Is China's coastal engineered defences valuable for storm protection?

Abstract

China has a long history of building hard engineered coastal defences for storm protection, which enables us to examine the economic effects of the hard engineering to mitigate storm damage. Examining historical storm impacts between 1989 and 2016, a significant negative relationship exists between the relative economic damages (i.e., TD/GDP) by storm and the length of existing hard engineering within the storm swath. This indicates that hard engineered defences play a critical role in storm mitigation. We estimated that the storm protection value provided by hard engineered defences in China is CNY 3.18 million/km [US$0.50 million/km] on average, with a median of CNY 1.69 million/km [US $0.27 million]. They provide an annual economic value of CNY 6.04 billion on average. Despite their great contribution to reduce total economic damages from storms, hard engineered defences are not as efficient as coastal wetlands. Coastal wetlands are more cost effective based on comparison from China and USA. This study highlights the need for the Chinese government to transfer focus from prevailing hard engineered defences to ecosystem-based measure or the combination of both measures to prevent storm damage in the future