A calibrated, watershed-specific SCS-CN method as applied to Kainji Dam watershed in Niger State, Nigeria

Abstract

This paper explores the application of a calibrated, watershed-specific soil conservation service curve number (SCS-CN) method to the Kainji dam watershed in Niger State, Nigeria, addressing the challenges and opportunities associated with its implementation. The SCS-CN method is versatile and popular for quick runoff estimation is relatively easy to use with minimum data and it gives adequate results. This study presents a new CN_0.056 of 59 against the conventional CN_0.2 of 65. The E index increased by 5.2%, the BIAS of the predictive model was reduced by 58.3% and the model's RSS was lowered by 12.1%. In the event of rapid urbanization and climate change, SCS practitioners can conduct regional-specific calibration for the SCS model as proposed to derive region and time-period-specific CN values for the Nigerian watershed.