Water impounded by the uncompleted Dol-y-mynach Dam (nprn 32178) forms the reservoir which has a surface area of 26 acres. It supplies water to the Foel Valve Tower (nprn 32527) via the Dol-y-mynach Tunnel (nprn 309538), thereby making available the waters of the Claerwen River to the Scheme (nprn 96459).
B.A.Malaws, 24 November 2003.