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The Thames Barrier

November 9, 2018
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By Paul Homewood

 

 Photograph of the Thames Barrier

The Thames Barrier

 

We looked at the recent CCC report on coastal flooding last week. The Thames Barrier is I guess a useful bellwether for flood trends.

According to the Environmental Agency, there is little discernible trend in the number of closures due to tidal causes, as opposed to fluvial ones. (The exceptional number of closures in 2013/14 coincided with heavy flooding up stream during that winter. Barrier closure is designed to avoid making that worse by keeping the high tide out).

There were relatively few closures in the 1980s, but there is no obvious reason for this. It may just be that weather forecasting was not as reliable then to provide adequate notice.

 201802_ALL_TB_Closures_by_Flood_Season

https://www.gov.uk/guidance/the-thames-barrier

 

Exceptionally high sea levels rely on the coincidence of high astronomical tides with storm surge. As such, these events are fortunately extremely rare. Nevertheless EA data shows that the ten highest sea levels recorded at Sheerness, in the Thames Estuary, all occurred in 2005 or earlier.

The figures do only go up to 2012, so presumably the North Sea surge of December 2013 should also appear on the list.

Nevertheless there is nothing in the data to suggest that rising sea levels are a problem there.

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https://www.ntslf.org/data/hilev?port=Sheerness

The EA’s Thames Estuary 2100 Plan also looked at daily peak surges at Southend, and came to similar conclusions:

 

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https://www.gov.uk/government/publications/thames-estuary-2100-te2100

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12 Comments
  1. Don B permalink
    November 9, 2018 3:19 pm

    The detrended UK sea level shows no trend. That is, there is no acceleration of sea level from human activity.

    https://www.ntslf.org/products/sea-level-trends

    • Jack Broughton permalink
      November 9, 2018 3:53 pm

      Will look out for this report on the BBC tonight …. …. maybe not!
      The Fear-campaigners use the well proven Goebbels / Religion method of repeating the lie until the plebs believe they must be true. The models say that we are about to drown, so the measurements must be wrong.

  2. Chris Lynch permalink
    November 9, 2018 4:20 pm

    To be filed under inconvenient facts and never to see the light of day again.

  3. It doesn't add up... permalink
    November 9, 2018 6:55 pm

    There appears to be a very interesting level guage on the opposite bank, with some black and grey bands to mark the depth set into some red brickwork.

    Oh no, It’s a block of flats!

  4. November 9, 2018 8:40 pm

    Hmmm…

    I thought the EA had the budget and UKMO/IPCC manufactured justification for build a series of taller flood defences all out the Thames estuary to save London from Global Warming and their mates from having to work for a living.

    I have been following this since 2012 and the emphasis in promotion of the scheme has morphed from CAGW sea level panic to protection from tidal surges – damn … I should’ve waybacked a lot of stuff regularly over the last 6 years..

    These documents explain the plans for managing tidal flood risk in the Thames estuary to the end of the century and beyond. They look at out how the Environment Agency will protect 1.25 million people and £200 billion worth of property from tidal flood risk.

    is quite simply NOT how I recall the scheme being presented a few years ago.

    The revision history of the document linked above doesn’t tie with my recollection over the years. The early document had nothing that I recall about tidal surge frequency or even planned heights of defenses calculated from the scary sea level rise – all that sort of designy – engineery stuff was referred to as being part of the “TE2100 Technical Document” – which never actually materialised on the EA’s project web presence – but is now it seems integrated in part into the main PR effort.

    It has the telltale signs of a boondoggle.

  5. November 9, 2018 9:00 pm

    The EA volunteered that their plans factored in their interpretation of UKCP09. (p27 / p28 for scary graphics and the IPCC)

    There some quaint activist outfit logos that are past their sell by date scattered around.

