As a summer of record-breaking dry weather and prolonged heat begins to come to a close, thousands of citizen scientists are preparing to take part in the Big River Watch to help monitor the impacts of extreme weather and pollution on river health and inform vital conservation work by The Rivers Trust.

From 18th – 24th September 2026, the public are invited to record observations of pollution, wildlife, and river conditions through The Rivers Trust's free Big River Watch app. Surveys take just 15 minutes to complete and key results are published in near-real time on the Big River Watch online dashboard, allowing anyone to see and help build a national picture of river health across one week.

Being the UK and Ireland's largest mass-participation river health survey, the Big River Watch returns at a crucial time following a summer of climate-change induced weather extremes which have caused significant stress for rivers and waterways. As much of the UK and Ireland begins to see rain return, the risk of 'weather whiplash' could increase pollutants entering waterways through soil runoff, or it may trigger significant flooding across the landscape, further exacerbating the poor state of rivers, endangering wildlife and causing anguish for communities. Now more than ever, The Rivers Trusts needs the public's help to fully understand the impact this is having on our waterways.