The rainfall-runoff process in a catchment is a complex and complicated phenomenon governed by large number of known and unknown physio graphic factors that vary both in space and time. Application of mathematical modelling techniques to the constituent processes involved in the physical processes of runoff generation has led to better understanding of the processes and their interaction. Conventional hydrological models for the prediction of runoff particularly over a basin require considerable hydrological and meteorological data. Collection of these data is expensive, time consuming and difficult process. Remote sensing technology and Geographical Information System can augment the conventional methods to a great extent in rainfall runoff studies. In the present study a Semi Distributed conceptual rainfall-runoff Model was chosen. The advantage of formulating a semi distributed model for the basin is that it enables to divide any big catchment into a number of small catchments and accordingly runoff can be generated over each sub catchment.