Report on the Shing Mun Valley Waterworks
Scheme by Mr. R. M. Henderson,
M. Inst. C. E., Chartered Civil Engineer.
Population
Owing to disturbances in Canton and the Province of Kwong Tung, Increase in Hong Kong has become a sanctuary for many thousands of refugees. Many of these refugees return to their homes, but quite a large pro- portion find the conditions in Hong Kong so much to their liking that they remain and make their permanent homes here, with the result that the populations of Victoria and Kowloon have increased at an abnormal rate, and restriction of water supply has had to be resorted to.
Supplies
The present calculated capacities of the Hong Kong and Kowloon Existing Water Works during the minimun recorded dry period are roughly 8 million gallons and 12 million gallons per day respectively, and works now under construction will raise these quantities to roughly 9 million gallons and 24 million gallons per day respectively. The full develop- ment of the Island Catchment Areas will only yield barely another 2 million gallons per day, making a total of not quite 11 million gallons per day as their ultimate capacity. The full development of the exis- ting Kowloon Catchment Areas can only raise the existing supply to roughly 4 million gallons per day.
It will be seen from the accompanying graph of consumption that, Consumption without restriction, the normal consumption during 1924 for Hong Kong might be estimated at fully 10 million gallons per day and for Kowloon about 3 million gallons per day - figures which nearly ap- proach the ultimate capacities of our existing Catchment Areas when fully developed.
Investiga
In 1921 investigations of new sources of supply were commenced Preliminary and in 1922 a short Report was submitted making original proposals, tions which included the complete development of the Shing Mun River Valley and Southern Slopes of Taimoshan Mountain. These rough proposals were approved by Executive Council and in July 1923 after further surveys had been completed a further detailed report was sub- mitted (when it was decided to proceed with the work.)
Description
The Scheme consists of the complete development of the Shing General Mun Valley from Lead Mine Pass to the sea and the Southern and Eastern Slopes of Taimoshan, a mountain 3,130 ft. in height. It will include nine storage reservoirs varying in capacity from 55 million gallons to 1,700 million gallons, aggregating a total storage of 4,500 million gallons and draining approximately 13 sq. miles of catchment area, a large proportion of which is included by means of catch waters. The water will be conveyed by means of gravity tunnels and conduits to the filter beds situated in the lower Sheklaipui Valley and from there by pipe lines to Kowloon and Hong Kong,
The scheme as outlined is estimated to give a daily supply of 17 million gallons per day during the driest known period.
Dam No. 1, T. W. L. 710 O. D., which will have a length of 890 Dam No. 1 ft. and a height of 145 ft. above the stream bed, impounding 900 mil- lion gallons, will have a direct catchment area of 2,130 acres, but, by means of catchwaters discharging through Lead Mine Pass, an extra 514 acres will be obtained. The total Catchment Area of 2,644 acres will be sufficient to fill this reservoir with 15 inches effective rainfall.