ENG-1963 — Page 308

PUBLIC WORKS AND UTILITIES

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behind an earth dam, and gravitates via a tunnel to a pumping station at Pui O from where it is delivered to treatment works overlooking Silver Mine Bay, having a filtration capacity of 35 million gallons a day. The water then passes through eight miles of twin 30 inch submarine pipeline to Sandy Bay at the western end of Hong Kong Island from where it is re-pumped to the 30 million gallon Mount Davis reception reservoir. From there it gravitates to service reservoirs. To provide the feed to these service reservoirs, approximately 16,000 feet of welded steel main varying in size from 24 inches to 48 inches were laid.

The capacity table for the reservoir, giving the quantity in store for each foot of depth, was compiled by aerial survey supplemented by computer calculations and illustrates the advances made in this field of surveying in recent years. Good progress was made on the construction of the 30 million gallon reception reservoir at Mount Davis and the pumping station at Sandy Bay and although neither of these works were ready by the end of the year it was possible to receive water when available by using temporary pumps to the existing Elliot Service reservoir.

Good progress was made on the Plover Cove scheme which basically provides for the conversion of the sea inlet of Plover Cove to a fresh water lake with a useable fresh water storage of 30,000 million gallons. This will be done by the construction of a 1 mile long main dam together with two subsidiary dams. The vast reservoir so formed will be largely filled by the run-off of the stream yields from the hills between Sha Tin and Tai Po. Water in these streams will drop down shafts of up to 300 feet deep to the main collecting tunnel. This main tunnel is being constructed so that the water will gravitate through to Plover Cove for storage. The same tunnels will be used to draw-off from the reservoir by pumping when the streams are yielding less than that required to meet the demand. The supply to the 80 million gallons a day Sha Tin treatment works will be balanced by a 1,000 million gallon reservoir being constructed below the Jubilee dam of Shing Mun reservoir which will also be used to conserve the overflow from the latter. From the treatment works the water will be pumped by 48 inch mains laid under the carriageway of the road tunnel below Lion Rock to service reservoirs on the southern slopes of the Kowloon Hills, and thence to supply.