Coastal erosion in Port Denison threatens key infrastructure as Irwin Shire explores long-term options

Coastal erosion at Surf Beach in Port Denison continues to put major community infrastructure worth up to $40 million at risk, prompting the Shire of Irwin to assess future options to manage the issue. The affected area spans about 600m, where coastline is retreating steadily between Grannies Beach and Nuns Pool Reef along Surf Beach. Irwin shire president Mark Leonard said the erosion had been progressing for many years, with natural processes possibly influenced by changes to the coastal environment and the construction of the Port Denison marina by the State Government in the 1970s. He said the impacts were no longer confined to the beach itself. “Interestingly, we seem to be gaining beach south of the marina, and eroding the beach north of the marina,” he said. “Unfortunately, the shire — and therefore the Irwin community — have significant assets under threat from the erosion in this area.” Among the at-risk infrastructure is a wide range of public facilities, including the shire’s recreation centre and precinct, football oval, skate park, Ocean Drive, carparks and community housing. The total estimated replacement cost of these public assets sits between $30m and $40m. Private homes and properties in the area are also becoming increasingly vulnerable as the shoreline continues to shift inland. About five years ago, portions of the Surf Beach carpark and foreshore footpaths were claimed by the ocean. In response, a stabilised earth shield —made from a mix of existing sand and cement — was constructed as a short-term defence. “Since then the State Government has provided financial assistance over the past five years to assist the shire to carry out works to stabilise this area of erosion, which, while only ever a short-term solution, has done its job until now,” Mr Leonard said. “With the shield deteriorating, we’re at the point where longer-term solutions need to be explored.” He said it was important to act early while there was still time to carefully consider the most effective and sustainable path forward, whether that meant strengthening existing defences or making room for the coast to move naturally. “If we act now, we have time to make a considered decision on the cost-benefit of any actions to either defend or retreat,” Mr Leonard said. “Waiting until the buildings, roads etc. are falling into the ocean before acting is poor planning.” While in the early stages, the shire is working with coastal experts to understand the available options and determine how best to manage the area in the future, and will look to seek financial assistance from relevant State Government departments and ministers.