March 02, 2026

Hydraulic Design for Mixed-Use Developments

Mixed-use developments — projects that combine residential, commercial, retail, and sometimes hospitality uses within a single building or precinct — have become a defining feature of urban development in Perth. From the perspective of hydraulic engineering, these projects are among the most complex we work on. Each occupancy type has different water demand profiles, different drainage requirements, different fixture densities, and different expectations from end users. Designing a hydraulic system that serves all of these needs reliably and efficiently requires careful analysis and close coordination with the broader design team.

At Devlin Engineering & Management, our hydraulic engineers begin by mapping the demand profiles for each use within the development. A residential tower will have peak demand periods in the early morning and evening, while a ground-floor restaurant will peak at lunchtime and dinner service. Retail tenancies may have minimal water demand but significant grease waste management requirements. By understanding these profiles in detail, we can design supply and drainage systems that are appropriately sized for actual demand rather than worst-case assumptions, avoiding both undersizing and the unnecessary cost of oversized infrastructure.

One of the most critical coordination challenges in mixed-use hydraulic design is the interface between the building’s internal systems and the external authority infrastructure. Water Corporation requirements in Western Australia govern the connection to mains water supply, sewer, and stormwater systems, and these requirements can vary depending on the development’s location, scale, and mix of uses. Our team manages these authority interfaces as a core part of the design process, preparing applications, coordinating with Water Corporation engineers, and ensuring that the building’s hydraulic design aligns with the capacity and configuration of the surrounding network. Early engagement with the authority is particularly important for large mixed-use projects, where connection capacity or sewer capacity constraints can influence the project’s feasibility.

Stormwater management is another area where mixed-use developments require thoughtful hydraulic engineering. With large roof areas, podium levels, and often constrained site conditions, managing stormwater runoff to meet local government requirements for detention, retention, and water quality treatment demands integrated design. Our engineers design stormwater systems that work within the architectural and landscape framework of the project, using a combination of on-site detention tanks, rainwater harvesting, permeable surfaces, and water-sensitive urban design principles. The result is a development that manages its stormwater responsibly while maintaining the amenity and functionality that residents, tenants, and visitors expect.