Intense storms with a lot of rainfall cause stormwater to move across the land, as it makes its way to drains and creeks. The storm's intensity influences how much runoff flows across the land, as well as how much runoff can get into our drains.

The stormwater map shows the location of the stormwater overland flow path for the 1 in 100 year storm, in our local drainage catchments.

It is the path stormwater takes when flowing over the land, as it makes its way to drains and creeks.

The 1% Annual Exceedance Probability (1% AEP) storm is a large storm. It has a 1% chance of happening in any one year.

The 1% AEP event is sometimes referred to as the 1 in 100 year or 100 year storm. This does not mean a place that experiences a 1% AEP storm will not see another for another 100 years. Large storms can happen more often.

Yes, we need the map. Many people may not recall such a large storm affecting their neighbourhood. This is because the last local 1 in 100 year storm may have happened many years ago.

The 1 in 100 year standard helps us consider stormwater impacts on land development.

Yes, Merri-bek has a history of infrequent but notable storms.

For example, in December 2011 a large storm moved across metropolitan Melbourne’s northern and western suburbs. This storm caused stormwater overland flow paths that affected parts of Merri-bek.

More information about past storms in Merri-bek is available from the Victorian State Emergency Services website.

No. The risk is associated with the size of the storm.

Smaller, more frequent storms are normally contained in drains and roads. Larger, less frequent storms cause stormwater overland flow.