February 21, 2014
Upgrade works to commence next week
Upgrade works on the Anzac Parade / Kowhai Park stopbanks in Wanganui are set to begin next week.
A contract has been awarded to New Plymouth based Whitaker Civil Engineering Ltd to undertake the larger part of the
upgrade works, which will comprise raising earth stopbanks, constructing timber retaining walls and concrete floodwalls
and modifying roadways within Kowhai Park.
Horizons councilors agreed to the works approximately 12 months ago after an investigation of the existing stopbanks
found significant variation in the standard of protection they provided.
Horizons group manager operations Allan Cook says “the works will result in a consistent standard such that a flood that
has a 2% probability of occurring in any year, commonly referred to as the 50-year flood, can be contained, without
freeboard”.
The present low standard of protection was demonstrated in October last year when a 23-year return period flood was only
just contained with hastily erected sandbag walls. Since then, temporary measures have been in place aiding prevention
of a stopbank breach.
The works to start next week will generally raise existing stopbanks but also widen narrow sections, improving their
ability to withstand high flood levels.
“For safety reasons it will be necessary to close off public access to sections of the park as works progress. Some
disruption for the public is unavoidable however we will do our best to minimise that and wherever possible will provide
alternative passageways around the works site,” Mr Cook says.
The works are expected to be substantially completed within 12 weeks. The estimated cost of the overall flood protection
upgrade project, including works in the Matarawa Stream immediately above Anzac Parade, for which tenders are yet to be
called, is $1,020,000.
“Completion of the project works will protect an estimated 57 houses from flooding in the 50-year flood and will result
in significant savings in wider community disruption, emergency management and clean up costs presently incurred at
progressively increasing levels in anything larger than a 20-year flood.”
The works will be undertaken within three separate zones, with works to be substantially completed in each before the
next commences.
The first zone comprises the arboretum extending from Georgetti Road to the Matarawa Stream. Works activity will then
shift to the area between Dublin Street and Helmore Street, while the final zone comprises the area adjoining the
children’s playground.
ENDS