Riverine flooding information for communities on the Clyde River and its tributaries

Version 1.0 December 2024

Bothwell flood map
Hamilton flood map Tasmania

Riverine flooding is a risk

  • in the townships of Bothwell, Hamilton, and
  • in the surrounding areas and roadways.

This area responds rapidly to rainfall.  Flash flooding often occurs in the steep upper sections and narrow valleys of the Clyde River. Flooding can last for hours or days, depending on rainfall.

The main areas at risk of inundation during a moderate to major flooding event in Bothwell are around

  • Arthur Crescent,
  • Nant Lane,
  • High Street and
  • William Street.

Properties in the east of the town may flood between

  • Patrick Street and High Street, and
  • High Street and Franklin St.

Clyde River flooding may cut the Highland Lakes Road.

In Hamilton, the showgrounds are likely to flood.  The Lyell Hwy may flood towards Ouse, including the bridge over the Clyde River. Sections of Hollow Tree Road between Hamilton and Bothwell may flood. Depending on where the rain falls and how heavy it is, Dennistoun Rd and other minor roads may flood and so be impassable for a short time.

The maps in this guide show flooding that has a 2%, 1% and 0.5% chance of happening any year (known as the Annual Exceedance Probability or AEP). 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 or heard about.

Even if your home is not inundated, you should prepare for isolation plus potential power and telecommunications outages. 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 you are in danger. If you need to evacuate, you should leave early, before flood waters rise. Never drive through floodwater.

Listen to ABC local radio 936AM for warnings and advice.

Are you at risk of flood?

The Clyde River has a long history of flooding, including in January 2011 when prolonged heavy rainfall caused major flooding, with widespread damage to roads, bridges and homes, and disruptions to essential services including power and water.

The Bureau of Meteorology has records of flooding in the Clyde River in 2009, 2001, 1960, 1931, 1929, 1923, 1922, 1910 (when half the bridge washed away in Hamilton),1905, 1903 and 1880, in all months of the year.

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. Consider if you need to evacuate before a flood. See Get Ready for Emergencies – A guide for individuals and households to prepare for emergencies.
  • 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.

The landscape north of Bothwell with modelled 1% AEP flooding (Tasmanian Strategic Flood Mapping)
The landscape north of Bothwell with modelled 1% AEP flooding (Tasmanian Strategic Flood Mapping)
The landscape between Bothwell and Hamilton with modelled 1% AEP flooding (Tasmanian Strategic Flood Mapping)
The landscape between Bothwell and Hamilton with modelled 1% AEP flooding (Tasmanian Strategic Flood Mapping)

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 Clyde 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 Clyde River reaches the following levels.

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
Clyde River at Bothwell 0.9m 2.0m 3.0m 4.0m
Clyde River at Hamilton 2.4m 2.4m 3.5m 4.5m

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

Rainfall Observations at Bothwell, Ouse, Interlaken and Liaweenee 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 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.

 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.

Clyde River Flooding

Minor flooding

A minor flood can inundate low lying paddocks.  Stock should be moved for their safety. Think about equipment such as pumps in these areas.  There may also be some flooding across minor roads, low bridges and parkland areas. Riverside areas like the Hamilton Campground may also flood.

Moderate flooding

In addition to the above, moderate flooding will be more extensive. Agricultural land and some buildings may flood to above-floor-height. Some properties may be isolated for a few hours as some roads become flooded.

Major flooding

When the Clyde and its tributaries are in major flood, multiple properties and roads in Bothwell and Hamilton and surrounding areas are likely to be inundated and isolated. Some areas may need to evacuate. Extensive rural areas will flood, and major traffic routes may be closed. Services like electricity, water and sewerage may be cut for some time.

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

Ready to Go

  • Battery powered radio and torch, spare batteries
  • Important information, such as your emergency plan
  • A list of emergency numbers
  • Food and water
  • First aid kit
  • Rubber or strong leather gloves

Pack when needed

  • Warm clothes, sturdy shoes or boots
  • Medicine, glasses or other essential items
  • Mobile phone and phone charger
  • Pet food and anything else they need
  • Photos and special keepsakes
  • Money
  • Important documents, for example
    • insurance papers
    • passports and
    • birth certificates

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. 

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

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

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.