TR(BR)-16/98-99 : Development of a distributed catchment model

Abstract

The rainfall-runoff relationships are the most complex hydrologic phenomena to model due to large amount of spatial and temporal variability of watershed characteristics. Distributed models have been developed to represent the variability in physical watershed characteristics.

In this study a spatially distributed unit hydrograph was developed using ARC/INFO GIS package. The catchment of Kolar basin up to Satrana (863.125 sq.km.) in Madhya Pradesh was selected for this study. The rainfall values for Brijeshnagar, Birpur and Jholiapur rainfall stations and the runoff values for the Satrana gauging site were used for developing the model. Landuse details were derived from FCC of IRS LISS II of path/row 27/52 and 28/51 of post monsoon season, 1989. SCS CN method has been used to derive the effective rainfall hyetograph. The GRID module of GIS ARC/INFO was used to develop and compile isochrone map by summing up the time of concentration in each grid cell. S hydrograph technique has been used to derive the spatially distributed unit hydrograph. Six storms (19.08.1983, 09.08.1984, 30.07.1985, 13.08.1985, 14.08.1986 and 26.08.1987) were considered for the comparison of the convoluted direct runoff hydrographs with the observed hydrographs. The time to peak and peak discharge of event number 3 and 6 are matching better than other storm events.