Navigational Channel Maintenance Dredging in the Corrie Channel
Overview of Project
The Great Lakes Council (now called the Mid Coast Council) engaged Neumann Dredging 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, a high recreational boating activity during peak periods, particularly for cruiser-type vessels. A bathymetric survey indicated that the channel had in-filled some 21,000m3 since the previous dredging campaign. In addition, sand shoaling within the channel has occurred to such an extent that it restricts access to larger vessels. Therefore, the Great Lake Council urgently required dredging of the channel to maintain navigation and ensure public safety and access to Port Stephens/Tea Gardens.
We used the Nu Discovery (cutter suction dredge), a floating booster pump and support vessels for this project. The Nu Discovery is a new 250mm Cutter Suction Dredge and is ideally suited to this type of dredging work.
Scope of Works
- 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 in the stockpile area.
- Maintaining timely access for the marine traffic in the Corrie Channel and associated work areas.
Nu Discovery CSD used on this Project
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 (a 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 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 can dredge 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 dredge operator uses the three-wire anchoring system to maneuver the Nu Discover, allowing him to set up to cut the entire width of the 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. In addition, the dredge can quickly move to one side of the channel to allow for vessel movements.
