History in Structure

Craig Coch Dam & Valve Tower

A Grade II* Listed Building in Rhayader, Powys

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Latitude: 52.305 / 52°18'17"N

Longitude: -3.624 / 3°37'26"W

OS Eastings: 289364

OS Northings: 268669

OS Grid: SN893686

Mapcode National: GBR 9C.WY3C

Mapcode Global: VH5CN.4BGC

Plus Code: 9C4R893G+X9

Entry Name: Craig Coch Dam & Valve Tower

Listing Date: 31 July 1995

Last Amended: 31 July 1995

Grade: II*

Source: Cadw

Source ID: 16198

Building Class: Water Supply and Drainage

Also known as: Cronfa Craig Goch
Craig Coch Dam & Valve Tower, Elan Valley

ID on this website: 300016198

Location: About 8km W of Rhayader centre.

County: Powys

Community: Rhayader (Rhaeadr Gwy)

Community: Rhayader

Locality: Elan Valley

Traditional County: Radnorshire

Tagged with: Dam

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One of series of dams in Elan Valley built by City of Birmingham 1893 to 1904. Engineer James Mansergh. The scheme was amongst the greatest civic achievements of the late C19. The Corporation of Birmingham employed direct labour for the scheme which involved the construction of 53 km of railway to transport materials from the Wye Valley line at Rhayader, 4 dams, an aqueduct 126 km long, and a village for construction workers.


The height of the reservoirs enabled water to reach the outskirts of Birmingham by gravity alone, without the expense of pumping. Provision was made for future expansion in the Claerwen Valley where the scheme was brought to its current state by the Claerwen dam in 1952.

Bronze plaque from dam (removed to visitor centre) says
" Craig Coch Reservoir
Total Capacity 2,000,000,000 gallons
Top Water Area 217 Acres
Top Water Level 1,040 feet above Ordnance Datum
Height of Dam above River Bed 120 ft
Depth of Foundations below River Bed 10 ft
Length of Weir 390 ft
Thickness of Dam at Base 104 ft

Estimated quantity of masonry 80,000 cubic yards"

Curved masonry dam with massive heavily rock-faced blocks. To ends, spillways with parapet walls, spillways broaden as they drop, surfaced with hard grey stone; walls turn, becoming parallel with river. On East side is outlet partly submerged at time of inspection.

Dam supports viaduct on 13 arches carrying roadway over dam. Contrasting rock-faced and smoother stone. Piers support segmental arches with keystones; bandcourse at road level, parapet with coping and heavy rock-faced capstones; 3 arches from each end, is polygonal refuge corbelled out. Abutments to viaduct have doorways to interior of dam. Opposite E refuge is attached polygonal valve tower; copper dome with lantern and fish weathervane, waterspouts to parapet, paired windows to each face set back from buttresses; this stage corbelled out over narrower stage, with barred intakes, which runs down below water level.


Interior said to contain original operating machinery.

Reasons for Listing

Graded II* as part of one of the greatest civil engineering projects of C19.

External Links

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