Buried seawalls will be the last line of defence

Sunshine Coast Council - Queensland - Australia

Sunshine Coast Council will only need to construct a buried seawall at Maroochydore to protect community infrastructure if significant erosion puts the council’s beachside assets at risk.
Division 8 Councillor Jason O’Pray said the seawall would only be considered in an extreme emergency where assets were in serious jeopardy and would be built as a last line of defence.
“The $3.75 million seawall will protect council assets along a 750m stretch between the Maroochy Surf life Saving Club and Maroochydore Beach Holiday Park,” Cr O’Pray said.
“As part of today’s (Thursday, March 27) Ordinary Meeting decision, council also considered a cost-benefit analysis associated with protect-or-retreat options for the Maroochydore Beach Holiday Park.
“To build and maintain a buried seawall at the holiday park section would cost $1.475 million over 30 years, compared to a net revenue loss of $2.601 million if 34 park sites were affected by erosion.
“Given those figures, it makes financial sense to protect the holiday park.”
Cr O’Pray said the seawall would be located as far landward as possible and would be complemented with beach and dune nourishment to conceal the structure.
It would include pedestrian and cycle pathways similar to those at Moffat Beach. Council has initiated discussions with State Government approval agencies.
Division 4 Councillor Chris Thompson said the southern seawall was already in place at Alexandra Headland Surf Life Saving Club and is in good condition
Cr Thompson said the council would continue carrying out integrity checks and minor maintenance works to provide longevity.
“However we have a completed design and while we are hoping for the best, we are planning for the worst.”
Cr Thompson said the Minister for Transport and Main Roads had advised the council that at this stage there were no State funds to protect a 700m central section of State Government-owned road on Alexandra Pde.
“Council will continue to seek the State Government’s commitment to fund a $3.5 million seawall to protect that important infrastructure, should a severe storm event put Alexandra Pde at risk of closure,” Cr Thompson said.
“Over the past two years, council has spent $2 million on constructing a pipeline, dredging, dune protection works and beach nourishment to rebuild the sand profile at the Maroochydore section.
“An additional $65,000 has been spent over the last five years on minor operational maintenance to undertake sand movement and rebuild eroded foreshore areas.”
Council has also committed to a major sand sourcing and replenishment study to look at longer term options for maintaining a healthy sand supply to Maroochydore Beach to protect the entire beach in the future.

  • Northern seawall section 750m – Maroochy Surf Life Saving Club, council stormwater infrastructure, Unitywater infrastructure and Maroochydore Beach Holiday Park (proposed council-led works: $3.75 million);
  • Central seawall section 700m – State-controlled Alexandra Pde (proposed State-led works: $3.5 million);
  • Southern seawall section 250m – Alexandra Headland Surf Life Saving Club, council open space facilities (proposed council-led works $1.25 million, if required).