London's flood risk (Supplementary) [1]

Session date: 
February 26, 2014
Question By: 
Jenny Jones
City Hall Greens
Asked Of: 
The Mayor


I am glad you have said that because obviously there are several aspects.  As you say, we have talked about river restoration before, which is an important component.  There is also the fact that the Thames Barrier has been closed 40 times already this year and it was always imagined it would only ever open 50 times a year, so it has already opened almost that many times.  Have you met with the Environment Agency or anybody to discuss whether or not we need to bring forward plans for a review of whether we need a new Barrier, whether we have to work downstream on the Thames or whatever?

Supplementary To: 


Answer for London's flood risk (Supplementary) [1]

Answer for London's flood risk (Supplementary) [1]

Answered By: 
The Mayor

Yes.  The answer is yes, Jenny.  I do want a review of the Thames Barrier.  It is absolutely fascinating how it has functioned in the last few months and how it really has prevented huge potential damage in London in ways that I do not think its authors conceived of.


Jenny Jones AM:  That is the whole point.


Boris Johnson (Mayor of London):  What it has done is it has stopped the aggravation of the problem by stopping the tidal waters coming in at the same time as the fluvial waters are coming down.  It has turned the Thames in London, which is heavily embanked now, into a gigantic sump, which has prevented considerable damage.


Jenny Jones AM:  That is my point, really, because it ‑‑


Boris Johnson (Mayor of London):  My information is that the Barrier is good, Jenny, for another 75 years.  However, clearly, as you rightly say, in view of the many times that 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.


Jenny Jones AM:  I am glad.  That figure of 75 was obviously done on previous forecasts and those previous forecasts now look as if they might not be quite accurate.


Another aspect to avoiding flood risk here in London is the whole surface water issue and the fact that we have so many paved areas.  Your own London Plan says there will be an increased risk of surface water flooding.  I am wondering what you are going to do about that.  Are you going to have some sort of Mayoral announcement that would encourage people not to pave over any more land and to put permeable surfaces in or find other ways to make themselves safe?  People do not understand the risk they are putting themselves under when they start paving their gardens and so on.  All developments, of course, ought to have permeable surfaces.


Boris Johnson (Mayor of London):  Yes.  You are absolutely right.  Through the Drain London programme and working with the boroughs, we are encouraging people to understand the potential risk.  If you go down to the A22 where there was considerable flooding, basically the Caterham Bourne burst its banks and came out of the culvert.  You could see so clearly how the water was coursing on pavements, on tarmac and on bits that had been lost to natural drainage.  Therefore, it is very important that we encourage people not to concrete over their front gardens if they possibly can, to think of drainage schemes and, yes, to plant more trees and to deculvert rivers in the way that we are.


Jenny Jones AM:  Could you also push the boroughs to produce all of their surface water flood risk plans?  There is a bit of a lag there.  They have all undertaken to do them but they have not, actually.


Boris Johnson (Mayor of London):  They have a statutory obligation to do so and I will certainly take it up with Jules [Pipe, Chair, London Councils] and with London Councils to ensure that they are.