Hawkesbury-Nepean Valley

Floods. What's your plan?


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.

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Know how to receive weather warnings and when to act

What causes significant floods


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 advice


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:

  • A Flood Watch provides early advice that flood-producing rain is expected to happen in the near future. Note: a flood watch is updated daily but it is not a warning of imminent flooding.
  • A Flood Warning is issued when the Bureau is more certain that flooding is expected in a specific area and is typically issued when rainfall has started to fall.
  • A Severe Weather Warning is issued for very heavy rain that may cause flash flooding or abnormally high tides that can affect flooding. Localised flash flooding occurs after intense rainfall and is also referred to as overland flooding.

Leading up to and during a flood, NSW SES issues:

  • Flood Bulletins that provide information on likely flood consequences and what actions you should take to protect yourself and your property.
  • Evacuation Warnings that warn when evacuation routes are likely to be cut or when floodwaters are expected to inundate property. These warnings aim to get people prepared to evacuate and to respond quickly if an Evacuation Order is issued.
  • Evacuation Orders that advise people what to do in an evacuation and where to go. You might hear an evacuation order that is relevant to you on radio stations, or by automated telephone and/or SMS, NSW SES social media, or door knocks.

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.

Know the weather warning signs

Understand where to go

Know when and how to leave


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.

Get familiar with the local routes


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.

Follow the signs


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.

Know your local evacuation routes

Prepare a Get Ready to Go Kit

Why you need a kit


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.

  • The kit should contain what you will need during and immediately after evacuation, whether you are going to family and friends, or to an evacuation centre.
  • Some key items to include in your kit are a battery-powered radio which will be handy if the power and internet goes out, a torch and batteries, waterproof bag and some personal hygiene items.

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.

Maintaining and storing your kit


  • Your kit should be kept in a waterproof storage container and stored in a safe place that is easy to access.
  • On a regular basis, check your Get Ready to Go kit (remember to check use-by dates on batteries and medications) and restock items if you need to.
  • Also, keep a list of emergency numbers near your phone or on your fridge.

Prepare a Get Ready to Go Kit

Learn more about your flood risk, based on your suburb

Introduction


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.

Richmond and Windsor


Watch the video to see how flooding can impact bridges and roads in the Hawkesbury as well as turning some suburbs into flood islands.

Snapshot of flooding in Richmond and Windsor

Penrith and Emu Plains


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.

Snapshot of flooding in Penrith and Emu Plains

South and Eastern Creeks


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.

South and Eastern Creeks

Understand more about floods in the Hawkesbury-Nepean Valley

Why floods are so dangerous in the Hawkesbury-Nepean Valley


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.

Why floods are so dangerous in the Hawkesbury-Nepean Valley

What are the natural warning signs?


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
such as:

  • predictions of heavy and/or prolonged rainfall
  • East Coast Lows affecting the region
  • heavy, sustained rainfall is occurring in upstream catchments such as the Blue Mountains, the Southern Highlands, Goulburn and Wollondilly regions.

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.

It will flood again

Floods. The Risk Is Real

During a flood

What to do during floods


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. 

  • Floodwater may be deeper or faster flowing than it appears and contain hidden snags or debris. 
  • Floodwater may contain chemicals, raw sewage, snakes, spiders and much more that could cause illness and even death. 
  • Roads and surfaces underneath floodwater often wash away and may not be visible from the surface. 

Never drive, ride or walk through floodwater.

When a Flood Warning is issued


  • Stack possessions, records, stock or equipment on benches and tables, placing electrical items on top. 
  • Secure objects that are likely to float and cause damage. 
  • Relocate waste containers, chemicals and poisons well above floor level. 
  • Activate your home or business emergency plan. 
  • Keep listening to your local radio station for information, updates and advice. 
  • Keep in contact with your neighbours. 
  • Be prepared to evacuate if advised by Emergency Services. 
  • Act early as roads may become congested or close. 
  • Never drive, ride or walk through floodwater. 

For more information on what to do during a flood, download the During a Flood Factsheetin the resources section.

When an Evacuation Warning is issued


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. 

  • Locate important papers, valuables and mementos. Put them in your emergency kit.
  • Keep listening to your local radio station for information, updates and advice. 
  • Follow instructions given to you by Emergency Services. 

For more information on evacuation warnings, download the Evacuation Warning Factsheet in the resources section.

When an Evacuation Order is issued


When an Evacuation Order is issued and you leave your house: 

  • Turn off the electricity and gas at the mains before you leave and turn off and secure any gas bottles. 
  • Take your pets with you. 
  • Never enter or travel through floodwater. 
  • Keep listening to your local radio station for information, updates and advice. 
  • Follow your home or business emergency plan. 
  • Follow all instructions given to you by Emergency Services. 
  • Stay with family or friends, if possible. 
  • Evacuation Centres may be set up if an Evacuation Order is issued.  
  • Choose the safest route to travel where roads along the route are open. 
  • Roads may become congested or close, ensure you leave enough time to travel safely. 

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.

Learn more about high risk flood plains in Sydney

George's River

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