Estimation of water balance and water yield in the Reedy Fork-Buffalo Creek Watershed in North Carolina using SWAT

To use water resources sustainably, it is important to understand the quantity of water resource spatially and temporally. Therefore, the work presented here attempts to preface future modeling applications within a watershed in North Carolina, by assessing the performance of the Soil and Water Assessment Tool (SWAT) model in analyzing watershed hydrology and variability of streamflow in the watershed. Statistical model performance measures, the coefficient of determination (R²) and Nash–Sutcliffe Efficiency (NSE) were used to evaluate the correlation between the observed and simulated monthly streamflow. The result shows a good agreement between the observed and simulated flow. Both NSE and R² were found to be greater than 0.7 for the calibration and validation period. A scenario analysis performed to determine the effect of future land use change on runoff and water yield shows a 13.9% and 8.32% increase in the surface runoff and water yield respectively, in 2030, when impervious percentage increases from 24.2% in 2010 to 36.5% in 2030. This interesting performance obtained with the SWAT model suggests that SWAT model could be a promising decision support tool to predict water balance and water yield in other watersheds in North Carolina for sustainable water management of water resources where the impact of recent state mandates regarding water quality and quantity is a critical issue.