Rottnest Island Infrastructure Upgrades

Cossill & Webley has been supporting the Rottnest Island Authority in the planning, design and delivery of critical water, wastewater and transport infrastructure across the island since 2019.

Working within a highly sensitive coastal and environmental context, our role has focused on improving essential services while supporting the island’s long-term sustainability and growing visitor demand.

Key project contributions include:

• Sewer Network Modelling
  Undertook modelling of the island’s sewer network to assess existing capacity and performance under future demand scenarios. This work informed a strategic upgrade program for wastewater infrastructure across the island.
• Transport Infrastructure Upgrades
  Designed access and transport improvements at key visitor destinations including Oliver Hill, The Basin and West End in collaboration with the Rottnest Island Authority and landscape architects.
• Wastewater Pumping Infrastructure
  Delivered the relocation of wastewater pumping stations to facilitate the development of Samphire Rottnest, along with the design of new pumping stations and pressure mains to service staff housing projects.
• Emergency Storage & System Upgrades
  Designed and superintended the construction of emergency overflow storage tanks at Thomson Bay, including upgrades to existing pumping infrastructure and preparation of asconstructed drawings.
• Construction Superintendence
  Provided superintendence for the delivery of the Parker Point wastewater pumping station (relocated from the Samphire site) and pressurised fire mains.
• Water & Power Infrastructure – Geordie Bay
  Designed watermain and power upgrades at Geordie Bay, including close coordination with Rottnest Island Authority and specialist contractors to address installation constraints.
• Island-Wide Water Network Upgrades
  Design of watermain upgrades to the island’s water distribution network, including connections to existing, new grouped dwelling meter arrangements and set out of water pump station and decommissioning of existing water pump infrastructure.

Through a long-term partnership approach, Cossill & Webley has helped deliver resilient, efficient infrastructure solutions that balance operational needs with the unique environmental and heritage values of Rottnest Island.