Protection work nears end

MAJOR protection work on the banks of the Pohangina River near Totara Reserve Regional Park, where a carpark has been washed away, is now about two-thirds complete.

Contractors are working alongside Pohangina Valley East Road, at the southern end of the park, and below the area where the 10 metre-wide carpark had been established off the road seal.

Roading Team Leader, Jim Mestyanek, said about 18 months ago the river started to scour into the carpark at the toe of a bluff and in an area that had not sparked any previous erosion concerns.

“Once it started, it continued to scour, taking away the outside side rail and dropping pieces of the carpark six to eight metres into the river,” he said. “And it seemed the more scouring that occurred, the more aggressive the action.”

Mr Mestyanek said early remedial work, however, was washed away, and although the scouring had not encroached onto the road, there was a need for protection work to be undertaken.

Horizons Regional Council contributed towards a river diversion – taking the bulk of the current away from the scour site and on to the other side – and providing professional services for the design of a rock-lining feature beneath the road.

The rock-lining is similar to what has been carried out near Fitzherbert Bridge in Palmerston North.

Manawatu District Council then contracted out the supply and placement of semi-rounded, volcanic boulders that will help line the curvature of the affected riverbank.

“The work aims eventually to put the river back where it was originally, but now the road will be protected,” said Mr Mestyanek. “The aggressive flows and destructive eddies will be minimised and the water will be able to flow away along a gentle curve.”

He said it was hoped that an existing access track down to the river would be maintained for fishermen and other recreational users.