Thursday, 23 August 2012

From drought to flood – An Olympian Summer for hydrological change

Just four months ago more than ‘half of Britain was in drought’ with the UK facing its most severe water shortage since 1976. The Environment Minister was urging households to cut back on the amount of water they used, some rivers in England were at their lowest April levels for 36 years, and your correspondent was quoted in the Guardian stating “This [the late April rain] is not the solution for the deep aquifers which have been at some of the lowest levels ever recorded. We are still looking at next winter rainfall to recharge these.”

As many of you will have noticed the driest March in the UK for 59 years was followed by the wettest April in 101 years. The accumulated rainfall since then has been remarkable. In the four months from the beginning of April to the end of July rainfall amounts were the highest on record (from 1910) by a considerable margin in almost all regions of Great Britain, and provisionally the highest in the England & Wales rainfall series from 1766. Groundwater resources have recovered to levels that expert hydrologists and geologists had thought wouldn’t occur until the end of a (hopefully wet) winter 2012-2013. All hosepipe bans in southern England have been lifted and although groundwater levels remain low in slowly-responding parts of the Chalk and the Permo-Triassic sandstone, our most recent monthly Hydrological Summary for the UK was able to confidently state “The transformation in water resource status since early April is without any close modern parallel.”

Back in early May I was also asked by John Vidal of the Guardian to comment on what may happen if the ‘monsoon’ like conditions in April continued. My words, reproduced in the next day’s paper, were, "If it carries on like this for another few months things may improve [from a hydrological point of view]. But by then we will all be totally fed up." My prophecy was partially correct, the rain did carry on, and things did improve, but as far as I can tell, we’re not all totally fed up, perhaps thanks to an amazingly successful Olympics! Oh well, I suppose two out of three isn’t bad!

Barnaby Smith

April to July 2012 UK River flows

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