Minimising the impact of floods

Floods are natural and inevitable, and large cities like Melbourne can’t be protected from all flooding. However, some floods are extreme and we aim to minimise their risk to people, property and infrastructure.

​Why we can’t prevent all floods

It is impossible to completely eliminate flooding. This is due to a range of factors, including:

  • extreme weather events, which are unpredictable and can exceed scientific expectations
  • previous town planning standards – much of Melbourne was built before the mid to late 1970s, when developers did not need to plan how water would flow overland when the drainage system was full

While we can build some drainage infrastructure for areas with extreme flood risk, we cannot replace all of Melbourne’s older infrastructure due to:

  • excessive costs, which would take funding away from other aspects like schools and hospitals
  • social impacts – undertaking such works would disturb people, their homes, traffic and access to key services
  • the time needed to do such works, which would be longer than the life of the buildings they aim to protect

Although we can’t prevent all floods, we’re working with councils, other authorities and the community to reduce their severity and impacts.

Assessing and prioritising flood risk

Flooding occurs naturally; however, some floods are extreme and we must reduce their severity and impacts.

An example of flood mapping - Bass River, southern Victoria

We determine flood risk across Melbourne by identifying the extent of flooding under different scenarios. These scenarios include floods of varying severity and likelihood, ranging from floods that have only a 1% chance of occurring in a year, to those with a 20% chance of occurring.

Our Flood Risk Assessment Framework guides our process for assessing flood risks, taking into account their social, safety and economic consequences. We prioritise flood risks which we’ve determined should be reduced or eliminated almost regardless of the cost – we call these extreme flood risks.

Details on the framework’s key features and how it was developed are in the following document:

Our activities to manage flood risk

As the regional drainage and floodplain management authority for the Port Phillip and Westernport region, we deliver a variety of projects and services to minimise the impacts of flooding. These include:

Drainage works, Frankston
  • identifying the extent of flooding in storm scenarios ranging from frequent to less common, which helps us determine and prioritise flood risks that should be reduced or eliminated
  • assessing and placing conditions on town planning permits, which ensure flood risks are considered when developing or redeveloping land in flood-prone areas
  • installing, upgrading and maintaining infrastructure like stormwater drains and retarding basins, which aim to minimise flood risks and impacts
  • adapting to the future risk of sea level rise by assessing coastal development applications and modelling sea level rise scenarios
  • using our monitoring network of rainfall and river level gauges to predict major river floods, and advising the State Emergency Service and Bureau of Meteorology, who issue flood warnings
  • supporting education and awareness programs for communities in flood prone areas, in collaboration with local councils and the Victoria State Emergency Service

These activities are funded by part of the Waterways and Drainage Charge, which is paid by 1.8 million customers across Melbourne as part of their water bill. You can read more about the charge, or see what activities it’s funded in your council area over the past financial year:

Protecting yourself and your property

Everyone has a responsibility to help reduce the effects of flooding around Melbourne. If you live in a flood-prone area, make sure you’re aware of the risks and that you and your family are adequately prepared.

Find out if your property is in a flood-prone area

There are several ways to find out if your property is in a flood-prone area:

  • check your property’s planning scheme
  • request a property information statement from your retail water company or other companies that offer this service – fees apply

The following page has details on obtaining flood level information for properties:

Prepare for flooding – further information

The Victoria State Emergency Service is the control agency for flooding and storms, and plans for and manages responses to them.

They run programs that provide information on preparing for and dealing with the aftermath of floods, including how to protect your home and keep your family safe:

If your property is flooding, it’s most important that you and your family get out safely. If you need assistance, call VIC SES (132 500), and if your situation is life-threatening, call 000.

Copyright Melbourne Water