Below ground The river is sourced by three tributaries: the
Sruh Croppa, the
Aghinrawn and the
Owenbrean; all of which sink into limestone on the Marlbank (a plateau on northern Cuilcagh Mountain) and join underground in the extensive Marble Arch cave system. The Sruh Croppa and Aghinrawn flow together for a short distance from Cradle Hole into Marble Arch Cave, before joining up with the Owenbrean at The Junction. In normal water levels, the Marble Arch Caves tour begins by boat, underground on the initial stretch of the Cladagh, and passes The Junction before continuing upstream along the Owenbrean. Halfway along Cladagh Glen, another large resurgence joins the Cladagh at Cascades Rising. This is the discharge for the ''Prod's Pot–Cascades Rising'' section of the Marble Arch Cave system, which takes water from a large catchment including Gortmaconnell (2 km), Brookfield (2.5 km) and more surprisingly
Badger Pot and other East Cuilcagh sinks, 5.5 km away, as well as a portion of the Owenbrean River from small sinks upstream of its main sink at Pollasumera (Gunn, J.). == Environment ==