A NEW FLOOD ALERT METHOD FOR EXISTING BRIDGES BASED ON CALIBRATION INSTANTANEOUS UNIT HYDROGRAPH
Based on traditional instantaneous unit hydrograph, water marks elevation and relationship between water level and flow, calibration instantaneous unit hydrograph was put forward to do flood alert for existing bridges. Its basic idea was as follows: Calibrated drainage area depending on water marks on piers left by historical flood and the corresponding rainfall series; Then flow duration curve of new rainfall series could be figured out, and biquadrate polynomial fitting was done at high flow segment, so that peak discharge and delay time (peak time lag) from maximal rainfall falling to peak discharge getting to bridge site, could be fixed. Simultaneously, water level-flow function was established beforehand, and flood-peak stage could be got through it. Compared with traditional instantaneous unit hydrograph, calibration instantaneous unit hydrograph has many advantages. Firstly, it doesnt need drainage area, so field work can be largely cut down. Secondly, average gradient of drainage basin could be corrected indirectly. Thirdly, it also can make up shortcomings aroused by regional simplification, widely used in traditional instantaneous unit hydrograph method. Finally, the conversion from calculation to water level makes the outcomes much simply and clearly. Calibration instantaneous unit hydrograph method can forecast flood disaster ahead of time, and gain precious preparation time for guarantee traffic safety and flood fighting. And it will have good prospects in the aspect of forecast flood disaster for existing bridges in the future.
flood alert calibration instantaneous unit hydrograph flood-peak stage peak time lag water mark
Zheng Li Yu-Song Wen Dai-Hai Chen
School of Civil Engineering and Architecture, Centre South University, Changsha 410075, P.R. China
国际会议
广州
英文
925-930
2009-11-28（万方平台首次上网日期，不代表论文的发表时间）