Lock Chambers 31 & 32 with attached walls, Glamorganshire Canal

Cadw's description

Location

On the S side of Ynysangharad Road and to the rear of the Bunch of Grapes public house.

History

The Glamorganshire Canal Act was passed in 1790 and the canal opened in 1794 from Merthyr Tydfil to Cardiff, primarily to serve the growing output of the ironworks at Merthyr Tydfil. Its engineers were Thomas Dadford and Thomas Sheasby. The steep gradient between Merthyr and Cardiff - a fall of 165.5m in 40.2km - was overcome by erecting 51 locks, instead of the inclined planes favoured on other canals. These included a triple lock at Nantgarw (which has not survived) and the double lock at Pontypridd. The rapid growth in output of iron soon led to congestion on the canal, however, but the large volume of trade from the ironworks ensured that the canal survived the opening of the Taff Vale Railway in 1841. Traffic declined sharply when the ironworks declined in the late C19 and coal companies preferred rail transport. The upper section N of Pontypridd was almost disused by the late C19, but the section between Nantgarw and Pontypridd did not close until a breach at Nantgarw in 1942.

Exterior

Comprising 2 adjoining lock chambers with rendered walls and hammer-dressed flat copings. The gates are missing, but the recesses that housed them have coursed hammer-dressed stone walls (part replaced in brick to the N end of the upper lock). At the junction of the 2 locks, on the E side, is a wall of thin coursed rubble stone, possibly to carry a bridge. On the corresponding W side is a later brick abutment.

Reason for designation

Listed for industrial archaeological interest as a surviving double-lock combination necessitated by the steep gradients on the Glamorganshire Canal and as 2 of the few surviving locks on the Glamorganshire Canal.

Group value with the adjacent canal bridge and Newbridge Chainworks canal basin.