New coastal flood risk maps developed

WELLINGTON: New maps showing areas where extreme coastal flooding could occur aim to fill gaps for places that do not have this data available.

The maps were created by Niwa and the Deep South National Science Challenge.

They show a large storm tide along with the sealevel rise the country is expected to experience with climate change.

Niwa chief coastal scientist Dr Scott Stephens said the maps would help shape decisions on how to adapt to sealevel rise.

‘‘Coastal flooding is a global hazard that impacts New Zealand, with rising sea levels already causing more frequent and intense flooding along many coasts.

‘‘We have created maps that help identify the changing risk to land, property and infrastructure from rising seas, at a regional and national scale.’’

It was hoped the information would help councils and government to know where to conduct detailed investigations when developing adaptation strategies to protect coastal communities.

Coastal flooding was particularly likely when high tides, storm surges and large waves occurred simultaneously, Dr Stephens said.

At those times, lowlying areas could be inundated when high seas topped or even broke barriers and caused rivers to back up inland.

That could be lifethreatening, as well as destroy property and infrastructure and have severe impacts on the natural environment and ecosystems.

The maps were used in new research that examined New Zealand’s increasing exposure to coastal flooding with sealevel rise.

They were also intended to help the financial industry, infrastructure and service providers assess risk. — RNZ