Skip to content

Somerset Floods – Rainfall Was Not Unprecedented, So Why Did The Levels Flood?

January 13, 2016

By Paul Homewood     

 

image_thumb19

 

I mentioned about progress on the Somerset Flood Action Plan last week. We have not had any rainfall anywhere near as much as the winter of 2013/14 since, so it is difficult to say whether the Plan will totally solve flooding problems.

But a look at the local rainfall records reveals that the area has had similar or greater amounts of rain as 2013/14 on several occasions in the recent past.

First though a quick recap.

 

 

The floods in Somerset two years ago followed about a month of heavy rain. In other words, they were not flash floods. The rain began in earnest on Dec 5th, following a dry November, when rainfall was more than 40% below average.

By early January, there was talk of “unprecedented” flooding, which progressively became worse as heavy rain continued through January, peaking in early February.

 

The Met Office publish weather data from Yeovilton, the RAF base 5 miles north of Yeovil and close to the Somerset Levels. This only has data back to 1964, so unfortunately misses some of the really wet periods in earlier decades.

 

image_thumb21

 

The rainfall data in 2013/14 was:

 

  mm
Nov 2013 42.9
Dec 2013 121.4
Jan 2014 166.4
Feb 2014 131.2

 

 

As we can see from the Top 20 analysis below, even the January figure was not a record, having been beaten in October 1976 and November 2002, and effectively tied in December 1989.

I have only included the “Winter Six Months”, from October to March, on the basis that heavy summer rainfall is quickly absorbed, evaporated or carried away with a low water table and river levels.

 

 

image

http://www.metoffice.gov.uk/pub/data/weather/uk/climate/stationdata/yeoviltondata.txt

 

Bear in mind that we saw “unprecedented” floods even after the December rainfall of 121.4mm, which was certainly not an unusually high amount.

Of course, heavy rainfall continued throughout January, so are the two-month rainfall numbers in any way unprecedented? In fact, not.

The wettest two month spell was Sep/Oct 1976, when 339mm fell, compared to 289mm in Dec/Jan 2014. Of course, after the dry summer of 1976, the flooding potential may have been reduced in that year. But we also find rainfall of 335mm in Oct/Nov 2002, a time of year when Somerset has often suffered flooding.

But perhaps most comparable was Dec 1989/Jan 1990, when 270mm fell, nearly as much as two years ago. If we compare the rainfall series for the two, we get close similarities:

 

mm 1989/90 2013/14
November 48 43
December 166 121
January 104 166
February 133 131

 

According to the Met Office monthly report for December 1989, the weather was largely dry up to the 11th, when a series of storms set in, bringing the worst flooding in years at Plymouth on the 16th.

In other words, the rainfall in December 1989 was much more intense than we had in December 2013, which brought “unprecedented” floods to the Somerset Levels. Into January and February, we find that the cumulative rainfall was only marginally greater in 2014.

 

The Somerset Levels have always been prone to flooding, and certainly would not have escaped in 1990. However, it is evident that the flooding problems of 2013/14 were much more severe than would have justified by the rainfall amounts on their own.

Of course, in 1990 the rivers were still being dredged and the pumping stations kept operational.

Either way, it is clear that “climate change” had nothing to do with the floods at all.

One further question – why did we hear none of this at the time from the Met Office?

8 Comments leave one →
  1. Bloke down the pub permalink
    January 13, 2016 1:11 pm

    The air base at Yeovilton is the Royal Navy air station HMS Heron.

  2. Ian Magness permalink
    January 13, 2016 2:10 pm

    In answer to your closing question, it’s because Julia Slingo has decreed that anything that happens now is due to “climate change”, whereas anything similar in the past was just due to unseasonal “weather”, which we can therefore just ignore.

  3. January 13, 2016 4:13 pm

    Can’t help but notice where the castle was built. What did they know?

  4. john cooknell permalink
    January 13, 2016 8:35 pm

    If you reclaim land from the sea by draining, pumping and dredging, and then you stop draining, pumping and dredging, then the sea will claim the land back.

    The EA experts say that dredging is not the always the answer, there are other solutions, but what the EA experts chose to do was nothing at all so the land flooded.

    • johnmarshall permalink
      January 14, 2016 11:01 am

      Unfortunately most flood mitigation methods creat paths for water to flow into new unflooded areas so making the problem worse. Dredging is the only answer to clear water away to the sea.

  5. January 14, 2016 8:24 am

    The real time monitoring (via radar and level gauges) of precipitation and watercourse flows is entirely do-able at sensible cost (NOT if the EA do it though!) . It is abundantly clear that public servants for a variety of reasons are choosing to lie and obfuscate evidence.

    I’m given to understand that the EA have rain gauge assets that they do not publicly expose. At the time of the flood episode I requested rainfall records for Bristol AIrport which apparently has a rain gauge – this was blocked….

    The EA has a “temporary” chairperson in the shape of Emma Howard Boyd who is sponsored by prominenteco activist NGOs (+ “charities”) like Greenpeace, WWF-UK, Friends of the Earth and Comic Relief who have proven themselves serially cavalier with claims and evidence about the climate.

    The carnival of unequivocal lies, misattribution of events and larceny of public funds looks set to keep rolling on – great eh?

    • johnmarshall permalink
      January 14, 2016 11:18 am

      The EA has a habit of quoting rainfall from the wrong catchment. I did a study of the 2004 Boscastle flood and used the rainfall figures from a local farm, which gave high readings. The EA used an “official” guage from a separate catchment which were much lower. Mitigation measures were based on the lower rainfall figures.

      • January 14, 2016 9:12 pm

        The EA are funda-mentally arithmetically challenged – there is a cottage industry of water consultants making a tidy living either challenging their wonky arithmetic or actually producing wonky results as dictated by the bent goons in middle and senior management.

        In a flood risk analysis locally – the EA decided that one hydro scheme must be presented an “increased flood risk”. The sim ran for “with scheme” and “without scheme”.

        The simulation results (unvalidated) – showed a small increase in water height at low flows when the weir was functional and no flooding was occurring but an insignificant or non-existent difference when the river levels/flows attained “flood / drowned weir” full spate conditions.

        This result was portrayed in reporting and official documents as a negative factor of “increased flood risk” in the decision matrix for the water abstraction license.

        I don’t think they actually care that people deeply resent their institutional mendacious-ness and hold many aspects of their operations in utter contempt.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: