Part of the Elan Aqueduct (nprn 95469), itself part of the Elan Valley Water Scheme (nprn 96459), the Dulas Syphon carries the pipeline under the Black Brook and River Dulas. It consists of the syphon inlet (nprn 309616), a washout chamber (nprn 309617) and the syphon outlet (nprn 309618) and covers a distance of some 0.95km.
B.A.Malaws, 08 December 2003.