Weather-proofing the water industry

The recently published report by the Adaptation Sub Committee (ASC), part of the Government’s Committee for Climate Change, is a wake-up call for the UK. There is now a broad scientific consensus that changing weather patterns are unavoidable, even if governments around the world do manage to drastically reduce carbon emissions in future years.

The climate is already on the move. Temperatures are one degree higher on average than they were in the 1970s. Eight out of the last ten years have brought serious flooding events to Britain. Climate scientists predict that temperatures will continue to rise and weather become more extreme over the

next few decades. The water industry can take some pride in that it was highlighted by the report as one of the industries that has moved to the “second rung” of the ladder in preparing for climate change. Many major players in the sector have guidance and policy in place to deal with climate change – considered the first rung of the ladder – and are now using climate change projections as part of their planning.

But as the ASC’s report spells out, moving quickly to the third phase, adaptation, is crucial if risk to assets is to be properly managed in the medium to long term. Water companies, governments and regulators now need to work together to agree a road map for adapting water infrastructure including wastewater treatment plants and sewer systems against extreme weather events.

This is easy to say. Implementation is another matter. Until now progress has been slow. The main obstacles to progress have been uncertainties in projections on climate change and the large costs that go with changing infrastructure.

One major challenge is that climate can no longer be regarded as “stationary”. Traditionally, engineers have based their designs on models that predict extreme events such as a one-in-a-hundred-year flood or a one-in-ten-year drought. With the uncertainty brought by climate change it is difficult to use these traditional models in a meaningful way. The water industry needs to quickly get to grips with the UK Climate Projections 2009 (UKCP09) and the implications for resilience of assets and systems. Given that companies are now commencing analyses to inform the 2014 Price Review (PR14), and that the UKCP09 projections are the standard, the industry needs to agree a common approach to their use – and this approach needs to be robust to the uncertainties expressed in the projections.

Most of the UK’s ageing sewer network handles both sewage and surface water drainage. As intense rainfall events increase, flash flooding in cities will become a growing problem. For future residential developments, it is strongly recommended that developers consider separating the sewerage network

from surface water run-off. This will help to protect properties from sewer flooding caused by intense storms in decades to come, and is reasonably easy to action in new-build projects.

Because new housing stock is being built at a slow rate, these measures will not solve the problem in most of the UK’s urban centres. Adapting the existing sewerage system to cope with sudden influxes of water is a challenge. We need to improve infrastructure resilience so that it can cope with short-term crises and longer-term effects of climate change.

UK Water Industry Research (UKWIR) has developed new guidance on Climate change modelling for sewerage networks. The guidance, written by Atkins, draws on the latest science on extreme rainfall changes and is intended to act as a guide for the use of UKCP09 projections for design, storm and time series applications. Uncertainties in the science remain, but the UKWIR guidance presents the best evidence available and a basis from which we can develop adaptation plans. The guidance advocates a risk-based approach whereby the modelling approach – and adaptation solution – is dependent on the sensitivity of the system to extreme rainfall and the size of potential investment. This is particularly important in the current economic climate where we need to focus effort where it is most needed. In general – and in the short-term at least – this will be where we have existing problems. We also need to place this in a wider context: the UK’s key infrastructure networks – water, waste, energy, transport and telecommunications – are highly-integrated and interdependent. They are vulnerable to extreme weather events.

To help address these kinds of issues, all our infrastructure industries need to work together in finding solutions. Atkins is working as part of a new consortium which brings together experts from academia and a range of industries. The Infrastructure Transitions Research Consortium, led by Newcastle University, will test complex national infrastructure systems against a range of future scenarios. This will be key for a thorough understanding of asset resilience and flood risk to our critical infrastructure in the future.

If we are to move to adaptation phase efficiently, cross industry cooperation – including agreement on approaches and the sharing of knowledge and best practice – will become increasingly important. It is essential that all parties are clear on where individual responsibilities lie and how they should be communicating with the wider industry.

Collaboration will be essential, particularly given that local authorities’ increased responsibilities are not being matched by a proportionate increase in their budgets following the Comprehensive Spending Review. The Flood and Water Management Act passed in 2010 should encourage organisations to work more closely together and its success will ultimately be measured in the pace of adaptation in the years to come.

We need to act together, today, if we are to make our assets more resilient against a much less certain future.

UK Water Industry Research (UKWIR)’s Climate change modelling for sewerage networks guidance, written by Atkins in collaboration with the universities of Newcastle and East Anglia, will be available from www.ukwir.org.