Balickera Tunnel remediation
Hunter Water has completed rehabilitation of the Balickera Tunnel, which will ensure ongoing reliable transfer of water from the Williams River to Grahamstown Dam via the Balickera Pump Station.
The 1.2km tunnel was constructed in 1962 and is a key piece of the region’s water supply infrastructure.
Contractors Abergeldie completed work on behalf of Hunter Water over the summer and autumn of 2021-22, which included upgrades to existing access tracks and major rehabilitation works inside the tunnel to stabilise the rock surface.
Environmental assessment
Balickera tunnel is a known roost site for a number of threatened microbat species and the remediation work was deemed likely to have a biodiversity impact on these colonies due to temporary exclusion from the tunnel. The affected species are listed as ‘Vulnerable’ under the NSW Biodiversity Conservation Act 2016 (BC Act) and include:
- Little Bent-winged Bat (Miniopterus australis)
- Large Bent-winged Bat (Miniopterus orianae oceanensis)
- Southern Myotis (Myotis macropus).
Managing impacts during remediation work
We temporarily excluded all bats from the tunnel while the remediation work was carried out. To reduce impacts to the bats during construction, temporary habitat such as bat boxes were installed along Balickera Canal and surrounds.
In the last week of May 2022, once work inside the tunnel was complete, we reopened the tunnel to microbats and noticed some species started to return soon after. Over the next two years ecologists will continue to carry out surveys every quarter to track their return as part of the project’s Microbat Management Plan.
The Microbat Management Plan can be viewed in Appendix J of the Species Impact Statement.