Cof Cymru: National Historic Assets of Wales · Wales
Clywedog Siphon outlet house
Llanbadarn Fawr, Powys, Wales
The record
- Designation
- Listed building, Grade II
- Broad class
- No class recorded
- Date of designation
- 10 December 2004
- Locality
- Fron
- Community
- Llanbadarn Fawr
- Unitary authority
- Powys
- Country
- Wales
- Coordinates
- 52.28470, -3.33596
- Cadw reference
- 83365
Slide toward Today to fade the historical sheet and see the modern map underneath.
David Rumsey Map Collection, Stanford LibrariesDavid Rumsey Map Collection, Stanford LibrariesDavid Rumsey Map Collection, Stanford LibrariesDavid Rumsey Map Collection, Stanford LibrariesDavid Rumsey Map Collection, Stanford Libraries
Shown on 5 historical map sheets, the earliest the 1608 "(13) Cambriae Typus." (David Rumsey Map Collection, Stanford Libraries).
Cadw's description
Location
In a field on the E side of the A483 S of Woodside Cottage, approximately 1.1km N of the main road junction in Crossgates.
History
Part of the Birmingham Corporation scheme to supply water to the city from reservoirs in the Elan Valley. The project began in 1892 with the construction of the reservoirs and opened in 1904. Chief engineer was James Mansergh, joined and later succeeded as project engineers by his sons Ernest Lawson Mansergh and Walter Leahy Mansergh. The water was conveyed principally by means of a subterranean aqueduct, but where the river valleys caused the ground level fell below the hydraulic gradient one of the solutions was to direct the water into siphons that carried the water under the valley floors. Siphons consisted of cast-iron pipes of 42-inch (106.68cm) diameter, the relatively small dimensions of the pipe being offset by the high velocity of flow. Each siphon was designed for 6 pipes but only 2 were built in 1904, the remainder being reserved for an increase in future demand. A third pipe of 60-inch (152.4cm) diameter was completed in 1939 and a 4th pipe of the same diameter was constructed in the 1950s. Each siphon has an inlet and an outlet house where water is channelled to and from the main aqueduct. The water flows into a bell chamber beneath the railed forecourt, then into the pipes situated below the inlet/outlet houses, which house valve controls.
Exterior
A single-storey outlet house of brick with freestone dressings and rusticated quoins, on a rock-faced plinth. The roof is concealed behind a moulded cornice of reconstituted stone. The E side has central steel doors (beneath inscription bands now chiselled out) flanked by cross windows. The rear has 3 similar windows. The E front has forecourt railings with diagonal sides to a central gate.
Reason for designation
Listed for its special architectural and historic interest as an integral component of one of the foremost civil engineering projects of the early C20 in Wales.
Nearby in the register
- U-plan farm ranges at Coedgwgan HallAgriculture and Subsistenceunder 1 mi
- Coedgwgan HallDomesticunder 1 mi
- Milestone on A483No class recordedunder 1 mi
- Cefn Farmhouse, including attached farm rangeNo class recordedunder 1 mi
Other entries of the same register within about three miles of this one, by straight line.