SA Water has announced that construction is complete on its new 1ML concrete wastewater storage tank in Stirling as part of a suite of network upgrades across the Adelaide Hills, designed to manage sewage flows during rain events.
The 21m long by 13m wide tank – which is partly underground – was built near the intersection of Gould Lane and Mount Barker Road to provide additional capacity within the local sewerage network.
Groundwater or stormwater infiltration can typically occur in a sewerage network, such as through inspection points or incorrect connections, and compounds the flow and volume within the system.
SA Water’s Senior Manager of Capital Delivery, Peter Seltsikas, said the storage will play a critical role in helping reduce the risk of sewage overflows during heavy rainfall events.
“While it’s normal to have a level of stormwater infiltration, the Adelaide Hills typically experiences more rainfall compared to the metropolitan area, so this compounds the volume of stormwater entering our sewerage network,” Mr Seltsikas said.
“This increased flow elevates the risk of overflows to the environment or onto a person’s property, and this has occurred several times in the area over recent years.
“We want to minimise the chance of this happening in the future to ensure our sewers are able to continue protecting public health.
“By constructing this new storage tank in Stirling, we have increased the capacity of the local network to build in a redundancy should we experience a significant rainfall event.
“The tank provides a temporary holding storage to take the pressure off the connecting network should flows increase in volume, helping regulate this movement of sewage to our Heathfield Wastewater Treatment Plant.
“When the pump station at the site reaches capacity, sewage flows into the new tank via an overflow pipe and is held there until flows stabilise, which triggers the tank to be emptied back into the network.
“To ensure minimal impact from construction, including to the site’s visual amenity, we implemented a range of measures during our works – including soil nails and steel mesh to support excavated areas – commissioned independent pre-construction and post-construction dilapidation reports, and carried out native revegetation.
“Importantly, the independent reports – which assesses the condition of internal and external components of a property – confirmed our construction work had no impact on any neighbouring properties,” Mr Seltsikas said.
Elsewhere in the Adelaide Hills, SA Water has now wrapped up work in Bridgewater to install 40m of gabion walls along two small sections of Cox Creek to prepare for an upgrade of 100m of sewerage pipe which will commence in 2023.
“We’ve also recently completed an upgrade of a sewerage pump station at Aldgate, including relining the concrete well that catches sewage before it’s transported to one of our plants for treatment,” Mr Seltsikas said.
Featured image: SA Water wastewater tank. Courtesy of SA Water.