Warragamba Dam, was built by the Metropolitan Water Sewerage and Drainage Board and is the largest and most important source of water supply to the Sydney area. Construction began in 1948 and was completed in 1960. Water flows by gravity through this valve house into two pipelines that feed the raw water to Prospect Water Filtration Plant and via off-takes to the smaller filtration plants at Orchard Hills and Warragamba. This image is part of a fold-out postcard which contains 10 colour postcards.