Draining 21st Century Cities

As part of ICE’s work on urbanisation and resilience, Professor John Bridgeman – vice chair of ICE’s Water Expert Panel – considers the priorities for improving the resilience of the UK’s drainage infrastructure, and reports on Water UK’s initiative ‘Delivering 21st Century Drainage for our Customers’ which aims to tackle the challenges

Our drain and sewer infrastructure is under increasing strain from population growth, rapid urbanisation and climate change impacts, as well as the need to meet environmental directives.
Our drain and sewer infrastructure is under increasing strain from population growth, rapid urbanisation and climate change impacts, as well as the need to meet environmental directives.
  • Updated: 10 May, 2016
  • Author: John Bridgeman – Vice Chair, ICE Water Expert Panel

ICE's thought leadership paper on Urbanisation challenges civil engineers to ask themselves some key questions:

  • What does a smart city look like?
  • Is it possible to balance sustainable environments with a sustainable economy and a sustainable society?
  • How should we consider the overlapping impacts of climate change and urbanisation and how this challenges our processes and tools for decision-making and design?

Clearly, these are questions that touch on the whole of the built environment, but as we drill deeper we can focus on specific issues. For those involved in managing the urban water cycle, the challenge is to identify the major implications that urban development has for urban wastewater drainage systems.

UK drainage infrastructure – the scale of the challenge

To put this issue into context, the UK water industry operates a sewerage network of around 250,000 miles of sewers; that's enough to go 10 times around the Earth. There are nearly 6,000 sewage treatment centres in the UK that return around 10 billion litres of treated wastewater a day safely to the environment.

And yet, our drains and sewers are under ever-increasing levels of stress, be that from anticipated population growth and urbanisation, climate change, emergent environmental standards, UWWTD infraction risks or simply legacy issues associated with running aged infrastructure. So the focus for water engineers is on how to build and maintain affordable and agile sewerage infrastructure that is responsive and can flex to changing needs and environment.

To help address these specific issues, ICE has recently accepted an invitation to join a Water UK programme that seeks to address the key issues involved in 'Delivering 21st Century Drainage'. The programme has been established to better understand the current and long term issues facing the drainage sector, and to report to UK governments, their regulators, and the water sector as a whole – with the aim of developing future policy, regulatory guidance and more resilient engineering design.

What does ICE see as the priorities?

The intentions behind Water UK's initiative are precisely in line with the thinking of ICE's Water Expert Panel, which believes that the priority areas for addressing drainage and sewerage challenges should include:

  • Reviewing our regulatory and other frameworks to facilitate improved collaboration between all stakeholders involved in urban flood management
  • Developing our understanding of how urban drainage systems work now and in the future so as to improve controls on development in areas of flood risk
  • Mainstreaming new and/or novel designs such as SuDS for new build and retrofit, with clarity over long-term ownership and maintenance – of both individual assets and urban drainage systems as a whole
  • Establishing what steps we must take to reduce the volume and intensity of surface water entering the foul sewer network
  • Improving asset monitoring coupled with greater application of data analytics, modelling, rainfall prediction and real-time control so as to better focus available investment for the benefit of customers

Water UK 21st Century Drainage Programme

Water UK's exciting initiative is focussed on a 'whole sector', partnership-based approach, with input from water companies and authorities, regulators, governments, local authorities, and NGOs. The initiative is led by a Fellow of ICE – Tony Harrington, Director of Environment at Dŵr Cymru Welsh Water.

The programme's aim is to understand the current and long term requirements of our drainage networks; to ensure the planning and operating of our systems in a proactive, visible, and sustainable manner; and so provide resilient and affordable drainage for customers; all of which needs to be underpinned by a new capacity intervention framework and regulatory guidance.

A Programme Board has been established, with seven workstreams beneath it:

  • Communications and Engagement
  • Drainage Capacity Planning
  • Overflows
  • Drainage Misuse
  • Groundwater Inundation of Drainage
  • Enablers to Progress
  • Drainage Infrastructure Deterioration

And so, although we currently enjoy our best ever river and coastal water quality, there remain many new challenges ahead. We must balance the needs of people and their expectations of the urban environment with the mega challenges of climate change and extreme weather, changes to demographics, and resource depletion.

The 21st Century Drainage Programme is about meeting the needs of tomorrow affordably, in a sustainable manner, in partnership with other key stakeholders – all towards an endgame of providing evidence to enable development of new policy, regulatory guidance and engineering design approaches.

About the Author

John Bridgeman is Professor of Environmental Engineering and Head of the Department of Civil Engineering at the University of Birmingham. He is Vice Chair of the ICE's Water Expert Panel, and represents the Institution on the 21st Century Drainage Programme Board.

Growing cities and building resilience

Find out more about ICE's work exploring the challenges that mass urbanisation poses to city infrastructure. Let us know your opinions by joining the debate.

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