Marchlyn Mawr Dam, Snodownia, Wales
Inspection & maintenance contract for asphaltic concrete lining
In 1996-1998 Hesselberg Hydro performed inspections and some remedial work on several dams with asphaltic waterproof linings, in the UK, Norway & the Faroe Islands. In 1998 they were asked to inspect and maintain the Marchlyn Mawr Dam nestling high in Snowdonia.
A thorough investigation was carried out and some minor surface defects were detected. These were closely monitored over the next seven years. It was discovered that the defects were generally vertical surface cracks along construction joints, with other minor defects apparent on the lining in various locations.
The defects were on a steep upstream face of the dam and with the potential for vicious winds and heavy rain, remedial work can become a challenge even for specialists. On top of this the power station operation was not to be interrupted so the asphaltic membrane works could only occur between 1200 – 2400hrs and the lining had to be left impermeable at the end of each shift.
- 30,000 m2 asphaltic lining to be inspected and maintained
- First inspection and minor maintenance in 1998
- Maintenance to panel cracks in 2005
- 20,000 m2 new seal coat placed in 2006