Study On Layout Mode And Operation Scheduling Optimization Of Irrigation And Drainage Dual-purpose Channels In Large-Scale Irrigation Areas In Sanjiang Plain

Sanjiang Plain is a national commodity grain base dominated by green japonica rice,with a paddy field area of 34.81 million mu.Most irrigation and drainage canals in the existing irrigation area are arranged separately,occupying a large amount of land resources.The existing paddy field is mainly irrigated by groundwater,which has been in the state of overexploitation,and the guarantee degree of irrigation water is low.In order to meet the new requirements of supply side agricultural reform.Therefore,in the process of irrigation area planning and design,a dual-purpose irrigation and drainage mode based on the existing drainage ditch is proposed,which can not only undertake irrigation tasks,but also undertake drainage tasks.Research on the layout of irrigation and drainage channels to meet the needs of agricultural irrigation water,and carry out water-saving transformation of modern irrigation areas;It can make better use of water resources,reduce the amount of land occupied,save project construction costs,reduce social instability factors,and the majority of farmers have a high degree of recognition.There is no detailed design process and perfect calculation method for the ditch design of the combination of irrigation and drainage.Taking Longtouqiao irrigation area in the hinterland of Sanjiang Plain as the research object,this paper studies the layout scheme of canal system in the irrigation area,the optimal design of irrigation and drainage dual-purpose channel and the optimal operation of irrigation,drainage and water conveyance in field engineering.The main research results are as follows:(1)Based on the factors of water source,water level and quantities in the irrigation area,the layout scheme of irrigation and drainage canal system in Longtouqiao irrigation area is studied.For the zoning of different water sources,different water levels and existing engineering conditions,the corresponding reasonable layout scheme of irrigation and drainage canal system is put forward,and the rationality of each scheme is analyzed.(2)Taking the design elements such as flow and water level of irrigation and drainage dualpurpose channel as the boundary conditions and aiming at the optimization of channel quantities,the design of vertical and horizontal sections of irrigation and drainage dual-purpose channel is analyzed.On the premise that the flow and water level meet the basic requirements of irrigation and drainage,the channel engineering design is optimized.(3)Based on Navier Stokes equations,the water process model of irrigation and drainage dualpurpose channels in typical areas is established.Based on this model,the operation mechanism of conventional channel scheduling is analyzed with the goal of the highest efficiency of water transmission and distribution and the highest efficiency of water resources utilization.For the two key periods of soaking period and supplementary irrigation period,the corresponding regulation mechanism of channels is proposed,which provides a new method for the operation and scheduling of irrigation and drainage dual-purpose channels.In short,based on the current situation of the project,this study makes rational use of water and soil resources within the irrigation area,gives full play to the advantages of irrigation and drainage combined channels,and gives a reasonable and optimized operation mechanism in the operation and dispatching of irrigation and drainage dual-purpose channels,which provides a technical basis for the water-saving transformation of modern irrigation areas in Sanjiang Plain.