GCCC Recycled Water Release Plan

Stage 1 involved extensive marine, hydraulic and structural works, including twin DN1100 subsea PE pipelines with service lines, reinforced concrete buoyancy weights for towing and sinking, river crossing augmentation, valve pits, diffuser upgrades and connection works. The scope also included upgrades at Coombabah and Benowa facilities, incorporating structural modifications to reinforced concrete and steelwork within large pumping stations.

Key challenges included constructability of long marine pipelines, strengthening existing pump station structures and integrating new pumps within constrained buildings. The existing overhead crane was unsuitable for lifting the new pumps, and adjacent holding tank walls required strengthening. Works had to interface with operational assets while maintaining system functionality and structural integrity.

Phronis provided project management and detailed structural design through to Issued for Construction documentation. We delivered design for subsea pipelines, buoyancy weights, valve pits, river crossing augmentation and associated connection works, along with structural modifications at Coombabah and Benowa facilities.

Major works included reinforced concrete and steel strengthening, new structures, access platforms, stairs and installation and upgrade of overhead cranes. We worked with the pump manufacturer to relocate lifting lugs on the new pumps, allowing them to be lifted using the existing crane and avoiding roof dismantling and height increases.

Innovative strengthening solutions were developed for the adjacent holding tank walls, and drilling techniques were adapted to suit site constraints and structural requirements.

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The project successfully upgraded the Coombabah and Benowa pump buildings, enabling installation of new and additional pumps while strengthening and modifying the existing structures. The bridge crane was upgraded and structural works were completed to support ongoing operations.

Relocation of pump lifting lugs eliminated the need for roof modifications, avoiding significant additional cost and construction complexity. Innovative wall strengthening solutions and adapted drilling techniques addressed structural weaknesses while maintaining constructability.

The completed works enhanced capacity and reliability of key recycled water infrastructure, delivering Stage 1 of the Long Term Recycled Water Release Plan with integrated marine, civil and structural outcomes.

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