Suitability of the SWAT Model for Simulating Water Discharge and Sediment Load in a Karst Watershed of the Semiarid Mediterranean Basin

This paper presents a case study conducted in the Upper Argos River, in southeast Spain, to verify the applicability of the SWAT model for prediction of the water discharge and sediment load in a Mediterranean semiarid karst basin. For this purpose, the monthly and yearly discharge and sediment load records at the Argos reservoir gauge during the period 1976–2000 were used to calibrate the model, while data from 2001 to 2017 were used for validation. For both stages of the modeling the performance of the NSE, RSR, and PBIAS indices was good in the case of the monthly flow rate (NSE = 0.62 and 0.70 for calibration and validation, respectively; RSR = 0.61 and 0.54; PBIAS = −20.60% and − 16.09%) and acceptable for the estimation of the monthly sediment load (NSE = 0.52 and 0.58; RSR = 0.70 and 0.64; PBIAS = 10.65% and 15.20%). These indices showed a substantial improvement in the annual simulations, particularly in the calibration, for which the respective values of NSE and RSR were 0.89 and 0.32 for the flow rate and 0.81 and 0.42 for the sediment transport.