To assess the ecological status of a river, watchdogs use several metrics, including the analysis of invertebrates in samples collected from watercourses, such as mayfly larvae, worms, snails, dragonflies or shrimps
Official classifications of the health of England’s rivers could be relying on data that is up to a decade old, campaigners have warned.
To assess the ecological status of a river, the watchdog uses several metrics, including the analysis of invertebrates in samples collected from watercourses, such as mayfly larvae, worms, snails, dragonflies or shrimps.
These species play a vital role in understanding river health because of their sensitivity to pollution, lower oxygen levels and habitat degradation. But the Environment Agency has been relying on samples taken years earlier to inform its official river health classifications, according to analysis of the watchdog’s data obtained by campaign group WildFish through freedom of information laws.
The agency carries out invertebrate assessments every six years, with updates every three years, under the Water Framework Directive – a Europe-wide initiative to help water bodies reach good ecological status and prevent deterioration.
The last major classifications for England’s rivers were released in 2019, with the new update for the 2025 cycle expected soon. In 2019, only 16% of English rivers and canals were classed in “good” ecological health, and none was found to be in good chemical health.
However, WildFish’s analysis found that the EA heavily relied on older data then and may have to again for 2025. It argued that the upcoming classifications could therefore mislead the public, who may assume the monitoring is based on up-to-date information.
Sam Green, a senior freshwater ecologist at the environmental group, said: “We can only take action to save Britain’s rivers when we know what’s going on under the surface, and so a lack of up-to-date science and a reliance on rollover data from previous years is deeply concerning.”
Of the 3,645 water bodies assessed in 2019, WildFish found that only 1,781 had new monitoring for invertebrates – or 52%. The rest then used “rolled over” data from the previous update in 2016. Areas with the highest percentage of data rollover were the South West at 63.1%, the South East at 62.6%, and the Humber at 54.0%, while Anglian had the lowest percentage at 39.9%.
Janina Gray, head of science and policy at WildFish, said: “The public and those who work to protect our rivers I think will be surprised and dismayed to find out the data used by regulators to assess our rivers is so out of date. Protecting our rivers starts with us all working together to ensure we have transparent, accurate and current data that can be used not only to identify environmental stressors but also track progress.”
Elsewhere, the group argued that all rare chalk streams should be classified as special scientific areas of conservation – protected sites such as the River Itchen, which the EA gives greater resource and monitoring prioritisation.
An EA spokesperson said: “We are working with many partners including citizen scientists to understand more about our water bodies to help protect the ecosystems and wildlife they support. We are expanding where we monitor and the diversity of data we collect and our 2025 invertebrate classifications will use new information from over 1,300 monitoring sites across the country.”
The agency currently allocates around £7.5 million to Water Framework Directive monitoring each year and makes use of suitable data from a host of other environment monitoring programmes it delivers, the spokesperson added.
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