Drainage/stormwater upgrade

Why do we upgrade the stormwater in our city?

Council undertakes stormwater/drainage works for one of 2 reasons:

1. Age of the pipe or pits (renewal)

This is where the existing pipes that are structurally showing signs of deterioration and failure and must be replaced.

Council undertakes regular audits of its pit and pipe network and forecasts when these works will be required so it can adequately plan and budget in advance.

2.System capacity (new/upgrade)

While West Torrens sits proudly between the city and the sea, this also means there are large upstream catchments of stormwater that flow through within underground stormwater pipes, creeks and channels, or overland through our streets.

With urban infill increasing and heavier rainfall events due to climate change causing more stormwater runoff, we need to respond to the risk of flooding by installing larger underground stormwater systems to mitigate this.

Common practice is to provide underground pipes minor one in 5 year storm events (20% chance it will occur in any given year), while the major one in 100 year storm events (one percent chance it will occur in any given year) is too large to be contained within pipes and is designed to travel overland in the road reserve:

What will the works involve?

Stormwater works often involve deep excavation into the roadway (1.5m or greater) and wide trenching (one to 2 metres wide) to install concrete pipes. Part of the stormwater system’s effective operation is having side entry pits to capture the water and convey it underground to the newly installed pipes so typically there will also be excavation of the kerb also to install new pits.

Installing stormwater pipes is a long and expensive process. It first requires excavation to the correct depth, the installation of a bedding layer, and then carefully lifting the pipe in and joining it to the other sections. Often there are services to work around (water, gas, electricity) and tight spaces for workers. The pipe then needs to be carefully backfilled to make sure there is no settlement of the soil and that no excessive loads go onto the pipe to cause cracks or damage.

What will be the impact on access to my property?

The alignment of the stormwater pipe is often dictated by service utilities and avoiding clashes with gas, water, or sewer works. While we aim to construct adjacent the kerb to minimise disruption to traffic and residents and still maintain some traffic flow in streets, sometimes it is unavoidable to have the pipe close to the centre of the road meaning road closures.

During stormwater drainage upgrade it is likely:

• The road will likely be completely closed during works.
• Access to properties will be limited for up to a week at a time, with the requirement to park vehicles in the street or adjacent streets outside of the excavation zone.
• Generally works occur between 7am and 6pm Monday to Saturday.
• Works may involve considerable noise, including horns and reversing beeping to keep workers and the community safe.

FAQs