197
18
19
Drawings.
Borings (Analysis of).
HONG
KONG.
SHING MUN VALLEY WATER SUPPLY.
REQUISITION No. 3621.
SPECIFICATION TO BE OBSERVED IN SUPPLYING, CONSTRUCTING, AND MAIN- TAINING PIPE LINES, WITH VALVE CHAMBERS, CONNECTING PIPES, SLUICE VALVES, AND ALL ACCESSORIES, AUXILIARY PLANT, AND OTHER WORK REQUIRED TO CONNECT ACROSS HONG KONG HARBOUR, THE WATER MAINS IN KOWLOON WITH THE WATER MAINS IN VICTORIA, FOR THE PURPOSE OF CONVEYING WATER FROM THE NORTH SIDE OF THE HARBOUR TO THE SOUTH SIDE.
I.
WILLIAM FAIRLEY, M.Inst.C.E.
DESCRIPTION OF WORKS.
Consulting Engineer.
The following drawings show the extent of the Contract and the proposed design of the Works :-
Hong Kong Harbour (Admiralty Chart).
Longitudinal Sections.
Borings Details.
Drawing No. I.
No. 2.
Site Plan.
"J
No. 3.
"
No. 4.
Cross Sections.
1
No. 5.
No. 6.
JJ
No. 7.
No. 8.
"
21
No. 9.
No. 10.
Pipe Lines and Shore Connections,
Valve Chambers-Pipe details.
Valve Chambers-Building details.
Gangways connecting to Shore, Details.
The drawings are based upon particulars received from the Colony and the measurements have been taken by responsible Government Officers. The nature of the Borings (Drawing No. 5), Current Lines (Drawing No. 1), and Sections (Drawings Nos. 3 & 4), are given for the information of the Contractor, but such information is not guaranteed by the Crown Agents in any way, and Contractors must accept the same on their own responsibility.
2. An examination and report on samples of borings received from the Colony has been made by Messrs. Riley, Harbord & Law (Chemists, Westminster), as follows:-
25th May 1925.
"We have examined the samples taken from the bores in Hong Kong Harbour and find they consist of ordinary inorganic rock material together with a certain amount of marine shells. We kept bores 1 to 10 distinct from II to 15, as they were slightly different in appearance, but from the results of our examination, it seems that the difference is only one of colour. Both samples are very slightly alkaline and are free from any organic matter or other constituent likely to cause more than the average corrosion of sea water on iron.
"The following are the results of our examination of the two samples :-
Bores 1 to 10.
Bores II to 15. 65.12
Insoluble residue
64.20
Alumina
2.72
2'03
Oxide of Iron
4-48
3*49
Lime
11.76
12.70
Magnesia
0.86
0.86
Sulphuric Anhydride
0*42
0.38
Sulphur as Sulphide
0.13
0.08
Loss
14.98
14.68
JH
99*55
99'40
3. A copy of the analysis of the water from a new source of supply has been Water (Analysis received from the Colony, as follows:-
Total Solids
::
of).
Average composition of Hong Kong Water (Filtered). Appearance (in 24
inch tube). Clear and bright. Colour Lovibond scale---
Yellow Red
2.3
I 0
Blue
0.3
Total colour units..
3.6
2-6 Parts per 100,000.
Total hardness Permanent hardness
2.5
do.
I 5
do.
Temporary hardness
1'0
do.
Free ammonia
0.0014
do.
Albumenoid ammonia
0.0040
do.
·
Oxygen absorbed (4 hours at 30° Nitrates;
0.031
do.
0'020
do.
Examination of the total solids-
Chlorides
Sulphates S.O. 3
Carbonates CO. 3
Nitrates NO. 3 Nitrates NO. 2. Phosphates PO. 4
Ammonia NH. 4
Calcium Ca. Magnesium Mg. Iron Fe. Manganese Alkalies Lead
0.700
do.
0 210
do.
Q'450
do.
0'020
do.
0.000
do.
0.920
do.
0.002
do.
0.190
do.
0.007
do.
0.020
do.
0'000
do.
0.080
do.
0'000
do.
0'000
do.
0'000
do.
Total
2'599
do."
4. Three Naval Anchorages will be crossed by the line of pipe shown on the Naval Anchorages. drawing, but these will be lifted by the Naval Authorities when the pipes are being laid, and again relaid by them, so that the lifting and relaying will not be included in the Contract.
Zinc Copper
5. The average currents to be expected in the Harbour are shown on the chart, Tide Currents. Drawing No. 1, but the currents will vary with the range of tide and prevailing wind.
A diagram showing the range of tides is set out on Drawing No. 2.
6. The site upon which the pipes, valve chambers, and connections are to be Site. constructed, is situated in the Harbour of Hong Kong between Kowloon Sea Wall on the North and Victoria Sea Wall on the South. The Works on the North to terminate behind the Sea Wall, with a connection prepared for joining up to a pro- posed 24 inch main, and to terminate on the South side, behind the Sea Wall, with a 24 inch pipe ready for connecting up to a proposed new 24 inch main in Victoria.
7. The Contract shall comprise the manufacture of all steel, cast iron, or other Extent of pipes, valves and special castings required, to the dimensions hereafter specified, Contract. together with all necessary materials, labour, implements, and things necessary in the manufacture, testing, transporting, delivery, construction, and setting to work, including all special plant required for testing on the site both before and after laying in position and connecting up the pipes from the shore; all special floating plant,
198
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