Council officers are locked in negotiations with contractors on how to clean Pukekura Park's sludge-clogged lakes now that the dredging approach has failed.
At $600,000, Whitaker Civil Engineering Ltd's was the cheapest of three tenders to rebuild the lake edges and remove tonnes of toxic sediment that had built up in the waterways in the past 50 years.
The lake edge repairs went off without a hitch and are all but completed. However, the subcontractor tasked with cleaning out the sludge was shut down on Tuesday when it was discovered tonnes of mud sucked out of the main lake was actually being pumped back in because of a failure in the dewatering process.
New Plymouth District Council park boss Mark Bruhn said he was "gutted" at the failure of the dredging project.
He said he believed the contractors had made the tender in good faith that the dredging process would work but would not say if its failure would cost the council.
"All I can say is we have a contract in place and there are contractual terms that need to be met before payment will be made."
Depending on the terms of the contract, it could be up to Whitaker's to pick up the bill.
With dredging seemingly unviable, the next option could excavating the sludge.
The removal of the sludge is part of a $2 million project to improve the quality of the park's water systems. Metres deep in places it is highly toxic, containing, among other things, decades worth of leaded petrol runoff.
Whatever happens with the current contract the mud will not be removed until next year at least, as no work can be done during the park's festival season from November to March.
However, before then, contractors will have to remove the tonnes of mud inadvertently pumped back into the lake system and now clogging up the section of water above the boat shed known as the Serpentine.
- © Fairfax NZ News
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