Engineers responsible for construction or maintenance of flood defences can add a lot of value to these public works at little cost by marking a flood height within the defended area at the level of the adjacent defences, perhaps with a blue paint line on walls and posts.
After publication of the GLC report on Thames tidal flooding, I made this suggestion in a letter to The Times on 14 October 1970. I wrote that 'Borough engineers could have all lamp posts in the streets of the flood plane conspicuously marked with lines at the level of the . . . defences.' My suggestion was not adopted in 1970, perhaps because it was thought alarming for the public, but if I had been asked I would have argued that we should treat the public as adults.
It should be regarded as normal practice everywhere in the world, particularly in the presently planned developments of housing on the Thames flood plain.
Andrew Schofield (F), ans10@cam. ac. uk