Council is the Local Drainage Authority and looks after our smaller, local drains.

Melbourne Water is the Main Drainage Authority and looks after creeks and our larger, main drains.

Melbourne Water is also the Floodplain Management Authority for all of Melbourne.

Landowners are responsible for their property drains.

On most occasions, stormwater runoff from properties goes downhill to Council's drains, then to Melbourne Water's larger drains before flowing into creeks.

Council asked engineering experts to prepare an initial stormwater map. This initial map was released in 2021 and is being used by building surveyors for land development. Then, work continued so an updated map could be prepared because Council wanted to ensure new information was included and the changing national engineering guidelines were considered. The updated map is now being released.

You can find more information in a Technical Report (PDF 5.5MB).

The Special Building Overlay is a planning tool, so the stormwater map can be part of the Merri-bek Planning Scheme.

Having an SBO, means land developers need a planning permit to develop on land that is affected by 1 in 100 year stormwater overland flow paths.

Others have done this. Melbourne Water and various councils have been preparing stormwater maps and putting them in planning schemes for over 20 years.

The SBO Schedule 1 (SBO1) is for 1 in 100 year stormwater flows in Melbourne Water's drainage areas in Merri-bek. This stormwater map for Melbourne Water’s areas is already part of the Merri-bek Planning Scheme.

Council has prepared its stormwater map for the Council's drainage areas. A planning scheme amendment is expected to happen in the future so the Council’s stormwater map can also be part of the Merri-bek Planning Scheme. This would result in a second schedule to the Special Building Overlay, known as an SBO2.

The SBO2 would be used when the stormwater maps are part of the Merri-bek Planning Scheme. Then, the SBO2 is used when land development is proposed on land affected by the map for Council's local drainage areas.