People in Britain and Ireland are being asked to monitor their local rivers for pollution so a leading water charity can measure the scale of the sewage crisis.

The Rivers Trust is this week launching the Big River Watch, asking people to record observations of their local rivers on a free app. The results will be made available through an interactive dashboard, and will help the organisation, as well as individuals and communities who can all access the data, to take action to improve rivers.

Volunteers will be asked to identify sewage pollution, sewage fungus, minewater and silt, along with other indicators of river health, so pollution hotspots can be identified and tackled. The Rivers Trust is hoping for it to be the UK and Ireland’s biggest ever mass participation survey of river health.