台灣西部與越南中部海岸侵蝕及災害管理之比較研究

Although Taiwan and Vietnam are located in different regions in Asia, they face the same threat of coastal erosion-related disasters in the future. Global warming’s most direct impacts on the coast are the rise of global sea levels and the increase of extreme weather events, such as storms and typhoons, which result in coastal erosion and hazards in greater scale and frequency. In response to coastal erosion, engineered structures, such as seawalls, groins, and detached breakwaters, are frequently used in Taiwan to protect the shoreline and to prevent the loss of life and property in hazardous typhoon events. These protective measures, however, are clearly lacking in their adequacy to combat strong waves and storm surges. Even worse, the presence of such concrete structures also result in negative effects on beach preservation. The Coastal Management Act, adopted recently by Taiwan government, addresses future climate change and coastal disaster risks and emphasizes the need to retreat or adapt land use in disaster-prone areas. The thinking surrounding coastal protection has gradually changed from relying on the traditional goal of “conquering disasters” to taking the concept of "weighing disaster risk against a certain level of protection” and proposing disaster prevention strategies according to local conditions. Since Taiwan's coastal development predates Vietnam's development, its experience in coastal management and disaster prevention strategies could be mirrored for the Vietnamese coast. In comparing individual case studies of western Taiwan and the central coast of Vietnam, it is evident that the western coast of Taiwan is trending towards industrialization, with various industrial parks, power plants, and natural gas receiving ports continuing to expand, while central Vietnam is dominated by the development of fisheries and the tourism and leisure industry. Such rapid land development, which relies heavily on the engineering structures, may become the main causes behind coastal disasters in the future. Coastal zones with high population density account for 17% of Vietnam’s total land area and play an essential role in the nation’s socio-economic development. Yet, since the last century, the coastline of Vietnam has suffered severe erosion caused by both natural forces and anthropogenic activities. The central coastal zone of Vietnam, from Thanh Hoa to Binh Thuan province, for example, has been severely eroded since 1950, with more than 260 erosion sites recorded. This study shows that many reported erosion spots resulted from short-term and impactful natural events, where beaches and coastal systems can be restored quickly back to its normal state after the events. Permanent erosions, however, are closely related to human activities of coastal utilization and the construction of engineering facilities.