P.W.E, Hong Kong.
The invert of the Reservoir is composed of 1:2:4 cement concrete laid in slabs 12′ square with asphalte joints and having a fall of 1 in 100 to the draw off sumps. The side and division walls, of gravity section, are constructed of 1:3:5 displacer cement concrete with a 3" layer of cement mortar on the inside face. The walls are also provided with expansion joints. The roof is constructed of reinforced cement concrete of the flat slab and beam type, supported on R.C. Piers at 12′ centres and is laid to a fall similar to that of the invert, the dimension from invert to top of roof slab being 26'6". The roof is covered with a 12" layer of earth and turf and is drained into channels surmounting the side walls.
An 18" C.I. Bypass main is also provided to divert the water direct from the Filter Beds to the 18" Distribution main and was laid around the West end of the Reservoir.
The Access Road is from Stubbs Road at about 50 yards below where it is crossed by Bowen Road. The roadway is 7' wide, has a concrete channel on one side and a concrete kerb on the other, and is surfaced with 4" of lime and cement concrete finished with pea gravel in cement mortar. The gradient to the upper beds is 1 in 10′ from thence to the Lower Beds is 1 in 8.
The Watchmen's Quarters have accommodation for Watchmen, 14 Coolies with sleeping and living Rooms, Kitchen, Store, Bath-room and Latrines. The building is single storied in brick work, having a concrete floor and double roll and pan roof.
To form a spoil site for the excavation and to deal with the drainage, it was necessary to construct a covered nullah 615′ in length. This was built of 1:2:4 cement concrete, 242 lineal feet being under the filter beds.
The works under this Contract were commenced in April 1922 and finally completed in June 1928, portions of the work being brought into use as they were completed.
Messrs. Wing On's final account, which did not include C.I. Valves, Pipes, Reinforcement, Bricks, and Tiles, amounted to $393,149.32.
(g.) 18" C.I. Distribution Main from Reservoir to Monument Happy Valley.-A length of 2,100 lineal feet of this main from the Monument to the South end of Happy Valley was laid in 1920. A further length of 1,000 lineal feet from the South end of the above section to the South end of Wong Nei Chong Old Village was laid in 1924. From this point to a point 110' North of the Reservoir, a length of 1,100', it has not been possible to lay the main owing to the fact that the proposed road has not been formed and a temporary diversion consisting of a 12" C.I. Pipe is at present in use on this section. The remaining section from the Reservoir to 110' North thereof was laid in 1926 when the East half of the reservoir was first brought into use.