Using a method first devised by anglers, Riverfly sampling is a way of gauging the water quality of rivers and streams by estimating the abundance of a set range of invertebrates. This is a national scheme which is recognised by the Environment Agency and the water companies. Regular sampling can not only reveal natural seasonal variations in invertebrate numbers, but it can also act as a warning system to report pollution incidences.

Friends’ volunteers have been trained and accredited by Groundwork Wigan to act as Riverfly citizen scientists so that regular sampling of the River Chor at specified locations can take place and be officially recorded.