Tuesday, June 9, 2015

London Sewerage System


Introduction
                The first question that the inquiring reader will ask is what exactly the London Sewerage System is. The simple answer is that it is the extensive sewer system below the streets, houses, and parks of London. This system has been in place for well over a hundred years, and has many complexities. 
The Instigation and Designer
                It was in 1858 that Parliament decided a real sewer system was needed, due to the Great Stink. This event, which took place in summer of the same year, was a horrible stench throughout the city of London. The sewers were open and overflowing, the smell was unbearable, and illness rampaged through the city.
                Sewage had not been a problem in London prior to 1815. It was around that time that flushing toilets were first installed. Prior to that, the only sewerage system needed was to drain excess rain water. As more households got toilets, waste disposal became a bigger issue, culminating in the Great Stink.
                Parliament designated Joseph Bazalgette to design and build sewers throughout the city. Bazalgette was experienced in such matters. He had previously been a civil engineer, and part of the Metropolitan Board of Works. The system he is credited with is complex, but contrary to popular opinion, the ideas were not his alone. He was the man to put action to the words, but not the first to suggest an intersecting sewer system like he eventually built.
The Sewerage System
                The system that Bazalgette put into place was designed to empty into the Thames Estuary, downstream of the populace of London. It consisted firstly of six main sewers, totaling almost 100 miles in length. These were fed by 300 main intersecting sewers (totaling about 450 miles). And in turn, those were connected to around 13,000 miles of local sewers, too small for a man to comfortably enter. Just how extensive the sewers are is still a question considered by some. In the 1870s, 540 miles of them were surveyed. It is not unreasonable to assume that there could be easily 1000 miles of sewers easily accessible to people, and many more that are only comfortable for rats.
                The numbers of this project are immense. A total of 2.7 million cubic meters of dirt were excavated. The system used 318 million bricks. In addition, 670,000 cubic meters of concrete were used to craft the tunnels.
                The tunnels were designed to cope with ¼” of rainfall per hour. Rain in excess of that resulted in sewage and rain water combining, followed by localized flooding and culminating in run-off into the River Thames. Admittedly, this is what Bazalgette’s back-up plan had been – to have the excess overflow into the Thames. However, as time passed and London grew, this became an enormous health risk.
                In 1858, Parliament allotted three million pounds for the construction of the sewer. Total cost was £4.2 million. One source said that 82 miles of the sewer were built parallel to the River Thames, and that there were 1100 miles of street sewers, and many more minor ones. The original sewerage was built to serve 2.5 million people. However, between 1859 and 1865, the years in which Bazalgette was building, London’s population mushroomed, and by the time the project was completed, four million people were occupying the city. [1]

Pumping Stations & the Fleet River
                For the most part, the sewage and run-off rain was pulled eastward by gravity. Bazalgette took that into account as he built. So most of the time, the sewage would move on its own. At times though, it needed to be raised. At those points, Bazalgette placed pumping stations. One of the most prominent stations was the Abbey Mills Pumping Station. It was built on a site where there had originally been a watermill, hence the Abbey Mills name. In modern times, the pumping station function was moved to the next door building. However, the original Abbey Mills building still houses back-up electric motors for the modern system. The B Station was used as the idea for the Arkham Asylum laboratory in “Batman Begins,” the 2005 movie.
                Before the building of the system, the Fleet River ran above-ground. However, Bazalgette built over and around it, turning it to an underground river that doubled as a storm relief sewer. This is officially known as the Fleet Storm Relief Sewer, instituted in 1875. 
The Updated Sewerage System
                As the reader may imagine, the need for a smoothly functioning system has only increased as the population of London has increased. As of mid-2006, the population hovered around 7.5 million people. By the 2012 census, that number had jumped to 8.3 million. Naturally, with the population growing, there was a need for updates.
                Even the 20th century saw major improvements in Bazalgette’s original system. Some parts of it had decayed or become horribly bad. Slowly, improvements were instituted. In the late 1980s and early 1990s, 16 miles of drains were added to the Royal Docks. But more was needed.
                In 2004, the mayor of London allotted £1.7 billion for the required work, totaling over 22 miles worth. It is said that the work will be complete by 2020. However, minor improvements have been added onto it for years, and some sources say that it is now 100 times larger than the original built by Bazalgette.[2] The London sewerage system is now owned by Thames Water.
                One interesting profession related to the London Sewerage System is the people who “professionally” explore the tunnels, going to areas perhaps untouched by human feet since the original construction. Luckily for those of us who have no desire to actually walk in a sewer, some of these explorers are also expert photographers, employing long exposures and special lighting to photograph the beauty of something so basic as a sewer. Contrary to what the reader may assume, sewers can be lovely as these photographers prove.[3] Find photographs and information at the link at the bottom of this page. 
Conclusion
                The London Sewerage System is a vital link in the chain that holds London together and keeps it running well as a city. Bazalgette’s dedication and hard work resulted in a smoothly functioning system that works, even 150 years later. Further updates are in progress, and more are being discussed; the London Sewerage System will likely only continue to improve as the years progress. 

[1] Note: One source claimed that the work was not finished until 1868. While this is possible, the widely accepted date for completion is 1865.
[2] This author finds this number rather excessive and a little doubtful…simply because that would be truly massive. Internet sources can be unreliable and this may be one of those times.
[3] The article I most particularly found helpful and enjoyable can be found at the following link (please ignore the unfortunate title): http://www.sub-urban.com/close-encounters-of-the-turd-kind/

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