Abstract

The use of dredging at an appropriate location is a common practice introduced to maintain the flood capacity and the safety of the bridge. The effective zone and characteristics of sediment transport after dredging are important issues that need to be investigated. This study analyzes the fluvial processes in a selected river, Laonong River, by using the NETSTARS numerical model. The hydrodynamic behavior and sediment transport under flood of different return periods are investigated. The results show that Laonong River remains the trend of deposition in the present condition. The deposition accumulates at the upper reach, as the Laonong River is divided into the lower, middle and upper reaches. Great variation in the volume of deposition is observed at different reaches while different dredging locations are applied. However, the upper reach has a steady trend of deposition and is the main segment of deposition. Scenarios of dredging with different lengths and depths at different reaches are analyzed. From the comparison results, it is concluded that the effectiveness of dredging is influenced by the volume of deposition under the circumstances of this study site, in Southern Taiwan. Furthermore, it is also found that dredging at the lower reach is the most effective method for reducing the sediment deposition in the river.

Key words: Dredging, sediment transport, deposition potential, NETSTARS.