Greenlea Estate is a medium sized residential estate situated within the East Baldivis District Structure Plan area within the City of Rockingham. Subdivision and development works commenced in 2015.
Emerge Associates have provided a range of services for this project including environmental planning and approvals (including EPBC Act advice), bushfire hazard management, landscape architecture, hydrology/urban water management, ecological survey and acid sulfate soils investigations and management.
Of these the most prominent and complex has related to urban water management. The site is low lying, has limited separation to groundwater and has historically been drained for agricultural purposes with an agricultural drain traversing the site that discharges to the Peel Main Drain. We have undertaken pre-development groundwater modelling, prepared the local water management strategy for the structure plan covering the site, and more recently prepared the urban water management plan. This latter piece of work has included subsoil drainage modelling and detailed and linked 1D-2D surface runoff modelling to support subdivision design.
Significant up-front consultation undertaken with Department of Water and other stakeholders to ensure that the water management approach would be supported. The form of the arterial drainage system in the post-development environment was discussed with differing preferences raised, an open water channel versus a piped solution. We facilitated discussions with both parties and provided technical support that informed the outcome in terms of potential drainage widths, flow rates, treatments and environmental risks.
We promoted the co-location of major event storage within the sports field areas. The design considered the use of the sports fields and surrounding public open space area with treatment areas provided in formal basins in the edges of the public open space while major event runoff (in the 100 year ARI) was allowed to flood over the oval areas. This allowed for a fully integrated approach to drainage design.