Melbourne Water and Whittlesea Council are working together to update flood information for the Whittlesea area.

By sharing your experience about local flooding, flood modelling experts will receive the information you share with us and use that information to check their model against your experiences. If the data matches, it helps us know we’re on the right track. If it doesn’t match, it's helpful as it will trigger further investigations.

The information we receive during our Phase 1 community engagement will be added to existing Council, DEECA and Melbourne Water data to create comprehensive flood maps.

These maps can be used to inform planning controls, emergency management, community awareness and mitigation works where possible. This will help ensure future developments are better designed to minimise flooding and hazard impacts.

Floods are a natural part of our environment. They can be impacted by changing weather and landscapes, but understanding and preparing for them can help reduce their impact.

We know extreme weather is continuing to increase and technology has improved, meaning it’s important to make sure our understanding of floods in our community is accurate.

The updated flood information will look at floods from waterways and stormwater during extreme weather. Updating the flood information is important as we expect to see extreme weather more often and at times some people may not usually expect, like during summer.

With up to date flood information, decisions can be made based on the best available information.

Once this project is complete, Melbourne Water will review the flood information regularly. Any major floods may also trigger a review.

With up-to-date flood information, we can better plan and manage risks, and build the resilience of our city.

The updated flood information will:

• Identify where changes to infrastructure could reduce risk – like slowing the flow of water or stormwater pipe upgrades.
• Guide future development decisions for planning and building
• Improve our community’s resilience to extreme weather
• Support emergency management planning.

If your property is identified as at risk of flooding, it doesn’t mean it will flood. It highlights there is a small chance (1%) of your property experiencing overland flows in any year. Overland flow is water flowing across the land during heavy rain when it can't soak in or drain away.

The modelling is based on the 1% Annual Exceedance Probability (1% AEP), which also accounts for the increasing impact of extreme weather. A 1% AEP is a storm that has a 1% chance of happening in any given year and is sometimes referred to as the 1 in 100-year storm event, or the 100-year event.

By knowing your property’s flood risk, you can make informed decisions about emergency planning.

Melbourne Water has detailed information on floods, and a guide to preparing for floods. You don’t need to wait until the flood risk for the City of Whittlesea is updated to prepare for flood.

More information about preparing for floods is also available from Emergency Management Victoria.

Understanding the risk of flood helps you to be informed and better prepared to protect yourself, your loved ones and property.

We’re inviting you to share your knowledge of flood around our community on our interactive map. By dropping a pin about your knowledge of flood around the City of Whittlesea, you will help us validate the flood modelling. We’ll check the community knowledge against the flood modelling experts’ research and if the data doesn’t match, this will trigger further investigation.

Understanding the risk of flood helps you to be informed and better prepared to protect yourself, your loved ones and property.

Once the modelling is ready, we’ll share the maps with you so you can better understand your property’s flood risk and prepare. We will also update the planning scheme, which guides planning and building decisions. Changes to the planning scheme will involve community consultation. The changes would make sure new buildings are developed considering the flood information. Existing properties will not be required to get retrospective planning permits.

The updated flood information will also help identify where Melbourne Water and the City of Whittlesea could potentially upgrade infrastructure to reduce risk, including stormwater pipes.

Some people may ask if having a better understanding of flood information could lead to changes to insurance costs or property values.

The goal of modelling floods in our community is to help identify areas that are already at risk, particularly as that risk has changed due to increasing extreme weather.

Once the modelling is ready, we’ll share the maps with you so you can better understand your flood risk. We are unable to provide advice about your insurance or property. You can contact your insurance provider or real estate agent directly.

In 2016, Manningham City Council worked with specialist property advisors to give independent advice on whether their stormwater map would affect property values of the affected areas. Stonnington City Council also did a similar assessment in 2004. Both expert advisors found no connection between stormwater maps and property values, whether in the short or long term.

The updated flood information will show the risk based on future weather conditions, but with the land and buildings as they are now. This means while an area may not have flooded while you lived there, extreme weather and other impacts may have changed that risk making it more likely than before.

Once the flood modelling is completed, the updated flood information will be published on our Engage Whittlesea Platform.

The updated flood information will help us and Melbourne Water to assess potential long-term infrastructure changes that can help reduce risk, such as upgrades to stormwater pipes or infrastructure that slows the flow of water.

The maps will also be used to update the planning scheme. Any changes would involve community consultation. The changes will make sure planning and building decisions take the likelihood of flood into consideration to help keep the community safe.

Changes to the planning scheme – called a Planning Scheme Amendment – will help make sure new buildings are developed considering the flood risk. Existing properties will not be required to get retrospective planning permits.

By having an updated understanding of your property’s risk of flood, you can better prepare for your safety as well as for your family, pets and property.

Our Flood and Storm Emergency Plan (that SES and Council produce together) will also be updated, and the new flood risk will also inform the multi-agency Municipal Emergency Management Plan.

Planning schemes are legal documents that set out policies and provisions for the use, development and protection of land.

It's our responsibility to administer and update the Whittlesea Planning Scheme. From time to time, changes to the Planning Scheme are proposed by Council to reflect new circumstances or to improve the scheme.

Planning scheme amendments often change the way land can be used or developed.

The flood information developed through this project will identify the current flood risk and the risk for the year 2100.

Creating flood maps needs three main things:

1. A 3D map of the land's shape (made using special laser technology called LiDAR)
2. Details of Council's and Melbourne Water's stormwater systems (stored in a map format called GIS)
3. Weather data from different types of storms.

To make the maps, the process starts with hydrologic modelling (calculating how much water comes from rainfall and where it flows) and then uses hydraulic modelling (figuring out how the water moves through drains, creeks, and over land).

The final maps show us:

• Areas where flooding might happen
• How deep the water could get
• How fast the water might flow.

Water management and flood mitigation is responsibility we all share.

City of Whittlesea
Council manages our local drainage network, including street gutters and drains. We are also responsible for planning schemes, flood modelling of local drainage networks, supporting local emergency management planning and supporting community resilience.

Victoria State Emergency Service (SES)
The Victoria SES is the designated control agency for floods in our state. They are responsible for leading emergency preparation and response, providing emergency assistance when flooding occurs and delivering community awareness and education programs.

Melbourne Water
Melbourne Water is the floodplain manager for the region. They coordinate the development and delivery of the Flood Management Strategy and drainage services in partnership with local and state government, emergency services, insurance agenices and the community.

Department of Transport
The Department of Transport manage the drainage along major road networks, including freeways.

Private property owners
If you’re a property owner, you are responsible for taking reasonable measures to ensure the property is protected from flood. This means maintaining pipes, gutters and downpipes on your property.