Flooding—flood risk statistics
Produced in partnership with Jill Boulton of JBA Risk Management Limited
Flooding—flood risk statistics

The following Environment practice note produced in partnership with Jill Boulton of JBA Risk Management Limited provides comprehensive and up to date legal information covering:

  • Flooding—flood risk statistics
  • Properties currently at risk
  • Is flooding really becoming more frequent? What is the evidence?
  • What are the factors contributing to it?
  • Climate change
  • Land use
  • What about the future?

Flooding—flood risk statistics

Properties currently at risk

1.4 million properties in Great Britain are at risk from river flooding and up to three times that number from surface water flooding. Add to that the approximately 98,000 properties that could be deluged by the sea—not counting all those that would flood if the sea came over and beyond the defences (as occurred during Storm Xaver in December 2013) and it is clear that the UK needs to take flooding seriously.

Is flooding really becoming more frequent? What is the evidence?

The river gauge data from JBA's Great Britain event set, which covers the period from 1960 to 2008 shows some interesting trends. All the events with a return period of at least 10 years at a minimum of one gauge were counted, for each year of the analysis period, and they are increasing in number (Figure 1). So within that time period, flood events became more frequent and this trend continues.

What about the severity of the events? Has that increased as well? To get an idea of that, we looked at the number of events each year with a return period of either 25, 50 or 100-years and calculated for each, what percentage they made up of the total number of events that year. Yet again, the trend shows that the proportion of higher return period events is gradually

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