Folw And Sediment Mathematical Model In SanMenXia River Networks And Analysis Of Fractal Characteristics In River Course

Since the Symposium on ecological protection and high-quality development of the Yellow River Basin was held,all departments have made corresponding plans to adhered to the policy of the Yellow River protection,and worked hard to ensure the long-term stability and promote the high-quality development of the Yellow River Basin.Sanmenxia reservoir is the first large-scale water conservancy project in the middle reaches of the Yellow River and it plays an important role in the regulation of water and sediment in the middle reaches.In order to realize the efficient allocation of water resources in the middle reaches and improve the joint operation ability of water and sediment,this paper takes Sanmenxia Reservoir Area as the research object,according to the river network flow model and Han Qiwei's unsteady and non-equilibrium sediment transport model,this paper establishes the flow and sediment mathematical model in Sanmenxia reservoir,and verifies the water level,discharge,sediment erosion and deposition in the reservoir area.In addition,this paper studied the fractal characteristics of the main channel in Sanmenxia reservoir,calculated the plane fractal dimension,longitudinal section fractal dimension and the cross-section fractal dimension,which provides a quantitative description of the complexity of the channel morphology in Sanmenxia reservoir.Firstly,the river networks flow model is established.The sparse matrix method is used to solve the implicit equations of unsteady flow,and it verified some simple network models,including zero branch,one branch and two branches models.Secondly,the river networks sediment model is established.The single channel sediment model adopts Han Qiwei's unsteady and non-equilibrium sediment transport model,and the branch point treatment adopts Fang Hongwei's branch point sediment distribution model theory.Then,the river networks flow and sediment mathematical model is applied to Sanmenxia reservoir.Firstly,based on the measured data,it analyzed the change rule of water level and discharge,and explained the treatment of key problems in the flow model,then it established the flow model and verified the process of water level and discharge in Tong Guan.Secondly,based on the measured data,it analyzed the variation rule of sediment and explained the treatment of key problems in the sediment model,then it established the sediment model and verified the amount of erosion and deposition.Finally,in view of the complexity of the main channel shape in Sanmenxia reservoir,it calculated the plane fractal dimension,longitudinal section fractal dimension and the cross-section fractal dimension and analyzed the variation rule of the fractal dimension with time and space.