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ADDITIONAL WORKS NECESSARY TO MEET PRESENT REQUIREMENTS.
125. Taking the present requirements for all purposes at 15 gallons per head per diem and the population supplied at 200,000 persons, the average daily quantity required for distribution is 3,000,000 gallons.
126. The existing works at Pokfoolum and Taitam can be relied upon to supply an average of 2,700,000 gallons per diem, of which, 2,400,000 gallons can be efficiently filtered with the existing filter beds.
127. It will therefore be seen that—
(a) Further works are necessary to render an additional average daily supply of 300,000
gallons of water available.
(b) Further provision for the filtration of 600,000 gallons of water per diem is required. (e) The construction in the Hill District of a service reservoir of 400,000 gallons capacity
is required.
128. On the completion of the works now in hand at Taitam, the capacity of the reservoir will. be increased to 390,000,000 gallons, making the total storage available at Pokfoolum and Taitam 458,000,000 gallons, but, as shewn in paragraph No. 106, the catchment areas can only be relied upon during the months of May to August to yield 692,000,000 gallons.
Now, if during that period an average daily quantity of 3,000,000 gallons be abstracted or a total of 369,000,000 gallons, there is only a balance of 323,000,000 gallons for storage which, added to the yield of the catchment areas during the months of September to April inclusive, viz., 290,000,000 gallons, gives the total available for distribution during the months of September to April inclusive as 613,000,000 gallons or an average daily quantity of only 2,500,000 gallons.
It is therefore necessary to increase the catchment area or to construct additional storage reservoirs for impounding water during the years of heavy rainfall for distribution during those of comparatively
small rainfall.
129. A catchwater contouring the hillside on the west of the Taitam Valley 3,100 lineal yards in length and discharging into the present reservoir will intercept a catchment area of 186 acres.
On the basis previously adopted, this would increase the available supply during the months of May to August inclusive by 61,000,000 gallons, and during the months of September to April inclusive by 25,000,000 gallons.
130. A catchwater contouring the hillside on the east side of the Little Hongkong Valley and discharging into the valley near the Wongneichong Gap would, with suitable reservoir accommoda- ' tion at this point, increase the available daily supply during the year by 300,000 gallons.
131. A suitable site exists for the construction of a reservoir in the valley near the Wong- neichong Gap by the construction of a dam across the valley having a maximum height of about 50 feet and a length of about 270 feet; the capacity of this reservoir would be 27,000,000 gallons. 132. Some minor alterations and extensions to the Pokfoolum conduit will be required with a view to increasing its discharging capacity and thus enabling full advantage being taken during the months of May to August inclusive of the yield of the Pokfoolum reservoir catchment area and the streams intercepted by the conduit.
With these additional works calculating on the same basis as previously adopted, paragraphs Nos. 104 and 105, an additional supply of 193,000,000 gallons per annum will be obtained.
133. The following statement shews the total supply obtainable on the completion of the foregoing works.
Catchment
Valley,
area.
Yield, May to August.
Yield, Sep- tember to April.
Total.
acres.
gallons.
Pokfoolum,
Taitam,
416
207,000,000
gallons.
62,000,000
680
339,000,000
Taitam Catchwater East,
220
72,000,000 30,000,000
gallons,
269,000,000
102,000,000 441,000,000
102,000,000
Taitam Catchwater West,
186
61,000,000
25,000,000 86,000,000
Streams Intercepted by Conduit,
74,000,000
96,000,000 170,000,000
Wongneichong Gap,
100
50,000,000 15,000,000 65,000,000
Catchwater,
90
30,000,000
12,000,000 42,000,000
833,000,000
342,000,000 1,175,000,000