Island Barn Reservoir

Island Barn Reservoir was authorized by the Lambeth Water Act 1900 (63 & 64 Vict. c. cxli). It was built by Sir Robert McAlpine for the Metropolitan Water Board, and opened in 1911. The contract was valued at £152,727. The reservoir was named after Island Barn Farm, which previously existed on the site, and was completely surrounded by the rivers Ember and Mole.

The embankment walls have a puddle clay core extending down through a gravel layer to the underlying blue London clay. The outside face of the embankment is grassed, the inner face is lined with concrete slabs. The key dimensions of the Island Barn reservoir are as follows. {| class="wikitable" !Parameter !Value |- |Capacity |922 million gallons (4,091 Ml) |- |Surface area |121 acres (49 ha) |- |Perimeter |1 mile 1,200 yards (2,707 m) |- |Base to top of bank |35 ft (10.7 m) |- |Base to top water level |30 ft (9.1 m) |- |Height of bank |24 ft to 34 ft (7.3 to 10.4 m) |- |Depth of puddle core |15 ft to 25 ft (4.57 to 7.62 m) |- |Embankment volume |1.27 million tonnes |- |Maximum height of…