Annell Aqueduct (upper section)

Cadw's description

Summary description and reason for designation

The following provides a general description of the Scheduled Ancient Monument.

The monument consists of the remains of part of a water channel, known as the Annell Aqueduct, dating to the Roman period. It is believed to have been constructed in conjunction with the Roman exploitation of the gold mines at Dolaucothi, probably in the later 1st and early 2nd centuries AD. The multiple channels on this stretch are thought to represent an effort to overcome a particularly steep drop; above and below this stretch there is no sign of more than one channel. Its source was originally presumed to be near SN 707 436, on the upper reaches of the Annell, the valley of which it is assumed to follow, hugging the contour of the hillside, towards Caio, swinging westwards from there towards the main mine area. A similar portion to this, further down this course, is scheduled as CM210. More recent work has suggested that the aqueduct may have extended further to the north-east, to tap the headwaters of the Gwenlais, which otherwise flows south-east towards Cilycwm. Parts of its course were probably carried on or supported by timber structures which do not survive. This is part of a network of leats serving the Dolaucothi mine, and an important demonstration of the sophistication of water management by Roman engineers.

On this stretch, one main channel, continuing that traceable from the source, clearly runs from the point where the aqueduct crosses a small side stream, right down the hillside, and into the adjoining property, where it is visible as far as the N-S fence. Beyond this point it might be expected to swing gently to the S around the top of the marshy area from which rise a number of small tributaries to the Annell, though some commentators have suggested that it may have passed across the col into the Cothi valley to join one of the aqueducts there (CM213 or CM200). Below this main channel, on the steepest part of the hill, lie two other parallel channels and traces of another, although any detail of how these other channels began and ended has been obscured, probably by water action. The fourth channel does not begin until about 40m beyond the beginning of the second and third channels, and ends quite abruptly. It may well be unfinished. There are some signs of a side channel capturing the small side stream and feeding it into the main channel.

The monument is of national importance for its potential to enhance our knowledge of Roman structural engineering and mining technology. The scheduled sections of the monument are generally well-preserved and an important relic of their Roman construction. They retain significant archaeological potential, with a strong probability of the presence of both structural evidence and intact associated deposits.

The scheduled area comprises the remains described and areas around them within which related evidence may be expected to survive. It consists of an area 45m wide by 520m long.