Quick Facts

Project Proponent(s): City of Port Adelaide Enfield
Project Manager(s): City of Port Adelaide Enfield
Principal Contractor(s): City of Port Adelaide Enfield
Total Cost: $4.5 million (estimated)
SMA Contribution: $1.5 million
Other Funding Contributors:
• City of Port Adelaide Enfield
• Renewal SA


The North Arm East catchment covers the suburbs of Blair Athol, Broadview, Clearview, Enfield, Gepps Cross, Kilburn, Lightsview, Northfield, Northgate, Sefton Park and Wingfield in the City of Port Adelaide Enfield. Stormwater from the catchment drains via the North Arm East channel to the Barker Inlet Wetland.

The Barker Inlet Wetland provides an important function in improving the quality of stormwater discharged to the Barker Inlet. However, the wetland also provide storage (during periods of high tide) for floodwaters from the North Arm East catchment and other adjacent catchments to the west.

Within the catchment lies the intersection of three major arterial roads at Gepps Cross: Grand Junction Road, Main North Road and Port Wakefield Road. Historically the area around this intersection has been prone to stormwater flooding. As this area is relatively flat and the trunk drainage capacity is of a relatively low standard, floodwaters tend to pond in the area with no readily available overland flood flow path to escape. This ponding impacts private residences and businesses and poses a hazard to motorists travelling on the major arterial roads.

The City of Port Adelaide Enfield completed a Stormwater Management Plan for the North Arm East catchment in 2015. The Plan confirmed the previously identified Marmion Avenue diversion drain as an effective strategy for reducing flooding around the Grand Junction Road intersection. The diversion drain works by diverting flows from a drain along Main North Road that would otherwise meet and connect with a drain along Grand Junction Road that is under capacity. The diversion drain therefore relieves pressure on the Grand Junction Road drain during heavy rainfall events. Diverted flows are piped underground in twin 1200 millimetre pipes along the entire length of Marmion Avenue and into the North Arm East channel at Kilburn.

Construction of the drain commenced in January 2018 and is expected to be completed by January 2019. For more information see the City of Port Adelaide Enfield project website.