Shek Pik Reservoir – Construction
The Shek Pik reservoir is part of a larger scheme to supply Hong Kong Island with a water supply through submarine pipeline from Lantau Island. The reservoir has a capacity of 24.5 million m3 with a direct catchment of 7.8 km2but with the completed catch waters the catchment area is expanded to 53 km2 or 40% of the area of Lantau Island.
The dam is constructed of earth fill up to 55m high and required around 4.8 million m3 of fill. The upstream slope is protected from wave action by rock rip-rap and the downstream slope is protected from rain erosion by turf. The cost of the reservoir was around HK$3,3 million (at 1964 prices).
Following site preparation, a grout cut off curtain, up to 70m deep was installed to prevent water passing below the dam. Work then commenced on the main dam in October, 1961. Working 19 hours a day, six days a week placement of the bulk fill was substantially completed within 21 months. By July, 1963 4.2 million m3 or 87% of the total fill had been placed and compacted.
Problems were encountered with the natural material found on site that had been intended to use in the dam construction, and to avoid a major delay the unsuitable alluvium material was replaced with 0.6 million m3 of imported sand. During the later stages of construction of the embankment, cracks were identified in the dam core. Following investigations it was concluded these were as a result of settlement of the foundations of the dam. The cracks were grouted and monitoring indicated negligible water leakage.
Impounding and filling of the reservoir began in 1963 and was complete after the 1964 wet season.
In addition to the reservoir construction, there was the construction of an extensive catch waters network and transfer tunnels to supply the reservoir.
This article was first posted on 11th February 2014.
Shek Pik Dam by William Johnstone Carlyle – Resident Engineer for the Works
Institute of Civil Engineers Paper 6841, presented 27th April 1965
Thomas Ngan adds: I wonder if the by-product of this construction should also be mentioned. South Lantau Road, Silvermine Bay vehicular ferry pier, etc.
See: Shek Pik Reservoir