Erosion repair comes at cost

THE Manawatu River under the Ashhurst Bridge will no longer be swimmable. PHOTO: ALECIA ROUSSEAU

Horizons Regional Council will use groynes to stop further erosion of the Ashhurst Domain, but the once popular recreation spot is now deemed unsuitable for swimming.

The three-month project will soon be underway and will see the creation of rock groynes to deflect river flows away from the bank.

Once these are established, further erosion will be prevented however there will be no swimming or river access from this area.

It is also hoped the work will ensure the structural stability of the State Highway 3 bridge, and protect the nearby walkway.

The project is expected to cost Horizons up to $300,000 — while the remaining figure of up to $500,000 will be shared between the NZ Transport Agency and the Palmerston North City Council.

Horizons group manager Ramon Strong said they were pleased with how plans had progressed.

"The first part of this project has been underway since last year with the Linton quarry doing a great job of stockpiling rock near the site. This is a huge task as it is a big order and there are specific sizes of rock required."

PNCC general manager Ray Swadel said they were also pleased to hear work would commence on site soon.

"We've been working closely with Horizons and NZTA and are satisfied with the work already done. This is an important project for us ... we know our community is looking forward to it being completed."

Significant protection will also be provided for the above highway, NZTA regional transport systems manager Ross I'Anson said.

"This work will the improve the resilience of the transport network and ensure the structural integrity of the riverbank is restored before any damage to this key piece of infrastructure occurs."

The area will be vastly different to what it is now once completed, with a contoured bank and riparian planting to take place throughout winter.

Mr Strong said they would work with Council to ensure signage informing users of any potential hazards would also be in place.

Goodman Contractors won the tender for the repair work — the same firm who shifted material away from this bank in May last year.

"Thanks to this work the area fared well over winter and will allow the groynes to be constructed on a gravel beach rather than in the water," Mr Strong said.

"We're pleased to have a contractor such as Goodman's on board as projects like this require specialised equipment and the firm has a track record for delivering on time and to budget."

The domain has been eroding since a major flood in 2015 and was particularly affected by last year's Cyclone Debbie. It was unclear whose responsibility the 700m stretch of riverbank was so, the PNCC sought a multi-party agreement to establish protection work as soon as possible.