When many people think about London, they think about the famous River Thames.
But, with 39 million tonnes of sewage flowing into the river each year, you might think twice about swimming in it.
Sue Hitchcock is a civil engineer working on the Thames Tideway Tunnel, a new engineering project which, along with the Lee Tunnel and upgrade of London's major sewage treatment works, will update London's Victorian sewer system to cope with the many millions more people now living and working in the capital.
The engineers need to avoid disrupting historic sites such as Tower Bridge, as well as the tube lines whizzing busy Londoners about. And, when it's complete, engineers will have helped create a cleaner, healthier River Thames.
Name: Sue Hitchcock
Job title: Third Party Infrastructure Manager, Thames Tideway Tunnel
University: Southampton University, Civil Engineering with European Studies
A-levels: Maths, physics, chemistry, German
Why do engineers need to design and build the Thames Tideway Tunnel?
London has an old sewer system built in Victorian times by Sir Joseph Bazalgette (a 19th-century civil engineer with a fantastic moustache - Ed). In recent years the population of London has grown and a lot of the open areas have been paved over (the population of London in the 1860s was just over 3 million and London’s official population in 2011 was 8,174,100). So now, when we have as little as two millimetres of rainfall, this can cause the existing system to overflow into the River Thames.
There are a lot of people who use the Thames, such as rowing clubs and people walking along the foreshore. We want to make it a place where people can have leisure facilities and activities, and use the river without health risks.
We also want to create a cleaner river where fish can thrive. Approximately 39 million tonnes of sewage go into the river every year at the moment and fish and plants can’t survive in those conditions. Thames Water’s London Tideway Improvements programme, which includes the Thames Tideway Tunnel, Lee Tunnel and the upgrade of all five major sewage treatment works along the tidal River Thames will help stop sewer overflows and improve water quality in the River Thames.
The Thames is an historic and iconic part of the city of London and we need to improve it so it can be used by today’s society and into the future.
Tell us about the project:
The Thames Tideway Tunnel is the proposed solution to intercept and control the 34 most polluting combined sewer overflows that discharge into the river.
The tunnel will run from Acton in west London to Beckton in east London and it will be one of the deepest tunnels ever built in this country. It will be about 22km in length, will span across 14 London boroughs and have an internal diameter of 7.2 metres - that’s wide enough to park three London buses side by side! The tunnel will take the sewage flows, currently discharged into the River Thames, out to east London for treatment before they go back into the Thames in a safe, clean form.
What do you do?
I have a team of people who look at the possible impacts of our project on all the existing infrastructure, such as bridges, tunnels, utilities and river walls.
There are already a lot of underground tunnels in London including the Tube tunnels, large communication tunnels and some water tunnels. We have to be careful as we construct the Thames Tideway Tunnel not to cause any damage to those assets. We need to ensure that people can continue to travel safely on the Tube, without disruption, and also make sure that any supplies such as water and electricity remain available to people in their houses.
One of the most challenging parts of my job is to assess the impact of this project on some quite old structures. For example, Tower Bridge was built a long time ago (between 1886 and 1894 – Ed) and some of the drawings of how it was built are quite old. It takes a long time to look at them, understand how that structure is built and therefore look at how our tunnel could impact on that structure.
How did you become interested in engineering?
At school I enjoyed maths, physics and solving challenging problems. When I was looking at university courses I thought engineering would be an interesting subject and would lead to a career that would provide daily differences in my job, lots of challenges and problems to solve.
What did you study at school?
When I was at school I studied maths, physics, chemistry and German at A-Level. Maths and physics are important as they form the basis of engineering and problem solving and were essential to go on to study my course at university.
And then at university?
I studied Civil Engineering with European Studies at Southampton University with a year abroad at Darmstadt University in Germany.
Which part of your job do you enjoy the most?
My favourite part of my job is working with lots of people, taking a problem and providing a solution. It’s not always straightforward and can sometimes take quite a long time but it’s always very satisfying when a solution is achieved.
What other engineers do you work alongside on the project?
We have a number of different engineers working with us on the Thames Tideway Tunnel. I’m a civil engineer and we also have electrical and mechanical engineers and tunnelling engineers who are experts in how to do tunnelling works. We have hydraulics engineers looking at how the water will behave within the tunnel and then we also have environmental specialists and planning specialists so it’s a very multi-disciplinary team.
We also need to work with a number of different organisations including the Port of London Authority, Transport for London, Network Rail and anyone that owns an asset or has an interest in the river or the project. We have to meet with them regularly to explain the design work that we’ve been doing and work with them to develop solutions to problems and issues.
So are communication and team work important for being an engineer?
They’re essential because there are a lot of different people who feed into the final solution so we don’t tend to work independently. Lots of people bring different skills and we all have to work together.
What advice would you give to young people who are interested in engineering?
There are a lot of exciting projects you can look at, read about and maybe even visit in this country and overseas. Keep your eyes peeled for lots of other exciting projects such as new airports, flood defence structures or tunnelling projects - there’s a lot going on in the world!
This project is also forecasted to create 4,000 direct jobs, many of which will be apprenticeships, so there are lots of ways that people can train and learn new skills and get involved in the Thames Tideway Tunnel project (construction is planned to run from 2016 to around 2022 – Ed).
If you could go back in time and invent anything, what would it be?
I would invent the water pump because water is such an essential part of people’s lives and we see that people struggle in places like Africa when they don’t have access to a clean water supply.
Tunnelworks: Education resources for post-16 students from Thames Water, focusing on the Thames Tideway Tunnel.
Engineering at Southampton University
The Institution of Civil Engineers
The Thames Tideway Tunnel website