A large covered hilltop reservoir, presumably the successor to that marked as a three bay structure on the 25 inch O.S. map of 1906. It consists of a rectangular concrete tank ca 14m x 70m., divided internally for roofing purposes into thirteen bays, each covered by curved sheets of corrugated iron, supported across the width of the tank by lengths of railway track, in turn propped centrally with iron posts. Surrounding the site are several large grassed over spoil heaps, the largest of which is roughly oval in plan and ca 20m x 10m x 3m high. The purpose of the reservoir is probably to provide an emergency water supply in the event of fire as suggested by a handwritten annotation of a 25 inch O.S. map of 1906 at the National Library of Wales. The present tank may be a rebuilt version of an earlier, smaller reservoir.
John Latham, RCAHMW, 20 July 2016