Environmental Engineering Reference
In-Depth Information
The outputs from the refined Band Model was ultimately used to demonstrate
that the potential quantum of deaths was in the same order of magnitude as the
potential gains from a predator control operation at a large breeding area, thus
allowing for the quantitative determination of the no net loss threshold for internal
migratory shorebird species required by biodiversity offsetting.
Nevertheless, predicted bird deaths from wind farms compared with other known
sources of mortality need to put in perspective. Road kills, predation, flying into
powerlines or fences, aircraft strike and occupied nests being destroyed by agricul-
tural machinery or off-road recreational vehicles are probably the largest sources of
mortality for SIPO and wrybill (Sagar et al.
2002
). These likely far outweigh the
potential losses from HMR and Taharoa C wind farms combined.
In addition, this case study shows that, even where wind farms are sited adjacent
to potentially high risk migratory flight paths, the application of scientifically
accepted modelling based on data from robustly designed field surveys, accompa-
nied by biodiversity offsetting including a no net loss objective, can be used to find
a mutually agreeable solution to an initially unresolvable position between the wind
farm developer and an objectors focused on a precautionary approach to risk
assessment.
Key Learnings, Failings in the Process, How Could
It Be Done Better
The failure of the bird expert teams to agree on many of the model inputs and the
resulting mortality estimates as well as the likely outcome of the offset mitigation
program meant that both the applicant and the DoC had to invest large sums of
money into expert time and legal proceedings. The Judge and the rest of the Board
of Inquiry refused to decide between expert evidence and instead directed a negoti-
ated decision. If this action had taken place earlier, considerable funds could have
been spent on initiating the offset mitigation. This had always been the applicant's
preferred position. Early in the process, Contact Wind had agreed to commit to
undertaking full predator control in the Upper Rangitata Valley, but was forced
through appeal to be required to undertake only as much control as was necessary
to offset measured collision mortality. It is likely that this will result in control of
only part of the valley.
The monitoring program has provided a wealth of data that can be used for future
wind farms and as general knowledge of the species involved. In addition, the
program required the development of measures of variance around Band Model
predictions (see also Boothroyd and Barea
2013
). The biodiversity offset measures
were also a first for a New Zealand consent application and have become a common
feature of subsequent applications. The decision to accept “like for like” mitigation
is also a first when the law allows minor negative effects.
