| With the increase of Operation Years in the Yellow River Irrigation area,sediment deposition has become a problem that can not be ignored.Sediment deposition makes the operation cost of the Yellow River diversion project increase and the water delivery efficiency is low.In order to reduce the operation cost of the project,improve the water transfer efficiency,and make the Yellow River diversion irrigation area run scientifically and efficiently,this paper takes Weishan Irrigation area,the largest yellow river diversion irrigation area in Shandong Province,as the research object,and establishes the sediment transport model based on MIKE21 software.Through the simulation and analysis of the water and Sediment Movement in the study area,an optimal sediment regulation scheme is designed to make the sediment settle to a reasonable position,reduce the operation cost and improve the water transport efficiency.The main findings and findings are as follows:(1)Analysis of water and sediment dynamic change and sediment transport characteristics in the study area.Based on the hydrological and sediment data of Weishan Irrigation area,the dynamic change of water and sediment and the characteristics of sediment transport were analyzed.Based on the analysis of the annual variation of water and sediment,it is concluded that the variation trend of sediment yield is consistent with that of water diversion,but the variation of sediment yield lags slightly behind that of water diversion.Based on the analysis of annual variation of water and sediment,it is concluded that the annual water diversion is related to the irrigation season and the annual water inflow is mainly concentrated in spring irrigation.Based on the analysis of the characteristics of sediment transport,it is concluded that in recent years the diversion flow is 5～60 m3/s and the sediment content is 1～6 kg/m3.(2)Establishment of sediment transport model in Yellow River Diversion Irrigation area.Based on the analysis of flow and sediment transport characteristics,the sediment transport model is established based on Mike21 software according to the hydrological and topographic data of irrigation area and DEM elevation data.The parameters of the model are calibrated by the data of the designed water level in the irrigation area,and the hydrodynamic model is validated by the four times water diversion process.Based on the data of sediment content in typical sections,the parameters of sediment model were calibrated,the simulated deposition elevation was compared with the measured one year later,and the sediment model was validated.(3)Simulation of water and sediment transport schemes under different scenarios.According to the characteristics of sediment transport,the ranges of inlet and outlet discharge and sediment content of the model are determined.According to the combination of different discharge and sediment content,9 schemes are designed,and the simulation results are analyzed.According to the variation of sediment concentration in typical section,the settlement ratio of sediment in each part of the study area is determined,and 6 schemes which meet the requirements of sediment deposition and 3 schemes which do not.(4)Selection of Sediment Regulation Scheme.A sand control scheme is designed by changing the location and height of the Sand Control Bin.Considering the variation of water diversion discharge and sediment concentration in different seasons,aiming at the maximum comprehensive benefit,and based on the theory of Engineering Fuzzy set,a variable fuzzy evaluation model is established to evaluate and optimize the scheme,at the same time,the economic benefit is the highest.Finally,the optimum scheme is:setting two rows of sand traps with height of 1M in the middle of the basin(control section d,e). |
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