6.50. The two old dredgers continued to operate alternately using only one crew. They carried out maintenance dredging at nullah outfalls and pier approaches. The total quantity of spoil removed during the year by these two dredgers amounted to 55,139 cu. yd. In addition, assistance was given to Marine Department by dredging around harbour moorings so that they could be lifted for maintenance purposes.
6.51. The self-propelled hopper dredger continued dredging work in the Central Fairway and removed a total of 289,500 cu. yd. of spoil.
6.52. The Division's divers carried out underwater inspections of seawalls, piers, pumphouses, sewage submarine outfalls and water-mains. A total of 454 hours of diving time was recorded.
Boring and Surveys
6.53. 227 marine boreholes totalling 7,892 feet were sunk at various places in the Colony waters. In addition, 25 probes totalling 7,524 feet were sunk in site investigations.
6.54. Current observations were carried out at West Tsing Yi and Kau Yi Chau in connection with the Kwai Chung Container Scheme and at Tsim Sha Tsui to supply information on tides to Marine Department. Echo-sounding surveys were made to check the seabed level along the Cross-Harbour mains, the dredging at Central Fairway, the proposed bridge to Tsing Yi and the approaches to the proposed container berth at Kwai Chung. Surveys were also carried out for checking the progress made on reclamations, for periodic level checking of the existing seawalls, for the measurement of works in progress, and for investigating sites of proposed works.
General
DRAINAGE WORKS DIVISION
Chief Engineer:
F. E. SHORT, C.Eng., M.I.C.E.
W. D. S. CANT, C.Eng., M.I.C.E., M.I.Mun.E. (Acting)
J. W. THOMAS, B.Sc.Tech., C.Eng., M.I.C.E., M.I.Mun.E. (Acting)
6.55. Following the re-organization of the Civil Engineering Office in September 1969, the Drainage Works Division has now taken over from the Highways Office the investigation, planning, design and con-
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