Flooding frequently asked questions

Flooding occurs when water covers land that is normally dry.

The main cause of this in Parramatta is heavy rainfall, although high tides can have minor impacts in some areas.

There are two types of flooding from heavy rain:

• overland flow
• riverine flooding.

Overland flow

Overland flow is where water floods land as it makes its way to the river or creek and can sometimes be caused by blockages or lack of capacity in street drainage.

Riverine flooding

Riverine flooding is when rivers and creeks become full and overflow onto the land. In most floods, both types of flooding occur.

Flooding cannot be completely prevented.

Flooding is a natural part of how rivers work and will always be a possibility when large amounts of rain falls.

However, infrastructure can be designed to reduce the impacts and risks of flooding by slowing the water down, stopping it reaching certain areas, or by building in a way that we make space for water.

Floods are the second deadliest natural hazard in Australia behind heatwaves.

Between 1900–2015, 1,859 people died in floods in Australia.

Two thirds of all recent deaths were from people entering flood waters either on foot or in cars. However, a simple way to increase your awareness and reduce your risk is by signing up to FloodSmart Parramatta warnings and to avoid walking or driving in flood water.

Everyone has a role to play in managing the risks of flooding – individuals, as well as federal, state and local government.

Individual residents and businesses have a responsibility to know their flood risk, to plan for flooding and to act in a way that protects themselves and their property.

NSW State Emergency Service (SES) are the flood combat agency coordinating emergency response when floods happen.

Local and state government bodies create flood policy, provide funding, build defences and set land use planning regulations. These measures try to reduce the frequency of flooding and reduce the impact of floods when they occur.

City of Parramatta complies with the NSW Flood Prone Land Policy and Floodplain Development Manual (2005).

This means that council collects and monitors flood information, reviews the information to understand the flood risk across the local government area (LGA) and develops measures to reduce flood impacts.

Council has flood maps that cover most of the LGA and you can view them at Floodplain Risk Management. These maps are currently being updated and you can provide any information you have about flooding including pictures and videos at Share Your Flood Experiences

Council also enforces planning and development controls aimed at making buildings as safe as possible. City of Parramatta Council owns and maintains a number of flood detention basins, levees, stormwater drainage assets and river banks that all aim to reduce flood risk and the impacts of flooding.

FloodSmart Parramatta is a partnership project between Council, NSW State Emergency Service, the Bureau of Meteorology and NSW Department of Planning, Industry and Environment, and aims to support communities with flood risk information and early warnings.

No, all data used on the website and as part of FloodSmart Parramatta has been available to the public and insurance companies for many years.

Insurance companies also have their own individual methods of determining what prices they charge and how they will provide flood insurance.

Speak to your individual provider to find out more, or for information about how flood insurance works, visit Insurance Council Australia's website, Understand Insurance.

Flood risk may be a factor in any valuation of your property. However, all data used on the website and as part of FloodSmart Parramatta has been available to the public for many years as part of the NSW Floodplain Development Manual requirements.

Properties that are impacted by Council’s Floodplain Risk Management Policy and flood planning and development controls are already indicated on Council’s section 149 certificate. 

House prices vary continuously with changes in the real estate market, and are based on a large range of criteria such as location, size and age etc. and are not under the control of Council.   

FloodSmart Parramatta provides access to the information you need to prepare for a flood and offers a free flood warning service.

Additional information can be found on the following websites:

• NSW State Emergency Service
• Bureau of Meteorology
• NSW Office of Emergency Management

Be prepared for a flood gives you all the information you need to prepare for flooding. 

This includes signing up for flood warnings, preparing a flood plan and a flood kit.

Everyone’s situation is slightly different so a big part of being prepared is taking time to think about what is the safest thing for you to do if a flood happens.

This means that your property is not expected to flood but there could still be local incidents of overland flow or street drainage not coping with rainfall amounts that could lead to localised flooding.

Properties in the ‘No data currently provided’ area can submit a Flood enquiry application

This will provide you with detailed information and maps for your specific property, showing flood levels and associated conditions, if Council has this information. There is a processing fee for this service.

You can submit a Flood enquiry application

This will provide you with detailed information and maps for your specific property, showing flood levels and associated flood hazard conditions, where this information is available. There is a processing fee for this service.

The data used in the Know your flood risk maps comes from the 2004 Upper Parramatta River flood study carried out by the Upper Parramatta River Catchment Trust.

It includes riverine flooding but not overland flow.

City of Parramatta follows the NSW guidelines as set out in the Floodplain Development Manual.

The process involves collecting flood data, creating a flood model, and flood maps.

The flood model is used to understand the flood risk in a catchment and engagement with communities is carried out to make sure it is as accurate as possible.

The end result is the development of a Floodplain Risk Management Study and Plan which sets out how the City of Parramatta will manage flood risks.

The flood maps developed as part of this process are used to show where flood affected areas are located.

No model is 100% accurate, however the mapping being used was created by the Upper Parramatta Catchment Trust in 2004 and at the time was the best available data using the latest industry techniques to understand flood risk.

