Why was the assessment undertaken?
Site selection, rotor swept area (RSA), ground clearance of the rotor, wind turbine height and layout all have the potential to impact the level of risk of blade strike for birds and bats.
A Bird and Bat Strike Risk Assessment (contained at Appendix G.5 of the Modification Application Report) was prepared by Umwelt to assess the removal of 12 wind turbines, increase in tip height, increase in rotor swept areas and change to the ground clearance of the rotor. The assessment examined the change in potential impacts to bird and bat species from the Approved Project to the Modified Project.
As requested by the Department of Planning, Infrastructure and Environment (DPIE) Biodiversity and Conservation Division (BCD) in their submission received during the public exhibition period, a revised Biodiversity Development Assessment Report ( Revised BDAR) (Contained at Appendix B of the RTS Report) was prepared and included an assessment for the impacts of wind turbine strikes on threatened species in accordance with the Biodiversity Assessment Method (BAM).
What was the approach?
The Bird and Bat Strike Risk Assessment was prepared in consideration of the relevant conditions of the Development Consent and for those species where the assessment indicated an increased risk associated with the Modified Project, the impacts were assessed against the:
- Biodiversity Conservation Act 2016 (BC Act), and
- Environmental Protection and Biodiversity Conservation Act 1999 (EPBC Act)
What did we find and how does it compare to the approved project?
Due to the increase in RSA, several high-flying aerial species are likely to be placed at greater risk of blade strike.
Threatened species known to occasionally or regularly occur 30m above ground level (AGL) such has the Superb Parrot, Dusky Woodswallow and White-fronted Chat are likely to be at a higher risk of blade strike associated with the Modified Project. For species which rarely occur above 20m AGL, the difference in blade strike from the Approved Project to the Modified Project is expected to be insignificant.
The assessment found that the Project is unlikely to increase the risk of blade strike or have adverse impact on species listed under the BC Act or EPBC Act.
Due to the increase in RSA, several bat species are likely to be placed at higher risk of blade strike.
However, the assessment found that the Project is unlikely to increase the risk of blade strike on any threatened bat species listed under the BC Act. It should be noted that no bats listed under the EPBC Act were recorded in the Project Area.
The Revised BDAR included a prescribed impact assessment for nine threatened bird species, one non-threatened bird species and four threatened bat species. The wedge-tailed eagle was also included due to its susceptibility to blade strike. The table below provides a risk rating for each of these species.
|Common Name||Likelihood||Consequence||Risk Rating|
|Large bent-winged bat||High||Moderate||High|
|Yellow-bellied sheathtail bat||Moderate||Moderate||Moderate|
|Eastern false pipistrelle||Moderate||Moderate||Moderate|
What are the proposed mitigation strategies?
To manage the potential impacts to bird and bat species, Tilt Renewables will prepare a Bird and Bat Adaptive Management Plan that will monitor and respond to actual collision results and blade strike rates.
Assessment against Development Consent
The Modified Project can comply with the existing conditions of the Development Consent relating to bird and bat blade strike risk.