Multi-objective Optimal Allocation Of Irrigation Water Resources Based On Water Supply Risk

The economic and social development of our country is seriously constrained by the water shortage.Through a large number of water control data and practical experience,it can be found that optimal allocation of water resources is a direct and effective measure to alleviate the contradiction between supply and demand of water resources.China’s agricultural water consumption accounts for more than 60% of the total water consumption,mainly irrigation water.However,the efficiency of irrigation water is only56.5% and water waste is serious.Therefore,scientific planning of irrigation water process,rational allocation of irrigation water proportion and establishment of optimal allocation model of irrigation water can not only make efficient use of water resources,but also promote sustainable development of regional ecological environment and social economy.A multi-objective bargaining model based on water supply risk(RMOBM-Ⅰ)is established by taking the maximization of economic benefits and the minimization of environmental pollution as the objective functions.This thesis adopts the methods of multi-objective programming and bargaining.And the water supply of the water source is assumed as a random variable.Then the water supply risk is defined as the possibility that the actual future water supply is less than the planned water supply aiming at the unbalanced supply and demand of water resources in the water shortage area.Considering the water loss in the process of water transfer,this thesis takes the water transfer loss into the above model and constructs a multi-objective bargaining model based on water transfer loss and water supply risk(RMOBM-Ⅱ).Finally,the two models are applied to the agricultural water distribution in Handan city,which takes Yuecheng Reservoir as the water source.And the water distribution schemes of different hydrological years are obtained under three of low,medium and high risk levels.The two models are compared with the deterministic bargaining model(DMOBMI)and the deterministic multi-objective bargaining model based on water loss(DMOBMII)respectively.The results show that :(1)the schemes obtained by the two models are more flexible and diverse and decision-makers can choose corresponding water distribution schemes according to different risk levels;(2)as the target water level and the planned water supply increase,it is more difficult for the actual future water supply to reach the planned water supply,that is,the water supply risk is higher,the economic benefits are greater and the environmental pollution is more serious;(3)compared with the existing deterministic models,the water distribution difference is the largest in normal year,followed by wet year,and the smallest in dry year under the low water level scenario.And the difference of dry year is the largest,followed by wet year and normal year under the medium and high water level scenarios.