At the Brockwell Lido plaque there is an information board which begins by explaining the function of stink pipes:
"What is a stink pipe?
The lofty green pipe behind you is a Victorian stink pipe, a hollow pillar built to allow noxious (and smelly) gases to escape from underground sewers into the air, high above our heads. Often unnoticed by passers-by, stink pipes ensured that gases didn’t build up to dangerous pressures in the sewage pipes below.
The ‘lost’ River Effra
Stink pipes such as this one can be found along the course of the ‘lost‘ River Effra, which flowed from springs in West Norwood and Dulwich, passing Herne Hill and meandering through Brixton and Kennington before emptying into the Thames at Vauxhall. The once sparkling Effra was heavily polluted by people and factories until it eventually became an open sewer. The contaminated river was incorporated into the Victorian sewer system in the 1860s. Now the stink pipes are the only remaining signposts to mark where the river flows beneath the streets of Lambeth and Southwark."
The board goes on to explain that while the river has gone, its valley remains and exacerbates flooding in the area. People are encouraged not to pave their gardens. We applaud the message and all the work that is being done on this problem.
For the route of the Effra see Turney and Burbage.
Diamond Geezer has a very informative post about the plaques that mark the route. We haven't found them all. Do let us and DG know if you find any more.