London’s Great Stink
In the early 1800s, the banks of the river Thames in London were pleasant areas to live, work and visit. Fish thrived and could be caught in the waters between the Vauxhall and London bridges; in the upper reaches it was not uncommon to find salmon; and the area supported a thriving community of fishermen. The waters of the Thames were clear, pleasure boats abounded and the air was fresh. Houses whose gardens reached down to the river were highly prized and inhabited by the wealthy. The area provided Londoners with an attractive place to meet and walk on a summer’s evening.
By the middle of the century it was a different story. The high-class houses had been abandoned and were growing derelict, the river was filthy and stinking, and the fish were dead and gone. No one took to the water unless they were forced to do so for commercial purposes.
The reason for such a disastrous change can be summed up in one word: sewage.
As the first flush toilets began to appear, the amount of water and waste that poured into cesspits increased, frequently overflowing into the drains and elementary sewers, most of which were little more than open ditches sloping down to the Thames. The drainage system had originally been designed to cope only with rainwater, but in the 1840s, cesspits were abolished as it became compulsory to drain household waste into sewers. Soon the overloaded and overflowing drainage system not only took the sewage from the houses, but also the outflows from factories and slaughterhouses. By then, the population of the city that had grown up along the banks of the river amounted to about 2.5 million people who, between them, produced some 60 million gallons of sewage and general filth every day, all of which oozed its way along the streets’ inadequate drainage systems to be dumped straight into the Thames. To compound the situation, Londoners were prone to throwing the contents of their chamber pots out of upstairs windows, into the streets below.
The streets of London smelt vile and the river was little more than an open sewer. To make matters worse, there was no real central body to oversee the drainage and sewage systems of London, just eight different districts with their own commissioners, who were concerned only with their own areas.
One factor that led to the creation of a proper sewage system for London was the discovery that cholera, of which there had been several outbreaks since the first case had been recorded in 1831, was not spread in the way many thought it to be. The popular belief at the time was that the disease was spread by bad smells in the air. But deduction by physician Dr John Snow traced one major outbreak to crosscontamination of water supplies and the inadequate sewage system.
Things came to a head in the particularly hot summer of 1858, when a combination of the heat and the heavily polluted Thames resulted in Members of Parliament finding it necessary to hang sacking soaked with deodorising chemicals at the windows of the House of Commons that bordered the Thames at Westminster. It became known as the year of The Great Stink.
The mills at Plaistow in East London, where concrete was made for the sewers.
Laying the concrete foundations of the Northern Outfall tunnels.
Constructing the concrete embankment across the Plaistow Marshes.
The summer ended with heavy rain that helped clear some of the problem, but by then the government, prompted by the smell literally outside their own windows, had rushed a Bill through Parliament to provide the money to construct an ambitious sewer system for London. The Bill became law in eighteen days, and the man who took on the task of designing the system was Joseph Bazalgette, Chief Engineer of the Metropolitan Board of Works. Work began in 1859 and carried on for nine years, at a cost of £4.2 million. It became the biggest civil engineering project in the world.
The main objects of the new system were waste disposal, land drainage and the introduction of safe drinking water. It had also to take into account that the river Thames was tidal. Therefore, anything discharged into the river in Central London might be washed downriver with the tide, but would surely return when the tide turned. To be effective, if waste were to be dumped in the river, it had to be at a point closer to the Thames Estuary, and from there into the sea.
Pumping Station at Deptford.
Driving a tunnel at Peckham.
The proposal was to intercept the sewage on its way to the river, and by means of both gravity and pumping stations along the way, divert it to two locations in the Thames Estuary, about 14 miles east of London Bridge and at a suitable distance from the main population of London. The northern outfall site was at Barking Creek, a few miles outside the main town of Barking, in Essex. The southern outfall was at Erith Marshes, which at that time stretched between the towns of Erith and Woolwich, in Kent.
At each of these places the sewage was contained until the commencement of the daily ebb tide, the period between high tide and low tide when the water of the river flowed towards the sea. During the first two hours of this period, the sewage was pumped into the bottom of the river, where it would be diluted by volumes of water twenty times greater than was the case in Central London, whilst conveying it another 12 miles towards the sea, never to return.
The construction of the sewers was complicated by the fact that London was built on many different levels, ranging from the high elevations of places like Hampstead and Highgate in the north to districts like Lambeth in the south, much of which was actually below the level of the river. A good deal of the system was built underground, but in places the drainage and the pipe systems involved were routed above ground, over rivers, canals, railways and roads, involving engineering work to lift the outflow from low to higher levels. Work also had to be carried out alongside the London Underground system, which was in development at the same time.
Outfall Works at Barking Creek.
Bottom of a shaft in the southern high-level sewer at Peckham.
The system on the north side of the Thames was divided into three distinct drainage areas, called the high, middle and low areas, each separated by a main sewer, cutting off at right angles all the local drains that ran into the Thames. The three met at what was called a penstock chamber, the name given to a gateway designed to regulate the flow of waste and water. From there, the sewage was pumped onwards to the outflow at Barking Creek.
The southern system worked in a similar way, but with only two drainage areas instead of three.
In an account such as this, it would be pointless (not to say a little boring) to go into intricate details of the construction of every branch of the system. But, to give an idea of what was involved in the building, and the materials used, consider just one small part of the whole network.
The northern high-level sewer was 9 miles long from its start in Hampstead to the penstock chamber at Old Ford. From Hampstead, it passed through Stoke Newington, intercepting the old river Fleet sewer, which would otherwise have emptied its contents into the Thames at Blackfriars Bridge, as well as the old Hackney Brook drain. On its course, it passed under the Great Northern Railway and the New River, an artificial waterway opened in 1613 to supply London with fresh drinking water, then on to Old Ford. At its upper end, the sewer was 3 feet in diameter, growing to 12 feet, as subsidiary sewers were connected to it, when it reached the penstock chamber.
Construction of the high-level sewer at Peckham.
Barrow hoist to lift excavated earth at Peckham.
Construction of the Fleet sewer.
The penstock chamber at Old Ford.
This section alone involved excavating about 1 million yards of earth from the trench in which it was constructed, and the laying of 40 million bricks. To form the foundations, backings and coverings, 100,000 cubic yards of concrete were deposited, involving 200,000 bushels of Portland cement and 350,000 bushels of lime. Among other materials used were 20 tons of hoop iron. The average depth of the sewer varied from 30 to 50 feet and it was built on a slope that drove its contents along at about 3 miles per hour.
Memorial to Joseph Bazalgette on the north bank of the river Thames in London, close to Hungerford Bridge.
In November 1861, while building was still in progress, writing about the southern system, The Illustrated London News summed up the achievements of all concerned thus:
The works already executed throughout the whole length of the southern mains drainage are of unexampled excellence, a most unusual and, in the eyes of contractors, most unnecessary degrees of perfection being assisted upon, by Mr Grant [John Grant, Assistant-Engineer to the Metropolitan Board of Works], under whose personal superintendants the whole is carried out, at all points deep in the belt of the earth, where no human being will ever see it after it is once in work. The brickwork is executed as beautifully as though it could be handled in the most aristocratic thoroughfares of the metropolis. This is as it should be. These important works that, when once finished, are buried for ever, require to be much greater excellence than those above ground, whose defects, if any, maybe easily discovered and remedied.
When Joseph Bazalgette began building the system, it was to serve a population of about 2.5 million, and he anticipated that it would cope with a population that could rise to 4 million. Today, an extended version of that same basic system serves more like 8 million Londoners.