Numerical Simulation Of Water And Sediment In Sediment-Laden River Water Diversion Model Based On CCHE

Economic and life style in Xinjiang region is mainly based on agriculture and animal husbandry. water resource demand in irrigated areas is the main restrictive factor for its economic activity, using natural rivers for channeling water without dam has more than one hundred year history in Xinjiang,however, Xinjiang has unique geomorphic feature, mountain river, its volume of runoff has been small in the past years, which causes rivers to have “limited water and multiplied sediment”, thus forming the different water-sediment characteristics from other parts of the Mainland. Diversion from rivers causes many unavoidable problems, especially in sediment-laden river, rapid development of sediment accumulation makes river bed evolution fierce, which causes water and sediment distribution change rule to be complicated, sediment damage issue is extremely prominent. Fully grasping sediment transport rules in water diversion hub, properly designing structural layout of hub and using scientific management adjustment to reduce engineering damage brought by sediment problems have become the urgent issues for water conservancy project construction and management in Xinjiang.In this paper, the CCHE software is used to establish a two-dimensional water-sediment mathematical model and to analyze the sediment movement situation of Xinjiang low head diversion project such as water flow movement, sediment transport rule, the scouring-silting changes of riverbed, bed load sediment particles distribution and bed load rate per unit width.Taking the hydraulic models of Wusiman diversion project in the Tarim River basin and Tashimilike diversion project in the Gaizi River basin as research objects, the paper establishes a two-dimensional flow and sediment mathematical model and analyzes the water flow characteristics near the water diversion project, the flow pattern, velocity distribution and typical section water-depth variation before and after the layout optimization of water diversion project. Combined with bed load sediment data, the paper analyzes the scouring-silting changes of riverbed, which agrees with the results of model test and verifies the reliability of the model.By the verified mathematical model, the scouring-silting changes of riverbed of the project completed are simulated. Meanwhile, the following rules have been analyzed: the bed load sediment particles distribution, the scouring-silting changes of riverbed and the bed load rate per unit width. According to these data, potential sediment problems of diversion project caused by its long-term operation and countermeasures have been discussed and optimization scheme of gate operation mode have been simulated. The optimization scheme of “intermittent sediment scouring” provides reference for solving the sediment accumulation problems.The features of water and sediment movement of diversion project are extremely complicated and the factors affecting it are numerous. In this paper, water and sediment movement of diversion project is simulated with the CCHE2 D model, some of methods and suggestions have been made about such problems as mesh generation computing, original riverbed terrain setting, sediment grain size confirming and buildings scouring property choosing.