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.

The area it occupies was originally the Kwun Mun Channel (官門海峽), which separated High Island from the Sai Kung Peninsula.

Its history starts as a result of the water shutdown by mainland China during the 1967 Hong Kong riots.

One was built at the west of High Island connecting it with the Sai Kung Peninsula at Yuen Ng Fan (元五墳).

Aqueducts totalling 5 miles in length were also constructed to transfer water from streams around Sai Kung Peninsula to the reservoir.