During the dam construction some of the navvies rioted damaging buildings in the village, several rioters were shot, one dying the next day.

[2] The dam is almost 400 yards (366 m) long and is concrete cored with slate buttresses, the resulting depth of the tarn being around 80 feet (24 m).

An experiment in 1992–1993 to reduce the acidification by using a phosphorus-based fertiliser increased the pH from 5.1 to 5.6 and changed the levels of the different species of the rotifer assemblage significantly.

[6] Work began in 2010, when the downstream face of the main dam was cleaned and loose concrete, efflorescence and other surface deposits were removed.

A reinforced concrete wave wall was constructed to the same dimensions and levels as the existing but it extended into the high ground at the left and right ends of the dam.