People across the UK and Ireland urged to become citizen scientists and gather data on river health as part of the Big River Watch from 24-30 April 2026.

As concern grows over the state of waterways across the UK and Ireland, thousands of citizen scientists are gearing up for the Big River Watch to help monitor the challenges impacting river health that The Rivers Trust is working to address.

Running from 24 – 30th April 2026, The Rivers Trust initiative invites the public to spend just 15 minutes by a river or stream, recording observations of pollution, wildlife, and river conditions through the free Big River Watch app. Survey results are published in near-real time on the Big River Watch online dashboard.

The Big River Watch - the UK and Ireland’s largest mass-participation survey of river health - is already delivering real-world impact. Contributors have identified more than 30 previously unrecorded barriers to fish migration in England, helping to highlight obstacles affecting endangered species including Atlantic salmon, European eel, and twaite shad. Data gathered during each Big River Watch helps fill critical gaps in environmental monitoring – particularly in smaller rivers, streams, and headwaters where pollution often begins but oversight is limited. Once verified, this can be logged on national databases, enabling positive action such as barrier removal or fish-pass installation.