5 May 2005

Orakei Creek dredging closer to implementation

Auckland City Council’s Works and Services Committee has approved a ‘dredge and replace’ programme to remove contaminated sediment from Orakei Creek.

The contaminated sediment will be removed and replaced with clean, imported material. This will remove about 60 per cent of the pollutants from the creek.

Councillor Neil Abel, chairperson of the Works and Services Committee, said the dredging would be the result of months of work.

“Officers have been working closely with key groups, particularly the Orakei Basin Protection Group, to find the best solution to the sediment build-up in the basin and creek.

“Eleven options have been looked at and the approval of this dredge and replace programme is the result of a lot of research and consultation,” Mr Abel said.

Studies have found that contamination levels were highest in the upper reaches of the Kelvin and Meadowbank arms and downstream where the two arms meet. These areas will be given priority.

Several replacement materials have been investigated. The material used has to have lower contamination levels than the existing sediment and be stronger to resist erosion.

Imported material will have to be used to replace the sediment because material from within the basin is not strong enough. Materials considered acceptable for importing into the basin include sealing chip made from greywacke and greywacke peastone.

The dredging project was deferred by the then Works Committee in 2004 because of a threat of land instability.

These issues have been addressed through using replacement material to backfill.

ENDS

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