The reservoir is 125 acres (51 hectares) in area with a depth of 97 feet and has a holding capacity of 1,408 million gallons, making it the largest of the water supply reservoirs in the immediate Sheffield district. The catchment area is the Langsett Moors to the west and this covers an area of 5,203 acres (2,105 hectares). The embankment is 1,156 feet (352 metres) long with a height of 117 feet (35 metres) from the bottom of the old river bed. The embankment is 720 feet (219 metres) wide at the bottom tapering to 36 feet (11 metres) at the top and contains 900,000 cubic yards of infill in the puddle wall and concrete trench, making it one of the largest earth embankments in Great Britain.