Cumulative building exposure to extreme sea level flooding in coastal urban areas

• DOI: 10.1016/j.ijdrr.2021.102612
• Publication Date: 2021-09-30T12:52:57Z
• Authors: Ryan Paulik; Scott Stephens; Alec Wild; Sanjay Wadhwa; Rob G. Bell
• Keywords: Coastal flood

Global sea-level rise (SLR) is expected to increase the frequency of extreme sea level (ESL) flooding. Flood mitigation strategies often focus on reducing built-asset exposure relatively infrequent but high magnitude ESL events, though frequent lower events in response SLR could accumulate be more costly for urban areas. We analyse this phenomenon twenty major coastal areas New Zealand by quantifying average annual building replacement value (AAERV) within 1–10, 10–50 and 50–100-year recurrence interval (ARI) ranges, up 2 m above present-day mean sea-level. found that smaller more-frequent flooding 1–10-year ARI range contributed than 80% total AAERV, half 0.3 SLR, nearly all after 1 SLR. A Cumulative Hazard Index (CHI) showed positive CHI values one area 0.6 indicating primarily driven rather larger less-frequent as sea-levels rise. With projected region anticipated reach next ∼25–50 years, signals an urgent need investigating future impacts from events.