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3
Original
Report.
1st Section Costs.
Existing Kowloon Supply.
Byewash Dam.
Island Supply.
Report on Shing Mun Scheme-Second Section.
In April 1924, I submitted a general report on a scheme for the complete development of the Shing Mun Valley and Southern slopes of Taimoshan Mountain, dividing the scheme into five sections. I recommended that these sections be undertaken as additional water was required in Hong Kong or Kowloon, as with a pipe line across the harbour, the water would be available both to the mainland
and the island.
In June 1924, the 1st Section of the Scheme was approved by the Secretary of State with the proviso that before any further Sections were commenced the Scheme should be submitted to him and be passed by his technical advisers.
The 1st Section of the Scheme as set forth in the report comprised the following works :—
Estimated Cost,
Actual Cost.
Access Road
100.000
Intake Dam & Temporary pipe line of conduit..
North Conduit
135,000
North & South Tunnels & South Conduit
1,100,000
Reception Reservoir
175,000
Filter Beds (1st Section)
200,000
Sheklaipni Service Reservoir (Kowloon)
400,000
Trunk Main
700,000
Cross Harbour Pipe
800,000
122,345.79
73,269.63
72.028.07
1,073,644.13
164,273.88
206,390.27
350,000*
500,000*
260,000*
Public Gardens Service Reservoir (Hong Kong).
400,000
Pipers Hill Service Reservoir (Kowloon).
140,000
136,699.97
*Approximate Costs.
All the above Works are now completed with the exception of Sheklaipui Service Reservoir and The Public Gardens Service Reservoir. The former should be sufficiently advanced to allow of one side being brought into use in about another month, but the latter has been held over meantime owing to the necessity of pro- ceeding with more urgent works.
With the completion of these Works, the total supply available in Kowloon is about five million gallons per day.
Last year the Byewash Dam below the existing Kowloon Reservoir was com- menced and should be completed early in 1931. With this additional Reservoir, the water available in Kowloon will be about 5.66 million gallons per day.
The existing supply on the Island is rated at 74 million gallons per day, but with the addition of the Aberdeen Valley Scheme, now under construction, this figure will be raised to 9.37 million gallons per day by the middle of 1932.
With the linking of the Kowloon and Hong Kong Supplies by the Cross Harbour Pipe, the capacity of the two Supplies can now, up to a point, be calculated
as one.
With works now in hand the total supply available to the Colony (apart from Total
Supply Village Supplies) in 1932 will be 5.66 and 9.37 million gallons per day from Kowloon 1952. and Hong Kong respectively, or a total of 15.03 million gallons per day.
Require-
In my report on the Water Supply of the Colony dated 20th February, 1928, Total I estimated the requirements of Kowloon and Hong Kong in 1932 at 4.9 and 11.6 merts million gallons per day, or a total of 16.5 million gallons per day.
There will therefore be a shortage of 1.5 million gallons per day in 1952 after allowing for the completion of all works now under construction, so that further extensions are necessary.
1932.
The next extension to be undertaken to give any considerable quantity of Extensions. water would appear to be the Second Section of the Shing Mun Scheme which was calculated to give an additional supply of about four million gallons per day and cost $4,750,000.
Works.
The Second Section of the Shing Mun Scheme as set forth in my original 2nd Section report comprises the following works :-
Access Road (Continuation).
Dam No. 1 (Shing Mun Village Dam).
Dam No. 2 (Shing Mun Gorge Dam).
Dam No. 2A (Needle Hill Dam)
Catchwaters discharging through Lead Mine Pass.
Filter Beds (Extension).
24" Pipe line (Duplication).
The lay out of the Access Road is contingent on the number, size and posi- Access tion of the reservoirs to be built so cannot be dealt with until the position and size Road. of the reservoirs are settled.
Dam No. 1 or Shing Mun Village Dam. This Dam from the first has been Dan No. 1. somewhat problematical owing to its great length in comparison with its storage capacity, and surface indications on the West side were not favourable. The trial pits and cuttings which have been made show the rock to be rather deep on the West Side but fairly near the surface on the East Side.
Drawing No. 4 shows the estimated foundation levels and sections for a Dam at this site having a Top Water Level of 710 A.0.D. a maximum depth of water of 150 feet and a maximum depth to bottom of foundations of 168 feet. Such a dam would impound approx. 1,000 million gallons and I estimate would cost $4,200,000 to construct giving a unit rate of $4,200 per million gallons.
Dam No. 2 or Shing Mun Gorge Dam. The Shing Mun Gorge has all the Dam No. 2. appearance of a most excellent Dam Site but on closer inspection it has not been found so favourable, as there is a rather steep fall in the river bed at this point. The capacity of the reservoir is also disappointing owing to the basin being very narrow with almost precipitous sides.
A Dam with a Top Water Level of 565 A.O.D. would impound 1,000 million gallons and would cost approx. $2,500,000 to construct giving a unit rate of $2,500 per million gallons.
Comparing the above two dams it is seen that the unit cost per million gallons of Dam No. 1 is very much greater than the cost at Dam No. 2 and both work out fairly expensive in comparison with existing reservoirs.
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