The Bowden Road stormwater treatment facility is part of Auckland’s initiative for protecting the environmental and recreational values of the city. The facility captures sediment, litter and associated contaminants. Tonkin & Taylor provided stormwater design and construction monitoring for the project. The facility comprises a settling basin and floating litter trap retrofitted at an existing stormwater outfall. The basin was constructed using deep piles and precast concrete walls, providing an open structure for ease of maintenance. The facility benefits the marine ecosystem and helps promote water based recreational activities in the area. Innovative features include a fish passage and a permanently positioned litter trap able to move vertically over a water height difference of 4 m.
Preparation of a structure plan for the 1500 lot Cambridge North deferred residential zone that provided solutions for staged development of stormwater, sewage, water supply and roading infrastructure to allow development to proceed in this area in a progressive and orderly process. The structure plan has provided the basis for plan changes and for engineering design of infrastructure extensions and upgrades.
The Northern Gateway project involves construction
of a 7.5 km section of motorway between Orewa
and Puhoi. The route crosses areas of native bush
which has high environmental sensitivity and steep
topography requiring a number of major bridges,
tunnels and deep cut/fills. The project is currently
the largest roading works in New Zealand valued
at $360 M. Tonkin & Taylor has been a full alliance
member of the project design and construction
team providing stormwater and geotechnical
design expertise.
T&T’s stormwater design included many innovative
features to minimise the motorway footprint and
protect and enhance ecological habitats. The
stormwater design objectives were to meet road
safety criteria, conditions of consent and the
project objectives for engineering and
environmental excellence.
The Ohope Escarpment Drainage project was
implemented following landslips that occurred
during heavy rainfall in 2004.
A signifi cant contributing cause to the slips
was stormwater runoff and soakage as well as
soakage from septic tank systems at residential
developments at the top of the escarpment.
Stabilising of the escarpment required the
installation of stormwater and wastewater
drainage systems to convey the water away from
the escarpment.
The project required the installation of over 9 km
of pipeline, some as drilled pipeline through the
cilff face of the escarpment.
St Kilda Residential Zone Plan Change Review, Cambridge, NZ
Client : Waipa District Council.
Discipline : Multiple
Technical review on behalf of Waipa
District Council for a proposed
280-lot subdivision near
Cambridge. Key issues included
the water quality and economic
effects of proposed stormwater ponds,
stormwater discharge into a nearby stream
subject to winter flooding extending on to the
development site, the impact of development
on Council’s water supply and wastewater
infrastructure and a geotechnical site assessment.
The Tauranga Harbour Link Stage II project involves
construction of a duplicate bridge adjacent to the
existing harbour bridge and a 600 m elevated
expressway connecting the crossings to the
existing roads. Tonkin & Taylor provided stormwater design and
management for the 3.8 km expressway project.
The stormwater was designed to meet the stringent
safety and environmental requirements of the
project. It included the collection, treatment and
discharge of stormwater into the harbour through
both existing and newly consented outfalls. The
project site is very low lying and particularly
sensitive to climate change effects, so the
stormwater was designed to allowed for future
sea levels and rainfall intensities.
Apart from the stormwater design component of
the project, T&T also provided coastal protection,
reclamation design and innovative geotechnical
design and support.