The modelling from 2004 did not include overland flow and, due to this, it is possible for flood impacts to be seen where we have no previous flood risk mapping.

Flood modelling is updated when new data is available.

City of Parramatta is currently developing a new flood model using the most recent flood techniques that will include overland flow. Once this is completed, you may see changes in City of Parramatta flood map information.

City of Parramatta is currently updating and developing new flood mapping.

The new maps will then be put on public display for comment before being officially adopted.

It is expected that this will happen in 2020. Once this is finalised the online maps will be updated.

A flood warning is an email, text or voicemail that will be sent out by FloodSmart Parramatta when we predict that flooding is possible.

The seven warning areas will each receive a specific message that will explain the severity of flooding and local impacts.

When you receive a flood warning you should always check that you, your family, pets and neighbours are safe. It may be that your property will not flood (although areas around you may flood).

Each flood warning will detail the severity level (minor, moderate or major) and explain which risk areas will see the most flooding. You can find out what risk area your property is in by visiting the Know your flood risk page. If your property is at risk, you should enact your flood plan if you have one. 

Even if your property is not at risk, never walk or drive in flood waters and stay aware of the changing situations through warnings and messages from FloodSmart Parramatta and NSW State Emergency Service.

ABC local radio stations are another good source of up to date information.

If you feel unsafe at your location move to higher ground and seek shelter. 

In a life threatening emergency call 000.

Yes, you can sign up to any number of flood warning areas.

However, if you do, please be aware that you will receive multiple warning messages during a flood which could be confusing. 

Yes, even if your property is not within one of the seven flood warning areas you can still sign up.

Simply provide your normal address and then choose which warning area you want to receive warning messages for.

No, currently this area is not covered by flood warnings as we are waiting on new flood modelling.

City of Parramatta hopes to expand the flood warning service in the near future. 

Flood warnings are like weather forecasts and they are only a prediction, which means they are never 100% accurate. 

FloodSmart Parramatta warnings are based on real-time river levels and rainfall information using the latest Bureau of Meteorology forecasting data.

This information is provided to you so that you are not caught unawares by local flooding.

You can then assess your specific situation to make an informed decision about what to do.

Every storm is different and we will be collecting flood data after every event to improve forecasts.

If you become flooded without receiving a flood warning, please contact us using the Share Your Flood Experiences so that we can investigate your situation and improve our future warnings.

The Parramatta River catchment has 28 river level and rain gauges which provide information about what the current conditions are.

To forecast what will happen in the future, FloodSmart Parramatta uses Bureau of Meteorology products.

All the data is run through a flood model to predict where and when flooding may occur.

No, the depth of flooding changes in each location and is dependent upon land topography and the intensity of the rainfall.

For this reason, flooding can produce different levels at various locations depending on where the rain falls. 

Any information provided as part of this questionnaire will be used to improve Councils understanding of flooding.

Improvements will be considered to Council’s flood modelling, flood warnings and flood response.

No individual data will be shared outside of Council’s floodplain risk management work.

All personal and site specific information provided through the questionnaire will be treated as confidential and will not be disclosed publicly.

Please see answers provided in general flooding FAQs.

Please call the City of Parramatta Customer Contact Centre on 1300 617 058 and they will either answer your questions directly or pass your details onto someone who can help.

A flood plan or flood kit will help you prepare and react quicker if there is a flood.

Simply knowing if you are at risk and planning what you would do, will allow you to make better decisions which could protect your property and help you stay safe. 

For more information on creating a flood plan or flood kit, visit Be prepare for a flood or the NSW State Emergency Service

The decision to evacuate is made by the NSW State Emergency Service (SES) as the flood combat agency.

If the flood is big enough, they will issue an evacuation order which will go out by a separate text and through the media via TV and radio.

The data is updated approximately every 15 to 20 minutes.

These are terms used to explain the water levels on the river and rain gauges.

Australian Height Datum

FloodSmart Parramatta graphs will be shown in Australian Height Datum (AHD) which indicates the number of metres above mean sea level.

Local Gauge Height

Local Gauge Height (LGH) indicates how deep the water is at the gauge location. The title of each gauge will show the value that can be subtracted from the AHD to produce the LGH at the gauge.

FloodSmart Parramatta can only provide river levels where there are gauges to collect the information.

Most of the gauges are not owned by City of Parramatta and we do not control where the gauges are placed.

The Parramatta River is a natural watercourse and is prone to flash flooding.

This means that while flooding can happen very rapidly, the water levels also recede quickly.

This is a naturally occurring phenomenon. 

Council does not own or control any gates or sluices which are used during a flood to manage river levels.

The water is allowed to flow quickly through the catchment to reduce flooding as much as possible. However, there are flood mitigating measures such as basins and levees which passively reduce the impact of flooding.

This would cause confusion in the flood warning system and modelling tools as all the river and rain gauges and Bureau of Meteorology forecasts are produced in Australian Sydney Time.