ANALYSIS ON MORPHOLOGY OF RIVER CHANNEL AND VARIATION OF DISCHARGING CAPACITY IN THE ESTUARINE REACH OF THE YELLOW RIVER

摘要

According to the measured data of incoming water-sediment and river sections in the estuarine reach below Lijin in the period of Qingshuigou path, the longitudinal and transverse variations of sections, bankful flow and water stage have been analyzed. On this basis, the flood discharging capacity and situation of flood control of the existing estuarine reach have been briefly studied. It is shown from the research results that the longitudinal and transverse variation of sections are related to incoming water-sediment, estuarine deposition and extension, and shifting of river course closely, and the bankful flow is changed with the variation of section morphology. The continuous small runoff and less sediment incoming from 1986 to 1996 and estuarine deposition and extension have made the sections shrink, the bankful flow reduce, the water stage under the same flow raise and the flood discharging capacity lower. The retrogressive erosion in the estuarine reach was once caused by the diversion of river branch of Qing-eight section in 1996. However it has been back-deposited gradually since 1998. At present because the bankful flow in the estuarine reach is comparative small and the harnessing project is not consummate yet, the situation of flood control cannot be optimistic.