Many New Zealanders live on floodplains and damaging flood events will occur more frequently. They will affect rural and urban areas differently. Near the coast, floods will be exacerbated by rising sea levels and storm surges. Away from the coasts they will increase erosion, siltation and building damage.
About two-thirds of New Zealand’s population lives in areas prone to flooding. Flooding is New Zealand’s most frequent and, after earthquakes, most costly insured disaster.
Extreme heavy rainfall events are expected to become more frequent in most parts of the country, by a factor of up to four, especially those regions where an increase in average rainfall is expected.
Engineering solutions such as stop-banks, and static planning measures such as land-use zoning, while helpful in the short term, could reduce New Zealand’s ability to respond as flood risk increases over time. Communities will need to find sustainable solutions and manage on-going risk.