High Island Reservoir East Dam
The High Island Reservoir, located in the far south eastern part of the Sai Kung Peninsula, was opened in 1978 helping to alleviate water shortage problems in Hong Kong. Its water capacity is approximately 273 million cubic metres. The area it occupies was originally the Kwun Mun Channel, which separated High Island from the Sai Kung Peninsula.
Its history starts as a result of the water shutdown by mainland China during the Hong Kong 1967 riots, the government responded with the High Island Reservoir. It was expected to be the same size as Plover Cove. The construction, contracted by an Italian company cost more than HKD $400 million.
(the above info is from the internet)