珠江三角洲地区风暴潮灾害工程性适应的损益分析

在全球增暖及海平面上升背景下,风暴潮极端事件愈加严重,修筑海防工程是沿海地区应对和适应风暴潮灾害的主要工程性措施。以珠江三角洲为研究区,基于风暴潮历史灾害数据,分析了风暴潮增水与社会经济损失的关联性;提出了定量评价工程性适应风暴潮灾害的经济损益理论关系模型;推算了未来极端事件情景下,珠江三角洲海防工程建设的适应效果。结果表明,珠江三角洲地区风暴潮灾害的灾损率与增水呈显著正相关。海防工程建设高度在1.69~11.85 m内处于收益状态,其中5.22 m时收益最大。基于2030年、2050年以及2100年海平面上升叠加风暴潮情景,将海防工程设防标准定为应对2100年20年一遇风暴潮时的收益最大,标准定为应对2100年100年一遇风暴潮时收益最小。

Benefit-cost analysis of engineering adaptation for storm surge risk in coastal areas: A case study on the Pearl River Delta

Sea level rise will magnify the adverse impact of storm surges on the coast, and extreme high water level will increase the risk of coastal damage. To mitigate the impacts of extreme events, building levees is chosen to be a corresponding engineering adaptation strategy to protect the infrastructure. This paper investigated the economic impacts of storm surge and sea level rise based on the historical disaster dataset in the Pearl River Delta. First, the protection level of the levees in the PRD was identified, and the relationship between economic damage and surge was discussed by analyzing the historical disaster data. Then the loss due to storm surge was calculated from the relationship between the rate of damage (direct economic loss/GDP) and surges. And the cost of heightening levees was deduced. Then a theoretical model that quantitatively evaluates the effects of building levees was established by conducting benefit-cost analysis, according to which, the benefit of heightening levees is the difference between the loss due to storm surge with no adaptation and the cost of heightening levees for protection. Finally, the model was applied to calculate the effects of heightening levees under different future scenarios. The results showed that the rate of storm surge damage was positively correlated with storm surge in the Pearl River Delta. The coastal areas will benefit from implementing levee projects with the height in the range of 1.69-11.85 m. The benefit was approaching a maximum at a height of 5.22 m, and it decreased and became negative while the height is higher than 11.85 m. Under the scenarios of 2030, 2050 and 2100, the largest benefits occurred when the levee was designed to combat a 20-year return period of storm event with sea level rise in 2100, and the smallest occurred in a 100-year return period of storm event with sea level rise in 2100. The research will provide important scientific basis for coastal areas to cope with and adapt to sea level rise and storm surge events.