Published Paper Details:

The SCS-CN method is the most widely used method and the curve number is a function of land use and hydrologic soil group. The Curve Number (CN) is a land-cover index for the given land use-land cover class, elevation and soil type to determine the amount of rainfall that infiltrates into the ground and the amount that becomes runoff for a specific storm event (USDA,  1986). Usually the curve number is classified according to the United State land features classification which may not be applicable to the Indian land features. A high curve number means high runoff and low infiltration (urban areas), whereas a low curve number means low runoff and high infiltration (dry soil). In this study, a rainfall map of the study area was prepared by Thiessen polygon method for years 2000-2014 and the rainfall data for daily was obtained from which normal average monthly, yearly was analyzed. Soil maps have been prepared for the watershed. GIS is used to explore spatial patterns of the trends over the entire Kaddam basin. GIS software can easily handle, store, analyze, manipulate and retrieve spatial data map preparation can be easily implemented using GIS environment. The data over the years was collected and maps were obtained with the help of GIS. Eight rain gauge stations namely Inderavelly, Ichoda, Bazarhathnoor, Boath, Naranoor, Khanapur, Kaddam and Utnur located within the Adilabad district, Telangana, have been analyzed for the period 2000–2014. The land use and land cover map have been obtained by the supervised classification for the different seasons of kharif and Rabi. Giving the input of land use land cover and soil map the Curve Number (CN) grid have been obtained by the SCS method.  In terms of land use and hydrologic soil group combination, the lowest CN value was found to be 30 in Agriculture area and the highest CN value was found to be 85 in low forest area. There has been considerable increase in the percentage of runoff during the years 2003, 2005, 2010 and 2013 in which rainfall has been high.