By 2090 Riverton could - in an extreme weather event, see storm surges and wind waves driving sea water through much of its low lying areas, according to an advance presentation on climate change by Great South to the Southland District Council (SDC) yesterday (1st Oct).

Riverton in 2090, best case and worst case scenarios. Graphic: SDC

The presentation, including modelling, sea level rise and exposure information, looked at the possible effects by 2090 on six southern coastal communities including Colac Bay, Curio Bay, Fortrose, Riverton, Oban, and Waikawa.

The presentation forms part of a SDC commissioned report intended to help the council better understand the possible effects of climate change on its coastal communities.

A full peer reviewed report is expected to be presented to the council in late November and will also include 2130 and 2300 scenarios.

Colac Bay in 2090, best case and worst case scenarios. Graphic: SDC

Sample maps in the summary presentation outlined best and worst-case scenarios for the six south coast locations by 2090.

A best-case scenario for 2090 considers sea level rise, vertical land movement and mean high water spring (spring tides), while a worst-case scenario also adds extreme sea levels from a one-in-100-year storm event creating storm surge and wind waves.

Great South GM strategic projects Steve Canny said the area of climate change-induced sea level rise was a dynamic and changing area of science. 

Curio Bay in 2090, best case and worst case scenarios. Graphic: SDC

“It is expected that the guidance from the Ministry for Environment will be updated as climate science knowledge is further refined, and an agreed rate of climate change is confirmed,”Canny said.

“Accordingly, the modelling shown may change as updated climate science information becomes available.”

SDC Chief Executive Cameron McIntosh said communities were already experiencing the effects of sea level rise and changing weather patterns.

Fortrose in 2090, best case and worst case scenarios. Graphic: SDC

“Council has a responsibility to identify natural hazards, including those that will result from the effects of climate change in the future, and do our best to draw on this information in short, medium and long-term decision-making," he said.

McIntosh said Council had commissioned the work to provide a basis for better decision-making into the future.

Waikawa in 2090, best case and worst case scenarios. Graphic: SDC

Oban in 2090, best case and worst case scenarios. Graphic: SDC

CLICK HERE to view a livestream of the Great South presentation.

CLICK HERE to email the SDC regarding coastal hazards.