Work on the damming and flooding of north Wales: the Stwlan dam/reservoir above Tanygrisiau and Tryweryn Valley's Llyn Celyn reservoir.

The dammed and the drowned: Anglesey-based film-maker David E Sutcliffe worked as a ‘stringer' for the BBC i.e. he was the point of contact in the area for any story of note. He ventured into the Moelwyn Mountains to obtain shots of the building of the Stwlan dam/reservoir, part of Ffestiniog's hydroelectric scheme. He also took his camera to Capel Celyn, a village that was about to be evacuated, demolished and drowned in order to provide water for the industries of Liverpool.

The building of the Stwlan dam/reservoir took place between 1957 and 1963. The work enlarged an existing ‘corrie' known as Llyn Stwlan, a steep-sided mountain hollow filled with water. Llyn Celyn involved the drowning of a community - 12 dwellings, a village school, chapel and post office, acres of farmland. The decision was made to flood the valley in 1955, the work was finished in 1965.