Hydraulic Calculation Of Drawing Water Based On Digital River Networks

Calculation of unsteady flow in river networks as a foundation of hydraulic research has developed in the past decades and plays an important role in such as water resource planning and management. The generalization of basic river network information and the selection of boundary condition in calculation of unsteady flow in river networks gets concern little, and there is little research on the digital information of river networks combined with hydraulic numerical model. In order to improve numerical model, it is necessary to research on the basic information of river networks and boundary conditions which are proposed in this paper to accurately reflect hydrodynamic properties in river networks and to effectively direct engineering practice.On the basis of previous research results, theoretical research and practical application about hydraulic calculation of drawing water based on digital river networks is proposed in this paper.(1) The characteristic and development of different hydraulic calculation models of river networks is analyzed. For GIS digital technology combined with river network numerical model, digital river network is used to generalize river network reasonably to ensure the precision and simplification of calculation. The tributaries being not brought into the computing river networks are considered as reservoirs with equal area. The lateral flow is adopted to compute water transport discharge from main stream to tributaries in the river network so that numerical calculation performs much more reliably.(2) Using software MIKE11 developed by Denmark Hydraulic Institute, a hydraulic calculation model based on digital river network is proposed. For lateral flow process and lower boundary water level changes with time, they are considered as time-dependent that improves calculation precision.(3) The hydraulic calculation model based on digital river network is applied in practice. The total water discharge of the drawing water project from Caoe River to Cixi which is an important part of eastern Zhejiang province drawing water project and its discharge distribution in Shangyu, Yuyao and Cixi City are calculated. The time cost and the water discharge distribution into each city under different water level is computed. On the base of increasing storing capacity, according to the drawing water program proposed by the feasibility study, the results after calculation and analyze indicate the water discharge distribution in Shangyu, Yuyao and Cixi satisfy design demand.(4) In view of the fact that eastern Zhejiang province lacks of water resources, the advice is brought forward that enhancing research on water resource regulation, expediting construction of water resource storing projects such as tideland reservoirs, and developing numerical models for water discharge and water quality of river networks based on digital technology in much larger area, which provides eastern Zhejiang province drawing water project and other hydraulic programming with scientific evidence.