How healthy is your local watercourse? Anna Forbes of Action for the River Kennet (ARK) demonstrates how to carry out a survey of the aquatic insects in rivers and streams. With training, riverfly monitoring can reveal evidence of pollution events and provide a valuable insight into the ecology of our watercourses. Includes footage of a survey, close ups of key indicator species and where to get more information. A film for woodlands.co.uk by Clearwater Photography UK.