Simulation-optimization Model for Multi-water Resource Distribution in Irrigation Districts

Abstract

【Objective】 Based on the semi-distributed water balance simulation model and the Pareto genetic algorithm, a coupled simulation-optimization model for multi-water resources distribution was constructed to improve water management in irrigated areas. 【Method】 The water diversion ratio of different water resources were taken as the decision variables, the coupled model was used to optimize the allocation of multi-water resources in typical years and long time series in the irrigated rice area in Sanjiang Plain, Northeast China. The objectives of the optimization were to minimize water cost, maximize water use efficiency and keep groundwater table within a constrained range. 【Result】 ① Water distribution obtained by the model for typical years can deal with complex relationship between different objective functions, and the multi-water resources distribution schemes for different objectives are obtained; ② Multi-water resource optimal distribution in long time series can regulate water resources in irrigated areas between years, control water cost, improve water use efficiency, and control groundwater level to achieve dynamic balance between groundwater usage and recharge. ③ By adjusting the objective functions, the model worked out the multi-water resources distribution schemes to rise groundwater table. Compared with the existing water distribution scheme, the water use efficiency of the optimal scheme under conventional irrigation and controlled irrigation are basically unchanged, but the water cost are reduced by 4.3% and 23.8%, respectively, and groundwater recharge are increased by 0.52×105 m3/hm2 and 1.73×105 m3/hm2, respectively. 【Conclusion】 With the comprehensive consideration of water use efficiency and cost, the simulation-optimization model can obtain multi-water resources distribution schemes, which are conducive to the sustainable use of groundwater in irrigated districts, and provide technical support for irrigation districts’ multi-water resources distribution.

Keywords

• multi-water resources distribution
• multi-objective optimization
• genetic algorithm
• simulation-optimization model
• long time series