The most commonly used hydrological models for runoff estimation in soft bedrock, is the Soil Conservation Service Curve Number (SCS-CN) model. For a heterogeneous geomorphic land form the model may limit its applicability. Therefore, the SCS-CN model is tested to a small watershed, Udaygiri mandal of Nellore district, Andhra Pradesh. A linear regression method was employed to quantify the SCS-CN model performance. SCS-CN method estimation was evaluated with the help of runoff data, simulated data and actual rainfall data. It was found an accuracy of R2=0.966 for a 5 years (2012-2016) rainfall data. © IAEME Publication.