汉江上游郧县曲远河河口段全新世古洪水水文状态研究

对汉江上游河谷郧县曲远河河口剖面进行了沉积学、粒度、磁化率和烧失量的研究。结果表明：夹在古土壤中的灰白色沉积层是典型的古洪水滞流沉积物，记录了一次特大洪水事件，用地层对比法和OSL方法确定其发生时间为4 950~5 450 a B.P.。用古洪水SWD尖灭点法确定古洪水行洪水位高程为169 m，采用比降法恢复其洪峰流量为60 577 m3/s。根据2011年汉江上游洪水洪痕，用相同的方法对洪峰流量进行了反演，误差为-411％，说明用比降法恢复的古洪水洪峰流量是可靠的

PALAEOFLOOD HYDROLOGICAL STUDY IN THE QUYUANHEKOU REACH IN THE UPPER REACHES OF THE HANJIANG RIVER

Through the research of the sedimentary profile in the Quyuan river mouth site on the first river terrace in the upper reaches of the Hanjiang River,a major tributary of the Yangtze River，a set of palaeoflood slack water deposits（SWD）were found in the profile.Samples were taken from field and the grain size,magnetic susceptibility and ignition loss amount were analyzed in detail in the laboratory.The results show that the palaeoflood slack water deposits contained in the profile were different from the palaeo soil and the flood slack water deposits recorded a group of palaeoflood events occurred in the upper reaches of the Hanjiang River.Combined with stratigraphic correlation and OSL technique,the age of the palaeoflood events were determined during 5000-5500 a BP.According to the theory of sedimentology and hydrology,using the palaeoflood slack water deposits pinch out method and slack water deposits thick sand content method,we found that the palaeoflood water level elevation recorded by this profile was 169 m and 171 m,respectively.Restored its peak flow by slope method,the flood peak discharges were reconstructed to be 60 577 m3/s and 68 978 m3/s.At the same time,the result was checked by various methods,such as the modern flood event occurred in 2011,which indicated the reconstructed peak discharge was reliable.This study provides important data for engineering construction in the upper reaches of the Hanjiang River,and provides an important reference for the Middle Route Project of South to North Water Diversion Project