Study On Water Resources Optimization Of Irrigation District Based On The Coupling Model

Irrigation water resource management is an important part of the management of the water resource management in the irrigation district.Optimal allocation of water resources is the most economical and effective method for the contradiction between supply and demand of water resources,and it is the most important technical measure to the management for the water resources.In order to improve the engineering efficiency to realize the efficient use for the soil and water resources in irrigation in district,always make reasonable adjustments to the distribution of irrigation and drainage engineering,and optimization to the operation management.Distributed hydrological model used to describe the spatial distribution characteristics and dynamic process of water resources system in irrigation area,so it used to simulate and predict the water resources system under different scenes in irrigation area.However,it is not good at solve the optimal allocation for the water resources in irrigation area.If we can combine the advantages of the distributed hydrological model and the optimal allocation model of water resources,constructing coupled model for irrigation district optimal allocation of irrigation water resources.Intuitively solve the problem of optimal allocation of water resources in irrigation districts.We constructing coupled model based on the distributed hydrological model and the optimal allocation model of water resources.Used it to optimize the distribution of pumping wells in well irrigation areas,the spatial and temporal of the water resource in irrigation areas with wells connecting canals,and the design parameters of the irrigation and drainage engineering in the irrigation districts with alternate flooding and drought.Different objective functions were selected to different problems,different kinetic model of water resources were embedded and an appropriate optimizing method was selected to obtain the optimal result,and the main results were as following:(1)Comprehensively considered the hydrogeological condition,the water demand characteristics and the irrigation technology for the irrigation areas,we construct the optimal model of well distribution in the wells irrigation areas,thus the well distribution was optimized.The results shows that the irrigation norms(225 mm in normal flow year in Tongliao)was higher,in order to keep the sustainable development of water resources,recommend using water-saving irrigation technologies such as drip irrigation in this area.The result shows that the average drawdown for the water surface of pumping well decreased 13.55 cm in the irrigation area during the one irrigation compared with the conventional method,.It indicated that it can be decrease the energy consumption to optimization distribution of pumping well using the coupling model.The results indicated that two-phase method in solving coupling model is feasible,and considering specific hydrogeological and recharge condition while optimization could make water resources planning more scientific and reasonable.(2)Union dispatch model of surface and underground water was improved;the distribution of canals and wells in irrigation area was optimized,and recommend the joint scheduling and allocation for the surface and underground water.The irrigating cost could be saved by establishing coupling model and using single-frame optimal method to optimization.The optimal wells and canals distribution could avoid the continue rise of upstream underground water level,and the secondary salinization of land could be effective control.It can alleviate the continuous decline of groundwater level in downstream areas,as a result,the balance of water supply and demand in irrigation area could be maintained,the natural precipitation could be used more efficiently and the amount of water diverting from the Yellow River could be reduced.(3)Comprehensively considered the single rainstorm and the assurance rate of waterlogging in the irrigation districts with alternate flooding and drought,we established the optimization model for the drainage system.The model was solved by iteration using dichotomies and other methods,and put forward the optimal arrangement form.When the excavation width is same,the investment of the engineering decreased with the spacing increasing space of the drainage pipes.But considering the drainage effectiveness,‘shallow dense type' has the good drainage effect and beneficial to the utilization of groundwater resources.Main innovative points of this paper:(1)Comprehensively considered the advantages of the water resources optimal allocation model and the stimulating model,and constructing a coupling model for irrigation areas,which have unified form and commonly used,thus realized water resources spatial-temporal optimal allocation.(2)The well-by-well two-stage method is used to solve the coupling model of machine-well location optimization in well irrigation area.The results show that the energy consumption of comprehensive pumping can be reduced compared with the traditional geometric method.(3)The well-by-well genetic algorithm is applied to solve the coupling model of groundwater and surface water joint dispatching.The results show that the total cost of irrigation can be reduced compared with the current management model.