Penygarreg Dam & Valve Tower

Masonry dam with massive heavily rock-faced blocks. To ends, spillways with parapet walls, spillways broaden as they drop, surfaced with hard stone, walls turn becoming parallel to stream; arched outlets. Towards top of downstream side, series of square windows, below these 2 rows of protruding blocks (used to support scaffolding during construction). At bottom of dam, massive circular outlet with keyblock set in aedicule-like surround with piers to ends, pediment over. To each end of dam, platform with steps on downstream side down to top of dam. At centre of dam is attached round valve tower; copper dome with lantern and fish weathervane, waterspouts to circumference, beneath spouts, square windows to upper section, round arches with 2-light windows below; towards downstream side, doorway onto raised platform rising from top of dam; platform has steps to top of dam; valve tower corbelled out over narrower polygonal stage (with barred intake windows) which runs down below water level. Interior said to contain original operating machinery.