Big machinery moves in

An important phase in the proposed project to divert the Manawatu River and stabilise Anzac Cliffs is expected to begin next week.

Horizons group manager operations Allan Cook says heavy machinery will be set up on the gravel beach opposite the cliffs to improve the foundation of the river bed, before realignment of the channel and re-contouring of a section of the cliffs.

“The initial work will involve drilling 800mm diameter holes in the river bed and replacing the weaker sandy gravel material with compacted graded ‘stone columns’ of greater strength. This will support the earth buttress which will be constructed against the cliff,” said Mr Cook.

“The columns will extend up to six metres below water level. Subject to achieving the desired improvement, we expect to build approximately 200 columns at this stage and work could take up to three weeks to complete.”

The more substantial channel realignment and associated earthworks, that will reduce the slope of and stabilise the cliff face, are scheduled to commence later in the year. Further foundation improvement work will be required as part of those works once the river has been diverted out of its present low-flow channel.

Mr Cook says the overall project is one of collaboration between Horizons, Palmerston North City Council and P M B Landco, who own land at the top of the cliffs.

“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; to mitigate the risk to public safety as a consequence of cliff collapse; and to 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 currently discharged into the river from cliff erosion each year.”

For safety reasons, the works site will be closed to public access. However, there will be minimal disruption to use of the shared pathway along the affected section of river, between Albert Street and Fitzherbert Avenue.

Ends

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