Port Otago in New Zealand has commenced a sand renourishment campaign in nearby Te Rauone Beach.
The work will be done in phases beginning with sand collection from the port’s maintenance dredge claim on the edge of the harbour channel, where the grain is of a suitable size.
Local contractor Divepro has laid about 400 metres of 200mm-diameter pipe from the beach out into the harbour. To ensure public safety, the pipeline is marked with a row of floating buoys.
Two 21-metre long piles have also been driven into the harbour away from the channel to provide a stable platform for pumping works. A dredger will moor alongside these piles, retrieve the flexible end of the discharge pipe (tied to the piles), and connect it to a 120kW submersible pump.
Port Otago said this setup is capable of pumping a sand and water mix at a rate of 800 cubic metres per hour from a hopper dredger through the new pipe onto the beach.
Meanwhile, on the beach, the sand will settle out and be distributed across the length of the beach. The pipe will be moved two to three times through the course of the renourishment.
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