From overflowing rivers in North Queensland, flash flooding across parts of NSW, VIC and in Hobart, record rainfall in Canberra and last summers’ flood catastrophe in Townsville, floods are become more and more common across Australia leaving behind severe damage and devastation.
Most of the losses in previous events have occurred in areas known to be flood exposed, so why are we surprised when the flooding rains come? In fairness, our knowledge of flood exposures is far from complete. Local councils and other statutory authorities have been reluctant to invest their resources in accurate flood mapping, either through lack of resources or a fear of opening the door to expensive litigation. This leaves property owners and occupiers often ignorant of the magnitude, if not the potential, of expected floods.
Exposure
Understanding the flood exposure for a particular location is the key to determining the risks. Flood maps are available for many Australian towns and cities but they are often difficult to find and access. Start with your local council, they often hold the information or know where to get it.
Key to understanding the flood exposure to a property is the nature of the flood risk. Is the risk from stream or riverine flows that result from a watercourse breaking its banks and flowing through the property? This brings with it the risk of high water velocities and the chance of severe structural damage or undermining of foundations. If the risk is from inundation from overland flows or backing up of drains or small tributaries, then the risk is more likely to be limited to water damage, still a significant source of loss.
Flood risk is usually presented as flood return intervals, given as heights on a map or against a known datum. Just be aware, a one-in-one-hundred flood risk does not mean one flood every hundred years. The probability of a second flood in the same year, or the next season, is independent of the flood history. Climate change modelling, and recent experience, is suggesting that Australia can expect so called one-in-one-hundred events far more frequently, perhaps more like one in 20 years.
A key facet of flood exposure is timing. With enough warning it is often possible to mitigate many of the impacts of a flood. Riverine floods can often take days to move downstream but flash flooding can occur with no warning, giving no opportunity for a considered response. Therefore, when assessing your flood risk, consider the type of flooding and the likely warning available.
Risks
The risks of flood damage may appear obvious but water damage to stock and equipment is only part of the story. Other impacts can be to the building itself, ranging from swelling plaster and particle board to structural collapse (through damage to foundations or physical displacement of the building). Other areas of exposure are services such as sewerage, water, power and telecommunications. In many cases the site may not be flooded at all but significant damage and business interruption can occur through inability to access the site or interruption to power or other services.
Mitigation
The best defence against flood is careful site selection. When purchasing or leasing properties, the risk of flood should be considered, and the cost savings sometimes realised in flood affected locations should be weighed against the potential risk. If relocation is not an option, then preparation is the key. A well-developed flood plan can be very effective, particularly if the plan is well thought out in advance and resources are set aside. Effective flood planning can be as simple as considering an orderly evacuation, preferably with enough time to gather critical business records.
When more time is available, it is possible to put some effective controls in place. This can range from sand bagging and elevating stock through to wholesale relocation or installing purpose designed flood barriers. Constructing levies and flood walls to protect individual properties is rarely practical with constraints of space, regulation or the impact on neighbouring properties.
Recovery
After a flooding event, time is critical. Water and humidity can cause ongoing damage and the priority should be to remove water and mud from the property as quickly as possible. Dehumidifiers and/or ventilation fans can assist. For best results call on the experts and get a professional salvage and recovery provider on board. The costs of this service will be more than offset by the savings in damage and reduced recovery time in most cases.
The key to business survival in a flood situation is preparedness and planning. Consider the risk and, if the threat impacts your business, Plan, Plan, Plan!
Mitigation measures:
- Sand bagging doors and openings
- Establishing pumping systems (and a place to pump to)
- Raising stock and equipment off the floor
- Removing or relocating computer and electrical equipment
- Waterproofing fixed equipment
- Contact your business salvage provider.