River Rhondda

The River Rhondda is a river in South Wales with two major tributaries, Rhondda Fawr and Rhondda Fach .

The river has two major tributaries, the Rhondda Fawr and the Rhondda Fach . Despite these names, both tributaries are of similar length. Both valleys display the U-shape cross-sections typical of glaciated valleys, having been eroded during successive ice ages. They cut deeply into the thick South Wales Coal measures which comprise sandstones and mudstones and coal seams of Carboniferous age. The whole form of the river and its surrounding urbanisation has been dominated by coal mining and the communities that grew up to exploit the rich coal seams. Much of the valley has suffered severe subsidence because of the removal of coal from beneath the valley floor. The houses and streets have subsided with the result that river levels are, in parts, higher than the surrounding houses. In order to contain the river and prevent flooding, walls have been built, sometimes across the ends of streets - these are known as "The Rhondda walls".

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