Working within tidal environments demands a balance of timing, precision, and technical control. At Downey Park, Commercial Marine Group (CMG) delivered a practical, purpose-built solution to help protect one of Brisbane’s key stormwater harvesting systems. The project brought together marine construction, diving, and fabrication expertise to restore an essential water-control asset that supports the long-term sustainability of a community recreation precinct.
The Scope
CMG was engaged to assist with reinstating the Downey Park stormwater harvesting system through the delivery of a new tidal-gate structure. The dual-gate design protects the network from saline water ingress, securing a reliable and sustainable irrigation supply for the local sports-field precinct.
Our Solution
Delivering this type of infrastructure calls for expertise across multiple disciplines: structural and hydraulic design, precision fabrication, underwater installation, and environmental management. CMG’s integrated team combines these capabilities under one framework, ensuring safe, efficient, and compliant delivery across diverse marine and civil environments.
CMG collaborated with Engineering Applications (ENAP) to construct a robust two-gate design using high-quality aluminium and stainless-steel components. ENAP applied precision weld-control techniques to minimise distortion and ensure long-term structural integrity.
Installation was undertaken by CMG’s commercial diving and marine construction specialists, supported by advanced lifting equipment, including a spider crane used to position each six-metre gate and supporting frame. The works were carefully coordinated around tidal conditions to achieve millimetre accuracy under the supervision of CMG Site Supervisor Ben Shepherd.
Testing and commissioning included leak monitoring and operational demonstrations to verify gate performance under a range of simulated conditions. To mimic tidal and rainfall events, CMG utilised a 15 m × 2.4 m Aqua Barrier system supplied by Apex Envirocare, along with twin six-inch pumps to simulate inflow and pressure variations.
Projects like Downey Park demonstrate the importance of coordinating engineering expertise with precision field delivery,” says Project Engineer Oliver Beechener. “For clients, this means one accountable team overseeing everything from design coordination to installation and commissioning, thereby reducing risk and ensuring confidence in the final result.”
From Design to Delivery
The project successfully reinstated a vital component of the stormwater harvesting system, enhancing its long-term reliability and protecting the precinct’s sustainable water supply.
The Downey Park tidal gate project showcases CMG’s ability to deliver complex marine civil works from initial concept through to completion, offering clients a true turnkey service built on precision, partnership, and environmental responsibility.
The collaborative model of integrating trusted partners such as ENAP and Apex Envirocare reflects CMG’s broader approach: combining in-house marine expertise with specialised supplier capability to deliver confident, coordinated results.
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