In the early 19th Century the River Thames was practically an open sewer, with disastrous consequences for public health in London. Proposals to modernise the system had been put forward in 1856 but were shelved due to lack of money, but after The Great Stink of 1858, Parliament realised the depth of the problem and resolved to create a modern sewerage system.

Civil engineer and Chief Engineer of the Metropolitan Board of Works, Joseph Bazalgette was given responsibility for the work. He designed an extensive underground sewerage system which diverted waste to the Thames Estuary downstream of the main centre of population. Six main interceptory sewers, totalling almost 100 miles (160 km) in length, were constructed, some incorporating stretches of London's 'lost' rivers. Three of these sewers were constructed north of the river, the southernmost, low-level one being incorporated into the Thames Embankment. The Embankment also allowed the construction of new roads to reduce traffic congestion, the creation of new public gardens, and works on sections of the London Underground railway system.

The interceptory sewers, constructed between 1859 and 1865, were fed by 450 miles (720 km) of main sewers that, in turn, conveyed the contents of of some 13,000 miles (21,000 km) of smaller local sewers. Construction of the interceptory system required 318 million bricks, 880,000 cubic yards (670,000 m²) of concrete and mortar, and excavation of over 3.5 million tonnes of earth.

Gravity was used to allow the sewage to flow eastwards, but in places (eg: Chelsea, Deptford and Abbey Mills) pumping stations were built to raise the water and provide sufficient flow. Sewers north of the Thames feed into the Northern Outfall Sewer which feeds into a major treatment works at Beckton. South of the river, the Southern Outfall Sewer extends to a similar facility at Crossness.

In the 20th Century major improvements were made to the sewerage system, to reduce pollution of the Thames Estuary and the North Sea.

The London sewer system plays a large part in English writer Neil Gaiman's 1996 novel Neverwhere.

External links

• Tales of the underworld from The Guardian Wednesday March 30, 2005

References

Trench, R. and Hillman, E. (1984) London Under London: A Subterranean Guide (London: John Murray).