Rivers, lakes and ponds
Several important rivers rise in Fforest Fawr's mountains as fast flowing streams.
These include;
- In the Towy catchment, the Afon Sawdde and the Afon Gwydderig.
- In the Tawe catchment, the Afon Twrch, the Afon Giedd and Nant Llech.
- In the west of the Geopark, the Afon Llwchwr, Afon Cennen and Afon Aman.
- In the Usk catchment, the Afon Crai, Afon Senni and Afon Tarell.
- Those of the Neath catchment such as the Nedd Fechan, Mellte, Hepste, Pyrddin and Sychryd.
- The Taf Fawr & Taf Fechan in the east of the area
The upland streams are fast flowing and birds such as the common sandpiper and the dipper are relatively commonplace.
Other water features include a number of reservoirs and small glacial lakes such as
- Llyn y Fan Fach,
- Llyn y Fan Fawr
- Llyn Cwm Llwch.
These rivers and lakes also provide habitats for brown trout, spawning Atlantic salmon, the white clawed crayfish and otters.
