River Walkover SUrvey Of The Afon Gwna

In August we carried out a river walkover survey on the Afon Gwna, a short river on Ynys Môn. The river rises near Llangefni and flows into Llyn Coron. From there, its waters continue as the Afon Ffraw, winding through the extensive dune system before reaching the sea at Traeth Mawr.

A river walkover is just what it sounds like – walking the length of the river from source to mouth (or, in this case, to Llyn Coron). These surveys are a valuable way to assess the river’s health and identify opportunities for conservation work.

Potential interventions might include fencing to reduce livestock access, planting trees to stabilise banks and provide shade, or other measures to improve water quality and habitat. Walkovers also give us the chance to gather information for detailed sediment loss surveys, helping us to understand how land use affects the river.

The Afon Gwna has long faced pressures from agriculture and habitat loss. While North Wales Rivers Trust has carried out walkovers and mitigation works in the past, it is vital to revisit and reassess the river to track changes and identify where further action is needed.

The recent survey revealed that sediment has settled across sections of the riverbed, smothering the clean gravels that migratory fish depend on for spawning. The walkover also highlighted several nearby streams and tributaries where corridor fencing could help reduce pressures and improve habitat quality.