Environmental Engineering Reference
In-Depth Information
have less environmental value (at least as assessed by agreed criteria) and/or any
impact from a development that is in an area of less signifi cance. Construction can
only take place within the envelope area as long as the identifi ed areas are managed
according to agreed plans. The uncertainties are dealt with via specifi c identifi ed
plans and protocols. Such an approach is well aligned with the mitigation hierarchy:
avoidance, minimisation and mitigation.
Case Study 1: Modelling Raptor Collision Rates
at Hurunui Wind Farm
Background
The proposed Hurunui Wind Farm is approximately 66 km north of Christchurch,
South Island, New Zealand approximately 13 km from the coast, being separated
from it by a series of north/south oriented ridges. The proposed wind farm lies in
the Motunau Ecological District which is characterised by coastal hills and valleys
draining eastwards into the Motunau Plain. The project site comprises six land-
owners collectively managing over 3,454 ha of land, mainly for cattle and sheep
grazing. Twelve vegetation community types were identifi ed in the wind farm
footprint and adjacent land. Pasture and mixed pasture/silver tussock associations,
characterised by introduced grasses and herbaceous species comprise most of the
vegetation present in the wind farm envelope. On higher elevations and steeper
slopes silver tussock
Poa cita
dominated grassland communities are present and
inter-grade with pasture and silver tussock which are also present in the gullies
intersecting the landscape.
The New Zealand falcon is a nationally threatened species that is known to be
present in the project region (Robertson et al.
2007
). The falcon is classifi ed as
Nationally Vulnerable in the Department of Conservation's Threat Classifi cation
System (Miskelly et al.
2008
) and identifi ed as at risk from wind farm construction
and operations (Powlesland
2009
). During early site investigations a pair of falcons
was discovered nesting in grey shrubland within the project site. The discovery lead
to detailed studies focused on understanding how the falcons used the landscape
with respect to the proposed wind farm and on their potential collision risk.
Methods
A pair of resident falcons were tracked using Telonics™ TR four radio telemetry
receivers and Kiwitrack™ backpack harness-mounted radio transmitters during
the 2010 autumn/winter period. Each falcon was tracked for 2 days per month
between March and July 2010. In order to evaluate seasonal variation and potential
