Research on Flood Resource Utilization Storage in Tianjin
天津市洪沥水资源化存储研究

Tianjin is a big city deficient in water resource,whose most apparent hydrographic features are uneven distribution of annual rainfall and little scarce in non-rainy season.With the booming development of society and economy,the contradiction between water supply and water demand became more and more serious in Tianjin.The conventional flood management measure of leading the floodwater into the sea by non-hazardous principles result in great waste of floodwater resources.Therefore,it is of great theoretical and practical significance to the study of the floodwater resources utilization based on the integrated management strategies of combining engineering measures with non-engineering measures.The focus of this paper is to illustrate the necessity and integrated exploitation mode of flood resource utilization in Tianjin.The conclu-sion,based on the successful utilization of numeric simulation of flood resource impounding into detention basins of the north river network,suggests that flood management in Tianjin should move away from its customary emphasis on heavy engineering towards the softer,natural style of rivers and detention basins rehabilitation. The development trend and reasons for wetlands degradation in Tianjin since last century ware exposited according to the historical hydrographic data and present status of regional water resources,and then the necessity of implementing flood resource utilization storage was discussed.Making use of software of ArcGIS,a 3-D demonstration module for impounding treatment was programmed to meet the demand of real-time calculation on impoundage and impounded area of a detention basin.A comprehensive impounding evaluation system for the detention basins was established which consists of several indexes such as submersion damage,flood preventing benefit,water supply benefit and ecological benefit.Utilizing fuzzy optimizing theory the optimum storing water levels were calculated which contribute to the quantified reference for scheme selection of flood resource utilization.Based on Newton-Raphson interation method and relaxation algorithm,a one-dimensional unsteady channel system hydrodynamics flow model was presented.Coupling with rivers,draw-gates,flood diversion orifices and detention basins,a combined schedule system of hydrographic net was established by applying present water conservancy facilities.Finally,the general implementation strategy of flood resource utilization was discussed which have fundamental significance in releasing water resource crisis and improving water ecological environment in Tianjin.