Lake Macdonald Bridge Upgrade

McIlwain was engaged by Seqwater to design and construct a new bridge and improve road access at Lake Macdonald, Noosa, ahead of the main dam upgrade works, aiming to provide safe access for construction traffic and ongoing Water Treatment Plant operations.

The project was delivered as part of Seqwater’s Dam Improvement Program to ensure dams across South East Queensland meet national and state safety standards. The existing bridge was a single-lane timber structure with limited flood immunity, restricting access during high rainfall events. McIlwain replaced it with a two-lane, single-span concrete bridge, constructed downstream of the existing structure to allow continuous access, accommodate heavy vehicles, and meet future operational requirements. The works included service relocations, approach road upgrades, erosion and service protection, and environmental management including aquatic fauna relocation.