A Soil and Water Assessment Tool model (SWAT) was developed for the Cuenca Independencia, a 6992 km2 watershed with a significant seasonal climate situated in the semi-arid highlands of Guanajuato State in central Mexico. This area is dominated by agricultural land cover (43.32 %), followed by pasture (25.7 %). Good to very good results for the coefficient of determination (R2, 0.66 ~ 0.89) and the Nash-Sutcliffe Efficiency (NSE, 0.65 ~ 0.88) were obtained during both the calibration and the validation periods, while the percent bias (PBIAS) was not so good as the former indicators, but with satisfactory to very good results. According to the projections of seven general circulation models (GCM) under Coupled Model Intercomparison Project Phase 5 (CMIP5) for climate change prediction, the Cuenca Independencia may experience more precipitation and higher temperature under emission scenarios of Representative Concentration Pathway (RCP) 4.5 and RCP 8.5 for the mid-century period (2030 - 2059), as well as the end of this century (2070 - 2099), compared to the baseline condition (1970 - 1999). Potential evapotranspiration (PET) and real evapotranspiration (ET) are predicted to increase continuously. Both mean annual surface runoff and aquifer recharge are predicted to increase more rapidly under the condition of scenario RCP 8.5 than RCP 4.5. However, increasing demands of agricultural irrigation are expected to consume the larger water volume seeping into the groundwater system, making aquifer recovery unlikely through natural processes under the current water resources management framework.
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