Benefit—Cost Analysis on Coastal Structures Design for Climate Change Adaptation in Hong Kong

Abstract

Some experts believe that Hong Kong will probably be subjected to more extreme weather conditions due to climate change. To better understand the potential implications of the effects of climate change on coastal structures in Hong Kong and to ascertain necessary revisions to the current design standards to minimize the risk of coastal flooding, the Civil Engineering and Development Department (CEDD) of the Hong Kong Special Administrative Region Government conducted a study to review the climate change situation in Hong Kong and its implications to coastal structures design. Projection method has been developed to project the two major climate change factors pertinent to design of coastal structures, i.e. the mean sea levels (MSLs) and extreme wind speeds, to different time windows of the 21st century based on IPCC AR5 scenarios. CEDD seriously considered investing in the future coastal structures by designing the new structures with climate change revisions as one of the adaptation measures against the climate change impact and undertook benefit—cost assessment to evaluate whether the adaptation measure is effective in coastal structures design. Three types of common coastal structures to cope with climate impact, i.e. sloping rock armor seawall, vertical blockwork seawall and piled-deck pier, were investigated. The cost-benefit analysis results demonstrated that the benefits of increased protection on new coastal structures to cope with climate change effects outweigh the additional costs incurred to construct and maintain these structures.