Work to realign the Manawatu River and stabilise Anzac Cliffs is back in action this week after closing down during high river flows over the winter months.
Horizons group manager operations Allan Cook says work to date has included realigning the river channel away from the cliffs to its approximate position of 1992; placing approximately 22,000 tonnes of rock to establish a new and secure left bank alignment; and back filling the old river channel with compacted gravels.
“People will notice equipment being moved back onsite this week and as soon as river conditions allow the contractor will start hauling rock across the river again and placing it at the downstream end of the realignment,” says Mr Cook.
“At the same time the contractor will push gravel that’s been deposited on the right bank up ready to take it across to complete the channel backfilling and buttress foundations. Subject to suitable river conditions, we are expecting to complete the bulk of works within the river over the next six to eight weeks.”
The next phase of the project will involve reducing the slope of the adjoining section of unstable cliff. While that part of the work is the responsibility of PMB Landco, who own land at the top of the cliffs, it will be undertaken by the same contractor and overseen by the joint project management team.
“Work on the cliffs is expected to get underway early in 2016 subject to soil and weather conditions and is scheduled to be finished by the end of summer. This will be followed by a three year planting project to establish vegetation over the entire re-worked area.”
Mr Cook says the overall project is one of close collaboration between Horizons, Palmerston North City Council and PMB Landco.
“All parties have an interest in seeing this project completed and have been working together through the design and planning stages for some years now,” says Mr Cook.
“The key drivers for the project are the need to protect the integrity of the City’s stopbanks opposite the cliffs; mitigate the risk to public safety as a consequence of cliff collapse; and prevent the river encroaching on existing community infrastructure and residentially zoned land in the Vaucluse Heights area.
“Other benefits include the opportunity for a walkway between Fitzherbert Bridge and Vaucluse Heights, and an end to an estimated 20,000 cubic metres of sediment that currently makes it way into the river from cliff erosion each year.”
Once the river work is completed the river side site that’s been temporarily fenced off to the public will be returned to its original state and there will be no further disruption to the walkway.