Abstract:
Urbanization and development of lands have increased significantly in last few years to fulfil the requirements of increasing population and economic and infrastructure development in India. The hydrological response of watershed is usually altered due to revolution in the watershed development. Thus it is necessary to quantify the likely changes in the surface runoff in a watershed as an impact of the planned or unplanned changes made in the land use. The landuse changes in the Beda river watershed and its effect on surface runoff has been examined by comparing the estimated surface runoff produced by the similar rainfall during the year 1989 and 2007. The land use/cover maps for the two periods were prepared from the satellite imageries and their spatial distributions have been compared using ILWIS GIS software. The weighted average Curve Numbers (CN) of Beda catchment for both the years have been calculated based on land use/cover type and hydrologic soil group as mentioned in the reports of USDA Soil Conservation Service. The direct surface runoff computed through the SCS Curve Number method have been compared with the calculated runoff from the observed hydrograph the for selected rainfall events during both the years. The surface runoff produced due to the similar rainfall during the past and recent year have also been compared. It was noticed that the runoff volume has been increased in recent years (i.e. 2007) in comparison to those in the past years (i.e. 1989) for the similar rainfall events.
