Offshore structures, sea mud accumulation and mangrove regeneration: Insights from the Vietnamese Mekong Delta, Vietnam

Offshore structures have been prioritized for controlling eroded muddy coasts, particularly in Southeast Asia. However, these structures have had limited accumulation of sea mud and a low level of mangrove regeneration. The reality shows that sea mud accumulation and mangrove regeneration greatly contribute to controlling erosion and establishing muddy coasts. Little is known as to how sea mud accumulation and mangrove regeneration have been integrated or referred to during designing and construction of offshore structures. I used construction of offshore structures along the Vietnamese Mekong Delta coast for answering the above question. This study was undertaken using critical review of the technical designs, semi-structured interviews with relevant stakeholders, analysis of satellite images and field measurements in pursuit of the objectives. The results show that sea mud accumulation and mangrove regeneration were not adequately considered by the design and construction of offshore structures. Attenuation of the wave energy and the transplantation were prioritized instead. Physical visibility and survival of interventions were two criteria used for designing the structure. Until now, most sites have been still in liquid sediment. Nether sea mud accumulation nor mangrove regeneration were recorded. The findings provide a technical reference to redesigning current offshore structures to improve their efficacy in accumulating sea mud and promoting mangrove regeneration in the region and in Southeast Asia in the future. � 2022 Elsevier Ltd