Abstract:
In order to study the riverbed evolution characteristics and trends of the braided waterway downstream of the Yangtze River after impoundment of the Three Gorges hydroproject and construction of the regulation works, the measured flow and sediment diversion ratio from 1960 to 2005 and a total of 31 topographic maps from 2004 to 2012 are collected in the Heishazhou waterway studies. A one-dimensional hydraulic model of HEC-RAS is used to calculate and analyze the flow diversion ratio of the Heishazhou southern waterway before and after regulation works. The geographic information system (GIS) and a digital elevation model (DEM) are used to calculate and analyze the changes in the area, volumes and location of the shoal of the Heishazhou southern waterway. The analysis results show that the shoal of the Heishazhou southern waterway was scoured from 2004 to 2009; and the shoal still keeps the characteristics of erosion and deposition after the impoundment of the Three Gorges hydroproject. The flow diversion ratio of the southern waterway during the low-water season is reduced by 1.5% and the shoal evolution trends toward deposition after completion of the regulation works. The research findings can be used as a reference for design and maintenance of the similar waterway works.