Local Govt | National News Video | Parliament Headlines | Politics Headlines | Search

 

New Viaduct Stormwater System Catches Contaminants

New Viaduct Stormwater System Catches Contaminants At Source

Relatively new stormwater technology will be used to reduce the amount of sediment reaching the Central Area Harbour Edge through stormwater outfalls.

The catchpit filters system (CFS) catches sediment at source, significantly reducing the amount of sediment and attached toxicants discharged into receiving waters.

The technology will be trialled on catchpits leading to a new stormwater outfall in the Port area, known as the “Captain Cook” outfall, which will largely replace four old outfalls at the foot of the CBD.

It is expected that installing the catchpit filters system throughout the Captain Cook catchment will reduce the amount of sediment entering the harbour by about 50 per cent, or between 100 and 150 tonnes a year.

The $300,000 system will also trap toxins attached to sediment, including copper, zinc and lead which are mostly attributable to vehicle use. It will be combined with dredging and trialled for a year in the 123ha Captain Cook catchment.

Nine outfalls covering a 708ha catchment currently discharge an estimated 1000 to 2000 cubic metres of sediment into the harbour each year. Much of the sediment settles near the outfalls, which are dredged as part of a Ports of Auckland dredging programme. However, City Works chair Cr Doug Astley says increasing environmental awareness has accelerated the need for more sustainable solutions like the CFS system.

“Interception at source has been trialled extensively with up to 80 per cent of stormwater-generated sediment being intercepted at source,” he said. “We’ll look at installing CFS on all of the other harbour edge catchments if this trial is successful.”

A CFS is a nylon-mesh bag which hangs within a metal frame from under the catchpit grate. Stormwater entering the catchment is “strained” through the bag, with debris and more coarse sediment retained within the bag.

The bags, holding up to 50kg of material, are emptied once every two to four months by a “sludge gulper” type of truck. The bag is replaced, with the old one being laundered before re-use.

Ends

© Scoop Media

 
 
 
Parliament Headlines | Politics Headlines | Regional Headlines

Zimbabwe: New Democracy, Or A False Dawn?

Gordon Campbell: Robert Mugabe = Hosni Mubarak. The current jubilation on the streets of Harare at the fall of Zimbabwe’s dictator Robert Mugabe is genuine, and one hates to be negative about the country’s future. Yet the situation is eerily similar to the scenes in Cairo in early 2011, when a popular uprising swept Hosni Mubarak from power in Egypt. More>>

 

Gordon Campbell: On The New Pike River Agency (And The Air Strike Wing)

Much of the sympathy the public still feels for the families of the Pike River miners has been sustained by the sense that the previous government – let alone the mining company and the processes of receivership and litigation – has never dealt honestly, or fairly, with them. More>>

ALSO:

Not Going Swimmingly: Contractor Cut, New Dates For Christchurch Sports Centre

“As an incoming Minister, I have been conducting a thorough review of progress on the Anchor projects and to learn of a $75 million budget blowout on this project was very disappointing..." More>>

ALSO:

Tertiary: Allowances, Loan Living Costs To Get Boost

“From 1 January, student allowance base rates and the maximum amount students can borrow for living costs will rise by a net $50 a week,” says Education Minister Chris Hipkins... further adjusted from 1 April 2018 in line with any increase in the CPI. More>>

ALSO:

Foreign Affairs: Patrick Gower Interviews Jacinda Ardern

Prime Minister Jacinda Ardern says discussions have already begun on how to bring climate change refugees into New Zealand under a Pacific seasonal employment plan... More>>

ALSO:

Gordon Campbell: On The Centre Right’s Love Of ‘Nanny State’

You’d almost think it was 2005 again. That was a time when the rugged individualists of the centre-right were being beset by government regulations on the nature of light-bulbs, the size of shower heads, the junk food available at school tuck shops and other such essentials... More>>

Speaking Of Transport: Public Engagement On Wellington Scenarios

“Our work on possible solutions for Wellington’s transport future is ongoing, but has progressed to the stage where we’re ready to share our ideas with the public and seek their feedback to help guide our next steps...” More>>

ALSO:

 
 
 
 
 

LATEST HEADLINES

  • PARLIAMENT
  • POLITICS
  • REGIONAL
 
 

Featured InfoPages

Opening the Election