It's important to always be prepared for floods in the Hawkesbury-Nepean Valley - floods can happen anytime.
If you live or work in the Hawkesbury-Nepean Valley you are at risk of flood and your home, family and animals may be vulnerable.
Now's the time to get prepared.
Most significant floods in the Hawkesbury-Nepean Valley are caused by intense low-pressure systems called East Coast Lows.
These weather systems can happen at any time and can occur several times a year. They often intensify rapidly overnight, making them one of the most dangerous weather systems to affect the region.
Official warnings and flood advice are provided by The Bureau of Meteorology (the Bureau) and the NSW State Emergency Services (NSW SES) on radio stations and social media.
The Bureau uses rainfall and flood gauges to predict the arrival time and depth of floodwater.
Working in cooperation with NSW SES, the Bureau issues three types of related forecasts and warnings:
Leading up to and during a flood, NSW SES issues:
It is vital that you leave if you receive an Evacuation Order. Learn more about Evacuation Orders and what to do under During a flood.
The Hawkesbury-Nepean Valley has a long history of damaging and dangerous floods. Floods can happen with little warning. You may only have a few hours to get out following an evacuation order. You will typically be asked to leave well before you see any sign of floodwater in your neighborhood. It is not safe to stay and shelter in your home once you have been ordered to evacuate.
To find out about evacuation orders and which routes are open listen to your local and ABC radio, or follow NSW SES Facebook, or NSW Police Facebook and Twitter.
You need to be prepared and get to know your evacuation routes, to keep you, your family and pets safe.
There are 12 designated evacuation routes that provide the quickest and safest way to exit the Wallacia, Penrith-Emu Plains, RichmondWindsor, South and Eastern Creek floodplains.
You need to be aware of more than one route because each flood behaves differently and evacuation routes will get cut by floodwater at different points. Some routes can get cut quite early in relatively small floods. For example, Windsor Road is cut by a flood that has a 98% chance of happening in an 80-year lifetime (also known as a 1 in 20 chance per year flood).
Even relatively new infrastructure can be affected by large floods. The Jim Anderson bridge at Windsor would be cut in a flood with a 55% chance of occurring in an 80-year lifetime (1 in 100 chance per year flood).
Once you know your best routes, have a conversation with friends or relatives to organise a place to go to. Remember, as each flood can be different, it’s important to follow evacuation orders when they are given.
More than 150 new flood evacuation signs have been installed across the Hawkesbury-Nepean Valley to guide drivers. There are several different types of signs, including a number of folded signs designed to be opened during a flood emergency to provide extra direction for drivers.
Signs to guide people along the regional flood evacuation routes towards safer areas.Download Image
A significant flood in the Hawkesbury-Nepean Valley will cause damage to people’s homes. It will also cause major disruptions to essential services such as water, electricity, gas, roads and rail lines.
By the time you know a flood might impact your property, there may be very little time before you have to leave. A key step to getting ready for floods (or for any other natural hazard) is to prepare a Get Ready to Go kit.
For more information and examples of what items to include in your kit, download the Get Ready to Go Kit Factsheet in the resources section above.
What to do now. What you can place in your kit earlier.
What to add to your Get Ready to Go kit when you are leaving.Download Image
The Hawkesbury-Nepean Valley floodplain is divided into 5 key areas. You can find handy information about your local area in the resources section.
To understand your flood risk you can use our flood risk tool in the useful links.
Watch the video to see how flooding can impact bridges and roads in the Hawkesbury as well as turning some suburbs into flood islands.
Watch the video to see how flooding can impact local icons such as the Bridge to Bridge walking track, the Joan Sutherland Centre, and Victoria Bridge.
Watch the video to see how flooding can impact suburbs such as Riverstone, Schofields, Shanes Park and Llandilo many kilometres away from the main Hawkesbury River.
The Hawkesbury-Nepean Valley covers a wide area in Western Sydney from Bents Basin near Wallacia to the Brooklyn Bridge. The area has a long history of dangerous and deep flooding.
The unique geography in the valley affects the extent and depth of flooding in the region. Most river valleys tend to widen as they approach the sea. The opposite is the case in the Hawkesbury-Nepean Valley, which means floodwaters flow into the valley more quickly than they can flow out, causing them to back up and rise rapidly.
Much like a bathtub with five taps (the major tributaries) turned on, but only one plug hole to let the water out. Watch this video to learn how the ‘bathtub effect’ makes this valley have one of the greatest flood risks in Australia.
The recent March 2021 flood was only the 15th largest recorded flood in the region – though the impacts were felt far and wide. Floodwater severely impacted over 600 homes, over 30 caravan parks, hundreds of farms, and transport routes and essential services such as electricity and water were cut. The estimated damage bill was several hundred million dollars.
However, there have been much larger floods in the valley including the worst flood on record. In 1867, river levels reached 19.1 metres above normal river height at Windsor and the region was decimated. If a similar flood happened now the consequences would be catastrophic – many lives would be at risk and almost 90,000 people would have to evacuate.
Flood are random, naturally occurring events. It’s impossible to predict when the next major flood will happen. History has shown that serious floods can happen many times in a single decade, and not again for many years.
Every flood is different, so you can’t rely on what you might have experienced or heard about in the past.
It’s important to pay attention to weather reports and be aware of some of the early warning signs
In the Hawkesbury-Nepean Valley, there may be only a few hours warning between heavy rainfall and being told to evacuate.
In most cases you won’t see flooding in your neighbourhood before being told to evacuate. This means your best source of information is the official warnings.
If your area is at risk, go to high ground away from flooded areas.
Never enter floodwater. If it’s flooded, forget it.
The major cause of death during floods is from people entering or travelling through floodwater. This includes driving, riding and walking through floodwater and children playing in floodwater.
Never drive, ride or walk through floodwater.
For more information on what to do during a flood, download the During a Flood Factsheet in the resources section.
When an Evacuation Warning is issued, you prepare to evacuate. Staying inside a house, even one which you think is high enough, may be very dangerous. If you are warned to evacuate it is always safest to move to a location away from the flood affected area before floodwater arrives.
For more information on evacuation warnings, download the Evacuation Warning Factsheet in the resources section.
The Hawkesbury-Nepean Valley has a long history of damaging and dangerous floods. You need to follow evacuation orders to keep you, your family and pets safe.Download Image
When an Evacuation Order is issued and you leave your house:
For information on roads, contact your local council for local road closures.
For more information on evacuation orders, download the Evacuation Order Factsheet in the resources section.