Three years ago the BBC made a short film warning that flooding in Paris was inevitable and they have been proved correct. The last time the Seine rose to such high levels was in 1910 and, although it didn’t burst its banks, the flood spread through tunnels, sewers and drains causing much damage.
Paris is again threatened by a high volume of water coming down the Seine after heavy rainfall. On the Pont de l’Alma there is a statue of a Zouave (a French soldier from North Africa) which is used as a rain gauge. Today’s crue is similar to 1910.
London has the same threat and the additional problem that the Thames is tidal as far west as Teddington. It’s not frightfully British to be prepared but in this case we are. In the 1970s the decline of the Port of London as a major commercial port made it practical to build a flood barrier. It was completed in 1982 and protects London from high tides and storm surges coming up the Thames from the North Sea. Of course the banks below the barrier had to be raised to prevent flooding downstream.
When there is heavy rainfall west of London the water escapes over Teddington weir but if this coincides with high tide the combination of flood and tide would make flooding in London likely. When this happens the barrier is closed until the tide has gone down. Towns further upstream are not so fortunate and in recent years have suffered serious floods.
The biggest threat to London flood-wise is that a vessel collides with the barrier putting it out of action. This has not happened since 1997 when a dredger ran into one of the ten piers in thick fog. It took about a month to refloat it.
