The Sunshine Coast Council (SCC) initiated a significant dredging project in the Maroochy River to manage sand accumulation. This operation involved the deployment of the 450mm Cutter Suction Dredge, “Nu Endeavour,” which navigated through the river mouth to extract 75,000m³ of sand. The dredged sand was transported through an existing 400mm diameter pipeline situated in the dunes and used to restore a 1.5km stretch of beach between Maroochydore and Alexandra Headlands Surf Lifesaving Clubs.
About the “Nu Endeavour” Cutter Suction Dredge
The “Nu Endeavour” is a 450mm Cutter Suction Dredge measuring 34.78m in length, with a maximum digging depth of 15m. It boasts a total power output of 1,454KW (1,500hp) and can pump up to 650m³ of sand per hour over a distance of 1,000m.
Scope of Works in the Maroochy River Dredging
The project entailed several key tasks:
- Provision of Equipment: Supply of the 450mm Cutter Suction Dredge, booster, and ancillary equipment.
- Sand Dredging: Dredging 75,000m³ of sand from the designated area within the Maroochy River.
- Sand Placement: Depositing 75,000m³ of sand to the specified beach locations and profiles as required by the SCC.
- Site Rehabilitation: Site rehabilitation and rectification as necessary.
Challenges in the Dredging Operation
The project faced constraints due to the migration and spawning activities of important fish species in the area. Dredging operations were prohibited during the two days before, the day of, and two days after the new and full moons to protect these species.
Project Completion and Success
Despite these restrictions and a four-month allotted timeframe, the dredging and beach nourishment activities were successfully completed in under two months.
Conclusion
The replenishment dredging at Maroochy River, executed by the Sunshine Coast Council with the help of the “Nu Endeavour” Cutter Suction Dredge, significantly improved the sand management and beach nourishment between Maroochydore and Alexandra Headlands Surf Lifesaving Clubs. The project’s success, despite environmental challenges, underscores the effective planning and execution by the SCC.