Designed to deliver increased water security to support the urban, agricultural, and industrial needs of the Lower Fitzroy and Gladstone regions in Australia, the Rookwood Weir is the first weir within Australia and New Zealand to be awarded an IS v1.2 Design Rating by the Infrastructure Sustainability Council: the project has been recognised for its Australian-first turtle passage and innovative fish lock designs. The passage and fish lock will allow for greatly improved aquatic species movement while maintaining the aquatic ecological values of the river and setting a new standard for best-practice sustainability outcomes for major water infrastructure projects.
Situated on the Fitzroy River in Central Queensland, the 16.2-metre-high and 350-metre-long mass concrete dam promises substantial regional economic development for Queensland. Simultaneously, it safeguards the natural habitat of aquatic species.
Rookwood Weir infrastructure innovation
Design and construction innovation
The design and construction of Rookwood Weir were carried out through a collaborative alliance featuring Sunwater as the proponent, GHD as the design team, and Acciona and McCosker Contracting as the contractors. This project is especially crucial as the Fitzroy River supports 37 diverse fish species and six turtle species, including the critically endangered white-throated snapping turtle (Elseya albagula) and the vulnerable Fitzroy River turtle (Rheodytes leukops).
Incorporating measures to safeguard the movement of aquatic fauna and support the lifecycle of species within their ecosystem was of paramount importance in the design and construction of the weir. The implemented design features innovative elements such as a two-lock fish chamber with castellated crest blocks and a 172-metre-long turtle passage. These initiatives significantly contributed to the project’s IS Design Rating.
The fish lock includes two chambers, five attraction slots and four exit channels. This innovative design significantly widens the operational range, enabling fish passage for more than double the capacity of a typical single-chamber fish lock. In addition, the spillway incorporates castellated crest blocks, introducing a novel approach to spillway flow control. This promotes flows that are fish-friendly and enhances effectiveness without the need for large supplementary water releases.
Inspired by the world’s largest freshwater turtle acoustic telemetry project, which monitored the movement behaviour of over 130 turtles within a 30 km radius of the Fitzroy River over five years, the turtle passage design reflects a deep commitment to preserving aquatic ecosystems. This ongoing study is instrumental in monitoring the project’s sustainability outcomes.
The weir is also set to achieve sustainability outcomes, primarily through a substantial reduction in concrete consumption by replacing up to 63 per cent of cement in structural concrete mixes. This reduction is expected to result in a lower carbon footprint, owing to diminished concrete production. Further, the design enhancements include the optimisation of the weir’s crest length and batter slope, yielding a savings of 300,000 m3 of extraction volume and significantly reducing energy expenditure during construction.
Some of the benefits of this project have been the collaboration between the different disciplines — from procurement, engineering, cultural heritage, and environmental. It’s been a team effort to get this sustainability rating across the line.”