Due to increasing leakage the dam had to be strengthened using high-capacity ground anchors. In total, 64 vertical DYWIDAG Strand Anchors were installed from the crest of the existing dam into the underlying bedrock to act as tie-backs. Double corrosion protected, the strongest anchors reach an ultimate strength of 8,100 kN.

Logistics was a major challenge for the contractors involved. The only access to the job site was via a narrow and winding single track road south of the dam on which only four DYWIDAG Strand Anchors could be delivered on each vehicle. Installation of the anchors had to be carried out from the top of the dam, as there was no possibility of working from a barge mounted crane due to the loch level having been drawn down for safety reasons.

A special 6,800kN long stroke jack, the highest capacity anchor stressing jack in the UK, was used for both the anchor tests and the final stressing as the DYWIDAG Strand Anchors are some of the highest capacity ground anchors that have ever been installed in the UK.