Estimation of Runoff in GIS using SCS Curve Number for Muddehalla Watershed

In the present study, the runoff from SCS Curve Number model modified for Black cotton soil condition has been used by using conventional database and GIS for Muddehalla watershed in Bijapur district, Karnataka, India. The major portion of the Muddehalla watershed is occupied by basalt and other trap intrusions and soil of black cotton soil. The watershed lies in the north side of Bijapur City and the normal annual average rainfall of Bijapur city is 590mm. In the present study, SCS method is used with GIS to estimate the runoff from Muddehalla watershed as a case study for agricultural watershed. The watershed having a geographical area of 20 square kilometer and the average annual rainfall is around 590 mm. The rainfall and land use data were used along with the experimental data of soil classification and infiltration rate for the estimation of the runoff for the study area. The results of the present study show that the average monthly runoff depth of peak months for the study area (Muddehalla watershed) is 41.77 mm. The amount of runoff represents 33.66% of the total annual rainfall. In the present study, the methodology for determination of runoff for Muddehalla watershed using GIS and SCS method is described. The obtained results could be used to plan various conservations measures for other watersheds.