Civil engineering and infrastructure planning for a 3,500-home community in Perth

Transforming the site into a connected residential community of around 3,500 homes required rethinking how transport, utilities and everyday services would function together to support a future population of more than 20,000 people.

At a glance The planning and enabling of a 3,500-home residential community at Henley Brook in Perth’s north-east corridor, supporting a future population of more than 20,000 people.Civil engineering and transport planning across roads, drainage, water, sewer and earthworks.550+ individual plots of land designed and delivered over six years, despite high groundwater levels, dewatering requirements and variable ground conditions.The challenge How do you design and deliver infrastructure for a new 3,500-home development on flat land with high groundwater levels?Transforming Henley Brook from farmland into a future suburb planned for more than 20,000 people meant solving complex challenges from day one.

These challenges were driven by the site itself. Flat terrain and consistently high groundwater levels imposed significant civil engineering and design constraints. Managing surface and subsurface water movement became a key planning consideration.

These conditions made stormwater management more challenging. Changes to natural runoff could increase downstream impacts or raise flood levels within the development. At the same time, the development needed to remain safe, viable, and deliverable as it progressed in stages.

Delivery added further complexity. Many areas sat away from the active construction front, requiring additional coordination and interim design solutions. From 2021, strong housing demand saw multiple developments progress at once, increasing pressure on staging, groundwater management, timelines, and cost.

Our approach How was the project delivered?From the outset, the focus was on coordination and continuity. Designs were developed in close collaboration with adjoining developers to ensure interfaces aligned and development could progress smoothly. This early coordination, led by KCTT (now part of Premise within the Amey Group), reduced disruption during construction and avoided costly retrofitting once works were underway.

At the same time, the team responded directly to the site’s water and servicing constraints. Stormwater systems were designed to maintain pre-development runoff conditions, manage internal flood levels, and protect key assets during one-in-100-year storm events.

High groundwater levels and flat terrain required trunk wastewater and drainage infrastructure to be extended at depth, using large-diameter pipelines to provide long-term capacity and reliable performance.

Development staging was managed proactively throughout delivery. With many areas not adjacent to the active construction front, additional enabling and interim design work was undertaken to support phased delivery. As housing demand strengthened from 2021 and multiple developments progressed concurrently, designs were adapted to manage groundwater perching, construction interfaces, and emerging time and cost pressures.

Delivery was approached as a partnership with the contractor. An alliance-style relationship allowed issues and latent conditions to be addressed collaboratively as they arose. A value-engineering mindset was applied throughout, identifying the most economical construction methods and refining designs to minimise rework and control costs across successive stages.

The outcome What was delivered at Henley Brook?50+ lots designed and delivered over six years

Civil design completed for more than 550 residential lots, including trunk road and sewer coordination.