55.
14
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Maintenance of City of City and Hill District, Water Works: The year opened with a ten hours supply daily, the period of supply being 6-11 a.m. and 4-9 p.m. and with the exception of three days at Chinese New Year (13th-15th February) when a constant supply was given, the ten hours supply remained in operation until 22nd June. On 23rd June a constant supply was introduced, but restrictions had to be reverted to on 15th November when the hours of supply were limited to fifteen per day (6 a.m. to 9 p.m.). In December the necessity for further restriction became evident, and on 21st December the supply hours were reduced to ten per day (6-11 a.m. and 4-9 p.m.) which arrangement remained in force until the close of the year. During the year, therefore, constant supply was maintained for 148 days as compared with fifty-nine days in 1933.
The removal of silt from the Lower Aberdeen Dam was continued during the first half of the year (from February-June inclusive). During that period 44,048 cubic yards of silt were removed from the basin and a final contour survey made disclosed that the effective capacity of the reservoir had been increased to 106.89 million gallons (see paragraph 226 of this Report). Since the reconstruction of this Dam commenced in 1932 it is estimated that, including an amount sluiced through the wash out pipe, a total of 129,082 cubic yards of silt, equivalent to 21.70 million gallons of storage, had been removed from the basin. The cost of removing and depositing this silt was approximately fifty-eight cents per cubic yard, or $3,450.00 per million gallon which is comparable to the unit cost of obtaining new storage by construction. On July 14th the reservoir was allowed to fill and on 24th July it commenced to overflow.
During the year drainage from an additional area of approximately 500 acres was diverted into Tytam Tuk Reservoir by the new catchwaters now under construction (see paragraph 235 of this Report).
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Inspections of the Cross Harbour Pipe revealed that pitting of the external surface had assumed such proportions as to necessitate protective measure. It was decided to scrape the defective areas, fix casing around the pipe and hand pack 2" of cement mortar over the entire circumference. By the end of the year 297 lineal feet of the pipe had been so dealt with, but with what measure of success it is not yet possible to say. The supply from the mainland was not at any time interrupted due to these operations and was in use for 184 days between 21st May and 29th November during which period 391.57 million gallons were delivered into the Gardens Service Reservoir, equivalent to an average daily supply of 2.13 million gallons.