National assessment of extreme sea-level driven inundation under rising sea levels

Frontiers in Environmental Science (2022)

This study implements a national land inundation area (IA) assessment from extreme sea-levels (ESLs) and relative sea level rise (RSLR) in New Zealand. The study addresses a significant hazard information gap, producing nationwide inundation maps for 2, 5, 10, 20, 50, 100, 200, 500 and 1,000 annual recurrence interval ESLs for 0.1 m RSLR increments up to 2 m above present-day mean sea levels. We implement a static model approach to map land inundation that 1) balances model complexity and data processing in a GIS environment operating on a personal computer, 2) supports a hybrid national topographical dataset comprising LIDAR and bias corrected SRTM DEMs, with mitigation structure representation 3) supports inundation mapping at different spatial resolutions and 4) that is easily updated with new models or data when available. New Zealand’s ESL inundation exposure is quantified and reported by region, and urban and rural land areas. Finally, we discuss the strengths and limitations of the national inundation mapping approach presented.