P.W.E. Kowloon.
88
The reclamation has an area of nearly 4.30 acres and is protected partly by a pitched slope and partly by a concrete and masonry sea-wall. The pier-head is also of masonry and concrete.
The concrete and masonry pier is 450 feet long by 30 feet wide. It is constructed on a rubble mound which extends to low-water level and is faced on the outer side with rough-punched granite ashlar and on the inner side with coursed granite rubble. The hearting is of lime concrete finished on top with cement concrete paving, 4 inches thick. Landing steps for boats are provided at the inner end.
The area enclosed within the breakwater is 165 acres, the depth of water at L.W.O.S.T. varying from 9 feet to 18 feet,—82% of the enclosed area has a depth exceeding 12 feet at L.W.O.S.T. and 56% has a depth exceeding 15 feet. There are two entrances, the northern of which has a width of 300 feet and the southern, or principal, entrance a width of 390 feet.
In all, 12,453 concrete blocks were used in the work, of which 11,379 were pitching and paving blocks of 2 tons each and the remainder principally foot-blocks for the inner slope, which were of the same weight. The foot-blocks for the two round heads of the breakwater weigh over 5 tons each, whilst those for the outer slope of the breakwater, which are entirely of granite, weigh 3 tons each. The pitching stones for the inner slope of the breakwater number 17,098 and average half a ton in weight.
A balance on the Contract remained outstanding at the close of the year.
In connection with this work, an endeavour was made to ascertain the actual amount of settlement which occurs when a mound of rubble is deposited on soft mud, such as is met with over a large area of the harbour. The apparatus employed consisted of an iron grid, 11 feet square, built up of angle irons and flat bars, to which a vertical member was securely attached. The vertical member consisted of a steel joist, 10" x 5", graduated in feet and inches and of sufficient length to extend above the platform of the breakwater when completed. As the base of the breakwater was 192 feet wide, a group of 3 such grids with vertical members was used at each point.
Two such groups were lowered into position at points 1,600 feet apart in the dredged trench before the depositing of rubble to form the mound was begun. Unfortunately, one set was rendered useless at an early stage by a somewhat extensive slip in the rubble mound which dislocated the vertical members to such an extent as to preclude any further observations. The other set remained intact throughout the construction of the breakwater and the following is a record of the settlement shown at the various stages of the work by the central indicator of this set, the measurements given being in each case below the surface of the dredged trench.