Riverine flooding information for communities including Ouse, Ellendale and north to Derwent Bridge and Bronte Park, in the upper reaches of the Derwent Catchment.

Version 1 December 2024

This plan covers areas prone to flooding from the:

• Derwent River
• Ouse River
• Nive River
• Dee River
• Jones River, and
• nearby minor waterways.

This part of the upper Derwent catchment has many large dams that will affect flood behaviour.

Rainfall events in this area may affect some parts without affecting others. The maps in this guide show the likely peak extent of flooding that has a 2%, 1% and 0.5% chance of happening in any one year (known as Annual Exceedance Probability, or AEP).

Major flooding over roads and bridges could cut off Ouse from other towns. Some properties near the river in Ouse could flood. Rural areas around Ouse can flood, impacting livestock, fences, equipment and lives. The Ouse River can rise quickly when Lake Augusta begins to overflow.

There are likely to be road closures during a flood in this area, including parts of the Lyell Highway near

• Ouse,
• Wayatinah,
• Tarraleah,
• Derwent Bridge and
• other locations.

Ellendale could be cut off with several roads flooded. The Wilderness Hotel in Derwent Bridge could be cut off. Campgrounds and parks in the area are likely to flood.

Miena, Brady’s Lake, Dee and Fentonbury are unlikely to be affected by flooding, but there may be power and internet cuts and flooded roads isolating these communities.

There is another flood guide for Bothwell to Hamilton and areas around the River Clyde.

In your lifetime, you are likely to experience flooding such as that shown in the maps. Tasmanians need to prepare for flood events that may not happen often, as well as the minor flooding they may have experienced.

Even if your home is not inundated, you should be prepared for isolation and potential power and telecommunications outages.

Travel in the area may be difficult or impossible until roads are clear.  If you are safe at home or elsewhere, it is usually best you stay where you are until the flooding subsides, unless there is an emergency. If you need to evacuate, you should leave early, before flood waters rise.

Listen to ABC local radio 936AM for warnings and advice, but please note that radio coverage may be poor in many parts of this area. It may be difficult to access up to date information in a situation that can change very quickly.

Are you at risk of flood?

The Derwent catchment has a long history of flooding. Most recently, in late August 2024, a prolonged wind and rain event caused widespread road closures and damage. In 2016, widespread flooding in this area caused the tragic loss of a life. There was also extensive damage to property, equipment, significant loss of livestock and community assets.

Other flooding events in the upper Derwent include August 2009, August 2005, August 2004, April 1996, August 1970, April 1960 (very significant), 1944, and others.

What should I do?

• Check the map to see whether your home or business could flood.
• Assess your home or business and prepare it to reduce possible flood damage.
• Check if you can safely get to your home, work, or school during a flood.
• Prepare a Home Emergency Plan.
• If you may be isolated and you must have access to services, you may need to evacuate early.

Floods like the one shown in the map, or worse, will occur again. No two floods are the same.

If you live in a low-lying area or near a watercourse, your house may flood. Even if your home is safe, you may need to detour around flooded areas or your road access may be cut. Never drive into or enter flood waters. Roads and bridges may be washed out or unsafe. Avoid travel during floods.

Knowing what to do can save your life and help protect your property. Having a Home Emergency Plan is one of the best ways to prepare. Decide on weather and rainfall triggers for when to act.

Bureau of Meteorology Forecasts, Warnings, and Observations

The Bureau issues a Flood Warning, Severe Weather Warning and/or Thunderstorm Warning for heavy rainfall that may lead to flash flooding whenever heavy rain is expected in an area. The time between the warning and heavy rain occurring can vary from an hour to 24 hours or more.

Whenever rain that may lead to flooding in the upper Derwent is expected, the Bureau will issue:

• A Flood Watch – a “heads up” early advice of forecast weather that may lead to flooding
• A Flood Warning – giving a prediction of when flooding is likely to develop at gauge locations and possibly forecasting the likely peak river level.  Warnings are updated regularly.
• SES and the Bureau will issue warnings when the Ouse and Derwent Rivers reach the following levels.

