Posted on February 19, 2016 · Posted in Blog

There are many companies which say have the ability to prepare a flood risk assessments. From my time as a regulator, it is clear that these assessments vary in standard. The most amusing submission which I reviewed was a one page report, with a sketch of a house and stick man surrounded by wavy lines to represent flooding. I also remember the one which described how they couldn’t use certain pipework, in case the squirrels ate it!


So why is preparing a good flood risk assessment so important? Well, flooding in a natural occurrence, but when you start putting people and property in the way of a flood, it becomes a hazard. Typical hazards include: depth of the flood, velocity of the flow, speed of inundation, duration of inundation, contamination of floodwater, debris and blown manholes. Flooding can therefore create a danger to life. Only 15cm of fast flowing water can knock you off your feet and cars can float in 30cm!

When assessing the risk it is also important to understand the nature of the risk, distinguishing between rare, extreme events and more frequent, less severe events. In some areas it may be impossible to avoid building in areas that are at risk of flooding, but what you still need to do is direct development to areas at least risk.

Flood risk management comes with a degree of uncertainty compounded by the effects of climate change. As demonstrated by the recent floods in the UK, it is difficult to accurately predict the precise location where flooding may occur and what the consequences will be.   However, a good flood risk assessment will attempt to assess flood risk which is specific to your site, rather than using indicative flood extents which are prepared on a strategic scale. When properties and lives can be destroyed by flooding, a high standard of flood risk assessment is essential for any developments, which are at risk themselves or have the potential to increase flood risk elsewhere.

Gaye McKay

Tuil Solutions Ltd

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