Wagonga Inlet pipe crossings
Project: Installing new water and sewer mains under Narooma's Wagonga Inlet
Timeframe: August to December 2023
Cost and funding: $3 million, Council funded
Page last updated: December 2023
Project details
We are working to:
- design and install new water and sewer pipelines under Wagonga Inlet
Benefits to the community:
- increased security of Narooma, Kianga and Dalmeny's water and sewer network
- reduced risk to the local environment
Background and purpose
Water and sewer services are provided to Narooma via pipes that lie on the bottom of Wagonga Inlet, east of Narooma Bridge. These pipes were installed in 1979 and are now nearing the end of their intended lifespan.
The ageing infrastructure poses significant risks, especially the potential for an environmental disaster if the sewer pipe were to fail. Additionally, the logistical challenges of transporting water and sewage via road to continue local services would be extensive.
To avoid such a situation, we are replacing both pipes with 450mm diameter high-density polyethylene pipes. These new pipes will provide more efficient transfer of water and sewage, and they have double the lifespan, ensuring their reliability for over 100 years. As a result, they present a safer and more robust alternative, significantly increasing the security and resilience of the local water and sewer network.
We will install the pipes beneath the inlet using specialised techniques, including horizontal directional drilling. This method means we only need to dig up the ground at either end of the pipe, minimising impacts on the local environment.
We will set up drilling equipment in the Mill Bay car park to create a tunnel beneath the inlet, stretching across to the other side at Ken Rose Park. While the tunnelling is underway, we will weld 12-metre lengths of poly pipe together to create two pipes that are over 400 metres long. As the pipes get longer, we will lay them out along the foreshore, heading toward the Narooma pool, and access will be restricted. Each new pipe will then be pulled into the tunnel and left in place. We will then modify the existing infrastructure on both sides of the inlet and connect the new pipes.
By taking these proactive measures and employing environmentally friendly installation techniques, the project aims to ensure the continued reliability of water and sewer services for the community while safeguarding the ecosystem of the inlet. The project is in line with plans identified in our Integrated Water Cycle Management Strategy for providing a robust and future-proof water and sewer system for generations to come.
A Review of Environmental Factors was prepared to assess the potential impacts that may result from activities associated with the project.
Project updates
December 2023
- With the new water and sewer pipes in place beneath the inlet, the contractors worked to connect the pipes to existing infrastructure at either end.
- Access to the foreshore was restored and Ken Rose Park was open again in time for Christmas.
October 2023
- The contractor drilled out two tunnels beneath the inlet.
- Once they were fully prepared, they pulled each pipe into position.
September 2023
- Drilling works got underway, creating the tunnels beneath Wagonga Inlet.
- The contractor closed off Ken Rose Park, the shared pathway and a section of the foreshore so they can lay out the 400+ metre long pipes.
August 2023
- The drilling contractor started setting up to drill the tunnel beneath the inlet.
December 2022
- We awarded the contract to design and construct the new pipelines to UEA Construction Pty Ltd.
More information
For more information please contact Council's Water and Sewer Cadet Engineer, William Inglis:
- T: 4474 1000
- E: Council