River Rhondda

The River Rhondda lies in South Wales, formed by two main tributaries, the Rhondda Fawr and the Rhondda Fach. Both valleys show deep U-shaped cross-sections from past ice ages, cutting into Carboniferous sandstones, mudstones and coal seams. The landscape still bears the marks of a century of coal mining, with subsidence making parts of the valley floor sink below river level. To stop flooding, high walls were built across streets, locally called ‘The Rhondda walls’. These barriers stand as reminders of how mining shaped both the land and the lives of people here. The river’s course begins high on Craig y Llyn and Mynydd Beili Glas, where small streams gather into the Rhondda Fawr and Rhondda Fach. The Rhondda Fawr drops steeply through Blaenrhondda before passing mining towns such as Treherbert, Treorchy and Tonypandy. The Rhondda Fach flows from Lluest-wen Reservoir down to Maerdy and Ferndale, joining its sister at Porth. Both branches meet the River Taff at Pontypridd after winding through valleys lined with terraced houses and chapels. Today the river is cleaner than it was for most of the 20th century. Mine water and raw sewage once turned the Rhondda black, but treatment works built since the 1970s have gradually restored life to the water. Walkers can follow paths beside the river through quiet wooded gorges or along rebuilt towpaths in towns. The Rhondda walls still stand among the houses, while herons and small fish now appear where only pollution once remained.