.45 It is proposed to dredge to a depth of 35 ft. C.D. in the first instance to provide for ships drawing up to 33 ft. The dredged material would be deposited at the spoil-dumping ground at Kau Yi Chau, some 3 miles from the site. If necessary, dredging to -40 ft. C.D. could be carried out later, also without encountering rock. The quantities of dredging in cubic yards are shown in Table 4.
TABLE 4: DREDGING QUANTITIES (CU. YDS.)
Stage
Stage 1
Stage 2
Stage 3
Total
To 35' C.D.
730,000
50,000
220,000
1,000,000
Additional to -40' C.D.
480,000
40,000
160,000
680,000
8.46 It is not possible to estimate accurately the maintenance-dredging commitment, if any, but consideration of the factors described in paras. 5.36-5.38 together with quaywall alignment chosen indicates that silting at the rate of a few inches per year average over the whole dredged approaches may occur. It is likely that the rate of silting would be greatest at the north end close inshore and least near Rambler Channel.
8.47
For the depth of silt described in the previous paragraph, it would not be necessary to dredge every year. However, it might be more convenient to work with a small suction dredger throughout the year, in which case it might be possible to arrange for the spoil to be pumped into Rambler Channel on the ebb tide.
35