Study on the erosion and deposition characteristics of Jiulongpo reach after the Three Gorges Reservoir filling at 172m

Jialing River flows into Yangtze River at the main city zone of Chongqing Municipality. The evolutional_mechanism of the rivers near the confluence site has been observed to show some estuary properties. In 2008 and September 2009, the Three Gorges Reservoir authority experimented in maintaining the water level in the dam at 172m. The consequence was that rivers near the Chongqing Municipality were located in the upper or middle area of fluctuating backwater region and consequently behaved as either reservoirs or natural rivers. On the basis of field data of the drawdown and reservoir impoundment process, the properties of sediment transport of Jiulongpo reach at the main city zone of Chongqing Municipality were investigated to study the waterway characters. The results show that in the impoundment process the reach is mainly experienced siltation, in the drawdown process the reach is scour-dominated. It was found that, at the Jiulongpo reach, a small amount accumulated siltation occurred. To study the influence of erosion and deposition on waterway, provides the basic materials for ports and waterway regulation.