Integrated Modelling Of Water And Food Nexus Under Water Management And Climate Change Scenarios In Baojixia Irrigation District

Climate change is an important part of the challenges of the Water and Food nexus in the context of sustainable agriculture production.Irrigation water is critical to agricultural productivity because water demand is primarily for agricultural water use.Therefore,the Food and Water nexus could be evaluated through the combined approach of water demand and supply.The combined approach was developed by integrating SWAT and WEAP models under water adaptive management and climate change scenarios.The SWAT model was developed by collecting and processing relevant geographic,hydrological and meteorological data.The 20-year observed monthly streamflow data at the outlet of Linjiacun Hydrological Station was used for model calibration and validation.An ensemble of three climate models(MIROC5,BCC-CSM1.1-M,and CCSM4)under RCP4.5 and 8.5 during the 2020 s,2050s and 2070 s were used to identify possible impacts of climate change.Based on two climate model projections(MIROC5and BCC-CSM 1.1-M),the future rainfall and temperature will be in increased trends for all projected periods,except CCSM4(dry scenario)during the 2030 s.The results show that the SWAT model is capable of simulating streamflow since the statistic indicator values show an acceptable range in the model performance rating(0.7 < NSE ? 1,±15 ? PBIAS < ±25 and 0.5< RSR ? 0)for both calibration and validation periods.Overall,under both RCP 4.5 and 8.5scenarios,the increased flow will be significant for most GCMs during all time horizons,except CCSM4 during the 2030 s.The seasonal increased flow will be higher in winter and spring for most GCMs during all projected periods under both emission scenarios.The scenario evaluation suggests that the combined effects of constructing reservoirs and the demand measures(e.g.,changing cropping patterns and improving irrigation efficiency)reduce supply requirements considerably.Therefore,the integrated measures of the demand and supply side seem more effective for diminishing the problem of water shortages than the strategy of building reservoirs only.In addition,future change in climate is expected to increase the variation of precipitation and temperature,leading to the change in water availability as projected by different GCMs.For MIROC5 and BCC-CSM 1.1-M projection,the future water availability will be increased,resulting in the decrease in water shortages during the 2030 s.However,based on the CCSM4 projection,the change in climate conditions would lead to an increase in both drought magnitude and frequency during the 2030 s.Therefore,water demand management measures such as changing cropping patterns and improving irrigation efficiency are extremely effective for reducing the vulnerability to water shortages and dealing with the effects of climate change.