Sessional_Paper_1896 — Page 256

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77. The principal dimensions of the engines and pumps are as follows:-

H. P.

Diameter of Cylinder, Inches.

I.

Diameter of Pump Rams, Inches.

Length of Revolution,

L. P.

Inches.

6

9

14

23

18

253

Displacement of Pumps per revolution, gallons.

0.773

78. The maximum height to which water is pumped is 1,780 feet above Ordnance Datum. 79. Water Tanks.-Six cast iron tanks have been erected in the District, viz., at the Peak and Mount Gough of 5,000 gallons capacity each, and at the Peak, Mount Kellet, Plantation Road and Magazine Gap of 10,000 gallons capacity each.

80. Mains.-Five and one-third miles of water mains have been laid in the Hill District; these are of wrought iron varying from 3" to 15" diameter.

81. The rising main from the Pumping Station to the Peak is of hydraulic piping fixed together with screwed socket joints, and is 4,390 feet in length.

82. These works were completed in 1891 at a cost of $32,585.00.

STREAMS INTERCEPTED BY CONDUITS.

83. Extension of Works.-The inadequacy of the water supply from the Taitam and Pokfoolum valleys alone to meet the requirements of the City became only too evident during the exceptionally dry winter of 1890 and 1891, and steps were at once taken to divert the waters of the several small hill streams crossed by the Pokfoolum and Taitam conduits, and to connnect the Albany filter beds with the Pokfoolum conduit by a 10-inch cast iron syphon.

84. The interception of these streams materially reduces the amount of water drawn from the Pokfoolum and Taitam reservoirs during the rainy season, and to not an inconsiderable extent increases the daily quantity of water available for distribution during the dry season.

PROJECT FOR INCREASING THE CAPACITY OF TAITAM Reservoir.

85. The failure of the water works to afford a constant supply of water throughout the year, necessitating the introduction of the intermittent system with all its attendant dangers, waste and inconvenience led the Government in 1894 to ask the advice of Mr. CHADWICK as to the best means of increasing the quantity of water available for distribution, and in a report dated the 7th August, 1894, he urged upon the Government the desirability of at once proceeding with the raising of the Taitam dam which had originally been purposely designed to admit of this. Indeed, Mr. PRICE had pointed out the desirability of this extension in a report dated the 25th October, 1886.

86. On my return from leave in October 1894, a definite project was prepared and received the approval of Mr. CHADWICK, involving raising the main embankment 12 feet 6 inches, and the overflow

■10 feet, admitting of an additional storage capacity of 78,000,000 gallons making a total of 390,000,000 gallons. This project further included the erection of movable sluices on the overflow sill admitting of the storage of a further quantity of 20,000,000 gallons in favourable seasons.

87. The addition to the main embankment has been completed and the overflow raised 5 feet, so that the present storage capacity of the reservoir is 350,000,000 gallons.

It is intended to raise the overflow a further 5 feet this year.

88. Extension of Catchment Area discharging into the Taitam reservoir.-The failure of the run off from the Catchment Area of the Taitam reservoir during the year 1895 to fill (after deducting the water drawn from the reservoir during the rainy season) the reservoir was only to be expected with the unprecedented small rainfall of 45.84 inches as pointed out in my report dated the 4th of February, 1889.

89. This experience has necessitated, in order that full advantage may be taken of the storage capacity of the reservoir, the adoption of measures to increase the catchment area discharging into the reservoir. An open concrete conduit or catchwater, 2,713 lineal yards in length and having a discharging capacity of about 1,500,000 gallons per hour, is being constructed contouring the southern and eastern slopes of the hills to the east of the Taitam reservoir. By this means, an area of 220 acres will be added to the catchment area making a total area of 900 acres discharging into the reservoir.

SUPPLY OBTAINABLE FROM EXISTING WORKS AND THOSE IN PROGRESS.

90. Having thus briefly described the works constructed and in progress, I propose now to consider the supply of water that these works may reasonably be expected to furnish.

91. As has been previously stated, the storage capacity of the two impounding reservoirs at Pokfoolum and Taitam (including the extension) is 68,000,000 gallons and 390,000,000 gallons respectively, so that, at the commencement of the dry season, provided these reservoirs are full, there is a supply of 458,000,000 gallons available for distribution during the dry season.