Research On The Character Of Rainstorm And The Ability Of Flood Routing About Main Haihe River In Tianjin

Haihe main river is a flood channel, which runs through Tianjin City Zone. It hasthe functions of storing water resources, regulating water allocation, flood drainageand shipping. Among them, flood drainage ranks the first.Since decades, great changes have taken place in the sub-base of Haihe mainriver which covers 1060 square kilometers, such as the hardening ground whichresulted in the changes of the storms and flood rules. So the runoff coefficient and theconfluence rates of flood increased. The flooded area , the depth of submergence andduration of flooding caused by the storms have increased recently in the City Zone.So it is very important to analyze the water levels and discharge capacities of Haihemain river according to the different levels of storms.Storms characteristics in the City Zone have been analyzed in this paper accordingto the flood data of Haihe main river since two decades by means of the method ofPearson Type â…¢ distribution curve. The quantitative relations between differentlevels of storms, the runoff and the confluence have been established according to thedata of water levels, discharge, rain height and gate opening in Xihe Gate, ErdaozhaGate and Haihe Gate. So the quantitative relation between the precipitation anddisaster can be easily determined.In conclusion, increasing discharge capability and the dam height and thedredging operation can alleviate flood disaster effectively.