Modelling Impact of Dredging and Dumping in Ebb-Flood Channel Systems

• 作 者: HIBMA A WANG Z B STIVE M J F Vriend H J de
• 机 构: Delft University of Technology, P O Box 5048, 2600 GA Delft, the Netherlands,Delft University of Tec
• 出 处: Transactions of Tianjin University
• 发表日期: 2008年04期
• 关键词: estuaries: morphology numerical model channel: shoal dredging: dumping

For a channel-shoal system in a funnel-shaped basin the impact of dredging and dumping is investigated using a complex process-based model. First, the residual flow and sediment transport circulations are analysed for the channel-shoal pattern, which has emerged after a longterm model simulation. Results are compared to the Western Scheldt estuary, which forms the inspiration for this study. Subsequently, different dredge and dump scenarios are modelled, according to a conceptual model, in which ebb- and flood-channels and enclosed shoals form morphodynamic units (cells) with their own sediment circulation. Model results show that dumping sediment in a channel further reduces the channel depth and induces erosion in the opposite channel, which enhances tilting of the cross-section of the cell and eventually can lead to the degeneration of a multiple channel system into a single channel. The impact of different dredging and dumping cases agrees with results from a stability analysis. This means that this type of model applied to a realistic geometry can potentially be used for better prediction of the impact of human interventions.

For a channel-shoal system in a funnel-shaped basin the impact of dredging and dumping is investigated using a complex process-based model. First, the residual flow and sediment transport circulations are analyzed for the channel-shoal pattern, which has b a longterm model simulation. Results are compared to the Western Scheldt estuary, which forms the inspiration for this study. morphodynamic units (cells) with their own sediment circulation. Model results show that dumping sediment in a channel further reduces the channel depth and induces erosion in the opposite channel, which enhances tilting of the cross-section of the cell and eventually can lead to the degeneration of a multiple channel system into a single channel. The impact of different dredging and dumping cases agrees with results from a stability analysis. Th is means that this type of model applied to a realistic geometry can potentially be used for better prediction of the impact of human interventions.