Road fully closed as Whanganui River drop-out repair work continues

Two layers of SP4W sheet piling are being installed along the site. Photo / Bevan Conley

Weak ground conditions have forced a stretch of Somme Parade to be closed until next year.

Whanganui District Council’s roading alliance - a partnership between council Downer - is currently repairing a drop-out site along the Whanganui River opposite Axiam Plastics.

A 160-tonne crane is part of the project, which involves installing two layers of SP4W sheet piling along the site.

A Downer spokesperson said as the crane has moved along the worksite, it has encountered weak ground conditions below its working platform.

It was no longer safe for it to continue along its current line.

“The full road closure to this part of Somme Pde means the crane can be moved further away from the unstable riverbank so it can continue installing the piles safely.”

Somme Pde is currently down to one lane for traffic heading into town from Aramoho.

The full closure will start at 7am on October 25 and is expected to be in place until January 26, with the existing detour route of Barrack Street, Seddon St and Kaikokopu Road operating for all through traffic.

Erosion to around 136 metres of the riverbank opposite 131 Somme began during Cyclone Dovi last February.

Stage one of the project involved anchoring a gas main, which supplies all properties upriver of the slips and across the river via the rail bridge to Whanganui East.

That required 9m steel columns to be driven into the ground, with the exposed pipeline then secured to them.

Following that, work began on riverbank stabilisation.

Inner and outer sheet pile walls will stabilise and protect the area from further erosion.

Sheet piles are most commonly made of steel, and are driven into the ground to provide earth retention and excavation support.

The price tag for the repair work is $3.5 million, but Waka Kotahi New Zealand Transport Agency will fund 60 per cent of it.

Residents between 92 and 122 Somme Pde can access their properties from London St via Russell St or Spier St.

Seddon St residents have been asked to use off-street parking if possible during the work period.

Access to the shopping centre and the shops fronting Somme Pde will still be available from Kaikokopu Road and the short section of Somme Pde immediately before the site.

Mike Tweed is an assistant news director and multimedia journalist at the Whanganui Chronicle. Since starting in March 2020, he has dabbled in everything from sport to music. At present his focus is local government, primarily the Whanganui District Council.