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


Built Wetland Opens In New Subdivision

The constructed wetland at the 361 hectare Drury South Crossing subdivision, the country’s largest industrial and residential development, is designed to improve water quality in the area. It will form part of an extensive new public recreation area and provide a habitat for endangered native eels, fish and birds.

The 35,000sqm freshwater wetland is one of the largest constructed wetlands in the country. Located in one of Auckland’s deepest flood plains, the wetland is designed to hold floodwater volumes of up to 58,900m3 – the equivalent capacity of 23.5 Olympic size swimming pools.

Peter Norfolk, project manager from Tonkin Taylor, says the new wetland is uniquely designed to act as a dam in both directions – holding the wetland water in during normal operation but overtopping into the wetland in very large flood events to provide additional flood capacity in the floodplain.

The wetland is designed in the shape of a tuna (eel), a culturally significant motif that provides the stormwater management system with a mechanism to reduce the speed of water entering the catchment area through a network of high volume intake pipes at up to 16m3 of water per second.

Dam design experts on the project worked with Ted Ngataki and Maaka Potini, local Maori artists, to incorporate Tikanga Maori and the concept of a tuna into the Wetland design.

The tuna was selected as having particular significance to iwi as they are indigenous to the area and were once prevalent and a key part of traditional diet and trade.

Norfolk says the tuna design was chosen for both its cultural significance to mana whenua as well as for functional purposes.

“The complexity of the S-shaped design with its winding curves and varying elevations is necessary to control the high velocity of the water entering the forebays through 2-2.5m pipes – reducing it to a slow meandering stream and filtering the water to allow the natural removal of sediment and pollutants before it passes through a green outfall into the Hingaia Stream and into the Manukau Harbour,” he says.

Norfolk says the wetland has taken two years to complete and required the excavation of more than 396,000 tonnes of earth.

He says the creation of the wetland with this degree of complex geometry would not have been possible within this timeframe without advancements in 3D modelling technology and integrated guidance systems for excavators.

“Bringing this design to life in a relatively short space of time required the latest in sophisticated 3D modelling and construction techniques – which are used to guide the excavators via GPS,” he says.

Stephen Hughes, Drury South Crossing CEO, says a number of environmental considerations have been integrated into the new subdivision and include removing pollutants such as zinc the most common of all heavy metal contaminants in urban rivers and streams, from roofing materials used on site.

“In the past, residential lawns and grass around houses would have helped contribute to capturing sediment from stormwater runoff however modern subdivisions tend to have less lawn which increases the need to capture runoff from surrounding roads and housing.

“While filtering stormwater and runoff is a key aspect of protecting our urban waterways, we have gone a step further by preventing unpainted roofing materials made with zinc from being used at the subdivision.

“The creation of this new wetland and public recreational area is designed to set a new standard for residential and industrial developments in the Auckland region,” he says.

© Scoop Media

Parliament Headlines | Politics Headlines | Regional Headlines

Gordon Campbell: On Yesterday’s Big Parliamentary Air Kiss To China

In order to obtain support from the two major parties, Act Party deputy leader Brooke Van Velden twice had to soften the language of her parliamentary motion yesterday condemning China’s persecution of the Uighurs. The key word “genocide” was deleted. Evidently, the kind of resolution passed by a conservative government in the UK proved to be far too tough for a centre-left Labour government and a centre-right National opposition to countenance. Yesterday, the two major parties were united in their fear of retribution from China... More>>


Government: Fair Pay Agreements To Improve Pay And Conditions For Essential Workers

The Government is delivering on its pre-election commitment to implement Fair Pay Agreements which will improve wages and conditions, as well as help support our economic recovery, Workplace Relations and Safety Minister Michael Wood announced today. More>>


Public Services: Government Sets Pay And Workforce Expectations For The Public Sector

The Government’s Workforce Policy Statement issued today sets out its expectations for pay and employment relations in the Public Sector, the Minister of Finance and Minister for the Public Service say. “New Zealand has had an exceptionally successful ... More>>


Government: Budget 2021 Reprioritises Nearly $1 Billion

Hon Grant Robertson Deputy Prime Minister Minister of Finance The Government’s strong pandemic response and the better than expected economic recovery means not all the money allocated in the COVID-19 Response and Recovery Fund has been spent, ... More>>


PM: Statement On The Speaker And Annual Review Debate

“The serious issue of alleged sexual assault and harassment at Parliament was poorly managed and inappropriately politicised last night. The tone of the debate did not reflect well on Parliament as a whole,” Prime Minister Jacinda Ardern said. ... More>>

Parliament: Mallard Fails To Give Taxpayers A Straight Answer

Trevor Mallard has confirmed he is unfit to be Parliament’s Speaker by failing to answer several important questions relating to the false rape accusation saga that cost taxpayers more than $330,000, Shadow Leader of the House Chris Bishop says. ... More>>

Local Government: Independent Review To Explore Future

Local Government Minister Nanaia Mahuta says an independent review of local government will explore how councils can maintain and improve the wellbeing of New Zealanders in the communities they serve long into the future. More>>


PM Ardern And PM Morrison: Commencement Of Two-Way Quarantine-Free Travel Between Australia And New Zealand

Joint Statement by Prime Ministers Scott Morrison and Jacinda Ardern Commencement of two-way quarantine-free travel between Australia and New Zealand Today, Australia and New Zealand have fulfilled their commitment to establish two-way quarantine free ... More>>




InfoPages News Channels