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Shek Lai Pui Service Reservoir.
This service reservoir, which is supplied from the adjoining Rapid Gravity Filtration Plant, is designed to regulate the supply of filtered water for distribution to Hong Kong and Kowloon.
A contract for its construction was let on September 14th, 1928, and by the end of July, 1930, construction was sufficiently advanced to allow the Eastern half of the reservoir to be brought into use. The whole reservoir was completed by the end of 1930.
The Reservoir, which was originally intended to store 5 million gallons, was increased to a capacity of 11.41 million gallons, and has a T.W.L. of 443.00 A.O.D., the average depth of water when full being 18′ 0′′.
The Reservoir is generally rectangular in shape, having the North-west and North-east corners cut off. The maximum inside dimensions are 432′ 0′′ × 270′ 0′′. A division wall 12′ 0′′ high divides it into two compartments, either of which may be supplied or drawn from independently.
The inlet conduit from the filtration plant discharges into a control house, from which water can be passed into either half of the reservoir, and in which pro- vision has been made to deal with the supply from future extensions of the filtration plant.
Two separate 24" diameter draw-off pipes, controlled by penstock valves, dis- charge into a wet well from which water can be drawn off into a 24" diameter trunk main, controlled by a similar valve. Provision has been made in the wet well for the control of two future trunk mains.
An overflow and means for washing out the Reservoir have been provided.
Access to the site of the Reservoir and Filtration Plant is effected by means of an access road from the Taipo Road, which was constructed under the contract for the Bye-wash Reservoir.
The main and division walls of the Reservoir, which have bitumen expansion joints, are constructed of cement concrete generally of gravity section but reduced in thickness where the nature of the ground was suitable. The invert is of cement concrete 9′′ thick with bitumen expansion joints. The roof, which is of the rein- forced cement concrete slab and beam type, is supported on reinforced cement concrete piers and is covered with turfed earth filling 12" thick.
The following are a few particulars of the works:-Area of roof 110,000 square feet; number of piers 522; length of main walls 1,276 feet; length of divi- sion wall 285 feet; concrete in walls, 4,620 cubic yards; concrete in invert, 2,700 cubic yards; concrete in roof, 2,000 cubic yards.
24" Trunk Main Kowloon.
This main forms the principal artery for the delivery of filtered water from the Shing Mun Valley to the several points of distribution in Kowloon and to the Harbour Pipe Line for a supply to Hong Kong.
Pipes, valves and specials were obtained through the Crown Agents for the Colonies, and delivery in the Colony was completed by the end of 1926.
A commencement was made with the laying of the main in May, 1927, and the work was completed by the end of February, 1930, when a connection was made with the Cross Harbour Pipe.
The upper section of the work, which is in difficult country, required two rein- forced concrete bridges to carry the main across the Shek Lai Pui and Lai Chi Kok Streams. This section was completed on June 10th, 1929, thus enabling the first