Piling specialist Bachy Soletanche is conducting remedial works at the Lower Carno Dam on behalf of Welsh Water.
The dam was built in 1911 and has recently started to develop leaks. The adjacent reservoir was emptied in 2005 so consultant Black & Veatch could inspect it.
Repairs are being carried out so the reservoir can be refilled to increase water supply to local towns and for future developments.
Over a two-phase project, Bachy Soletanche will construct a massive 200m-long diaphragm cut-off wall and provide comprehensive injection grouting to ensure the embankment dam continues to be stable for years to come.
For the injection grouting, Bachy Soletanche is using the Wassara water-powered drilling system, which uses down-the-hole (DTH) hammer drilling. This differs from conventional DTH systems as the hammer is powered by water as opposed to compressed air.
This has a number of environmental benefits. The system operates without producing large volumes of dust particles and oil mist. Also, since a high-pressure water pump is more efficient than an air compressor, the energy consumption is roughly 25% of a comparable air drilling system.