Only one overflow in record year
June 21, 2005
A combination of drier weather and improvements to North Shore City's wastewater network through Project CARE has led to
a near-perfect result in a long-standing battle with beach pollution.
The council was counting on getting through the 365 days to last Sunday without a wet weather sewage overflow - but
Saturday's rain and a minor overflow conspired to spoil the record, with the deadline only 26 hours away.
However, it is still seen as a considerable achievement as it is the first time since accurate records of pump station
overflows began 12 years ago that only one overflow has been recorded. The near-perfect result has meant fewer warning
signs, and cleaner streams and beach water.
That is a testament to the council's environmental innovations, says Mayor George Wood.
"It just shows that the time, money and effort we are putting into finding ways to cut down the number of overflows is
worth it," he says.
Mayor Wood says that while the past summer was exceptionally long and dry and yearly rainfall was down, the decline in
the number of wet weather overflows has fallen to virtually zero for the first time since accurate recording began 12
years ago.
"A goal of Project CARE - our $210m, 20-year programme aimed at improving beach and stream water quality - was to have
on average only two wet weather overflows a year, instead of 12."
Only one wet weather pump station overflow has occurred since June 19, 2004, although there have been dry weather
overflows caused by blockages and pump or power failures.
The city's beaches are now better protected by the new Kahika and Silverfield storage tanks, the re-commissioning of
four old storage tanks, and other work across the city to increase capacity and repair the network - such as re-lining
pipes and re-sealing joints.
North Shore City's water services general manager, Geoff Mason, says that despite these measures it is inevitable that
some stormwater will find its way into the sewerage system. Storage tanks work by collecting the increased flow and
releasing it back into the system at a controlled rate.
"Our storage tanks have a total capacity of 16,000 cubic metres, or about eight Olympic-sized swimming pools, and have
prevented 17 overflows since they were commissioned in 2002 and 2004 respectively," he says.
North Shore City Council has so far spent $50m in total on projects to reduce wet weather overflows in its wastewater
network since 1998 when Project CARE began, and is committed to spending a further $160m to complete Project CARE
improvements by 2021.
Drier weather and these kinds of prevention measures have also had a positive effect on the council's Safeswim
programme. Only one water quality warning sign was put up last season, compared to 28 the season before.
While North Shore City Council continues to upgrade the wastewater system, it is expected that homeowners will play
their part too.
Inspections of private sewers are currently being carried out in selected areas across the city and owners notified of
problems with their pipes. They must be remedied and re-inspected then recorded on the property file.
"We all need to work together to ensure we keep North Shore City's environment clean and green," says Mayor Wood.
(ends)