This spring, over 4,000 water samples were collected by citizen scientists as part of Earthwatch Europe’s Great UK WaterBlitz, testing sites across the country for nitrates and phosphates. This incredible collective effort continues to shine a light on the health of our rivers and streams, helping build a clearer picture of water quality across the UK.
Among the thousands of samples, just under 100 were taken from sites in the Cotswolds. Following the release of the national report, we have taken a closer look at what the data tells us about the local situation.
Nationally, 66% of samples showed poor water quality due to excessive nutrient levels. In the Thames catchment, this figure rose to a concerning 86%, making it, alongside the Anglian catchment, the worst effected in the country.
Additionally, Oxfordshire ranked third highest of all counties for nutrient pollution, with 92% of test sites returning unacceptable results, up from 81% last year. The Cotswolds basin showed 87% of sites with poor water quality, a similar result to the previous year.
For the first time, this Spring’s WaterBlitz included E. coli testing at 300 locations. Around 24% of those results would be classed as ‘Poor’ by bathing water standards, with E. coli levels exceeding 900 cfu/100ml.
Locally, two of the four E. coli samples taken from the River Windrush exceeded this threshold, including one below the Bourton-on-the-Water sewage treatment works, which recorded 1,987 cfu/100ml. Another sample from Emma’s Dyke in Witney returned a reading of 2,420 cfu/100ml, just under three times the safe limit.
A clear correlation was found between high phosphate levels and elevated E. coli counts. Given that phosphates often enter rivers via sewage discharges, the data strongly suggests a link between pollution and untreated or partially treated wastewater.
Commenting on the report, Earthwatch Europe’s Director of Science and Policy, Sascha Woods, said, “The results paint a stark picture of the persistent poor health of our UK rivers.”
Zooming in on the Cotswolds, the picture is even starker and reveals the extent of the challenge we face.
Yet amid the troubling data, there is a silver lining: the growing number of citizen scientists getting involved in the WaterBlitz, especially here in the Cotswolds. Their dedication is helping uncover vital evidence that supports local action and accountability.
A huge thank you to everyone who took part — and we look forward to going even bigger at the next WaterBlitz in the Autumn. If you live or work locally and would like to take part then please do contact the Cotswolds Rivers Trust.
