Wall planned for Motunau Beach

Press, 30 August 1988, Page 3

Wall planned for Motunau Beach

By

HEATHER CHALMERS

A 300 m-long protection wall will be built along Motunau Beach in an effort to halt cliff erosion which has put 18 houses at risk of toppling into the sea.

Costing $98,000, the wall will be made of gabions (rock-filled wire baskets). It will absorb wave action and help to retain cliff debris so that a stable slope can form behind the wall, limiting further erosion. A groyne will also be formed to halt sand loss at Sandy Bay, at a cost of $lO,OOO. The Hurunui County Council has agreed to fund the $lOB,OOO needed to do the work, as recommended in a report by the consulting engineer, R. W. Morris and Associates. The consultants said'

they could not guarantee the success of the protection work. “What is not certain is whether the reduction in the rate of erosion will sufficiently postpone or eliminate the risk to the properties lying within the coastal zone. Short of constructing a complete barrier to the sea and stabilising the cliff face at a cost several magnitudes higher, no such assurance can be given.” “All concerned with the cliff erosion at Motunau must be aware that the gabion wall proposal represents a form of coastal

protection that is believed to offer the best chance of limiting the rate of erosion at a reasonable cost but is nonetheless somewhat experimental in concept.” The report was commissioned by the council with the North Canterbury Catchment Board and the Regional Water Board. While the boards accepted the final report, both have declined to fund protection work. The County Chairman, Mr Clutha Mackenzie, said at yesterday’s council meeting that the Catchment Board should be

asked to contribute to the cost of the work, but conceded that any assistance was unlikely. A motion that the 120 ratepayers at the beach' contribute 10 per cent of the cost was rejected. Instead it was agreed that the council meet the full cost because money received from freeholding properties at the beach had been put into forestry for the benefit of the whole county. However, although agreeing to foot the bill the council accepted no liability for the cliff erosion.