Environmental Engineering Reference
In-Depth Information
case study, can contribute to a broader risk assessment framework through inclusion
in constraints maps that explicitly identify relative risk which can then guide the
project design and subsequent project approvals process.
Case Study 2: Development Envelope and Constraints
Mapping at Mahinerangi Wind Farm
The development envelope approach provides fl exibility for development and
construction whilst acknowledging the local constraints. Furthermore, when approached
alongside an adaptive management program (including the results of any quantitative
modelling), the ability to modify approaches to any risks to the environment are
enhanced as management decisions are based on sound scientifi c advice.
The development envelope approach has been used with varying success for
wind farms in New Zealand. Here we present a case study in which the development
envelope approach was used at the Mahinerangi Wind Farm (MWF) in the Otago
region of New Zealand.
Site Location and Proposed Development
The proposed MWF is located in Waipori Ecological District in the Lammerlaw
Ecological Region of Otago. The site is in the vicinity of the watershed boundaries
of Deep Stream, Lee Stream and the Lammerlaw Stream. At the time of resource
consent application the MWF envelope covered an area of 1,723 ha, with 981 ha
(57 %) in grazed pasture and 742 ha (43 %) in snow tussock (of which approxi-
mately 359 ha was in gully formations). Construction of each turbine tower required
a clearance of approximately 1,150 m
2
to establish the turbine platform and erection
of the turbine tower itself. Due to access and construction constraints turbine
platforms were generally confi ned to gentle, moderately sloping plateaus and side
spurs. An estimated 37 km of new roading with a maximum carriage width of 12 m
was proposed.
Vegetation and Fauna Habitat Assessment
A vegetation and fauna habitat assessment involved using a combination of
field-based surveys and collation and review of existing data from a variety of
information sources. Fieldwork was designed to provide a comprehensive “snapshot”
of the project area, to ground-truth and expand on existing information, and to address
