High Island Water system entailed the construction of two rock dams rising 64 metres above mean sea water level at the eastern and western approaches of the narrow strait running between High Island and the eastern end of the Sai Kung Peninsula to form a reservoir with a capacity of 281 million cubic metres.
Catching rainfall and carrying it to and from the reservoir, to eventually reach everyone's home, require engineers to carve an astounding 40 kilometers tunnel through high rock, form 12 kilometers of catchwater channels, lay 13 kilometers of pipelines, build 9 pumping stations, construct 55 kilometers of roads and extend a treatment works. The system now catches and stores the rain from an area of 70 square kilometers over Sai Kung, Ma On Shan and Sha Tin.
