Two years after the Greymouth port purchased a second-hand dredge from Tasmania, it is finally working.
The Greymouth Star was given a demonstration yesterday and witnessed how a mechanical cutter head is lowered 3-4m to the silted bottom of the Blaketown lagoon.
The head disturbs the bottom, creating a slurry of silt, which is then sucked up by a pipe at the cutter head and pumped back through the dredge to the stern, from where it is further pumped through a pontoon pipeline emptying alongside the sewerage outfall pipe in the Grey River, opposite the Blaketown Rugby clubrooms.
Grey District Mayor Tony Kokshoorn was hot on the heels this morning with news that the dredge "is working," after two years of repeated delays and issues.
"We need to put it to bed all the criticism about it being a lemon, because it's not a lemon," Mr Kokshoorn told the Star.
"The delay has been worth it. Yesterday we had it operating; it's all ready to go now. It's awaiting certification but we have been doing tests."
Council staff previously blamed a lot of the delay on the large tidal wake in the lagoon.
However, port staff said yesterday the dredge did not in fact need Maritime NZ certification.
Including alterations since it arrived in Greymouth, the dredge probably owed the council about $300,000, he said.
But the savings would be "enormous" and over time it would "save millions" in external dredging costs.
The last time the council commissioned a visiting dredge to clear the lagoon entrance, about eight years ago, it cost over $700,000.
Port team leader Franco Horridge said that as a non self-propelled barge, the dredge did not need ordinary seagoing certification.
"It's exempt from Maritime Safety NZ, because it's a barge," Mr Horridge said.
It was fixed in the lagoon by four anchors 20 to 30m out, but will require the help of the port tug Kotoku II to move it around the lagoon.
Mr Horridge said recent depth soundings showed the dredging priority would be the lagoon entrance and the turning area for large vessels adjacent to the Talley's and Westfleet wharf.
- Brendon McMahon
