Study On Water Storage Optimization Of Medium And Small Flood In Tianjin North River Network

Tianjin has a semi-humid continental monsoon climate in the warm Temperate Zone.The precipitation is scarce and has a great variety in years, also the rainfall centralizes and the space distribution is uneven.The flood calamity is frequent on history in Tianjin, but at the same time, the serious shortage of water resource is the resource environmental problem that needs to be resolved urgently.To solve these two problems overall, flood water resources utilization is put forward in Tianjin.Based on the fuzzy optimization theory, concerning about flood loss, flood prevented benefits, water supplying benefits, ecology benefits and water supply cost in storage and detention flood areas, the optimum storing water level is determined about the four storage and detention flood areas in Tianjin north river network.Based on the multilevel fuzzy optimization theory, concerning about capacity, inundated farmland area, migration population, mean annual flood prevented benefits, economy, risk of seismic induction, water quality, anti-calamity ability and social stabilization, the order of quality is determined about the four storage and detention flood areas.One dimensional river network unsteady flow numerical model is used to simulate water storage optimization of medium and small flood in Tianjin north river network. Four rivers are simulated, also the operation of gates and flood spreading process under different flood frequency are analyzed.The water storage in four storage and detention flood areas is the focal point in the simulation.The water storing processes in storage and detention flood areas are calculated concerning about upstream inflow flood cinditions, seawater intrusion caused by downstream tide, design flow of stream channels, order of quality and storage capacity.The quanlity of flood to be utilized is investigated in this part.