Evaluation of coastal protection strategies and proposing multiple lines of defense under climate change in the Mekong Delta for sustainable shoreline protection

Abstract

Coastal protection measures and management play an important role in coping with coastal disasters and climate-induced sea-level rise. In this study, the success and failure of typical coastal protection works of the Vietnamese Mekong Delta (VMD) are reported and documented from field observations over a study period of 10–15 years. The coastal protection structures evaluated include revetments, geotubes, t-shaped bamboo fences, Pile-rock breakwaters, Busadco's breakwaters, Semi-Circular breakwaters, and Hollow triangle breakwaters. This paper briefly reviews the current situation of coastline erosion problem and accretion in the VMD and illustrates the severity of the current erosion rate that threatens the safety of coastal communities. The paper then evaluates the advantages and disadvantages of various coastal management approaches currently in practice in the VMD to classify different types of possible measures for coastal management with the aim to find holistic measures for planning which require low construction investment. Integrated coastal management and planning are outlined at a regional scale followed by the lessons learned from the previous coastal protection works, and finally the multiple lines of defense (MLD) solution is proposed, which is a green infrastructure inspired nature-based solution. The MLD solution can improve biodiversity, facilitate mangrove forest restoration, and ensure sustainable livelihoods for local communities. Integrated coastal planning and management solutions that are based on the MLD principle are expected to withstand coastal disasters under future climate change, and sea-level rise on the VMD.