沮漳河堤防加固前后洪水过洪能力分析

沮漳河干流一直是宜昌市防洪重难点，防洪矛盾突出．1996年7月和2007年7月（9607、0707）沮漳河出现两次较大洪水．水文监测表明：9607沮漳河河溶站洪峰流量为2380m3／s，洪峰水位50．15m，在进行防洪加固后，0707河溶站洪峰流量为1950m3／s，对应洪峰水位却达到50．07m，不合常规．通过多因素对比分析，结果表明：洪水涨落率、糙率与水面比降影响因子、水库调度是导致该异常的主要原因，借此为汛期防洪安全及工程设计提供科学依据．

Analysis of Flood Garrying Capacity before or after Reinforcing Embankments in Juzhang River

The main stream of the Juzhang River has been one of the most difficult problems of flood control in Yichang. It＇s an obvious contradiction in flood controlling. The main flood control measures are strengthe-ning the embankments, reservoir operation, making area for flood detention zones,etc. Intense rainfalls in July 1996 and July 2007 （9607, 0707） the Juzhang River appeared two large flood processes. The result indicated.. The peak discharge of the Juzhang River was 2 380 m· s-1 and peak water level was 50.15 m in Herong hydrometric station in 9607. After engineering measures of burden the levee distances and reinforcement of levee, it was not accord with hydrological monitoring routine when the peak discharge was only 1950 m3 ·s-1 while the peak water level was for 50.07m in 0707. Through a comparative analysis of multiple factors, the result shows that the flood fluctuation rate, roughness and water surface gradient, reservoir operation are themain reasons caused the abnormality. This conclusion can provide scientific basis for flood forecast and control in the Juzhang River.