Two river systems, two kinds of flood behaviour
The NSW SES places the Liverpool local government area in two catchments: the Hawkesbury-Nepean and the Georges River. The council describes the area as sitting on a number of floodplains, with many areas subject to flooding.
The Georges River
About 100 kilometres long, flowing through Liverpool, Chipping Norton and Bankstown into Botany Bay, its only outlet for floodwater. The NSW SES counts it among the most flood-prone areas in NSW; its main floodplain runs from Glenfield to East Hills, across the Liverpool, Fairfield and Canterbury-Bankstown areas.
Its lower reaches are confined by narrow gorges that restrict the flow in large floods, and an East Coast Low is one of the weather systems that can set it off. Major tributaries include Cabramatta Creek, Prospect Creek and Harris and Williams Creeks.
The Hawkesbury-Nepean
The NSW SES says this valley has a long history of dangerous and deep flooding. Most river valleys widen towards the sea; this one does the opposite, so floodwaters flow in faster than they can flow out, and back up and rise rapidly.
For this catchment, the NSW SES offers an interactive flood mapping tool at suburb level, and says to contact your local council for detail about your property or street.
Flooding that never reaches a river
A flood, as Liverpool’s local flood plan defines it, includes water overtopping the banks of a stream or river and also local overland flooding associated with drainage before it reaches a watercourse. The council says its studies and plans are there to guide development on flood-prone land affected by both mainstream and overland flooding.
The fast version is flash flooding: too much rain falling too fast for too long, so the ground can’t absorb it. In urban areas, run-off drains towards lower-lying places, and flash flooding can also happen around bridges, drains, culverts, creeks and causeways. There may be little or no warning. The NSW SES suggests bringing children indoors in severe weather, away from drains, culverts and creeks.
The plan, endorsed in April 2023, records that Liverpool did not then have flash flood warning systems for its local catchments, and that the council was seeking State Government funding for them.
The council’s flood studies, catchment by catchment
Liverpool City Council says it has developed flood studies and floodplain risk management studies and plans for all major waterways in the area, to guide development on flood-prone land. Most can be downloaded from its floodplain risk management page.
| Study | What it covers | Published on |
|---|---|---|
| Georges River Floodplain Risk Management Study and Plan | All the Georges River floodplains in the Liverpool, Fairfield and Bankstown council areas, with those upstream of the Woronora River junction in Sutherland Shire. Commissioned jointly by the four councils. | Council page |
| Cabramatta Creek Floodplain Management Study and Plan | The Cabramatta Creek catchment, including Cabramatta, Hinchinbrook, Maxwells and Brickmakers Creeks. | Council page |
| Review of Liverpool Overland Flow Path Studies, Cabramatta Creek catchment | A draft study of overland flow, with flood extent and risk mapping, across parts of 21 suburbs from Liverpool and Warwick Farm to Cecil Hills. | Council page |
| Anzac Creek Floodplain Risk Management Study and Plan | A small Georges River tributary whose 10.6 km² catchment lies entirely within the Liverpool area. | Council page |
| Austral Floodplain Management Study and Plan | The Kemps Creek and Bonds Creek catchments within the Liverpool area. | Council page |
| Liverpool CBD Floodplain Risk Management Study and Plan | The city centre, roughly from Terminus Street to Campbell Street, between the railway and Bathurst Street. | Council page |
| Harris Creek Flood Study | Harris Creek and Williams Creek, through Holsworthy, Wattle Grove, Hammondville, Voyager Point and Pleasure Point. Listed as completed, published 15 January 2025. | NSW Flood Data Portal |
Under the Liverpool City Local Flood Plan, the council’s jobs include developing and implementing floodplain risk management plans, giving its flood studies to the NSW SES, and maintaining council-owned flood warning networks and flood mitigation works. Sydney Water, which takes part where it has stormwater assets, notes that local councils have primary responsibility for flood planning.
Checking the risk where you live
- The NSW SES page for Liverpool. It names the catchments, links Liverpool’s local flood plan and the Georges River flood map, and points to the Flood Data Portal.
- Local Flood Insights. An NSW SES tool with maps of flood-prone areas, historic flood events and modelled flood risks.
- The council. The NSW SES says your local council will have specific flood information relevant to your property.
- The people nearby. The NSW SES also suggests talking with your local SES unit, community organisations and long-term residents about local flood risks.
The three warning levels
The NSW SES issues flood warnings under the Australian Warning System, and the Bureau of Meteorology issues flood watches and warnings for river flooding and severe weather and thunderstorm warnings for possible flash flooding. You may not always get an official warning: rushing or pooling water and heavy rain are the natural signs.
- Advice
An incident is under way. Keep checking for updates, because things may change.
The actions the NSW SES lists under it: “Stay informed” and “Monitor conditions”, or, once the danger has eased, “Reduced threat” and “Return with caution”.
- Watch and Act
Things are changing. Act now to protect yourself and your family.
The actions the NSW SES lists under it: “Do not enter floodwater”, “Prepare to evacuate”, “Prepare to isolate” and “Avoid the area”.
- Emergency Warning
The highest level. You may be in danger and need to take action immediately.
The actions the NSW SES lists under it: “Evacuate now/before”, “Shelter now” and “Move to higher ground”.
The NSW SES asks people to download the Hazards Near Me app and set watch zones for floods and severe weather.
What the NSW SES asks of you
- Go early, before the roads close, to a relative’s or friend’s home, an evacuation centre if one has opened, or an assembly area.
- If you stay, it may be too dangerous for anyone to rescue you.
- If rising flash floods trap you, get to the highest part of a solid building, or to high ground, and keep moving so you stay above the water. Keep out of the roof cavity. Stay there, and call Triple Zero (000) if you need rescuing. The NSW SES calls this a life-threatening situation.
- If rising flash floods trap you in your car, get to the safest place you can: that may be inside the car, on its roof, or on higher ground. Keep moving so you stay above the water, and call Triple Zero (000). This too is life-threatening, the NSW SES says.
- Turn around on flooded roads and find a safer way.
- Throw out food and drink, including water, that has been in contact with floodwater.
- Plan ahead: the NSW SES may not be able to rescue you during a flood.