Modelling hydrology and water quality processes in the Pengxi River basin of the Three Gorges Reservoir using the soil and water assessment tool

•A Three Gorges Reservoir (TGR) specific database for SWAT suitable for the Pengxi River basin was developed.•Runoff was most sensitive to CN2, while N and P loadings were most sensitive to RCN and FILTERW, respectively.•The hydrology and water quality processes of Pengxi River Basin were evaluated.•The critical zone of non-point source pollutants was identified.