It is well known that ageing water mains fail more under extreme weather conditions. But as climate changes, water companies are facing new challenges in maintaining resilient infrastructure and ensuring reliable services.
I began helping water companies understand the impact of soil on their networks over 20 years ago. Since then, much of my research has focussed on helping Anglian Water to quantify specific impacts of soil and weather hazards on their pipe network.
In 2020, we built probably the UK’s first climate adjusted burst models to predict the impact of climate change on a water network. We identified the emerging vulnerabilities in Anglian Water’s pipe network and the impact of climate change on their pipes and customers.
Scientists are trained to never quite trust their work, so it was with some trepidation that I presented the stark view that the number of summer bursts on Anglian Water’s cement-based pipes would dramatically increase. Two years later, in the record-breaking hot summer of 2022, our predictions were more than confirmed. Cement-based pipes, in aggressive shrinkable soils, burst at a never-before seen rate.
Our research led to the Climate Vulnerable Mains project, to renew the most at-risk mains within Anglian Water’s water supply network. Our company, MapleSky, helped Anglian Water predict the impacts of climate change on their networks under four climate scenarios, and identify which pipes were likely to fail each decade up to the 2080s.
First, we built robust models of past asset performance and then ran a suite of bespoke forward-looking climate scenarios through these models. By integrating outputs from the MapleSky burst models with Copperleaf’s asset management system, Anglian Water can calculate the actual cost of climate impacts on their infrastructure, helping them prioritise actions and investments more strategically. Based on this intelligence, Anglian Water is now planning a programme to renew 8,241 kilometres of its most climate-vulnerable water mains.
East Anglia is one of the hottest and driest parts of the UK, and its summers are getting more arid. The region’s soils are corrosive and shrinkable, and the ground moves as they wet and dry. These extreme conditions significantly increase the risk of failure of buried pipes and associated leakage. Since our first climate model for Anglian Water, we have built climate-adjusted burst models for other parts of the UK, and this trend of increasing summer bursts is also seen in wetter regions. Of course, hotter summers also lead to increased water consumption, which without intervention and planning, could make usage restrictions more likely.
Future winters are set to be warmer and wetter. This, on average will lead to fewer bursts on old iron pipes in most winter months. However, longer intervals between significantly cold winters lead to a large population of weak pipes all primed to fail at the first deep freeze. So, when a cold winter does arrive, the number of iron pipes bursting will be high.
Our modelling has identified old pipes, with small diameters, buried in particular clay and peat soils are at the highest risk of failure in future summers. These pipes comprise about 10% of Anglian Water’s network. Even assuming no further deterioration, we anticipate ongoing increases in burst rates in these pipes.
Anglian Water can now understand which of its assets are most at risk and implement plans to effectively protect them and plan for mains renewal. They are proposing to invest £1.64 billion by 2060 in mitigating the premature failure of climate-vulnerable mains, £184 million of which will be invested within AMP8. This aligns with the forward-looking risk assessment approach to capital maintenance called for by the National Infrastructure Commission (NIC) and Competition and Markets Authority (CMA).
Identified vulnerable mains will be prioritised for replacement with polyethylene (PE) pipes, which are more flexible and resilient. More than one in three of Anglian Water’s pipes are polyethylene, and there are significantly fewer bursts in these assets.
At MapleSky, we are proud to have been part of this innovative project and working with Anglian Water to understand the uncertainties brought by the climate crisis, and ensure they are making the highest value investment decisions. This project sets a benchmark for the wider water industry, which must act now to secure the long-term resilience of their water supply networks.
