The UK’s newest dam, located on the Morvern Peninsula in the West Central Highland of Scotland, has been granted its preliminary certificate.
Loch Uisge dam, built by main contractor Amco for Scottish & Southern Energy, has a capacity of over 700M litres and will act as the headpond storage for the Kingairloch hydro power scheme.
The main source of water for the dam is the Abhainn na Coinnich. To maximise the load factor of the scheme a series of minor intakes and aqueducts have been constructed to transfer water from the three downstream tributaries – the Abhainn Ghardail, the Allt Choire Shalachain and the Cam Alltan. This has resulted in a 51% increase in the rainfall catchment area.
The Scottish Environment Protection Agency (SEPA) has set minimum compensation flows at all of the affected rivers and tributaries. At the minor intakes this has been achieved by the fixed structural design of the weirs; however in order to avoid ‘wasting’ water the dam has been equipped with a variable control valve which regulates the compensation flow at 60 litres/sec regardless of the level of the loch. The integrity of this regulation – achieved by means of a PLC and closed loop flow transducers – is maintained by a UPS designed to protect against power failure. The PLC also controls the six automated fish ladder gates. The construction has necessitated the diversion of the adjacent B8043 road by 1.7km.
Amco’s project team included designer Faber Maunsell, penstock gate manufacturer Adams Hydraulics and control systems sub contractor Seetech. Faber Maunsell were also appointed as the Panel Engineer.