Change Alley

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Monsoon Britain

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monsoon britain

Prepare for more floods. Last summer was the second wettest on record and experts who have studied over 250 years’ worth of rainfall and river flow patterns say we must prepare for worse to come. Professor Stuart Lane, from Durham University’s new Institute of Hazard and Risk, says that after about 30 to 40 less eventful years, we seem to be entering a ‘flood-rich’ period. More flooding is likely over a number of decades.

Prof. Lane, who publishes his research in the current edition of the academic journal Geography, set out to examine the wet summer of 2007 in the light of climate change. His work shows that some of the links made between the summer 2007 floods and climate change were wrong. Our current predictions of climate change for summer should result in weather patterns that were the exact opposite of what actually happened in 2007.

In looking at longer rainfall and river flow records, Prof. Lane shows that we have forgotten just how normal flooding in the UK is. Seasonal rainfall and river flow patterns dating back to 1753 suggest fluctuations between very wet and very dry periods, each lasting for a few years at a time, but also very long periods of a few decades that can be particularly wet or particularly dry.

In terms of river flooding, the period since the early 1960s and until the late 1990s appears to be relatively flood free, especially when compared with some periods in the late 19th century and early 20th Century. As a result of analysing rainfall and river flow patterns, Prof. Lane believes that the UK is entering a flood rich period that we haven’t seen for a number of decades.

“We entered a generally flood-poor period in the 1960s, earlier in some parts of the country, later in others. This does not mean there was no flooding, just that there was much less than before the 1960s and what we are seeing now. This has lowered our own awareness of flood risk in the UK. This has made it easier to go on building on floodplains. It has also helped us to believe that we can manage flooding without too much cost, simply because there was not that much flooding to manage.

“We have also not been good at recognising just how flood-prone we can be. More than three-quarters of our flood records start in the flood-poor period that begins in the 1960s. This matters because we set our flood protection in terms of return periods – the average number of years between floods of a given size. We have probably under-estimated the frequency of flooding, which is now happening, as it did before the 1960s, much more often that we are used to.

“The problem is that many of our decisions over what development to allow and what defences to build rely upon a good estimate of these return periods. The government estimates that 2.1 million properties and 5 million people are at risk of flooding. In his review of the summer floods Sir Michael Pitt was wise to say that flooding should be given the same priority as terrorism.

“We are now having to learn to live with levels of flooding that are beyond most people’s living memory, something that most of us have forgotten how to do.”

Durham University news release

Institute of Hazard and Risk Research web site

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Written by Pete Smith

May 9, 2008 at 10:51 am

3 Responses

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  1. “Prof. Lane believes that the UK is entering a flood rich period that we haven’t seen for a number of decades.”

    That should stifle a few barbecues and patio heaters then.

    Even so, there will still be a hose-pipe ban. 🙂

    Seriously though, floods have a devastating effect but UK floods are no comparison to those in places like Indonesia.

    Earthpal

    May 9, 2008 at 9:53 pm

  2. “UK floods are no comparison to those in places like Indonesia”

    Absolutely, and I wouldn’t dream of trying to equate ghastly disasters elsewhere with a few square yards of ruined Axminster in the Thames Valley. However, the Prof has some valid points about perception of risk. One wonders how the Burma cyclone is seen on the ground; a once in a lifetime event, or a logical progression of past weather events.

    Pete Smith

    May 9, 2008 at 11:43 pm

  3. Interesting study Pete. Flash flood near Swansea over the weekend but as London was enjoying its first real warm sunshine of the year, it hardly got reported.

    Matt (the water rat)

    May 13, 2008 at 7:12 am


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