrological units of the area and has helped to compute runoff volume, peak runoff rate, base flow, loss rate of the basin. In the present study for calibration and validation of the model the rainfall data for the basin for the period June 2008 and September 2011 and the observed flow at Adityapur gauging site has been considered. For calibration and validation of HECHMS model, the observed flow at Adityapur gauging site has been considered. For calibration of HEC-HMS parameters the guidelines available in the manual has been followed strictly. The calibrated and validated model is tested with Nash Sutcliff efficiency which shows that the model can simulate the rainfall runoff process with an efficiency of 82.3% (tested in validation). The result also shows that the parameter which affects the rainfall-runoff simulation process depends on the intensity of rainfall, land use and land cover of the catchment, catchment characteristics and topography of catchment to a great extent. The results can remarkably contribute to the monitoring system of the flood in both catchment and inundation area of the basin. The result can also effectively used for flood forecasting and flood plain mapping in the deltaic area of the catchment.

Keywords: HEC-HMS, Kharkhai basin, Nash Sutcliff efficiency, Rainfall-runoff simulate

INTRODUCTION

Precipitation is all forms of water that reach the earth from the atmosphere. The usual forms are rainfall, snowfall, hail, frost and dew. Of all these, only the rainfall and snowfall contribute significant amounts of water.

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