Analysis on Water Source and Characteristics of August 1992 Flood Occurred in the Yellow River
Lu Guangqi et al. (Bureau of Hydrology of YRCC, Zhengzhou, 450004)
In August 1992, there is a flood occurred at Huayuankou station on the lower Yellow River with discharge of 6260 m~3/s. The discharge of the flood is not big. but the water level is as high as 94.33m which is the highest level since the recording, causing heavier disasters and bringing widely to people's close attention as well. The flood is formed by a rainstorm happened in heavy sediment and eoarse sand areas on the middle reaches of the Yellow River. It is highly dispersed in time and space and with longer duration during the whole process of precipitation. It has the following notable characteristics: ①small peaks with high water level; ②peak discharge at Huayuankou is repmarkably increased comparing with that at Xiaolangdi; ③the Sanmenxia Reservoir area is severely aggradated and deaggradated; ④bankful discharge is smaller and travel time is longer. The basic reason of these abnormal phenomenas is caused by hyper-sediment concentration, severe deposition of the channel and obviously increased the river bed.