  6. lapogus permalink
    November 9, 2018 9:17 pm

    The 1980s (and the 1970s) were relatively dry decades north of the border, and may also have been in southern England. Hence many were surprised by the 1990 & 1993 floods on the Tay. The 1993 peak flow at Perth was 2200m3/s, which probably would have been at about 2700m3/s had it not been for the Rannoch & Tummel hydro schemes being able to impound water until the Dochart/Lyon/Tay peak wave had passed. Needless to say, the younger SEPA hydrologists (and older management) were quick to blame global warming, despite the fact they only had 10 or 20 years of data from a few upstream gauges. The senior hydro-electric engineers were not surprised by the 1993 flood, as they remembered the big rainfall and rapid snow melt events in 1947 and 1963. There have since been 2 floods on the upper catchment similar or greater in magnitude to 1993. And one of them (2006) was only a foot or so from reaching the top of the new flood defences at Perth. The 1993 Perth flood peak was also exceeded by at least 2 historic flows. And also by historic flows on the Tyne at Hexham in and also on the Findhorn in Moray (both with much smaller catchments than the Tay). So I fear we are overdue for a proper flood on the Tay, which we have not had for 100 or 200 years now.

    • Ben Vorlich permalink
      November 9, 2018 10:04 pm

      I remember some cold and very wet summers in Perthshire in late 1960s early 1970s. Grouse beating on Drummond Estate and getting soaked every day. As you say it was drier in the 1980s. I can’t remember which year but it was probably about 1969 and several rivers flooded into areas that I can’t remember them doing before or again upto the mid 1990s. The North and South Inch in Perth are areas you’d expect to be under water in most years winter/spring. Man’s activities upstream will have a greater impact than any supposed man made climate change.

      • lapogus permalink
        November 10, 2018 9:23 am

        Yes, but don’t fall for the current enviromentalist fallacy that different land use and ‘re-wilding’ upstream can mitigate extreme floods. This is maybe true with intermediate events, for example with summer thunderstorm floods on small catchments passing through urban areas, but in big river systems like the Tay, extreme floods only happen after a week or two of heavy rain and considerable snow melt, and the upstream catchment soils are already soaked to 100%, and in the water will find its way around every obstacle no matter what. And with big events on the Tay, it is best to get the water down the fast flowing tributaries as fast as possible, and use hydro to impound and slow the Tummel down, so the flood peak at Perth is stretched and flattened as much as it can be. This isn’t always possible depending on how fast the rain front is moving across the country, how cold it is (which can result in different snow melt rates in low-level and high-level catchments), and there is always the possibility that the flood peak gets to Perth just at High tide, which can add a foot or two to the river level. It is complex, but maybe not too complex to be modelled, which I don’t think has ever been done. Yes, the north and south inches would naturally flood each year or two, if it wasn’t for the new flood defences. If I lived in Perth what I would fear is a repeat of the extreme floods; in one historic account I read, trees and logs were being washed down what is now Dunkeld Road.

  7. Nigel Sherratt permalink
    November 9, 2018 9:39 pm

    https://www.ntslf.org/data/realtime?port=Sheerness has historic information as well as current (‘Custom dates’). 6 December 2013 was half way up my garden so I keep an eye on it. It shows just over 7 meters at about 2am that morning with a 1m surge. Luckily the predicted tide was only 6m. We are due 6.3m next year so it will be a close run thing if that is combined with a 1m surge! Subtract 2.9m to get OD so 7m above chart datum is 5.1m AOD. Chart datum is roughly the lowest predicted astronomical tide without weather effects.

  8. Nigel Sherratt permalink
    November 9, 2018 9:42 pm

    Ooops, 7m – 2.9m = 4.1mAOD of course!

  9. dennisambler permalink
    November 10, 2018 11:21 am

    The things they say….

    March 2004: The UK government’s chief scientist, Sir David King, has repeated his controversial remarks that climate change poses a bigger threat than terrorism

    http://news.bbc.co.uk/1/hi/uk_politics/3584679.stm

    “Terrorism was a very serious threat,” he said.

    But climate change could bring disaster to the world.

    “If we don’t do enough there could be floods every few years causing tens of billions of pounds worth of damage in the south of England,” he added.

    Sir David believes that a second Thames barrier needs to be built within the next 20 years to protect the city from rising flood waters.”

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