Adelaide: A coastal city considers its options

Adelaide Now: Adelaide is facing the same challenges as waterlogged Venice in dealing with the threat of flooding, according to one of Australia's leading coastal science experts. Dr Peter Cowell, an international expert on the coastal impacts of climate change at the University of Sydney, said Adelaide and Venice were "sister cities" when it came to the danger posed by rising sea levels.

While acknowledging South Australia's state and local authorities had led Australia in their response to rising sea levels and coastal erosion, Dr Cowell said the threat of flooding along Adelaide's coast would become far worse over coming decades. And Dr Cowell said there may come a time when the multi-million dollar defence of the coastline should be abandoned in favour of relocating residents and businesses away from the beachfront.

…"In Adelaide, the ground is going down as well as the sea going up, so Venice is a window on the future for Adelaide," Dr Cowell told the Sunday Mail. "So in 100 years from now, while the global sea level is likely to be about half a metre higher, in Adelaide it will be a metre higher. That is quite serious – and that is just based on the average expectation. If we go to the high side of the trend, that says sea levels will rise 1.4m by 2100 – that would be about 1.9m for Adelaide factoring the land subsidence.

…The whole sandy beach coastline of Adelaide is regarded as problematic. "And for many years now, the SA Government has put a lot of effort into coastal engineering and studies along that coast to try and stabilise it. But governments have got to continually ask, SA included: `Where do we give up and decide we'd be better off relocating rather than trying to defend this stuff?'

"That's not an answer that will have been definitively arrived at by anybody yet because it takes a lot of political courage to do something like that and there are big issues of compensation."

Dr Cowell is backed by CSIRO climate change modelling released in October 2007 that found rising sea levels would have implications for coastal inundation in parts of Adelaide where land subsidence is taking place.

His comments come as the Supreme Court this week rejected a developer's appeal for an 80-lot subdivision at Marion Bay due to rising sea levels. The court's decision is believed to be the first time sea level impact has been considered. The court heard the shoreline would erode inland by up to 40m over 100 years, affecting an erosion buffer zone and a coastal reserve in the council's development plan….

City of Adelaide, Australia, seen from the foothills by "Utente:Fluctuat," Wikimedia Commons