Evaluation of the Performance of Climate Forecast System Reanalysis Precipitation Data for Modeling Hydrology and Phosphorus Flux Using the SWAT Model in a Mediterranean Watershed in Algeria (North Africa): A Case Study of the Tafna River

The effectiveness of hydrological predictions using CFSR (Climate Forecast System Reanalysis) data varies regionally, and their suitability in North Africa's semiarid Mediterranean climate remains untested. This study represents the first of its kind in North Africa, focusing on the simulation of phosphorus, using CFSR data. We conducted a comparative analysis of hydrological simulations in the Tafna watershed using both CFSR data and real station data. Monthly and annual precipitation comparisons, as well as streamflow and phosphorus flux evaluations, were performed using the coefficient of determination ( R 2 ) and the Nash–Sutcliffe efficiency (NSE). Results indicated that CFSR data provided good statistical agreement with rain gauge measurements and generated accurate streamflow simulations (NSE = 0.63, R 2 = 0.64) comparable to real data (NSE = 0.50, R 2 = 0.53), particularly during calibration. Phosphorus simulations, while lacking precision, yielded values consistent with observations. This study demonstrates that CFSR data can serve as a viable alternative for the SWAT (Soil and Water Assessment Tool) model when real station data are unavailable, highlighting the originality of phosphorus simulations in this region.