Mapping future coastal hazards
UP to 5000 Coffs Coast properties could be inundated by rising sea levels, erosion and storm surges during the latter half of this century.
That’s the worst case outcome of the Coffs Harbour coastal processes and hazard definition study commissioned by council and now made available to the public.
The maps associated with the document were leaked several weeks ago but now the council has released the complete report having contacted all property owners in the areas under threat from the predictions for 2050 and 2100.
Council’s city services director Ben Lawson said it was imperative communication to homeowners was done thoroughly to avoid unwarranted alarm, particularly around the scale of properties that could be potentially inundated.
“While the likelihood of that scenario is considered extremely rare – in fact it’s never been witnessed in recorded history – it’s important that we recognise the full, potential extent so we can take steps to minimise any possibility of such an occurrence actually happening in the future,” Mr Lawson said.
“The study is giving a technical view of what could happen into the future, factoring in increased extreme weather events and sea level rises across the whole local government area.
“The two key problems are inundation from rising sea levels and storm events, and coastal erosion.
“It sets the scene for what could happen.
"No one is sure of what will happen.
“This isn’t an exact science but there is science behind it.
"The real value is understanding what could happen and what are the options to mitigate these impacts.”
Mr Lawson said sand dune replenishment and rock wall protection were options now being considered to protect properties.
He also said he did not think there had been a “huge level of alarm” since the letters were posted to affected property owners.
The study was prepared by consultants and uses the NSW Government’s scientific guidelines and forecast sea level rise.
The Government predicts a sea level rise of 40cm above the mean average sea level recorded in 1990 by the year 2050 and 90cm by the year 2100.
An extreme sea level rise of 1.4m in the year 2100 was also assessed during the study as a worst case scenario.
“The study looks at the risk of coastal erosion or coastal inundation hazards at three different timescales during extreme weather,” Mr Lawson said.
“These are immediate, by the year 2050 and by the year 2100. At each time frame, the maps show the extent of coastal erosion or coastal inundation that is almost certain, unlikely and rare.
“The coastal inundation zones shown in the maps are not permanent water levels but illustrate forecast inundation during a storm event, with or without sea level rise.”
The council report and maps are available to view at www.coffsharbour.nsw.gov.au/consultation.