Upgrade works have begun on SA’s Myponga Reservoir. 

SA Water’s $3.7 million project to refurbish Myponga’s dam spillway gates is now underway.

The project is designed to enhance the long-term security of the water supply and reinforce the structural integrity of the dam.

The reservoir, featuring three spillway gates perched on the dam wall, plays a central role in managing water discharge, due to its capacity to retain incoming rainfall from the catchment. 

Recent operations have seen the removal of the gates by a large crane, a task that required around 30 minutes per gate and the combined efforts of a 12-member crew.

Dr Daniel Hoefel, SA Water's Senior Manager of Infrastructure Planning and Strategy, has highlighted the importance of the upgrade. 

“Myponga Reservoir's arch dam is an impressive engineering feat and 60 years on, the wall remains in sound condition with our routine inspections identifying the dam’s spillway gates require an upgrade to ensure they keep operating reliably,” Dr Hoefel says.

The gates, consisting of curved steel plates reinforced by beams, are used to control the reservoir’s water level and safeguard the dam's structure. 

The upgrade includes refurbishing the gates' arms and bearings, replacing their seals, rollers, and sill plates, ensuring reliable operation during water discharge.

Authorities took several preparatory measures, including releasing water to lower the reservoir’s level for safe gate removal and the construction of scaffolding for easy access during the operation. 

“Importantly, we scheduled our work during late summer and autumn when the reservoir is at its lowest level to limit the amount of water we had to release, while maintaining a secure supply for our customers and ensuring the gates are back in action to maximise water capture across winter and spring,” Dr Hoefel said.

In addition to the spillway gates upgrade, Myponga will also see some enhancements at its reservoir reserve’s main entrance, following visitor feedback. 

These include a new kayak drop-off loop, BBQ and shelter facilities, a bitumen seal on the service road for dust suppression, and the creation of stormwater retention ponds to maintain water quality.