Myponga Dam safety upgrade

In 2024, together with major construction partner John Holland Guidera O’Connor Joint Venture, we began remediation works to the spillway gates and associated infrastructure. This was the first time since the spillway gates were commissioned in 1962 that they had been removed. These works ensure they will continue operating reliably into the future.

We will be undertaking final works in September 2025.  

Works are scheduled to commence on 29 September 2025 and take approximately 3 weeks to complete. 

Works will be undertaken from 7am to 5 pm, Monday to Saturday. The start and duration are dependent on weather conditions and any technical constraints we may encounter. No water releases are anticipated as part of these works.

Road closure 

To safely undertake works, access to Reservoir Road between the Myponga Reservoir Lookout and Forktree Road will be closed to the public.  

The area directly adjacent to the dam wall will be occupied by machinery, a crane and scaffolding.  

During the works, Myponga Reservoir Reserve will remain open for all recreational activities. 

Myponga Reservoir, nestled near the township of Myponga, is a critical piece of SA Water’s infrastructure, supplying safe, clean drinking water to the majority of Adelaide’s south.  

The reservoir was built between 1958 and 1962, at a time of rapid economic expansion in South Australia. 

Its construction increased the state’s storage capacity, supporting population growth and the expansion of industry in Adelaide’s south. 

Its capacity is managed via the Myponga spillway gates. When a rainfall event exceeds the dam’s capacity, water is released via the spillway gates into the Myponga River. 

Water from the reservoir is treated at the nearby Myponga Water Treatment Plant before it is supplied to homes, businesses, schools and hospitals on the Fleurieu Peninsula. 

The broader Myponga Reservoir Reserve is open to the public for recreational use, including fishing (with PIRSA permit), kayaking and canoeing.