COMMUNITY SAFETY

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FLOODS

• Types of Flooding
  
• Flood Preparation
  
• Flood Action Guide
  

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TYPES OF FLOODING

The flooding of rivers following heavy rainfall is the most common form of flooding in Australia. The overflow of drainage systems in urban areas can also be a major problem, particularly in heavily populated areas. Low-lying coastal areas can be inundated by storm surges associated with tropical cyclones. Snow-melt flooding is not a problem in Australia.

INLAND RIVER FLOODING

Flooding of rivers in inland areas of central and western New South Wales and Queensland, as well as parts of Western Australia, can spread for thousands of square kilometres and may last for weeks or even months. Floods in these areas can lead to major losses of stock and damage to crops, as well as extensive damage to road and rail links. Rural communities can be isolated for long periods. Food and other vital supplies, as well as food for livestock, must be provided by air. Advance warnings allow stock to be moved to high ground and crops to be harvested. Rural townships can prepare by closing temporary gaps in levee banks and arranging supplies of sandbags for the construction of temporary levees if necessary.

MOUNTAIN/COASTAL RIVER FLOODING

Flooding can occur more quickly in the hilly or mountain areas of these inland rivers as well as in rivers draining to the coast. The rivers here are steeper and drain more quickly, with flooding often only lasting for one or two days. These floods can potentially be much more damaging and can pose a greater risk of loss of life and property since there is generally much less time to take preventative action. Flood warnings can provide time for people to take action to protect their property, as well as allowing emergency services to prepare and plan for evacuations and other emergency action. Flood warning services in these areas must be linked closely to emergency action plans for responding to the warning if the maximum benefit is to be achieved.

FLASH FLOODING

Flash flooding results from relatively short intense bursts of rainfall, commonly from thunderstorms, and can occur in almost all parts of Australia. Because of the speed with which it occurs, this type of flooding poses the greatest threat of loss of life and can result in significant damage to property as well as causing major social disruption. It is a serious problem in built-up urban areas where drainage systems are unable to cope, as well as in very small creeks and streams. The flooding tends to be localised and it is difficult to provide effective warning.

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FLOOD PREPARATION, RESPONSE AND PERSONAL SAFETY 

A. KNOW YOUR AREA'S FLOOD HISTORY

Many devastating floods have occurred in Australia since records have been kept. You may be surprised to discover that in the past, floods may have affected the area where you live. It is important to realise that floods can occur at any time, and that floods bigger than any previously recorded will occur sooner or later. Ask your local government office these questions :

• What is the history of flooding in my area?
• Is there a local flood evacuation plan?
• What official river height will cause my home to be flooded?
• What flood advice will be given by Bureau of Meteorology and local counter-disaster authorities?
• Where is the catchment area in which heavy rain could result in floods near my home?

B. HEED WEATHER REPORTS AND WARNINGS

Following a flood warning for your area, typical actions you should take include :

• Move valuable/personal items to a safe place above expected flood level.
• Open doors of refrigerators and other heavy airtight items that could float, tip over and be damaged
• Switch off electricity and gas at supply points to the building.
• Protect/relocate stock and equipment in commercial/industrial premises.

The earlier you act, the better you will be prepared. Both during and after a flood, keep tuned to your radio. Where possible, you will be kept up to date with the likely duration and level of flooding and when it is over you will receive advice from local authorities on where to obtain medical care, assistance with food, clothing, shelter and how best to help yourself recover. Have a back-up portable radio with fresh batteries in case the power is cut by flood water.

C. MAJOR CAUSES OF INJURY OR DEATH

Water Depth and Current

The great majority of the deaths from flooding in Australia result from people attempting to drive, walk or swim through flood waters. Flood water depth and current are easily mis-judged and are capable of sweeping away and submerging even large vehicles. Also in small streams the water level can change suddenly. Some deaths have even resulted from people camping in, or near, normally dry river beds. People have also died when flash floods occur in storm water drains and irrigation channels.

