Rhymney River

The Rhymney River is a waterway in South East Wales that winds through the Rhymney Valley before joining the Severn Estuary near Cardiff. It rises on the southern edge of the Brecon Beacons and descends steeply past former mining towns such as New Tredegar, Bargoed and Ystrad Mynach. South of Machen the valley broadens into a flat plain where the river meanders gently toward the estuary. The river once carried heavy pollution from coal and iron industries that dominated the valleys in the 19th and 20th centuries. After the last mines closed in the late 1980s, water quality improved and wildlife returned. Natural brown trout and grayling now thrive, and culverts have been removed to let fish reach the upper reaches once more. Visitors can walk along the riverbanks or follow valley paths that pass former factory sites and old mining villages. The upper valley shows steep, wet hillsides while the lower plain offers wide, calm stretches of water. The river’s cleaner flow supports dragonflies, birds and other wildlife, making it a living example of recovery in a once-industrial landscape.