Australia’s SA Water has commissioned SMEC to provide a concept design for critical upgrades to Mount Bold Dam – the largest dam in South Australia – to enable the structure to meet current Australian National Commission on Large Dams (ANCOLD) guidelines.
The Mount Bold Dam is a vital infrastructure as it is the largest reservoir in the region with a total capacity of approximately 46 billion liters, providing 40% of the water supply in the capital, Adelaide.
The new upgrade will bring Mount Bold Dam into line with current guidelines by strengthening the dam wall’s central arch section by supporting it with mass concrete, and strengthening the existing gravity dam abutment sections with anchors later installed through the bedrock. It will also remove existing drain stream gates and the need for manual operation, provide a phased free drain stream to safely pass the full range of flooding, including flood attenuation for frequent floods, and incorporate a saddle dam to prevent overflow over a low-section lying at the edge of the reservoir.
Ultimately, the upgrade will strengthen the dam to safely pass floods and seismic events, while providing limited flood protection for the downstream community.
“We are proud to have been chosen as the project’s concept designer,” SMEC Project Design Director Francisco Lopez commented. “This is a critical role that helps protect one of the most important infrastructure assets for the Adelaide community. Much has changed since the dam was first constructed in 1938 and upgraded in the 1960s, which means that there is a need to reassess and modernize the Mount Bold Dam to meet current ANCOLD guidelines and industry standards. For example For example, the ability to withstand the maximum potential for flooding and seismic loads are the two main areas that will be addressed during the concept design phase.”
Constructed between 1932 and 1938, the Mount Bold Dam was designed and built as a water supply dam with the intention of maximizing storage levels. The dam is an important and cost-effective water supply asset, while also providing some flood mitigation benefits to downstream communities through controlled water releases. Water is also pumped into the Mt Bold Dam from the Murray River.
SA Water expects to begin and complete the detailed design of the upgrade in 2022. Construction is scheduled to begin in 2023 and construction will take approximately three and a half to four years, providing a safer and more secure asset for the future.