Australian Water Management Review Vol. 1 2014 | Page 40

“This job, with all of its complexities and risks,
provided an example of how direct and meaningful
engagement about safety and promoting best
practice outcomes is imperative. ACTEW made
it clear throughout the job that tackling safety
was a necessity and worked hard to ensure there
was involvement from all parties – management,
industry and workers. In essence, the fact that
the safety outcomes were of a high standard on
such a complex job go to the heart of what every
job requires – consultation, collaboration and
meaningful engagement, and action at all levels,”
he said.
Environmental considerations

• Management and rehabilitation of 420 hectares
of native land in the Cotter Dam catchment area
to offset the biodiversity impact of constructing
the new dam.

In enlarging the Cotter Dam, the Bulk Water Alliance
paid meticulous attention to protecting and enhancing
the neighbouring environment throughout the
design, planning and construction phases. Particular
environmental strategies included:

• Commitment to offset all carbon emissions
associated with the construction and operation
of the project, through securing 900,000 TCO2-e
(tonnes of carbon dioxide equivalent) of carbon
forestry offsets over 30 years.

• Around a million tonnes of foundation bedrock
was quarried and retained on site to be crushed
and used in the construction of the dam wall.
Processing and crushing this bedrock onsite
into aggregate for Roller Compacted Concrete
use saved a potential 2,856,400 kilometres
of construction vehicle journeys – enough to
circumnavigate the equator 71 times, or go to the
moon and back three and a half times.

34 | Australian water man age m e nt re v ie w

• Relocation of more than 120 Grass Trees
(Xanthorrea) from the inundation zone. These
were replanted on the Cotter Dam Discovery
Trail, at the Australian National Botanic Gardens
Canberra, at the National Arboretum and in
rehabilitated areas of the Cotter catchment.
• In consultation with the Yurung Dhaura
Indigenous work group, a nursery of bush
medicine and traditional food species was planted.

• More than 2,000 Aboriginal and European
heritage artefacts were surveyed and salvaged,
generating local employment and providing a
lasting legacy of the archaeological significance
of the Cotter area.
Importantly, the construction has also ensured
survival of the last viable population of the endangered
Macquarie Perch in the ACT, thanks to seven
kilometres of specially designed rock reef habitat
constructed from large boulders. A commitment to
protecting the endangered species was made from
the beginning, and ACTEW Water joined forces with
leading edge research partners like the University of
Canberra to ensure this was achieved.
A key part of the research tested different types
of artificial habitat to provide shelter for the fish
and protect them from predatory birds as the new
reservoir level rises by around 50 metres.