Riverine flooding information for communities on the Eastern side of the Huon River South of Huonville to Verona Sands

Version 1.0 August 2024

If the Huon River has a major flood, low lying areas along the river’s east side south of Huonville can be flooded, particularly if tides are high. The Channel Highway and Cygnet Coastal Road are likely to be impassable in several places. 

Some other areas can also have flash flooding from local minor waterways that join the Huon River if there is heavy local rain. Flash flooding means there can be little specific warning beyond forecasts for heavy rain or severe weather. Agnes Rivulet and nearby creeks can flood parts of Cygnet.  Kellaways Creek and its tributaries can flood parts of Pelvarata and Woodstock. There are also areas of Nicholls Rivulet, Gardners Bay and Garden Island Creek that can be flooded from minor local waterways.

The maps in this guide show the level of flooding that has a 1% chance of happening any year. You are likely to experience flooding such as that shown in the maps in your lifetime. 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 plus potential power and telecommunications outages. The Channel Highway may be cut at Huonville and some other places during a major flood event.  Depending on where the rain falls and how heavy it is, roads leading to the Channel such as Pelvarata Road, Nicholls Rivulet Road and Woodbridge Hill Road may also be impassable. Travel in the area is likely to 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.

Are you at risk of flood?

The Huon River has a long history of flooding, with major flood events in 1901, 1947, 1958, 1960, 1975, 1996, 2016 and 2022. The area often has minor flooding.

Areas south of Huonville are exposed to weather systems from the West, South and East. The area can have heavy rain. As an example, the area around Pelverata had major flooding in August 2022, damaging some properties, destroying a bridge and isolating surrounding areas. Cygnet has historically also had damaging floods, for example, in April 1917.

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 minimise 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 along the Huon River 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 Huon River reaches the following levels.

River gauges	Alert	Minor	Moderate	Major
Huon River at Harrison’s Opening	5.0	5.0	n/a	n/a
Huon River at Tahune Bridge		4.0	5.0	6.3
Huon River at Judbury	3.0	4.0	5.3	6.0
Huon River at Huonville	2.5	3.0	3.6	4.0

There are no formal warning levels for other waterways in the area as the river systems are too short.

Rainfall Observations at Hartz Mountain, Cannells Hill near Huonville, Grove, Woodbridge and other nearby rain gauges 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.

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.

Huon River major flooding

If there is major flooding along the Huon River, and depending on the tides, there may be flooding in low-lying areas close to the river.

A major flood on the Huon River means the river height is at least:

• 6 metres at Judbury and
• 4 metres at Huonville Bridge.

That level of flooding is approximately the level of the 2016 floods and there is about a 5-10% chance of such a flood happening any year.  Tasmanians need to be prepared for floods that have a 1% chance of happening every year.  In this level of flooding, the river height would be about:

• 9.5 meters at Judbury and
• 5.6 meters at Huonville Bridge.

Depending on where the rain falls and the tide level, this level of flooding is likely to

• Close the Channel Highway and Cygnet Coastal Road in several places, such as at Huonville, near Woodstock, at Cygnet and Nicholls Rivulet.
• Close the Cygnet Coast Road and Lymington Road in many places, isolating surrounding properties
• Flood some properties in low lying areas near the Huon River, such as around Gardners Bay, Randalls Bay, Garden Island Sands and Charlotte Cove if the tide is high.
• Impact low lying areas around Cygnet, such as Burtons Reserve

Minor or Moderate flooding along the Huon River is unlikely to cause significant impacts in the lower areas of the river south of Huonville, unless there is a particularly high tide.

Flooding from other waterways

If there is heavy local rainfall, there can be flash flooding

• Around Cygnet from Agnes Rivulet, Supplices Creek, and/or Golden Valley Creek
• Low lying areas around Lymington, including sections of Lymington Road south of Jetty Road and parts of the Robleys Road parkland
• In parts of Pelvarata and Woodstock from Kellaways Creek and its tributaries
• In parts of Nicholls Rivulet from the waterway of that name
• Around Gardners Bay from Gardners Creek
• In parts of Garden Island Sands from Garden Island Creek.

Minor flooding

A minor flood can inundate low lying paddocks, orchards and other farmland.  Stock should be moved for their safety.  There may also be some flooding across some minor roads and parkland 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

There is at least a 2% chance in any year of major flooding along smaller waterways that can flood homes and other buildings in parts of Franklin, Castle Forbes Bay and surrounding areas. 

This level of flooding could be as a result of about 50mm of rain over 6 hours, around Cannells Hill, south of Huonville, for example. Flooding can close the Huon Highway at several locations plus impact low lying properties in areas such as:

• In Cygnet on Channel Highway/ Mary Street/ Charlton Street, Slab Road, Charles Street, Garthfield Avenue, Guys Road, the Recreation Grounds, Caravan Park and Burtons Reserve
• Along low lying areas of Pelvarata Road and Nicholls Rivulet Road and Smiths Road, Nicholls Rivulet
• Garden Island Creek

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 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.