ENG-1987 — Page 229

LAND, PUBLIC WORKS AND UTILITIES

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inspected some 312 landslip and related incidents and gave advice on emergency precau- tions, evacuation and remedial works.

Expenditure under the Landslip Preventive Measures Programme was $65 million for the year. Major stabilisation works were completed on 27 slopes and retaining walls, and works were commenced on a further 24 sites.

Under the geotechnical advisory services to government departments, the GCO under- took in 1987 detailed geotechnical designs for 58 projects, advised on 115 other projects, and conducted geotechnical feasibility studies for major construction and tunnelling proposals which included an investigation to locate up to 100 million cubic metres of marine fill to be used in large-scale reclamation projects.

The Geotechnical Information Unit, which houses a large collection of geotechnical data including maps, a rock collection, field_photographs, serves as a reference centre for geotechnical information.

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Under the ongoing Hong Kong Geological Survey 1:20 000 scale maps and explanatory memoirs covering the northwest New Territories, south Hong Kong Island and Lamma Island were published. Geotechnical Area Studies Programme Reports were published for the central, west, northwest and north New Territories, and engineering guides on site investigation and on rock and soil descriptions were also published.

Quarrying and Materials Testing

The GCO manages the government quarry at Mt. Butler, and supervises five private quarries and two private rock-crushing plants operated under government contracts. The government quarry at Diamond Hill was closed and a site formation contract was underway to prepare for building development. The private quarry at Cha Kwo Ling was closed to make way for the Eastern Harbour Crossing. The territory's total production of aggregates, crushed rock fines and sand was approximately 10 million tonnes. The total consumption was approximately 18 million tonnes, with the balance of eight million tonnes being imported, mainly from China.

During the year, some 280 000 tests were performed on construction materials by the several laboratories situated throughout the territory operated by GCO. The materials tested ranged from soil and rock to reinforcing steel, concrete, timber, aggregates and bituminous products. Construction also commenced on the new Public Works Central Laboratory at Kowloon Bay.

Water Supplies

Full supply was maintained throughout the year. At the beginning of 1987, there were 352 million cubic metres of water in storage, compared with 396 million cubic metres at the start of 1986. The combined storage of Hong Kong's largest reservoirs, High Island and Plover Cove, was 293 million cubic metres. Rainfall for the year was 2319 millimetres compared with the average of 2 225 millimetres. Water piped from China during the year totalled 432 million cubic metres. The Lok On Pai Desalting Plant was not operated and continued to remain as a 'stand-by resource'. The salinity of water at High Island remained at about 11 milligrams per litre while at Plover Cove the salinity varied from 50 milligrams per litre at the beginning of the year to 38 milligrams per litre at the end of the year.

A peak consumption of 2.35 million cubic metres per day was experienced, compared with the 1986 peak of 2.22 million cubic metres per day. The average daily consumption throughout the year was 2.06 million cubic metres, an increase of 6.7 per cent over the 1986 average of 1.93 million cubic metres. The consumption of potable water totalled 750