Runoff Curve Number Estimation for Agricultural Systems in the Southern Region of USA

The NRCS Curve Number method is used to perform different rainfall-runoff analyses for different land use and soil conditions around the world, such as the estimation of design floods for small hydraulic structures, and best management practices to reduce agricultural non-point source pollution. Knowing that the calculated runoff is more sensitive to the curve number value than to the rainfall depth, estimation of the curve number values for local situations is pertinent. This study focuses on the effectiveness of the asymptotic method in determining curve number values for several agricultural management systems in the Southern USA, and analyzing effects of changing the initial abstraction ratio on these determinations. Runoff predictions are compared with observed datasets and model efficiency is determined contrasting differences based on variation of the initial abstraction ratios.