Cliffs work delayed

17:36, Nov 20 2012

The Manawatu River, not machines, will decide the shape of Palmerston North’s Anzac Cliffs for another year.

Horizons Regional Council has put off a $3m project to redirect the river away from the base of the cliffs until next summer.

The delay means earthmoving work by cliff-top landowner PMB Landco to reshape the cliffs into a hill will also have to wait.

The two-pronged approach to stabilising the cliffs was granted resource consent in August, subject to conditions imposed by independent commissioners.

Some of the conditions required extra geo-technical reports to be prepared, and time has run out to start the project early enough to guarantee it could be completed before next winter and the likelihood of floods.

Operations group manager Allan Cook said the original plan was to start work creating a new channel on the city side of the river about now.


But after waiting for the appeal period to expire and scoping the extra investigations required it became apparent it would be too late to start and finish the work during the months of low flows.

‘‘We would still have been doing work in the river through until May, which is too late.

‘‘It was a risk we did not want to take.’’

Floods or high flows could damage work that was only partially completed.

Mr Cook said the benefits of programming the work to ensure it could be completed in one summer outweighed the risks of a year’s delay.

It meant the cliffs remained unstable for another year, and the danger of falling debris remained, as did the continuing release of sediment into the river when parts of the cliffs slipped down.

The only work this summer will be the delivery of 8000 tonnes of rock to be stockpiled opposite the cliffs.

The consent requires the carting to be completed in 27 days, at the rate of 300 tonnes a day, to restrict the extent of truck movements at the end of Albert St.

The tender for the supply would be let soon, with trucking likely to start early in the new year.

Walkers and cyclists using the walkway would need to be aware of trucks crossing, but public access would not be otherwise disrupted.

Having the stockpile would enable a start on work on the city side of the river in July or August next year. 

‘‘We will be able to make optimum use of the short window of opportunity to do the in-channel work next summer.’’

Horizons needs to start its part of the project before the earthmoving on the cliffs begins.

Backfill from the cliffs will be needed to complete the new Aokautere-side bank of the river, but the recontouring and revegetation work might not be completed until the following summer.

‘‘It’s critical that we get out of the river before winter. The cliff has to be safe, but the balance of their work can be completed the following season.’’

The delay has prompted a reschedule of the balance of Horizons’ seven-year City Reach project designed to protect the city from a one-in-500-year flood.

This summer’s project will now involve raising the stopbanks at Buick Cres.

The $360,000 project involves work on 22 private properties downstream from Dittmer Drive.

Mr Cook said land-owners were being approached this week to discuss design and access.

The banks needed to be raised, on average, by half a metre.

‘‘On farmland it would be easy, but in people’s gardens, it poses particular challenges,’’ he said.

Some of the extra fill would have to be carried in by wheelbarrow to limit disruption and damage to people’s backyards.

Manawatu Standard