Corrie Channel Dredging 2016

Corrie Channel - Navigational Channel Maintenance

Principal: Mid Coast Council (formerly Great lakes Council)

Principal Contractor: Neumann Contractors

Location: Corrie Channel, Tea Gardens, New South Wales

Contract Value: approx. $450,000

Completion Date: September 2016

Neumann Contractors was engaged by the Great Lakes Council (now called the Mid Coast Council) to undertake the much needed dredging works in the Corrie Channel.

The Corrie Channel is the designated navigation channel/route between Port Stephens and the Myall River, and it also links Nelson Bay and the Port of Tea Gardens. The Corrie Channel also provides access to the Myall Lakes which during peak periods has a high level of recreational boating activity, particularly of cruiser-type vessels. A bathymetric survey carried out in 2015 indicated that the channel has in-filled some 21,000m3 since the previous 2010 dredging campaign. Sand shoaling within the channel has occurred to such an extent that it is now restricting access for larger vessels. Therefore, dredging of the channel was urgently required to maintain navigation and ensure public safety and access to Port Stephens/Tea Gardens.

The Nu Discovery (cutter suction dredge), a floating booster pump and support vessels were used for the project. The Nu Discovery is a new 250mm Cutter Suction Dredge and is ideally suited to this type of dredging works.

Scope of Work

  • Mobilisation of a 250mm cutter suction dredge, the Nu Discovery 1 x booster pump and 2.65 km’s 250mm poly pipeline.
  • Dredging of 21,000m3 of marine sediments from the Corrie Channel.
  • Pumping the sediment through, up to 2.65km of pipeline to the stockpile area at Corrie Channel.
  • Management of pumped material.

Challenges

  • Management of the dredged material and water at the stockpile area.
  • Maintaining suitable access for the marine traffic in the Corrie Channel and associated work areas.
Nu Discovery - Drawing.jpg

Nu Discovery
, a 250mm Cutter Suction Dredge

The Nu Discovery is a 250mm cutter suction dredge from the Nu Explorer series of dredges. The Nu Explorer series of dredges have been designed and constructed by Neumann Contractors to specifically suit the typical dredging conditions encountered in projects like the Corrie Channel. There are three dredges in the Nu Explorer series that currently complement our fleet (total of 9 Cutter Suction Dredges):

  • Nu Explorer(original dredge in the Nu Explorer Series) has been working in the OTML Mine in PNG for the last two years,
  • Nu Discovery has recently completed work in the Iluka Boat Harbour and Entrance Channel Dredging project,
  • Nu Investigator, is the latest in the fleet and has just completed initial trials and testing at Neumann Contractors, Corridor Sands plant at Woongoolba.

The Nu Discovery is a 227kW (305hp) 250mm three wire cutter suction dredge. The dredge is capable of dredging up to 120m3 per hour (in optimal conditions), dredge to a maximum depth of 6.5 metres, and pump the material up to 1,000m in distance.

The Nu Discovery is manoeuvred by a three wire anchoring system and can be setup to cut the entire width of a channel including any batters in just one cut width. The side anchor ropes remain on the sea bed while the dredge is in operation, which will minimise any inconvenience to other boating traffic through the affected channel areas. The dredge can easily move to one side of the channel to allow for vessel movements.