Riverine flooding information for the Huon River and tributaries at Huonville and Ranelagh townships

Version 1.0 August 2024

Huonville and Ranelagh are subject to flooding from:

• The Huon River
• Mountain River
• Skinners Creek

The maps show the expected 1% annual exceedance probability flood level in Huonville and Ranelagh. You are likely to experience a flood of this size at least once in your lifetime.

Huon River gauges at Tahune Bridge, Judbury, and Huonville measure real-time river levels and support flood forecasts and warnings for Huonville and Ranelagh. Other information comes from a network of real-time rainfall gauges. For flooding along the Huon River, the Bureau of Meteorology and the State Emergency Service will issue warnings that predict flood heights and timing at Huonville. These may be expressed as Minor, Moderate, and Major and/or give specific flood heights in meters.

Heavy rain in the South West wilderness can cause the Huon River to flood, and there is generally 6-12 hours warning time of flooding from the Huon River around Ranelagh and Huonville.  Rapid snowmelt sometimes enhances Huon River flooding.   High rainfall lower in the Huon River catchment and its tributaries can also add to flooding.

Mountain River and Skinners Creek are subject to flash flooding. This means there may be unexpected flooding without warning if heavy rain falls in and around Huonville.

Parts of Huonville and Ranelagh may also flood without warning due to storm water run-off when there is very heavy rain.

Are you at risk of flood?

The Huonville area has a long history of major flooding, including in 1901, 1947, 1958, 1960, 1975, 1996, 2016 and 2022. The area often has minor flooding.

What should I do?

• Check the map opposite to see whether your home or business is likely to be at risk of flooding during a flood.
• Prepare a Home Emergency Plan, including whether you need to evacuate in advance of a flood, where you will go and what you need to take.
• If you have a business in the area, you should have a plan that covers flooding.  Business Tasmania can help– see www.business.tas.gov.au/manage_a_business/ 
• If you need to evacuate or return home during a flood, make sure your route is safe.
• Asses your home or business and know what you need to do to prepare it to minimise possible damage from water inundation.

Floods like the one shown on 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 Huon River has several real-time river gauges and a network of rainfall gauges that can support flood warnings.  Floodwater at Judbury generally takes a couple of hours to reach Huonville. Monitor rainfall totals and river rises at www.bom.gov.au/tas/flood/ .

Whenever rain that may lead to flooding along the Huon River is expected, the Bureau will issue warnings when the river reaches specific heights.

Mountain River can rise quickly after rainfall and so there can be little to no warning of flooding.  There are no river gauges on Mountain River nor Skinners Creek.

Whenever heavy rain is expected in an area that may lead to flooding, the Bureau issues

• Severe Weather Warning and/or
• Thunderstorm Warning for heavy rainfall that may lead to flash flooding.

The time between the warning and heavy rain falling can vary from an hour to 24 hours or more. It is best to act on the warnings from the Bureau of Meteorology rather than wait for local flooding alerts around Mountain River and Skinners Creek.

Tracking Rainfall on Kunanyi/ Mount Wellington can help predict flooding around Mountain River. Go to www.bom.gov.au/tas/ .

The Mt Koonya Radar is useful to see when and where heavy rainfall is falling and is available on the BOM Weather app and website.

Download BOM Weather app and set your location to receive push notifications of warnings (more details at www.bom.gov.au/app/) .

Listen to ABC 936AM or go to tasalert.com for warnings.

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.

Flood levels around Huonville

While no two floods are the same, the following table shows what is likely to happen if there is flooding around Huonville. Even if your property is not flooded, you need to think about access.

The rainfall amounts that might cause such an event are examples. Other levels of rainfall can cause flooding depending on

• where the rain falls
• how heavy the rain is
• how long the rain lasts and
• how wet the ground is beforehand.

Minor flooding – over 4 metres @ Judbury / 3 metres @ Huonville

• Spill over riverbanks and cover nearby low lying areas.
• Causes minor flooding of agricultural and horticultural land along the river flats with some stock losses unless moved. Livestock should be moved from low lying areas near waterways.
• Can close the Channel Highway at Huonville
• Can inundate some minor roads, paths, tracks and low level bridges.
• May come up through drains in nearby streets.
• Affects low lying backyards and buildings below floor level.
• Covers riverside parklands, camping areas and may affect the caravan park.

Moderate flooding – over 5.3m @ Judbury / 3.6m @ Huonville

• Causes more extended and deeper flooding of agricultural and horticultural land along the river flats with some stock losses if not moved and damage to fences.
• Will close the Channel Highway at Huonville
• Spill over river banks and cover larger areas of land.
• Is likely to flood low-lying areas of Huonville with the possibility of water damage to some properties.
• May reach above floor levels in some houses and buildings, particularly along the Esplanade.
• Some properties should be evacuated.

Major flooding – over 6 metres @ Judbury / 4 metres @ Huonville

Huonville and surrounds have a 5-10% likelihood of experiencing such a flood in any year. A major flood will:

• Cause widespread and potentially damaging flooding of agricultural land, particularly in low lying areas.
• Water is likely to enter some commercial premises along Main Road to the south of the roundabout and surrounding areas unless preventative measures are taken eg sandbagging
• Affect utility services (power, water, sewage etc).
• It may be necessary to evacuate the occupants of some dwellings.
• The Huon Highway between Wilmot Road and Huonville Bridge may need to be closed, isolating multiple areas south of Huonville
• Is likely to have similar consequences to the flooding in June 2016, when flood peaks reached 6.5 metres at Judbury and 4.3 metres at Huonville.

Major flooding – approx. 5.1m @ Huonville

The type of flood that has a 2% chance of happening any year (current climate). Judbury water levels are likely to be around 8.9m. Flooding would likely extend north from the roundabout and affect surrounding areas, with flooding about 80cm higher than in 2016.

Major flooding – approx. 5.5m @ Huonville

The type of flooding that has a 1% chance of happening in any year (current climate). Everyone should be prepared for such an event. Judbury water levels are likely to be around 9.5m. Large areas of Huonville will become inundated, for example

• about 1.7m deep around Short St
• about 1.4m deep around the Huon Valley Council Chambers
• about 65cm deep around the roundabout
• about 15cm deep around the Huonville Library
• Areas not inundated may become isolated, including:
  • All areas South of the Huon River
  • Areas to the West of Main Road around Sale Street
  • Ranelagh and surrounds may be isolated for short periods if Mountain River is flooded.

Skinners Creek flooding

Recent works around Skinners Creek helps mitigate flood risks in surrounding areas. However, flooding may still happen in severe rain events, particularly if there is debris washed down from areas above. If Skinners Creek overtops, Sale Street and some surrounding properties may become flooded.

Huon Valley Council’s mitigation works mean that this extent of flooding is now unlikely with the same level of rainfall. However, people in this area should be aware that there may be some flooding in the area during severe rainfall events.

Mountain River flooding

If Mountain River floods, the areas most at risk of flooding include the caravan park plus nearby Glen Road and Wilmot Road. Ranelagh and surrounding areas may become isolated for a short time as Glen Road and access roads to the north may be inundated, however the new Lollara Road bridge is not likely to be overtopped unless it is an extreme event.

If Mountain River floods at the same time as the Huon River, this will lead to higher flooding in these areas and Huonville.

For flood information for areas upstream of Ranelagh, please see the Mountain River area flood guide.

Know your risk, get ready, reduce your 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 the SES website or Red Cross Rediplan.

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 

Huon Valley Council huonvalley.tas.gov.au 6264 0300

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.