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those of the invert. The side slopes of the Catchwater are 2½ to 1 in soft section and ¾ to 1 in rock section. Along the outside of the Catchwater a path of minimum width of 3 feet has been formed and this was carried over the overflows on reinforced concrete decking. Sandtraps, each having a washout pipe, have been constructed in the invert at all overflows.
243. West Catchwater.—First Section :-This work was referred to in paragraph 206 of last year's Report, when the first section was completed. The maintenance period expired on the 30th June and the retention money was paid to the contractors, Messrs. Foo Loong & Co., during the year.
Second Section:-A contract for this work was signed by Messrs. Sang Lee & Co. on the 12th April for $77,640.50. Work commenced immediately and by the end of the year such good progress had been made that the upper portion, 3,945 feet in length, and 4,000 feet out of a total of 4,405 feet of the lower portion, were completed. Fair progress was made on the difficult section joining the upper and lower portions.
244. Alterations to Existing Dam. This work was referred to in paragraphs 208 and 209 of last year's Report.
Reconstruction of Lower Dam:-The maintenance period for this work expired on the 30th April and the retention money was paid to the Contractors, Messrs. Kin Lee & Co., during the year.
Removal of Silt: The Aberdeen Lower Reservoir when taken over by Government was very badly silted up, the silt being of such a composition that, in addition to its being likely to cause a collapse of the existing dam, it was having a deleterious effect on the pumps, pipe line and filters and was also reducing the storage capacity of the Reservoir. In order to carry out the investigations of the structure of the existing dam it was necessary to remove an amount of 11,110 cubic yards of silt from the upstream face of the dam, in addition to which a further quantity of 21,799 cubic yards were removed during the reconstruction of the dam. As there was still a considerable quantity of silt in the Reservoir a Contract for its removal was let to Messrs. Yee Lee & Co. for $26,800 on 1st February. By the end of May approximately 40,000 cubic yards had been removed under this Contract and the Contract was extended by an amount of 20,000 cubic yards, but on the 4th August, when 52,075 cubic yards under this Contract and a grand total of 84,984 cubic yards had been removed, it was found necessary to impound water in the Reservoir, thereby closing the Contract. At the end of the rainy season 96.64 million gallons had been impounded. All the silt removed from the Reservoir with the exception of a quantity of 20,000 cubic yards sluiced through the washout of Dam, was