This is no longer exactly news, but for anyone who missed it the centre of Herne Hill disappeared under waist-high water on 7th August when something bad happened involving the water main and/or the drains. All the shops and the pub at the Half Moon junction were flooded, and the water tore up the road surfaces, brought down street lamps and left a thick layer of sediment behind.
The flood was of course a disaster for the businesses involved, a real shame because many of them are fine local establishments. It is also a historical curiosity. Nowhere in all the coverage have I seen any mention of the real force behind the catastrophe, the River Effra.
Herne Hill is on the course of the Effra, which buried along its entire course from Crystal Palace to the Thames at Vauxhall. The river flows below Burbage Road to Half Moon Lane, where it turns west and crosses the junction with Norwood Road and heads along Dulwich Road towards Brixton. The flood occurred at the low point around the junction which, until the 18th century, was called Island Green and was surrounded by river water. This is a particularly crowded junction, where five major roads meet along with the railway line, not to mention a lost river. This part of Herne Hill, despite the name, is a low point in a ridge running across south London, and therefore the easiest crossing place for everything and everyone passing through the area.
It is not the first time Herne Hill has found that although London's rivers may be buried, they are very much still there. The basements of houses along Half Moon and Dulwich Roads flooded often until the Effra Storm Relief Sewer was built in 1984. The water came back around ten years ago, a flood blamed on blocked drains. This time it is not clear what caused the flood: reports talked about a burst water main, but apparently taps in nearby houses still worked. It is likely that the drains around here overflow easily because of the volume of river water flowing through Herne Hill. Maybe this time Thames Water will sort it out. The mouth of the Effra at Vauxhall is the location for the oldest recorded signs of human habitation found in London. A mere 7000 years later, the Effra came back for a morning.