1300 083 042
Fitzroy River Barrage Fishway
About the project
A new cone fishway was constructed on the left (or northern) bank of the Fitzroy River. It supports the existing vertical slot fishway and cone fishway located on the right bank by allowing for greater passage of small and medium bodied fish that are currently limited by the significant biomass trying to pass upstream during mass migration events. The fishway allows fish to pass from the saltwater side through a series of 34 precast cone baffles up to the freshwater side, a rise of 3.5m. The fishway structure is made of 56 unique precast panels sitting on a total of 54 pile caps all built with in a tolerance of 5mm.
Location
Rockhampton, Queensland
Client & Duration
Sunwater
Sep 2023 - Nov 2024
Project Scope
- Design of temporary works
- Preparation works (dilapidation, monitoring and survey)
- Temporary works installation and dewatering
- Bulk earthworks
- Bored piling
- Precast panels (supply and erection)
- Cast in situ concrete works
- Scour protection works
- Large scale demolition of the existing barrage (70t of concrete)
- Structural steelwork and accessways
- Electrical control system (including design)
- Hydraulic gate works (management)
Challenges
- The removal of 70 tonne of concrete from a live weir posed various high risk environmental challenges, as well as risk of flooding and damage to operational work sites
- Due to the overhead barrage we were unable to utilise cranage to remove 70 tonnes of concrete. A skid steer structure and pulley system was built to winch the individual blocks of wire sawed concrete out
- Construction time frames were extremely tight and inline with the tidal conditions. The 4 meter high retaining wall designed and built on the edge of the riverbank footing works could only be undertaken on low tide
- The de-watering system in place was unable to keep up with high levels of unexpected groundwater, in turn impacting our work areas and was mitigated through temporary works.
Achievements
- A temporary wall structure was built to mitigate environmental risks with demolition works of the concrete (a specialist concrete wire saw contractor was engaged for the demolition works)
- A water treatment facility was purpose built onsite to treat all construction water, preventing contaminated water entering the river
- The installation of the 5.5 meter precast concrete panels were all executed within 5mm of the specified design. All inspections were carried out and passed
- The project team worked collaboratively with Sunwater, offering full transparency throughout project delivery
- Strong local community and business engagement delivering social and financial benefits to the local region.
