Freshwater ecosystems are today facing multiple pressures from a cocktail of pollutants, including chemicals, microplastics, pharmaceuticals, invasive species and land management practices.

Consequently, the majority of UK rivers fail to have good ecological status, with only 14% of waterways in England, less than half (46%) in Wales, 50% in Scotland and less than a third (31%) in Northern Ireland making the grade.

Poor water quality can result in loss of aquatic invertebrates and fish, threaten the structure and stability of the aquatic food chain, be dangerous for bathing and lead to enhanced drinking water treatment needs and costs.

Researchers have been awarded funding by the Natural Environment Research Council and Defra from the £8.4 million Understanding changes in quality of UK freshwaters programme to: 

• investigate how pollutants enter, leave and interact with rivers and supporting ecosystems
• determine how the movement of pollutants will be modified with changes in the water cycle
• create better tools to monitor and measure pollution.

The £1.6 million University of Bristol-led project will study how livestock farming practices affect UK water quality.

Livestock farming is the dominant farming type and source of organic matter pollution in UK freshwaters, with around 10 million cattle and more than 30 million sheep on 10 million hectares of grassland, representing more than half (57%) of all agricultural land in the UK.

Project lead Penny Johnes, Professor of Biogeochemistry at the university’s School of Geographical Sciences, said: “When livestock excreta are flushed to waters it drives changes in their physical, chemical and ecological quality and function. This material contains inorganic nutrient contaminants typically included in routine water quality monitoring programmes across the UK, but also many other compounds which are not being monitored.

“These include nutrient-rich organic matter, pathogens, pharmaceuticals and hormones likely to drive significant damage to freshwater ecosystems, and presenting a persistent problem for recreational water use, fisheries and shellfisheries and drinking water in livestock farming catchments.”

Climate change-induced increases in water temperature and alterations in flow regime are also accelerating the biological processing of this material in freshwaters, while increased rainfall may overwhelm on-farm storage capacity, thwarting efforts to reduce the effects of livestock farming on UK freshwaters.

Professor Johnes said: “The project will deliver new understanding on how these stressors, environmental characteristics and management efforts interact to drive changes in UK water quality in livestock-dominated catchments.”

The field sites comprise the Conwy, Bristol Avon and 50 further catchments across livestock farming regions in Wales, Scotland, Northern Ireland, and the north and west of England.

The programme’s Freshwater Quality Champions, Professor Pippa Chapman and Professor Joseph Holden, from the University of Leeds, said:“There are huge water quality pressures on UK rivers. These are likely to be exacerbated with climate change.

“Through this innovative programme we will develop cutting-edge environmental science which is focussed on improving UK freshwater quality. Through collaboration between researchers, water and land managers and policy makers, the programme will help ensure that our rivers and other waterways are more resilient to future climate and land-use change.”