Evaluation of Impacts from River Engineering Measures at Nanjing Reach of Yangtze River : An Application of Hydrodynamic Modelling and Sediment Transportation Simulations

University essay from Uppsala universitet/Elektricitetslära; Uppsala universitet/Elektricitetslära


The demand of electric power has rapidly increased in China along with the financial development. High pollution rates have pushed the development towards more renewable energy generating alternatives. In recent years larger investments of hydropower- generated electricity have been to satisfy the increased demand.

Hydropower can cause non-energy related problems when implemented in a large scale. In this project the Nanjing Reach of Yangtze River was investigated through a hydrodynamic and sediment transport perspective. Nanjing Reach consists of two river branches and the upstream construction of the Three Gorges Dam has caused an imbalance of sediment composition that leads to an increasing difference of the diversion ratio between the branches. This is causing a problematic navigational situation for larger vessels along the north branch.

In this project non-submerged water diverting dykes were modelled using two-dimensional depth averaged finite element method to estimate the impact on the hydrodynamic and sediment transport conditions. The examination showed that engineering measures at the downstream part of the reach were more effective than structures at the front, when taking both

hydrodynamic and the more long-term impacts from sediment transport into account. Although the results of the sediment transportation are uncertain, the long- term consequences with investigated engineering measures can be concluded to have negative impact on the sustainability of the reach, however short-term improvements can be achieved.

Other factors such as stability, material use, economics and marine conditions were not treated in this project but are vital for a reliable solution. 

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