Ancient Monuments

History on the Ground

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Gilwern Embankment

A Scheduled Monument in Llanelly (Llanelli), Monmouthshire (Sir Fynwy)

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Latitude: 51.8237 / 51°49'25"N

Longitude: -3.0983 / 3°5'53"W

OS Eastings: 324403

OS Northings: 214466

OS Grid: SO244144

Mapcode National: GBR F2.W83V

Mapcode Global: VH795.7FY9

Entry Name: Gilwern Embankment

Scheduled Date: 23 January 1996

Source: Cadw

Source ID: 4342

Cadw Legacy ID: MM251

Schedule Class: Industrial

Category: Industrial monument

Period: Post Medieval/Modern

County: Monmouthshire (Sir Fynwy)

Community: Llanelly (Llanelli)

Built-Up Area: Gilwern

Traditional County: Brecknockshire


The monument consists of the remains of an embankment and aqueduct carrying the Brecknock and Abergavenny canal across the gorge of the River Clydach. It dates to the industrial period. An aqueduct is a pipe or conduit for the purpose of transferring a constant supply of water from a spring or other source. Construction began in 1797, but the entire canal was not opened until 1812. It became an important artery for trade in iron, lime and coal to supply the Usk valley. The embankment is roughly 23m at it's tallest and is some 100m long.

The stone arch forming the aqueduct over the Clydach is 90m long to carry the enormous width of such a tall earth embankment. It is a massive semi-circular arch with buttressed portals at either end. A smaller aqueduct carries the canal over the former Clydach railroad at the north end of the embankment and an overflow at the south end has a small footbridge.

The monument is of national importance for its potential to enhance our knowledge of industrial engineering and technology. It retains significant archaeological potential, with a strong probability of the presence of associated archaeological features and deposits. The structure itself may be expected to contain archaeological information concerning chronology and building techniques, together with a strong probability of environmental evidence. Aqueducts may be part of a larger cluster of monuments and their importance can further enhanced by their group value.

The scheduled area comprises the remains described and areas around them within which related evidence may be expected to survive.

Source: Cadw

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