Sewer network upgrades roll into the Adelaide Hills

Work to upgrade more than 100 metres of sewer main in Bridgewater is set to commence next week, as part of SA Water’s ongoing investment securing reliable wastewater services for the Adelaide Hills.

The existing 100-millimetre-diamater pipe travels underneath Cox Creek from a pump station located on Ayr Street, which transfers the local area’s sewage to the SA Water’s Hahndorf Wastewater Treatment Plant.

Last year, gabion walls – which are specialised steel baskets filled with rock – were installed along a small section of Cox Creek to stabilise the banks and protect nearby sewer infrastructure in preparation for the network upgrade.

SA Water’s Senior Manager of Capital Delivery Peter Seltsikas said along with installing the new pipe, another gabion wall will be constructed to further improve erosion protection.

“Building more support structures to mitigate the risk of erosion or land slippage and upgrading this important sewer pipe will ensure reliable services for our customers for years to come,” Peter said.

"Ahead of this project, we undertook a risk assessment of our sewer infrastructure and the surrounding natural environment, which identified the creek channel had become significantly wider over time due to erosion.

“If left unaddressed, it poses a substantial risk of network failure and resulting sewage discharge to the creek, along with potential overflows to properties upstream of our pump station.

“To safely enable the new pipe installation, we’re building a temporary cofferdam using a sandbag system to isolate the flow of water to this section of the creek and keep it dry, with a bypass in place to manage normal creek flow around the work area.

“The pipe will be laid alongside the existing sewer main – which will be isolated from our network as part of the upgrade – by conventional trench and lay methodology, using PVC-O pipe, a modern plastic material known for its strength, flexibility and durability.

“We’ll also be constructing the additional rock gabion wall along the banks of Cox Creek opposite our pump station on Ayr Street, to protect our sewer infrastructure that follows the watercourse.

“Importantly, we’ve used feedback from the community to inform its design, which will include the planting of native vegetation and blending techniques including the layering of large stones for erosion protection.

"For the safety of our crews and the community, the short loop trail that branches off the creek crossing will be temporarily closed at times during this work, along with a section of the Bridgewater Linear Trail. The creek crossing will be permanently closed during our work.

“Clear signage and detours will be in place for the duration of our work to ensure the community and visitors to the area are aware of the trail access changes.”

Work to install the new sewer pipe will be undertaken between 7am and 5pm, Monday to Friday, and is expected to be completed by mid-2024.

Mr Seltsikas said more sewer network upgrades were underway in Bridgewater.

“As part of our ongoing investment program, we’re also upgrading two wastewater pump stations on Mount Barker Road and Towers Road to improve their condition and reliability,” Peter said.

“This work involves installing new permanent generators to keep them operational during power outages and replacing existing flow meters and switchboards, along with upgrading a concrete chamber lid.”

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