River Garw

The effects of coal mining in the valley, both from small family owned shafts and major pits alike, caused the river to become polluted and dirty with coal dust and other chemicals to the point at which it was once entirely black in colour, earning it the mainly local nickname of the "Black River".

[citation needed] It also runs through Bryngarw Country Park - a managed and publicly owned estate and nature reserve, where many types of birds can occasionally be seen.

[citation needed] During periods of prolonged heavy rain, the River Garw quite commonly bursts its shallow banks, causing minor flooding in all villages along its length.

As the villages are mostly up on the valley sides, this doesn't have any significant effect, save for a few places; a house that once stood next to what is now a small footbridge across the river near the children's playground on the valley floor at Pantygog was demolished some years ago due to constant flooding from the river[citation needed].

Its tributary streams, one of which joins at the boundary of Pontycymer and Pantygog, can turn from mere babbling brooks to raging torrents in a matter of a few minutes, and it is not unknown for this to occur very suddenly.