Environmental Engineering Reference
In-Depth Information
positioning to optimise the wind farm site. Despite some additional costs involved,
the proposed road layout was designed to avoid the high quality tussock grasslands
and turbine location avoided close proximity to high value gullies (and, in addition,
minimised the likelihood and requirement to store sediment overburden in these
gullies). Optimising turbine layout and type of turbine retains the developers
negotiating power when it comes to turbine procurement.
In the fi nal decision, the Environment Court required a siting plan indicating the
number and position of turbines, sediment disposal sites, tracks, cut and fi ll and
lay-down areas (Environment Court Decision NO. C 140/2008). The decision required
a narrower development envelope, the re-siting of turbines that intruded into signifi cant
ecological areas, as well as a series of Supplementary Environmental Management
Plans to provide for buffer zones and environmental management for areas of identifi ed
ecological signifi cance. Nevertheless, the constraints mapping and development
envelope approach has enabled the windfarm to proceed whilst reducing the risk of
impacts to the signifi cant ecological attributes of the site. The use of constraints
mapping and development envelope has since been applied successfully at other
windfarm sites within New Zealand (e.g. Kaiwera Downs Windfarm).
Benefi ts of Constraints Mapping for Managing Risk
As for bird collision at wind farms, the use of constraints mapping within a development
envelope has signifi cant benefi ts for reducing risk to the environment. It provides an
objective basis for a precautionary approach to development and to proceeding
with specifi c management plans within an overall adaptive management framework.
In this manner risk is not only reduced, but monitored, so it can be improved upon
as required. The constraints mapping allows 'what if' scenarios to be considered; in
the case of wind farms the impacts of the locations and areas proposed to be lost to
turbine platforms and access roads can be readily assessed. Even in the absence of
quantitative data, agreed constraints mapping can facilitate a pathway through the
regulatory environment including a basis for expert caucusing and agreement, a
mechanism used increasingly in New Zealand decision-making.
Concluding Remarks
A major limitation of environmental impact assessments often includes a paucity of
robust information and poor understanding of plausible scenarios with little capacity
to judge their likelihood of occurrence (Beyers
1998
; Jones
2000
). This limitation is
heightened when there is a high uncertainty associated with novel developments for
which there is little history and consequent opportunity to measure and monitor
potential impacts. Similarly, this reduces opportunity to explore, monitor and confi rm
agreed mitigation measures associated with potential impacts. Therefore, whilst an
environmental risk assessment can clarify potential risk to the environment that may
