A safety upgrade to the Mount Bold reservoir will prevent future devastating flood events, according to the City of Onkaparinga.

The federal government will invest $9.5 million to upgrade the dam, following years of advocacy from the local community and the council.

South Australian Senator Andrew McLachlan announced the funding last week.

“The recent floods along Australia’s eastern seaboard have once again demonstrated the devastation that can be wrought by major floods in this country,” he says.

“That’s why we are continuing to make significant investments to protect communities, individuals and businesses from disasters in an increasingly complex natural hazard environment.

“This funding will support the development of a flood attenuation system to safely pass the probable maximum flood over the dam’s spillways, without causing it to fail.

“In 2016, parts of Old Noarlunga were flooded twice in a matter of months, with residents having since reported that in order to include flood protection, their insurance premiums increased by up to 600 per cent.

"This funding will support increasing the level of flood attenuation provided, while Mount Bold Dam is being upgraded, to safely pass the probable maximum flood over the dam’s spillways, without causing it to fail.” 

City of Onkaparinga Acting Mayor Simon McMahon welcomes the funding through the National Flood Mitigation Infrastructure Program, saying the upgrade would help protect the lives and properties of the Old Noarlunga community.

“Securing additional flood protection has been a key focus of council since the funding shortfall was identified in 2019, and it has been the number one priority in our Advocacy Plan, so it's fantastic our hard work and funding commitment has come to fruition.” 

“This decision recognises the community needs to be future proofed from the impacts on the increased risk of flooding caused by climate change, minimising the risk of another devastating flood event in Old Noarlunga.”

Pam Scanlon, from the Old Noarlunga Community Residents Association says the funding announcement is an exciting development for Old Noarlunga residents' future.

"The 2016 floods were devastating for Old Noarlunga.

"While the town has flooded before, to varying degrees, it was the speed and level of the water, the flooding of roads first, making evacuation difficult and the lack of warning that is still in the memories of residents today.

"We live close to nature at the entrance to the Onkaparinga Gorge and while we can accept some associated challenges, the historic township and its residents are extremely grateful to be supported by federal, state and local governments with this grant for additional flood mitigation.

The $325 million Mount Bold Dam Safety Project is part of SA Water’s upgrade of the Mount Bold reservoir dam, which was to provide protection for a one-in-18-year Annual Exceedance Probability (AEP) flood event if the reservoir was full.

City of Onkaparinga agreed to join forces with the state government in its application for federal funding in February, and this included a council and state co-contribution of $1.5875 million.

The federal funding means a superior flood option can now be built, offering protection for a one-in-100-year AEP flood event if the reservoir is full.

Detailed design is currently taking place, with construction currently expected to start in 2023, and take approximately three-and-a-half years.