Temporary sand diversion works (“sand dams”) in the lower Burdekin River maintain irrigation pumping pools, but some configurations impede fish movement. This project addressed that connectivity gap by developing permanent fishway designs for two fixed bypass points, The Rocks weir and Warrens Gully offtake, within the broader development application pathway for temporary waterway barrier works.
A staged process was adopted, beginning with engagement with fisheries regulators (DAF) to confirm design requirements, followed by field inspections, survey, and 2D hydraulic modelling to progress concepts to detailed designs. Ten years of daily gauged flow records (2010–2021) were analysed to define the operating envelope. The fishways were designed to function from regulated low flows through to the point when diversion structures are typically breached (approximately 5,000 ML/day).
Two site specific solutions were developed to suit local conditions: a concrete cone fishway at The Rocks (dog-leg alignment; nine cells; ~0.8 m head difference) and a bedrock-based rock-ramp fishway at Warrens Gully (12 ridges; ~33 m long). Hydraulic modelling demonstrates that both designs provide low-velocity passage pathways across the target flow range. Project outputs include detailed design documentation, preliminary cost estimates, findings on vegetation impact (minimal or none), and a framework for maintenance and fish monitoring.
Aligned with the theme “Living and Evolving with Change,” the project demonstrates how fish passage can be integrated into a highly variable system by designing for shifting operational states—regulated low flows, seasonal escalation, and breaching events—while maintaining irrigation performance and supporting species movement, including barramundi and mangrove jack.