A combination of climate change and our increasing use of water is likely to result in significantly drier rivers during English summers by the end of the century, causing potential water scarcity across England. That is the finding of the most comprehensive analysis of its kind, which was carried out by a team of scientists, led by the UK Centre for Ecology & Hydrology, in reports for the UK Government.
Careful planning will be needed to cope with future demand from citizens, agriculture and industry, including the anticipated increase in clean energy production.
The research incorporated, for the first time, scenarios of future demands for water, alongside climate model projections, in order to provide realistic future river flow projections for English catchments. The Environment Agency uses flow measurements – which relate to the volume of water passing through a section of a river at a given time – to regulate how much can be abstracted by farmers, industry and water companies.
Reduced river flows
In their reports for the Department of Energy Security and Net Zero (DESNZ), the experts estimated future river flows up to 2080 compared to pre-2010 measurements. Their new free, interactive, web-based tool enables water companies, government departments, regulators, and researchers to explore these data, supporting long-term water resource planning.
The experts found that low river flows in England would, on average, reduce by around 20% even if global warming is limited to 1.5 degrees Celsius compared to pre-industrial times. In a scenario of 2 degrees of warming, summer river flows would reduce by around 30% on average, and by around 50% under 4 degrees of warming.
However, there are regional variations and the projected reductions in river flows are higher for Southern England, where droughts are expected to be more intense in coming decades.
Meanwhile, mean monthly flows during winter and spring are predicted to increase very slightly, by around just 1% on average.
Insights to improve water management
The researchers also looked at different levels of predicted future water use by society and their findings confirmed that global warming will be, by far, the biggest driver of changes in future water resources. However, people’s water use will still be a significant factor for particular catchments – something that has previously been largely overlooked in projections about future water availability.
Hydrologist Jamie Hannaford of the UK Centre for Ecology & Hydrology (UKCEH), who led the research, said: “Our projections have significant implications as they suggest potential future water scarcity issues in southern England by 2080, particularly for projections of 2 and 4 degree future warming.
“We believe our projections provide important insights to inform decision-making by government agencies, water resources managers and industry on sustainable water abstraction and discharge of sewage and industrial effluent at regional and national level.”
Regional differences
UKCEH hydrological modeller Dr Vicky Bell added: “The regional variations in the projected changes in drought characteristics and flows will require tailored water management strategies that consider the specific challenges and opportunities in each region, including energy production.”
The reports’ authors point out that the projected reductions in river flows will not necessarily result in an equivalent percentage reduction in availability of water for agriculture, industry and domestic use, saying further research will be needed to better predict changes for particular locations.
The researchers have now released a web tool that highlights where and when their projections suggest there will be less river flow available to support a healthy freshwater ecosystem.
The four reports on Future water resources for water intensive energy infrastructure, have been published on the gov.uk website while the web tool is available at environment.data.gov.uk/future-water
Further information
In addition to the reports and web tool, the research team has also released datasets on future projections of river flows and past water abstractions across England at a resolution of 1km square. These are both published on the CEDA archive.
These outputs have been produced as part of a four-year, £5.5 million research programme called Climate Services for a Net Zero Resilient World (CS-N0W). It is using the latest scientific knowledge to inform UK climate policy and help meet global decarbonisation ambitions.
The programme, funded by DESNZ, is being delivered by a group of research partners comprising Ricardo, University College London, Tyndall Centre for Climate Change Research, the British Antarctic Survey, the British Geological Survey, the National Centre for Atmospheric Science, the National Centre for Earth Observation, the National Oceanography Centre, Plymouth Marine Laboratory and UKCEH.