Record Closures Cause Concern for Thames Barrier’s Future

Only two short of annual recommended limit after Tuesday’s closure

The closure of the Thames Barrier this week to protect the tidal Thames area from flooding was the 48th so far this year. The recommended annual limit is 50, a figure which it has exceeded over the last twelve months. Over a quarter of the closures in the barrier’s 32 year history have been made this winter.

Speaking to the BBC, an engineer said that the repeated closures are causing stress on the system, but that there were a number of fail safes in place should the machinery stop working.

Previously it had been expected that a replacement for the Thames Barrier would need to be put in place sometime after 2030 but Jenny Jones, a Green party representative for the Greater London Assembly is arguing that improved flood defences should be investigated immediately. Mayor Boris Johnson has also called for a review of the Thames Barrier. He said, "My information is that the barrier is good for another 75 years, but in view of the many times it has been in operation and continues to be in operation over the last few weeks and months it is only prudent to have a full review of its operations."

The Thames Barrier is closed under storm surge conditions to protect London from flooding from the sea. It may also be closed under periods of high flow over Teddington Weir to reduce the risk of fluvial (river) flooding in some areas of west London including Chiswick and Putney. Dangerous conditions can be forecast up to 36 hours in advance using the Storm Tide Forecasting Service at the Met Office and information from the barrier's own computer analyses.

The graph above shows that the Thames Barrier has been raised 168 times since it became operational in 1982 up until the end of February since which time there have been further closures. During its operation, over three quarters of closures have been since 2000. It was closed four times in the 1980s, 35 times in the 1990s, and 100 times since 2000. In January 2014, the Barrier was raised on 13 consecutive tides to protect people and property as high fluvial flows and high spring tides coincided.
In February 2014, the Thames Barrier was closed on a record 20 occasions due to very high fluvial floods. There were 27 closures in the month, bringing the winter total to 44. Over 25% of all flood defence closures since the Thames Barrier became operational in 1982 have been during the winter of 2013/14.

The Environment Agency are saying that the recent increase in closures should be seen as an anomaly due to the wettest winter for 250 years. He said, "It might be that this year we do twice as many closures but next year could drop to 10."


March 7, 2014

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