Economic impacts of storm surge and the cost-benefit analysis of a coastal spine as the surge mitigation strategy in Houston-Galveston area in the USA

Rapid population growth, urbanization, and concentration of valuable assets and strategic infrastructure in coastal regions make coastal inundation, flooding, and storm surge national problems for many countries, including the United States of America (USA). Enhancing coastal resilience is a complex problem and involves an integrated risk management approach, entailing both structural protection as well as other risk reduction strategies (e.g., building codes and ecosystem preservation). The former is an increasingly recognized mitigation option for densely populated areas and industrial hubs. Fully justifying benefits of costly flood defense structures is crucial, particularly when lack of funding and other institutional barriers make such projects easy targets for omission from or cuts to a budget. Justification usually requires a comprehensive cost-benefit analysis. This paper explores the economic feasibility of a coastal barrier, i.e., coastal spine, as a potential storm surge mitigation strategy to protect the Houston-Galveston metropolitan area of Texas, one of the most flood-prone and economically important regions in the USA. We provide an assessment of residential and chemical manufacturing plant and refinery exposure to multiple synthetic hurricane storm surge events by comparing losses with and without a coastal spine. While under all scenarios, benefits exceed engineering costs of a spine, our results indicate that the project feasibility largely hinges on accounting for industrial losses and resultant indirect and induced effects. As many regions and industrial hubs globally are designing adaptation and mitigation strategies to combat the consequences of extreme events, structural solution to surge mitigation maybe one of the few mitigation options for them. Unlike population and residential structures that can retreat and insure, these options are not viable for industrial plants that are resource-based. However, expertise and knowledge pertinent to surge barrier systems are relatively scarce as there are only handful of barriers around the world and they are all unique in engineering designs. As storm surge is becoming a threat for many coastal urban centers, one of the recommendations is to consolidate knowledge base and research across countries in order to foster knowledge exchange internationally. This will help identify concerns associated with existing barrier systems, pragmatic ways to improve them and will also aid the investment decision, engineering designs, and operational aspects of barriers in other parts of the world. Furthermore, forming regional research collaborations with developing countries at risk of storm surge and the sea level rise is vital to further facilitate knowledge spillover and exchange of expertise.