River gauges	Alert	Minor	Moderate	Major
Ouse River at Ashton	2.4m	2.4m	3.2	4.5
Ouse River at 3B Weir		3.0	3.7	4.3
Derwent River below Meadowbank Dam	4.1m	4.1m	6.1m	7.3m

Rainfall Observations at Ouse, Hermitage, Lake St Clair, Derwent Bridge, Bronte Heights and Wayatinah can indicate possible flood risks. Given the very short warning times, it is best to act on the predictive BoM warnings rather than wait for any flood alerts during rainfall.

The Mt Koonya Radar is useful to be aware in real-time where heavy rainfall is falling.  Radar Rainfall estimates can also fill in gaps in areas where there are no rainfall stations.

Understand the warnings and key information

Keep aware of what is happening around you. Check forecasts, observations and warnings regularly.

• TasALERT.com
• your local ABC radio station or
• the Bureau of Meteorology’s website.

	Advice (Yellow): an incident has started. There is no immediate danger. Stay up to date in case the situation changes.
	Watch and Act (Orange): There is a heightened level of threat. Conditions are changing and you need to start taking action now to protect you and your family
	Emergency Warning (Red): An Emergency Warning is the highest level of warning. You may be in danger and need to take action immediately. Any delay now puts your life at risk.
	Community update (Blue): Specific information and updates for affected communities regarding a particular event or incident.
	Incident (White): an incident is the initial occurrence of an event before it becomes an emergency warning. As soon as an incident is reported, TasALERT published basic information including the type and location of incident.

For more information see www.ses.tas.gov.au/warnings/ .

Flood levels

While no two floods are the same, the following describes what you can expect at different flood levels around the area. Even if your property is not flooded, you need to think about access. Different levels of rainfall can cause flooding depending on its intensity, duration and how wet the ground is beforehand and where the rain falls. The Bureau of Meteorology will issue flood warnings of three levels, minor, moderate or major.

Upper Derwent Catchment flooding levels

Minor flooding

A minor flood can inundate low lying paddocks.  Stock should be moved for their safety, consider the location of equipment and mobile infrastructure like irrigation equipment.  There may also be some flooding across low-lying minor roads and riverside areas.

Moderate flooding

There is more extensive flooding of agricultural land and some buildings may be impacted to above floor height. Some properties may be isolated for a few hours as minor roads become flooded.

Major flooding

Major flooding may inundate multiple roads, including major roads, and some residential properties are at risk of inundation.

The following roads may be flooded:

• The Lyell Hwy at Ouse
• The Lyell Hwy between Derwent Bridge and Bronte – several locations
• Victoria Valley Rd heading north from Ouse
• Lake St Clair Rd near Derwent Bridge
• Ellendale Rd in multiple places – the town of Ellendale could be split in two
• Wayatinah Rd and the Lyell Hwy near Wayatinah

Many other roads in the area, depending on where the rain falls and how heavy it is.

Properties may be flooded in low-lying areas around:

• Wayatinah
• Derwent Bridge
• Ouse north of the Lyell Highway
• Ellendale near the Jones River.

In the areas outside of the towns, extensive flooding would occur in farmland and natural areas. Livestock and farming equipment could be at risk in low lying areas.

Know your risk, get ready, reduce risk where you can, connect with others, stay alert and act safe.

Before a flood

1. Know your risk

Flooding often happens in Tasmania and can cause widespread and significant damage. In the past 200 years there have been 78 flood related deaths in Tasmania. This guide is to help you understand flood risk in your area.

2. Prepare your household

Have an emergency plan that covers storms and floods

Thinking about what you would do in a storm or flood means you are more prepared and everyone is safer. Have an emergency plan that everyone in your household understands. There are checklists to help you think through your plan – see Get Ready for Emergencies – A guide for individuals and households to prepare for emergencies. 
Check your plan regularly and test it by everyone in the household thinking through a flooding scenario that may affect your household.

Prepare an Emergency Kit

Regularly test batteries in radios and torches.

3. Reduce your risk from flooding where you can

• Think about storms, flooding and other hazards when buying, maintaining or developing property.
• Trim or remove trees and branches overhanging your home, business or near powerlines on your property.
• Keep your gutters and drains clear.

