This article appeared in the Guardian yesterday – whilst we have been doing monthly chemical checks on the river for several years, and are about to start macroinvertebrate surveys, such mass action can only help by showing support. https://www.theguardian.com/environment/2022/oct/11/britons-urged-help-monitor-state-rivers-streams-autumn-water-watch
The link below takes you to the organiser’s website and contains a video as well as another link to the App. You can also report your results on line if you don’t want to use the app. https://planetpatrol.co/autumn-water-watch/
Good luck, and let us know how you got on if you give it a go.