Sediment Depositon In The River Network To The West Of Hangzhou Canal

The urban river water environment problem is very serious, greatly affect the quality of life for the residents of city and landscape, implement diversion engineering from constant flow river into the urban river network has become one of the most effective measures to improve the urban river network water environment quality.Hangzhou diversion engineering carry water from the Qiantang river into the river network to the west of Hangzhou Canal, aiming to improve the water environment in urban river network, and to provide quality water for the XiXi Wetland National Park. Due to the high sediment concentration at the Qiantang River estuary, with water diversion, the sediment is bound to transport and deposit at the same time, and will affect the diversion engineering in the long-term. So it is of great significance to study the spatial and temporal variation law of sediment transport through the river network and its characteristics to the diversion engineering in the long run.In this paper, according to the hydrologic and sedimental observation data through the whole year in river network to the west of Hangzhou Canal, calculate and analyse the water transport process, sediment transport and deposition in the river network "four brooks and four rivers "under the condition of water transport, come to the following conclusions and results:(1)For the first time, to observe the data such as flow and sediment obtained in the river network through the whole year, to establishment the relationship between turbidity and sediment concentration, get the total volume of water and sediment into the rivernetwork through the whole year, compute the average water flow and the sediment concentration and its change.(2)Use the digital river system of four brooks and four rivers " to the west of Hangzhou Canal and the MIKE11software for river network model, in consideration of lateral flow process, to numerically calculate the water transport process in the river network under the condition of various water diversion, analyse its hydraulic characteristics.(3)Adopts the viscous non uniform sediment incipient probability formula to improve the river suspended concentration variation calculation method, calculate the sedimentation under the condition of different water transport, analyse the spatial and temporal sedimentation law in "four brooks and four rivers" and the maximum thickness of the section in the river network through the whole year.(4)According to the river network time varying lateral flow theory and the carrying capacity of non uniform sediment formula, preliminary put forward river network time varying lateral sediment transport concept, provides a new train of thought to improve the river network sediment discharge calculation method.