4. Connect with others

Know your neighbours and get involved in your community.  A connected community is a safer and more resilient community in an emergency and can help everyone recover better afterwards. Check that family and neighbours are safe and aware of what’s happening.

See for example the Huon Valley Good Neighbour project.

During

5. Keep up to date

Keep aware of what is happening around you. Check forecasts, observations and warnings regularly. 

• TasALERT 
• your local ABC radio station or
• the Bureau of Meteorology’s website.

6. Act Safe

• Supervise children.
• Prepare for possible power, water or internet outages.
• Check your emergency kit is ready to go.
• Keep clear of flooded areas such as drains. NEVER walk, play, ride or drive in floodwater. You can’t always see what is under the water or how deep or fast-moving the water is. It is easy to be swept away and drown in as little as 20cm of fast-moving water. Flood water can be dangerous.

When your home may be flooded

• Put household items up high to minimise possible damage.
• Turn off the electricity and gas if it is safe to do so. 
• A great way to stop sewerage flowing back into your home is to place sandbags inside plastic bags and use them to block toilets and cover drains and sinks.
• Leave while you can get out safely.

If you need to evacuate

• Follow the advice from SES / Tasmania Police.  
• Take your emergency kit. 
• Go to friends or family in a safer place or an evacuation centre. 
• Let others know where you have gone.

Look after your animals

You are responsible for your animals in an emergency. If you have pets and other animals it will take you longer to evacuate in a flood or other emergency. Move livestock from flood prone areas well before flood waters may rise.  For more information see

• RSPCA’s guidance on preparing for animals in an emergency
• Huon Valley Council’s advice on preparing an emergency pet plan
• the Primary producer farm flood readiness toolkit.

Avoid travelling during storms and after storms

• Do not go sightseeing. Sightseers delay emergency services and cause accidents.
• Watch out for hazards such as
  • water over roads
  • damaged powerlines
  • landslides
  • damaged roads
  • falling trees or roofing iron.
• Never drive through flood waters. Most deaths and rescues in floods are from people driving through flood waters.
• Drive slowly and turn your headlights on roads not affected by flood waters.

After

• Keep listening for ABC Local Radio updates, road re-openings, community meetings, etc.
• If you left your home, do not return home until SES or Tasmania Police tell you it is safe to do so.
• Be aware of road hazards, such as mud or debris on the road, damaged roads/bridges and crews working on clean-up and repairs.

If your home has been damaged

• Stay at ground level while checking for damage. Be careful of fallen trees, broken glass, loose roofing or other hazards.
• Wear strong boots, gloves and protective clothes. 
• Use a torch, never use matches or candles inside flood affected buildings. 
• Boil all drinking water until you are told the tap water is safe again.
• Do not turn on it is tested by a licensed electrician or gas fitter for safety.
• If your home is damaged and you need to stay somewhere else, take your emergency kit and pets with you
• Take photos of any damage if safe for you to do so and contact your insurance company.
• Supervise children.
• Check neighbours are okay.

For further information go to www.ses.tas.gov.au

Staying informed and further information

Current warnings (TasAlerts) alerts.tas.gov.au

Bureau of Meteorology (BoM)

Emergency Broadcasters ABC 936AM

TASSES Social Media

• facebook.com/sestasmania
• twitter.com/sestasmania

Preparing for Flood Emergencies ses.tas.gov.au/plan-prepare/flood 

Central Highlands Council    centralhighlands.tas.gov.au               03 6259 5503

National Relay Service (NRS) relayservice.gov.au

Disclaimer

The maps show potential flooding risks from consistent levels of rainfall across catchments, such as a 1% Annual Exceedance Probability (AEP).  In flooding events, rainfall is likely to be more inconsistent across a catchment, so these flood maps should be considered indicative only.  The mapped areas of flood risk show higher probability of inundation. Other areas have lower probability of flooding, but in severe and rare events (rarer than 1%AEP), other lower areas may be also at risk of inundation.

The information in this guide is current at the date of publication. While every effort has been taken to ensure the validity and accuracy of the data presented, the State Emergency Service does not take responsibility for data error or omission. Please see the standard Tasmanian Government’s Copyright and Disclaimer Statement for more details.