Video | Agriculture | Confidence | Economy | Energy | Employment | Finance | Media | Property | RBNZ | Science | SOEs | Tax | Technology | Telecoms | Tourism | Transport | Search

 

Contractors Move a River for Whitebaiters

Contractors Move a River for Whitebaiters

Engineering and earthmoving company Taylors Contracting has been tasked with moving a river twice as part of a major bridge re-building project on the South Island’s West Coast – but the deadline has been determined by whitebait season.

The joint KiwiRail and NZ Transport Agency project to reconstruct the 120 year old Arahura road / rail bridge began 18 months ago. The new bridge includes a two lane road for state highway 6 between Hokitika and Greymouth and separates the rail line from the road.

HEB Structures are the main contractors for the job, with Taylors subcontracted for the river work. This involved constructing gravel guide bank and rock protections to enable abutments and pier heads to be built.

Taylors Contracting Project Manager Neil McKay says they first shifted the Arahura River 12 months ago, from hard against the North abutment back towards the middle of the bridge. Now they have until September the first to carefully move it back to its original position prior to the start of whitebait season.

“The river is privately owned and whitebaiting is a very important local activity. Part of the contract was to ensure whitebaiting wasn’t interfered with. This condition determined the deadline for the river movements. It’s all about doing the job with the least impact on the river, “he says.

Neil McKay says it’s the first time he’s known of whitebait to be a reason for a contract deadline.

Moving a river is not easy work. When diverting main river flows there are numerous environmental factors to consider such as using a method that allows fish to exit the old river flow and mitigating downstream siltation.

While Taylors used GPS technology on their diggers for underwater rock placement it was also utilised to achieve the new river depths.

“It is quite skilled to learn to work a machine by only looking at a screen in the cab. You’re effectively working blind when you’re under water. It’s muddy and there’s no visibility so we need the best technology to do the job,” says Neil.

Taylors have quarried, carted and placed about 60,000 tonnes of rock in the Arahura River and used a precision pattern to ensure each rock shows a smooth face to help water flow. The underwater walls are laid to an exact height. They had to be 2 metres deep and up to seven metres above the water surface in some places. This meant digging down as much as 4 metres below the riverbed and building rock back up.

“When you drive over the bridge people may not realise that there’s probably as much of the rock wall below river level as there is sticking out,” says Neil.

Neil McKay is confident they’ll make the September 1 deadline and he says it’s been a really great project to work on.

“We employed four locals from the coast and then we brought myself and another driver with the GPS experience. It’s been an awesome challenge, especially with the west coast wet weather!”.

The next stage of the job for Taylors is to complete remaining abutment protection works and from there on it’s all about site rehabilitation as well as assisting HEB and ONTRACK complete a heritage park which will display a section of the old bridge.

HEB Structures has been contracted to build the new 220 metre long bridge, which is due to be completed in January 2010. It consists of nine steel and concrete spans and 20 concrete piles. Work has been carried out in stages to keep State Highway 6 open throughout construction. The contract has been meticulous in its planning and HEB Structures in coordination with Taylors have ensured all works tracked precisely to program.
KiwiRail’s infrastructure arm, ONTRACK is leading the bridge construction and NZTA is responsible for the road approaches.

ENDS

© Scoop Media

 
 
 
Business Headlines | Sci-Tech Headlines

 


Energy Resources Aotearoa: Doubling Of Coal Use Shows Need For Local Natural Gas

New figures showing a near doubling of coal-fired electricity generation highlight New Zealand’s energy shortage and the need for natural gas as a lower carbon alternative, according to Energy Resources Aotearoa... More>>


E Tu: ‘Sense Of Mourning’ As Norske Skog Mill Set To Close

Workers at Norske Skog’s Tasman Mill now know they’ll be losing their jobs in little over a month’s time.
On Wednesday afternoon, workers were told the mill will be stopping production from the end of June... More>>




Stats NZ: Card Spending Sees Strong Growth In May

Seasonally adjusted card spending rose by $189 million (2.3 percent) between April 2021 and May 2021, Stats NZ said today.
Spending rose across all industries for the first time since New Zealand moved to level 1 in June 2020... More>>




Auction: 1.4 Million In Rare Vintage Watches, Gems, Jewels & Diamonds Go Under The Hammer At Webb’s

An auction event showcasing over 1.4 Million dollars in rare jewels, gems, diamonds and vintage watches is due to take place this Sunday by Auckland based auction house Webb’s... More>>

Catalist: NZ’s New SME Stock Exchange, Gets Licence To Go Public

New Zealand has a new stock exchange – designed specifically for small and medium-sized businesses (SMEs) to raise up to $20 million a year from the public.
Called Catalist, the exchange has already been successfully working the private investment sector.... More>>

E-Commerce: Over 40% Of Those Engaged In The Bitcoin Community Are Millennials

Bitcoin has emerged to be a popular topic among millennials with digital currency increasingly being viewed as a potential source of creating wealth through investments. The interest in bitcoin by millennials signals the role this age group plays in the possible realization of the digital currency’s mass adoption... More>>