Saltwater Creek Fishladder
CS Environmental is proud to have completed the design and construction of a nature-like rock ramp fishway on Saltwater Creek in the Coomera River catchment on the Gold Coast.
Restoring Fish Passage
The project restores fish passage at an existing sewer main crossing that had created a 500 mm high barrier, preventing many native fish from accessing important upstream habitat. By reconnecting the creek, the fishway helps improve the health and resilience of the waterway.
CS Environmental coordinated the design of the fishway and served as the principal contractor throughout construction, managing the project from concept through to completion.
The fishway features a nature-like rock ramp with a series of low ridges and resting pools that allow fish to gradually make their way upstream. Each ridge has a vertical drop of just 100 mm, enabling even small fish to pause, recover and continue their journey. A sealed low-flow channel ensures the fishway remains effective during the low-flow conditions that occur in Saltwater Creek for much of the year, while graded rock scour protection provides additional pathways for fish as creek flows increase.
Construction involved placing approximately 550 tonnes of rock and 17 m³ of concrete to create a durable structure that blends with the natural creek environment while maintaining fish passage across a wide range of flow conditions.
Like many infrastructure projects, construction presented several challenges. The team successfully managed high groundwater inflows, changing weather conditions and worked safely around critical infrastructure, including a sewer main, overhead powerlines, shared pedestrian pathways and an existing footbridge.
Reconnecting critical spawning, nursery and feeding habitats
The project was delivered under Queensland’s recently updated Accepted development requirements for operational work that is constructing or raising waterway barrier works, which require the involvement of a suitably qualified and experienced fish passage professional. CS Environmental’s Fisheries and Aquatic Ecosystems team fulfilled this role throughout the design and construction process.
Many of Australia’s native migratory fish move between freshwater and estuarine or marine environments during their life cycle. Most migrate upstream as juveniles and are unable to overcome barriers such as weirs, culverts and pipeline crossings under normal flow conditions. By restoring fish passage, projects like this reconnect critical spawning, nursery and feeding habitats, supporting healthier fish populations and more resilient waterways.
CS Environmental is proud to have contributed to the broader Saltwater Creek restoration project. We thank OzFish Unlimited for commissioning the project with funding provided through the Australian Government’s Urban Rivers and Catchments Program. We also acknowledge the City of Gold Coast—particularly the Environment, Heritage and Resilience team, and Fabrication Workshop team for their support and collaboration.
A special thank you goes to the Ozfish and CoGC project staff whose collaboration, support and commitment were instrumental to the successful delivery of this project. Their involvement was critical in helping bring this important restoration project to life. Finally, we thank Forward Hydro, UDEC and SRL Plant Hire for their valuable contributions to the successful delivery of this project.
