Research On Strategy Of Flood Resources Utilization In Tianjin

Tianjin is a city short of water resources, and the contradiction between watersupply and water demand are sharpening. The previous method to prevent flood isleading the floodwater to the sea. It is sure that under this method many useful waterresources were wasted. Therefore, it has a great theoretical and practical significanceto study on the floodwater resources utilization.In this thesis, the north river network in Tianjin is taken for example. Someproblems about flood resource utilization are investigated and discussedcomprehensively. The principal contents and achievement of this dissertation aresummarized as follows:(1) Research on flood development in river and water storage in flood storageregions. 1-D river network unsteady flow numerical model is used on the north rivernetwork in Tianjin. Four rivers are calculated and the water storage in fourstoring-and-detention areas under different flood conditions is analyzed. The waterstoring processes in storage regions are studied concerning about upstream inflowflood conditions, seawater intrusion caused by downstream tide, economical losingresulted from storing water in storage regions and the storage capacity. Comparedwith present studies which only focused on the conceptual aspect of flood resourceutilization, the quantity of flood to be utilized is investigated in this part.(2) Research on 3-D dynamical demonstration of water storing process andcomputation of storage volume and corresponding flooded area in storage regions. Byadopting COM technique, Visual Basic is used to make second-stage develop onArcscene which is supported by Arc GIS and a 3-D dynamical demonstration moduleis developed. The module can compute storage volume and corresponding floodedarea at different water level in storage region. In spite of providing a simple, effectiveand fast approach to estimate loss of storing flood,it also makes up the limitation oftraditional 2-D visualization on imagic and practical aspects.(3) Research on evaluation of water storing and optimum impounding scheme instorage regions. According to productivity and assets status in different flood storageregions, the economic loss and benefits are estimated and optimum scheme ispresented. On the principle of maximal comprehensive benefits concerning aboutthe flood loss, flood prevented benefits, water supplying benefits and ecology benefitsin storage regions, a method to determine the optimum storing water level is proposedusing fuzzy identifying theory.(4) Research on draining off waste and storing clear in flood season. In order tostore better water during flood season by controlling storage time according to waterquality in river, the view of using flood to flush waste is proposed. Then ahydrodynamics and water quality coupled river model is developed, the transportationand diffusion of contamination in river during different frequency flood condition isstudied。 And the corresponding floodwater discarding time is analyzed for providingreference on discharge water to storage areas and ocean reservoir.(5) Research on water salinity in ocean reservoir. Combing with the seawallprotection layout of Tianjin, a 3-D model dynamically coupled hydrodynamics andwater quality is developed in Yongdingxinhe estuary. The probability to usingartificial lagoon as freshwater reservoir during flood period is investigated on watersalinity aspect. The 20 years frequency flood condition is taken for example. Waterquality change processes on different reserving scheme are presented. Based onresults computed, best reserving scheme is indicated. Then water quality varietyduring water withdrawing process is modeled. And the lowest withdrawing waterlevel is discussed.