Countermeasure Study to Protect the Largest Offshore Barrier Island in Taiwan

Abstract

The objective of this study is to find the suitable measure for mitigating the existing erosion problem of the Wai-SanDing barrier island, the largest remaining barrier island off the Taiwan coast. After collecting enough hydrodynamic and morphodynamic data from the long-term field investigation, the erosion mechanisms of the barrier island were analyzed in detail. Based on the analysis of the erosion mechanisms, consideration of some measure options were proposed and firstly simulated by numerical model to find the two better solutions. Then, the two better solutions were further investigated and validated by physical model. The results showed that soft groins in the downstream and submerged artificial berms in the midstream are the effectively integrated measure to mitigate the continuing erosion problem of the Wai-San-Ding barrier island. Meanwhile, the plant evolution method and oyster cultch were also proposed to apply in mitigation of wind sand transport and stabilization of sand dune.