 The reservoir is one of two major sources of Dublin's water supply, the other major supply being Vartry Reservoir in east Wicklow.Between 1938 and 1940, 76 houses were demolished, and the bridges at Humphreystown, Baltyboys, and Burgage blown up, in anticipation of the flooding of the valley for the Poulaphouca hydroelectric power station.The Poulaphouca Reservoir supplies the three power stations along the River Liffey, which are located in Poulaphouca, Golden Falls and Leixlip.