Orrin Dam With Integrated Fish Pass, Conon Valley Hydro Electric Scheme

Orrin Dam, built in 1961, is part of the Conon Valley Hydro Electric Scheme and was likely designed by James Williamson and Partners, engineers for the North of Scotland Hydro Electric Board technical panel. This long mass gravity dam features a large central buttress that incorporates a fish pass. An access roadway extends over the fixed spillway, which is supported by tapered concrete piers. The dam is primarily constructed of mass concrete, with some reinforced concrete used in the central buttress and control towers. The downstream face is battered, and a large angled buttress is positioned at the center, flanked by tall square-plan control towers that rise from the downstream face. At the base of the buttress, there are dispersal valves and the entrance to the fish pass, along with a small single-storey turbine hall that houses the compensation set. Additionally, there is a small control tower located at the center of the buttress at roadway level.