Cornwallis Road & Drainage

Project Summary:

Menai Civil delivered critical flood resilience upgrades along Cornwallis Road, focusing on the reconstruction of key drainage infrastructure and associated roadworks to improve the area’s ability to withstand future flood events. The project involved the construction of reinforced concrete box culverts, channel reshaping and riverbank profiling to enhance water flow and reduce flood risk. Delivered within a constrained riverside environment, the works required careful staging, temporary diversion and dewatering measures to maintain site stability during construction. The completed upgrades strengthen the long-term resilience of this important local road corridor while protecting surrounding land and infrastructure.

Scope of Works:

Construction of twin reinforced concrete box culverts to improve drainage capacity and flood resilience.
Reshaping and construction of the approach channel on the lagoon side to optimise water flow through the culvert structure.
Earthworks and profiling of the riverbank and surrounding landform above the culvert structure to stabilise the area and achieve design levels.
Reinstatement of existing riverside gabion wing walls to maintain bank protection and structural integrity.
Relocation and reinstatement of existing services and utilities along Cornwallis Road to accommodate the upgraded infrastructure.

Key Features:

Culvert Construction

Installation of reinforced concrete box culverts including structural headwalls and wing walls.
Foundation improvement works to support culvert installation within variable ground conditions.
Implementation of scour protection measures, including rock riprap, geofabric and gabion mattresses.
Temporary diversion and dewatering systems implemented to maintain dry and stable construction conditions.

Road Works

Bulk earthworks including cut and fill operations to achieve final road design levels.
Application of two-coat 14/7 spray seal to reinstate the road surface.
Seamless tie-ins with existing road infrastructure to ensure smooth transitions and road continuity.

Environmental Protection Measures

Implementation of erosion and sediment control measures, including the use of silt curtains.
Dust suppression and noise mitigation strategies to minimise impacts on the surrounding environment.
Protection of works using a sheet pile cofferdam, supported by flood monitoring and evacuation procedures triggered by early flood warnings.