The Climate Change Committee has published a separate briefing summarising how the water sector has been assessed in the CCC’s third UK Climate Change Risk Assessment (CCRA) published today, and what types of action to adapt to climate change risks and opportunities would be beneficial in the next five years.

The CCC has assessed the following risks for the sector:

• Risks to infrastructure networks (water, energy, transport, ICT) from cascading failures
• Risks to infrastructure services from river, surface water and groundwater flooding
• Risks to infrastructure services from coastal flooding and erosion
• Risks to subterranean and surface infrastructure from subsidence
• Risks to public water supplies from reduced water availability
• Risks to health from poor water quality and household supply interruptions
• Risks to aquifers and agricultural land from sea level rise, saltwater intrusion

The briefing says that water infrastructure, including reservoirs, dams, pipelines, water treatment plants and sewage treatment plants, are all at risk from the impacts of climate change, especially increases in the frequency and intensity of surface water and coastal flooding.

Water infrastructure assets also represent “a key element of the UK infrastructure system and could affect, or be affected by, failures of other assets due to extreme weather, such as energy systems, transport and information and communications technology.”

Recent research conducted to support the CCRA has indicated that “the vulnerability of interconnected systems may be significantly underestimated” the briefing says. Vulnerabilities on one infrastructure network can cause problems on others – and water infrastructure represents a significant part of this system.

The briefing cites extreme winter rainfall which leads to more flooding, leading to flooding of sewerage infrastructure, reduced water quality and potential health impacts as an example of a cascading failure in relation to water. The CCC warns:

“The magnitude of this risk is high both now and in the future across all four nations.”

According to the CCC, the risk of network failures is already high, potentially affecting hundreds of thousands or millions of people every year.

The briefing suggests that buried infrastructure, such as water pipelines, potentially faces increased risks as a result of more frequent damage in future due to flooding and subsidence. In addition, more frequent flooding could also impact on water treatment facilities leading to potential reductions in water quality with knock-on effects on health.

Future projections of more frequent and intense dry periods could also lead to concerns around the availability of public water supplies in future, especially in England and parts of Wales.

Beneficial actions in the next five years suggested by the CCC include:

• Improving resilience to a single infrastructure sector (such as protecting electricity substations from flooding) - the benefits can become much larger when considering the cascading impacts that are then avoided.
• Using common formalised standards of resilience, such as the new ISO 14091 standard, across different infrastructure sectors including the water sector to help build systemic resilience across the whole infrastructure system.

The briefing describes river and surface water flooding as “already a large risk to UK infrastructure, with each season adding new evidence to underpin the significant magnitude of the threat.”

The CCC cites data which show that 487 water sites and 747 sewage treatment works are currently at significant risk from surface water flooding, with 147 water sites and 601 sewage treatment works at risk from river flooding across the UK.

Beneficial actions the CCC is proposing should be taken in the next five years include:

• Develop consistent indicators of flood risk resilience for water infrastructure assets, supply and networks to create the right institutional conditions for adaptation, allow improvements across the board to be better measured over time and building on improvement in local hazard information.
• Consistent indicators of resilience across sectors and for different sources of flooding to allow for improvements across the board to be better measured over time, to better understand the impact that adaptation is having.

The briefing flags up the Cabinet Office’s Resilience Direct platform which provides street-level surface water flood forecasts to local authorities and category 1 and 2 responders as a useful example.

Commenting on risks to infrastructure services from coastal flooding and erosion, the briefing warns that sea levels are currently rising and the rate of rise is accelerating, including around the UK and that these risks will therefore grow. Current projections show the likely change to be between 0.27 and 1.12 metres by the end of the century.

In total, 22 clean water facilities and 91 sewage treatment works across the UK have been identified as at significant risk from coastal flooding.

Beneficial actions suggested in the next five years include:

• The use of adaptation pathways for the long-term planning of flood risk management - first used in developing the Thames Estuary 2100 flood risk management strategy, has been shown to be a promising technique that can be applied more widely in the UK.
• ‘What if’ planning for high coastal risk scenarios which can help with understanding what could be done in the event of very high rates of change, given the uncertainties around sea level rise.

The briefing strikes an optimistic note on risks to public water supplies from reduced water availability, saying that adaptation efforts in the sector are “well advanced”, assisted by “five yearly Water Resource Management Plans, which take a 25 year outlook, and price reviews, where water companies set the price, service and incentive package for a five year period.”

Other beneficial actions which could be taken in the next five years include several options for further adaptation to reduce the risk of deficits further- for example, tightening building regulations, enhanced water metering and drought research.

Each risk or opportunity in the briefing has an identifier code linked to the full analysis of the 61 climate risks and opportunities for the UK in the separate UK Climate Risk Independent Assessment (CCRA3) Technical Report.

Water firms look to Environment Bill and Ofwat’s 2024 Price Review to develop right regulatory environment

Commenting in response, Sam Larsen, Water UK Director of Carbon and Programmes said:

“Today’s Assessment report by the Climate Change Committee shows how vital it is for the water industry, regulators, and customers to work together on tackling and mitigating the impacts of the climate emergency.

“Water efficiency, protecting and improving habitats and biodiversity go to the very heart of the challenges the industry and society faces, but something we’re helping address now with our industry-wide net zero commitments and by investing £5bn over the next few years to improve the environment today, and not tomorrow.

“The report also shows the water industry is making good progress in adapting to climate change; however, more work still needs to be done in addressing the long-term challenges. Adapting our infrastructure is as important as reducing our emissions as climate change impacts become more severe, and therefore, we are looking to the Environment Bill and Ofwat’s 2024 Price Review to help develop the right regulatory environment to empower water companies to deliver a carbon-neutral, nature-based future that is critical to protecting the environment, people and communities we serve.”

Click here to download the CCC Water Sector Assessment

Click here to download the UK Climate Risk Independent Assessment (CCRA3) Technical Report