Optimization towards sustainable development in shallow groundwater area and risk analysis

Abstract

The projected increasing food demand in the coming decades will require substantial water and energy resources. Practical approaches are expected to propose to realize enhancing crop production while towards sustainable development in shallow groundwater area. This study integrates a process-based model, multi-objectives, and fuzzy theory into optimization model to optimize crops water allocation pattern under uncertainties of water diversion and groundwater. The process-based model considers the water exchange between soil and groundwater, water stress and salt stress on crops, and ground water level changes. The multi-objectives defined in this study balances the conflicts of maximizing crop production, maximizing water use efficiency, and minimizing energy consumption. The uncertain amount of water diversion and groundwater is presented as fuzzy numbers. The optimized water allocation pattern of 3 crops in 12 water supply response units in Hetao Irrigation District show that the crop yield does not necessarily reach to the highest potential value, though wheat and maize are allocated more water than sunflower and have larger possibility to reach high crop yield. Significant energy investment is needed for extracting and purifying groundwater to ensure relatively high crop production at the case of possible low available water. Uncertainties of water diversion and groundwater will cause a greater range of ground water level in wheat field, a high risk of water stress in sunflower field and a high risk of very severe salinization in wheat field. The different changing directions of three sub-objectives demonstrate that optimal water allocation has no uniform rule but changes with available water.