About Me

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London, United Kingdom
I am an engineering academic at University College London where I work on the sustainability of urban water systems. I am interested in the role of engineers and technology in sustainable cities.

Wednesday, 16 January 2013

A democratic history of sewerage

Every culture has its mythologies and origin stories. These help us to frame our identities and provide a foundation from which to make sense of the uncertain world around us. Importantly, such stories usually tell us more about the present than the past. This is very different to the scholarly study of the past we call history, which requires painstaining research and detailed analysis*. The two are easily confused. What passes for 'engineering history' is more often 'engineering mythology'.

The story of Sir Joseph Bazalgette and the London sewers is one such touchstone, often deployed to support a particular view of the present, rather than to actually provide an explanation of the past. No better example can be found than this piece by John Kay in the FT. Kay's basic point is this - Balagette's far-sighted project to build London's sewer system would not have been possible today because of complicated project appraisal and planning procedures.

The project to build London's sewers was indeed a major engineering achievement, one of which my profession and city are rightly proud. This is one of the reasons why I teach the history of London's sewers to our second year students. However, the main learning outcome from this section of the course is that all major engineering projects happen in complex social, economic, ecological and political contexts. Taking a nineteenth century jewel of engineering and showing the messy details of political and technical negotiation runs precisely counter to the myths of engineering perpetuated in Kay's column.

The myth of London's sewers runs basically like this. There was a terrible environmental disaster. The politicians didn't know what to do. Our hero Sir Joseph Bazalgette stepped forward with the solution to the problem. The politicians gave him the money to implement his plans. The project succeeded, right up until the present day. The nineteenth century was the golden age of British engineering because politicians and activists did not stand in the way of progress. Engineers could solve all of today's problems if only the politicians, or more specifically the planning processes and environmental legislation, did not hold them up.

The history of London's sewers runs basically like this. London's population tripled in less than a century. The drainage and nightsoil systems that had been functioning reasonably effectively since the sixteenth century couldn't cope with the increased water and waste, leading to terrible environmental conditions with disastrous public health consequences. Until the 1840s the administration of sewers remained in the hands of decentralised vestries that had been formed hundreds of years earlier. Attempts to solve the sewer problem required institutional reform. Between 1848 and 1855 six separate 'Metropolitan Commissions of Sewers' were formed to try to come to an agreed solution. Engineers were involved in these commissions and presented an immense variety of solutions to the problem. There was much technical and political argument during this period, and the two often overlapped. In 1856 the Commissions were replaced with the Metropolitan Board of Works, a statutory body to solve the sewer problem. Joseph Bazalgette was appointed assistant surveyor to the Second Metropolitan Commission and worked his way up to being the inaugural Chief of the Metropolitan Board of Works. His original proposal as Chief Engineer drew on designs considered by the Commissions, and it was vetoed by Parliament on environmental and social grounds (discharge of sewage at Pimlico, concern about sewage flowing back into London on the incoming tide). Parliament was also concerned that Bazalgette had underestimated the cost of the project. The Great Stink and a change of government in 1858 led to reform of the bill governing the Metropolitan Board of Works, removing Parliamentary veto and providing Treasury guarantee of borrowing to finance the construction. Work started in 1859 on a modified proposal which did not discharge sewage into the Thames at Pimlico. The project was completed in 1888. During that time Bazalgette had to deal with a bricklayers strike, a sometimes hostile media, complex quality control systems and innovative contract management procedures.

If anything, the politics of sewers in London in the nineteenth century was more, not less, complicated than things are today (planning for the Thames Tideway 'supersewer' project has been remarkably smooth by comparison). Many of the consistent themes of British politics were present back then - centralised versus decentralised administration, expert led decisions versus democratic oversight and deliberation, managing the risks of government guarantee for major infrastructure investment in the capital, and the influence of strong personalities on debates and decisions.

The history of London's sewers shows us that democracy makes for better decisions about infrastructure. Bazalgette's sewers have served London well precisely because the options and plans were debated over many decades and because politicians and activists were present in the decision making, alongside the engineers. Let's all keep working together to make sure that democracy and good engineering are allowed to continue to deliver the infrastructure this city needs for centuries to come.
*I am not an historian. I have immense respect for those who are. For a full account of the history of the sewers and an insight into Bazalgette's life I recommend Stephen Halliday's book 'The Great Stink of London', published by Sutton Publishing in 1999.

Saturday, 12 January 2013

Radical Drainage

What is the most radical movement in urban ecology? Transition Towns? Urban food growing? Passivhaus? Cycling? All these are significant in  changing behaviour, technology and cultures of how people who live in cities consume resources and relate to each other and their local environment. However, the movement I think is most significant in fundamentally altering the relationship between cities and the environment is to be found in the boring old world of drainage. In the UK the movement is known as Sustainable Drainage Systems (SUDS), in Australia it's called Water Sensitive Urban Design (WSUD), and in the US it's Low Impact Development (LID). Recently the benefits of new approaches to drainage have been linked to biodiversity and the need to reduce urban heat island effects, coming together under the banner of Green Infrastructure (GI). Whatever the acronym, a quiet ecological revolution is under way in the drains and waterways of cities around the world.

For the last 150 years or more, the primary aim of an urban drainage system has been to move water away from streets and homes as quickly as possible so as to prevent flooding and stagnation of polluted water close to human settlement. This fits with a modernist separation of nature and culture. Cities are for culture, nature is 'out there', in 'the wild'. Cities are where nature is tamed, controlled, mastered for human benefit. There are some very good public health reasons for this. People drown in floods, and get sick and die of water related diseases such as malaria and cholera. 'Nature' uncontrolled can be dangerous.

The problem with moving water out of cities as quickly as possible is that it has to go somewhere. It disappears down a grate in the road during a rain storm, but then where does it go? One way or another the water ends up back in the local environment. This sudden rush of water can disrupt long established patterns of flow through rivers and wetlands, and the storm water is often contaminated. Furthermore, in the rush to build drainage systems many local waterways were culverted, concreted and covered over, converted from streams into drains to become the 'lost rivers' of our cities.

SUDS, WSUD and LID all started with concerns about the impact of the discharge of urban drainage systems on local aquatic environments. Moving up the pipe they proposed that instead of getting rid of water as quickly as possible, water should be given space in the urban environment. Cities and nature are perhaps inseparable. Techniques for holding water in the urban environment and letting it infiltrate or evaporate where it falls include ponds, rain gardens, permeable paving, swales, green roofs, rainwater harvesting, and the restoration of urban rivers and wetlands. Design techniques and technologies continue to develop, but what is most important is the fundamental shift in how water, as one of the most fundamental elements of nature, is conceived. Water is no longer a danger to be controlled, but an element to be celebrated and included in the city.

The move to more sustainable draingage systems and water sensitive cities has a long way to go and many hurdles to overcome (more on that in future posts). However, this fundamental shift in how engineers, planners and urban designers, and the communities they work with, approach water in cities is of momentous significance. If sewers are the conscience of the city, as Victor Hugo said, then SUDS may be a sign of our awakening to a more ethical relationship to the ecosystems that sustain us.