Study On Uncertainty Model Of Optimal Allocation Of Agricultural Water Resources Based On Fractional Programming

It will become the most urgent subject in the field of water resources,to reduce the water resources waste,to improve its utilization rate,to ensure that limited water resources are used rationally.In Heilongjiang Province,water resources storage is relatively rich,with uneven distribution of time and space.According to the present situation of water resources development and utilization in Heilongjiang Province,this paper achieve the sustainable use of water resources in Heilongjiang Province as a guiding ideology,and set continuous improvement of water use efficiency as the ultimate goal,different methods are used to optimize the water resources of Heilongjiang Province on different scales,some advanced achievements of the uncertainty optimization method are applied to the water resources system planning management to solve the complexity and uncertainty in the water resources allocation,then provide the necessary basis for the formation of decision-making program.The specific research contents are as follows.(1)Method Selection.Aiming at many uncertainties in the optimal allocation of water resources,concept,basic principle and application condition of the uncertainty optimization methods are described in detail.Based on the analysis of the advantages of various uncertain optimization methods,the fractional programming model are chosen to optimize the allocation of water resources.At the same time,three kinds of uncertain optimization methods are coupled to different degrees aiming to realize the improvement of water resources optimal allocation model.(2)Constructing fractional programming model based on multi-objective fuzzy programming.Many problems exist in an irrigation district with multi-water resources such as water shortage and water project is not functioning adequately,therefore,it is significant to implement joint dispatching of multi-water resources for alleviating water shortage and promoting the synergy ascension of crops and water resources.A fuzzy multi-objective programming for multi-water resources optimal allocation model was constructed taking Heping irrigation district in Heilongjiang province as an example.The model is capable of increasing water net benefit and decreasing water-use amount simultaneously,which will improve the effective allocation of multi-water resources of Heping irrigation district.Fuzzy multi-objective programming with nonlinear membership functions was adopted to solve the model,and the optimal schemes under different flow levels and water sources were obtained.Results show that water shortage exists in each growth period of rice under each flow level,and more water should be transferred from Liuhe reservoir under low flow level to guarantee the minimum water requirement.The water were allocated in the order of water diversion project,water lifting project and well irrigation project to ensure the total benefit of Heping irrigation district,and the stability of the multi-objective model operation under different scenarios was obtained as well.The developed model can effectively allocate the multi-water resources to the different growth stages of the study crop,which will provide reasonable decision schemes for administrative department.(3)Constructing fractional programming model based on conditional value-at-risk.For optimizing the water-use structure and increasing plantation benefit of unit water consumption,a multi-objective model for water resources utilization was established based on fractional programming(FP).Meanwhile,considering the stochasticity of water availability in the study area,the impact of the risk factor(?)from a quantitative and qualitative perspective was analyzed.The chance-constrained programming(CCP)and conditional value-at-risk(CVa R)models were introduced into five important major grain production areas in Sanjiang Plain,and the crop planting structure under this condition was optimized.The results showed that,after optimization,overall benefit of cultivation increased from 42.07 billion Yuan to 42.47 billion Yuan,water consumption decreased from 15.90 billion m~3 to 11.95 billion m~3,the plantation benefit of unit water consumption increased from 2.65 Yuan/m~3 to 3.55 Yuan/m~3.Furthermore,the index of water consumption,benefit of cultivation and plantation benefit of unit water consumption showed an increasing trend with the increase of violation likelihood.However,through the quantification of ? from an economic perspective,the increasing of ? could not enhance plantation benefit of unit water consumption significantly.In summary,the study on the optimal allocation of water resources on different scales can help managers to manage water resources comprehensively,on a certain extent,improving agricultural water efficiency,and optimizing agricultural water structure.The model established at present and the analysis results can provide a theoretical basis and decision-making support to achieve the maximum benefit of limited water resources in Heilongjiang Province and similar regions suffering water resource scarcity.