Mine 1796-1877. Recorded as 'old water course' by OS in 19th century. Cut in 1876 by Cwm Elan Company. Runs for 9 miles from Llyn Cerrigllwydion Isaf (SN844070000)
(PF 1995).
Generally characterised by bank 1-2m wide x 0.40m high
(RSJ 2000)