Peritas was engaged by the Rottnest Island Authority to update and validate the island-wide gravity sewer network model and assess the cumulative impacts of existing and future development on network performance. The project involved incorporating recently constructed infrastructure, reviewing sewer capacity across multiple catchments, and modelling ten future development scenarios to inform long-term infrastructure planning.

The assessment identified critical network constraints, quantified future loading impacts, and established a prioritised upgrade strategy to support development sequencing, asset management and capital investment decisions. The work provided RIA with evidence for growth planning and ensured future wastewater infrastructure upgrades were targeted, practical and aligned with anticipated demand.