Sharps Road Retarding Basin

BMD Urban was engaged by Australia Pacific Airports Melbourne (APAM) to construct essential stormwater drainage infrastructure for new developments in the Melbourne Airport Business Park.

The Sharps Road Retarding Basin has been upgraded to maximise its stormwater detention capacity. Featuring two bio-retention basins and a 5000m³ capacity sediment pond, it is capable of withstanding a 1 in 100-year rain event.

Upstream stormwater from the developed Macedon Way precinct is temporarily stored in the retarding basin until it can flow into downstream Melbourne Water drainage assets.

These upgrades ensure that downstream drainage discharge does not surpass the pre-development stormwater flow as infrastructure projects continue upstream in the Macedon Way precinct.

BMD prioritised environmental considerations, including the protection of Growling Grass Frog habitats and native grass.

Scope

The scope of works included:

• demolition of existing structures
• temporary water diversion from existing stormwater outflow
• bulk earthworks (40,000m³ clay/rock cut and fill)
• sorting and downsizing site sourced rock to be utilised in rock beaching and rock scour protection
• export of excess material to APAM approved disposal facility
• construction of a 5000m³ capacity sediment pond with stabilised liner and access ramp
• construction of two bio-retention basins with liners, drainage, filtration and planting
• installation of structural concrete elements (curved weir wall, culvert slabs)
• modification of stormwater pit
• construction of dam embankment walls
• installation of stormwater drainage and precast box culverts
• additional works included construction of access road pavement, 20,000m² of hydroseeding, and the installation of fencing, galvanised handrails and gates.

Key achievements

• Following design optimisation to update the 1200 millimetre pipe outfall surround and rock beaching specifications, the project team sorted, downsized and shaped site sourced rock to be utilised in rock beaching and rock scour protection. This approach reduced disposal and quarry imports, improving efficiency and aligning with APAM’s environmental and circular economy values.
• BMD implemented propeller drone software for site imaging, design, and level information, crucial for client coordination meetings. Due to airport constraints, the drone system was modified to incorporate data from traditional surveying instruments, facilitating comprehensive design comparisons across various project stages.
• BMD took an innovative approach to efficiency by trialling a 3D modelling program that allowed for stockpiles to be surveyed and a visual model built. Moving forward this 3D technology can be utilised on other projects where drone flight is not optional.
• To address time constraints from upstream developments tying into the current stormwater system, BMD increased resources on site. This ensured the project was completed on schedule without affecting upstream progress.
• The project was completed under budget and on time, accomplishing the entirety of the works (17,762 hours) without a recordable injury or safety incident.