Rhymney River

The Rhymney Valley, source of the Rhymney River

The river as it passes through Machen

The river as it passes through Ystrad Mynach

The river in its lower reaches, as it passes through Llanrumney on the eastern outskirts of Cardiff

Mouth of the river, as it reaches the River Severn just east of Cardiff

The Rhymney River (Welsh: Afon Rhymni) is a river in the Rhymney Valley, south-east Wales, flowing through Cardiff into the Severn estuary.

The river forms the boundary between the historic counties of Glamorgan and Monmouthshire.

Path of the river

The river runs south, through (in order):

• Rhymney
• New Tredegar
• Bargoed
• Ystrad Mynach
• Llanbradach
• To the north of Caerphilly, the river arcs east avoiding Caerphilly mountain
• Bedwas
• Trethomas
• Machen
• Draethen
• Llanrumney and Rumney, two districts of Cardiff

History

The Rhymney Valley (Welsh: Cwm Rhymni) was created as a glacial valley. Sourced within the valley, on the southern edge of the Brecon Beacons, the Rhymney River descends steeply through the town of New Tredegar towards Ystrad Mynach, and then onwards south across a flat plain before entering the Severn Estuary to the east of Cardiff. The villages of Groesfaen, Deri, Pentwyn and Fochriw are located in the Darran Valley and not the Rhymney Valley, which joins the Rhymney Valley at Bargoed.

Covering a distance of 30 miles (48 km), the catchment is divided into two distinct parts:

• Upper reaches: steep-sided, wet, mountainous upper valley
• Lower reaches: flatter wider valley below Machen, where the river assumes a lowland meandering character

Being located in part of the South Wales coalfield and South Wales Valleys iron producing area, the resultant black river had poor water quality through most of the 19th and 20th centuries. The river is culverted in many of its upper sections, including a tunnel under the former factory complexes in Rhymney, exiting at Pontlottyn.

Since the closure of the last of the coal mines in the late 1980s, the water has become a lot cleaner and is now full of fish and insect life and supports plenty of other wildlife. The river now supports a healthy stock of Grayling and natural Brown Trout, and a lot of work has been undertaken to remove former industrial restrictions on the river to allow the fish to gain access to its upper reaches. The river is presently in the care of the Environment Agency Wales and the South East Wales Rivers Trust.

External links

• Southeast Wales Rivers Trust
• Rhymney River Club - Marina