ENG-1960 — Page 21

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REVIEW

prompted a number of new measures which included further development in the Tai Tam valley, the first impounding of supplies in the New Territories, and a curious system of distri- bution in the city of Hong Kong-that of rider mains. This system is described by Mr Jackson:

'In order to make best use of the available water by reducing waste it was proposed to introduce universal metering of supplies. The proposal, however, was not well received by the Chinese residents and an amazing compromise solution was reached. Certain streets in the City were to be provided with duplicate mains, one to provide metered supplies and a second, called a rider-main, was unmetered. The reason for the duplication of the mains was that the unmetered (rider main) supply could be shut off during periods when the supply had to be restricted, whereas the metered supplies were not so restricted until the storage position became much more acute'.* The system of rider mains was not abolished until 1932 when universal metering was introduced.

Construction on the island included the Tai Tam Bye-Wash and Intermediate reservoirs, completed in 1904 and 1907 respec- tively, and in 1914 a new supply for the Peak district pumped from the West Point filters to tanks on Victoria Peak. In 1917 the Tai Tam Tuk dam was finished, the largest of the group in this valley, and the installation of new slow sand filter beds in 1919 and 1925 completed the main Tai Tam scheme. In the meantime thoughts had turned towards the resources offered by the New Territories and work began on the original Kowloon reservoir in 1902, to be completed in 1910. A second reservoir, Shek Li Pui, followed in 1922, and these two together provided Kowloon with a storage capacity of over 468 million gallons, which could be increased by the use of sluice boards. Each was accompanied by appropriate filtration capacity and a distribution system. Those in a position to judge the demand for water and the ability to meet it were evidently highly satisfied with Tai Tam Tuk for, when the dam was opened, it was described as one 'to satisfy the Colony for many years to come'. It was not the first

*The Hong Kong Waterworks, by Leonard Jackson, BEng, MICE, MIWE, published in the Proceedings of the Engineering Society of Hong Kong, Sessions 1948-9.