CTGM replacement Brookfield Tunnel to Burmi Creek
We're planning to replace the Chichester Trunk Gravity Main (CTGM) between Brookfield Tunnel and Burmi Creek. Condition assessments of the CTGM over the past few years have revealed the main, originally built in 1923, needs to be replaced.
Replacing the 12km section of the CTGM between Brookfield and Burmi Creek will:
- reduce leaks, which will help conserve precious drinking water
- improve safety for workers and the community
- help maintain a consistent supply of drinking water to the region.
What we're doing
We’re looking at two possible alignments for the replacement main:
- The first runs next to the existing main, through the Columbey National Park.
- The second alignment would divert southwest after Woerdens Road and follow an existing powerline easement towards Clarence Town Road in the south.
View route options
A preferred route for the replacement CTGM has not been selected.
Both alignments are under consideration. Key considerations in selecting the preferred route will include environmental impacts, community and property impacts, constructability, cost to build and cost to maintain, and relevant legislative requirements.
If the existing corridor is selected as the preferred route, it would mainly be an aboveground pipeline. For the alternate route, we are looking at an underground pipe, based largely on feedback from landowners along this route.
If the alternate alignment alongside the powerline easement is selected as the preferred route, we've identified two potential points where a connection could be made back to the existing CTGM corridor. Both potential tie-in points are still under investigation.
Additional site investigations needed.
Earlier this year, we carried out a range of site investigations on both alignments. This included aerial surveys, environmental assessments of flora, fauna and heritage in the area, flooding surveys, and geotechnical studies to better understand ground conditions beneath the surface.
Following these preliminary site investigations, it became evident that more targeted flora and fauna assessments are needed, particularly in the summer months when certain species are detectable. We will be returning to carry out further onsite investigations of seasonal flora and fauna on both alignments over the coming months.
Liaison with NPWS and Transgrid is ongoing. Seasonal ecological investigations will continue through to early next year.
We expect to inform the community of the preferred route for the replacement CTGM from early 2024. Key considerations in selecting the preferred route will include environmental impacts, community and property impacts, constructability, cost to build and cost to maintain, and relevant legislative requirements.
Once a preferred route is selected, we will start the concept design and detailed environmental assessment, which will take about a year to complete. We expect the concept design and review of environmental factors will be placed on public exhibition for community feedback from early 2025.
2015 and 2021
CTGM condition assessment
Business case and options development
From early 2023
Route selection (including site investigations)
Onsite investigations will help us better understand ground and soil conditions in the area. This information will be used to help inform route selection, preliminary design and environment assessment for the replacement CTGM.
Concept design and environmental assessment
Once a preferred route is selected, we will start the concept design and detailed environmental assessment, which will take about a year to complete.
Public exhibition of concept design and environmental assessment
We expect the concept design and review of environmental factors will be placed on public exhibition for community feedback from early 2025.