Identifying the risks of flooding and preventing the ensuing damage is becoming crucial in these times. As climate change progresses, unpredictable extreme weather conditions will continue to occur throughout the world, more frequently and with greater intensity. This means that events, which not long ago would have been considered disastrous, once-in-a-century phenomena, are now expected to happen once every 10 years. And fatally most of our flood prevention infrastructures apparently will be topped quite frequently in the future.
This also includes identifying the risks of sudden inundations - which are increasingly impacting formerly unaffected areas. Precious, idyllic locations are being swamped and devastated in a matter of moments - by unsuspected forces causing enormous damage, even claiming lives during and after the event. Nature makes no distinction.
Not perceivable - not predictable
The particular feature of this kind of danger is that it is not perceivable beforehand nor is it predictable in a wider time context. Both factors are fatal for people: firstly, they feel safe, when actually they are not. Secondly, if they start to prepare when the catastrophe literally appears on the horizon, for many of the precautions it is too late.
Flood risk is not restricted to shores of rivers and large rivers
It is important to recognise what many do not yet: the risk of flooding is not restricted to shores of rivers and large bodies of water and the range of affected regions is rising.
Through various means and the interaction between nature and topography, life-threatening inundations can arise more quickly and with more devastating power than one would imagine: even the smallest of brooks can become a torrent in the shortest space of time. In this way, tiny streams, hollows, dips, trenches, and of course slopes can, in the worst-case scenario, become sources of destruction. Moreover, many other dangers ripple concealed through subterranean passages, or one considers them – wrongly – to be at a safe distance.
Where present, the intention and function of preventive infrastructure, such as dams and dikes, certainly is to reduce damages and losses. Still nothing is absolutely safe.
Consequently, proactively taking one’s own additional protective measures that are targeted and individually adjusted to the situation and needs of both the location and the building makes a great deal of sense for most homes, developments and public buildings. In simple terms: what experts have already figured out is that advance planning and precautionary measures are the best protection.
After heavy rainfall, levels of small bodies of water can suddenly rise dramatically to many times above their average. The time span between the emergence and the occurrence of the flooding is usually very short, as is therefore the time available for advance warnings. This means those disasters can occur at very short notice or without any warning whatsoever.
Also, prolonged periods of rainfall, snow or melting ice can have a marked influence on large rivers. Generally, their water levels do take longer to rise, meaning there is more scope for advance warnings. The causes of high waters are manifold; they can occur together and reinforce one another. These causes and risks include storm surges and the overflow of flood control structures. Often dikes, dams, walls, reservoirs or mobile flood control systems come into operation. Particularly now as climate change leads to more extreme natural events, these measures do not necessarily eliminate the threat of flooding for the people living behind them.
The risk potential rises with prolonged periods of high water levels, leading to SEEPAGE WATER seeping through the dike or the protection wall. In cases of higher water levels, dikes and dams can overflow and the areas behind them, which they are meant to protect, can be inundated. More than that, where high flooding levels persist, dikes can even become saturated. In this process, small soil grains are flushed out of the dikes’ interiors. As a result, the dikes lose their stability, which finally can lead to them bursting.
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Heavy rains and torrents are weather phenomena which will occur more frequently in future. They can happen anywhere to anyone, as both do strike autonomously – independently of any stretch of water.
Even at supposed safe distances from bodies of water, flood risks exist, mainly resulting from water draining from the terrain’s surface. Topography plays a key role here – whether it is natural or man-made – as it directs the flow paths of the water. Those flow paths might be slopes, curves, depressions and hollows of any kind (gentle or steep – gradual, deep or smooth). Any house or property situated in such a flow path is in danger of being inundated.
Another danger that heavy rainfalls can create flows from gutters and downspouts (eaves guttering): when they can no longer discharge the water flowing from the roof such that they overflow in an uncontrolled manner, this excess water can enter the building.
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Every public sewer system has a limited water retaining capacity, and those system capacities can be exceeded during extreme wet weather events. Such events cause overloads and blockages in the main sewer lines resulting directly in sewage backing up into basements, or to the sewers overflowing outside onto the streets, and entering houses from there.
These are both very common scenarios and the water damage it creates also involves very unpleasant hygiene Problems.
Want to know how you can prepare your property against the flood danger posed by sewer backwater? Click here
This danger is often underestimated: floodwaters can also emerge through the subsoil and penetrate your property. Usually, such floods are slower, but they can produce more profound and permanent harm due to long lasting wetness, as the water needs more time to fall back to normal levels.
In this, as in many things, it is wiser to ask the right questions before buying the house rather than having to learn from experience. In terms of groundwater damage, it is also important to watch out for slopes, hollows and the proximity to water, as these factors make a property particularly vulnerable. To assess the situation on site, and to find out if there is a history of damage, make sure to ask around in advance in the neighbourhood and to query the local authorities and water associations to find out about any previous damage and the situation on site.
Want to know how you can prepare your property against danger of incoming groundwater? Click here
What you should know about floods.