Water and Energy International

Surface runoff is necessary for efficient planning and management of the available water resource. Soil Conservation Services (SCS-CN) model is most widely used for the estimation of direct runoff and the same was used for the estimation of runoff in the Arkavathi valley, Hebbala valley, KC valley, South Pennar valley, Vrishabhavathi valle. This is a less time consuming approach. Results obtained clearly shows the variation in runoff potential with different land use/land cover and soil conditions. The SCS curve number method uses minimum data as input and gives reliable output. It is observed that maximum runoff observed is 239.24 mm in Arkavathi valley during the year 2000 and minimum runoff 16.35 mm has occurred in the year of 2003. In the Hebbala valley the minimum runoff has occurred is 86.60 mm during the 2002 and maximum is 357.18 mm during 2005. In the KC valley minimum is 47.12 mm during the year 2002 and maximum is 359.99 mm during the year 1998. In the South Pennar valley minimum is 27.83 mm during the year 2003 and maximum is 477.402 mm during the year 1999. In the Vrishabhavathi valley has minimum is 38.44 mm during 2003 and maximum is 227.466 during the year 2009. Correlation coefficient values for all watersheds range from 0.76 to 0.86. It can therefore be said that there is a positive linear correlation between the annual rainfall and the annual runoff and it can be observed that the resulting runoff increases in the regression equation as the slope values increase. Runoff calculation using the SCS curve number approach can help to properly plan and control catchment yield for river basin planning.