Hidden Dangers 

Many of those thought to have drowned in floods, especially flash floods, may actually have been killed by the violence of the water, or as a result of having been struck by, or having struck, objects in the water or the river bed. Thus, simply being a good swimmer may not be enough to survive. THEREFORE DO NOT ENTER OR DRIVE INTO FLOOD WATERS, especially where an obvious current exists. If your vehicle becomes stranded in flood water, leave it and move to higher ground before the water level rises further. BE AWARE of other potential injuries or adverse effects from flood waters such as :

• possibility of exposure (hypothermia) after becoming soaked;
• risk of illness after drinking from water supplies polluted by sewage and other hazardous wastes in urban and recreation areas;
• injuries from vehicle accidents caused by road washouts, soft edges and damaged bridges; and
• electrocution by overhead or fallen power lines. If in a boat on flood water, be aware of power lines. They may be dangerously close to an aerial, mast, cabin, etc, or may even be in the water.

D. AFTER THE FLOOD - VITAL POINTS

Flood water can be extremely polluted so follow these rules to reduce risk of injury, sickness or infection :

• Do not eat food which has been in contact with flood water.
• Boil all water until supplies have been declared safe.
• Do not handle wet electrical equipment.
• Avoid wading even in shallow water as it may be contaminated - if you must enter shallow flood water, wear solid boots or shoes for protection.
• Beware of snakes and spiders which may move to drier areas in your house.
• Check with police for safe routes before driving anywhere.

Repairing flood damaged building information can be obtained from the CSIRO Built Environment web site

For people who live in flood-prone areas, more detailed information on flood preparation, safety and recovery is available in "A Personal Handbook of Flood Activities - What to do Before, During and After" published by Emergency Management Australia and available from your State or Territory Emergency Service. Further information on flood warnings is available from your Bureau of Meteorology Regional Office.

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FLOOD ACTION GUIDE

If your property is near a watercourse or is low-lying, it could be flooded, even if you have never seen flood waters there. This guide lists simple things you and your family can do to stay safe and protect your property. 

BEFORE FLOODING OCCURS

Ask your council or State/Territory Emergency Service about local flood plans (or records) which detail problem areas and evacuation routes and centres.
If your area is flood-prone, consider alternatives to carpets (eg removable rugs). In ground-level rooms, tiled walls are less likely to be damaged than others and are more easily cleaned. Have an emergency kit on hand which includes a portable radio, torch, and spare batteries; stock of canned food and fresh water; first aid kit and manual and garden gloves; waterproof bags for clothing and valuables. Keep a list of emergency phone numbers on display:

• State/Territory Emergency Service
• Police
• Local Council

WHEN YOU HEAR A FLOOD WARNING OR IF FLOODING APPEARS LIKELY

• Tune to your local radio for warnings and advice.
• Prepare to move vehicles, outdoor equipment, garbage, chemicals, and poisons to higher locations.
• Plan which indoor items you will raise or empty if water threatens to enter your home (see list overleaf).
• Check your emergency kit and remember your pets.

IF YOU NEED TO EVACUATE

• If you leave of your own accord, tell police or State/Territory Emergency Service, and your neighbours.
• Firstly, pack warm clothing, essential medication, valuables, personal papers, photos and mementos in waterproof bags, to be taken with your emergency kit.
• Raise furniture, clothing and valuables onto beds, tables and into roof space (electrical items highest).
• Empty freezers and refrigerators, leaving doors open (to avoid damage or loss if they float about). Turn off power, water and gas and take your mobile phone.
• Whether you leave or stay, put sandbags in the toilet bowl and over all laundry/bathroom drain-holes to prevent sewage back-flow.
• Lock your home and take recommended evacuation routes for your area.
• Don't drive into water of unknown depth and current.

IF YOU STAY, OR ON YOUR RETURN

• Stay tuned to local radio for updated advice.
• Don't allow children to play in, or near, flood waters.
• Avoid entering flood waters. If you must, wear solid shoes and check depth and current with a stick.
• Stay away from drains, culverts and water over knee-deep.
• Don't use gas or electrical appliances which have been in flood water until checked for safety.
• Don't eat food which has been in flood waters.
• Boil tap water until supplies have been declared safe.

 

Community Safety