ENG-1968 — Page 243

PUBLIC WORKS AND UTILITIES

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year. Water from the Plover Cove reservoir was used for supply purposes during the 1967-8 winter when some 5,000 million gallons were abstracted for this purpose. During March practical considerations associated with the rapidly increasing water salinity, when weighed against the very favourable overall storage position, led to a decision to discharge to waste the bulk of the 7,000 million gallons of saline water remaining, before the onset of the summer rains. When impounding recommenced the 37,000 million gallons capacity reservoir held just over 1,000 million gallons.

Proposals for the further development of the Plover Cove scheme were completed, including detailed proposals for the raising of the dam by 12 feet to increase the reservoir capacity by 10,000 million gallons to 47,000 million gallons, as well as the installation of permanent facilities to extract reservoir water down to 23 feet below mean sea level.

Throughout the year the reservoir was under surveillance by the department's marine biologist and chemists. Regular surveys were conducted on hydrology, benthos, marine and freshwater fish and algae. An experimental pilot fish stocking exercise, successfully completed during April, preceded a major stocking programme which was in hand towards the end of the year. Fish introduced included the silver, common and mud varieties of carp and edible goldfish.

All outstanding trunk mains to integrate the Plover Cove supply with the earlier systems were completed and the last of the associated service reservoirs, at Shek Kip Mei and at Ho Man Tin, approached completion as water from Plover Cove became available for supply to all principal concentrations of population.

Plant installation at the 200-million-gallons-per-day River Indus pumping station completed the final pumping scheme, at a total cost of $28 million, but full potential was not realized owing to mechanical and electrical teething problems. The full capability of this station is usable only during the period of heavy summer rainfall when the river water is pumped to Plover Cove for storage.

The Tung Chung scheme, which added some 3,000 acres of catchment to the earlier completed Shek Pik catchment area by intakes and a tunnel system, was completed at a cost of $34 million.