3.25. The operational planning for existing resources is carried out by the Distribution Division of Waterworks.
The Method
3.26. The planning of resource development must begin with an estimate of the need—in this case, the future demand for water. Crudely, this can be done by extrapolation of the past trend. This method, however, ignores possible changes in the community which may make the future increase in demand quite different from that in the past. A more sophisticated analysis can be made by subdivision of demand into categories—e.g., industrial, and various domestic categories—and with all available knowledge of future growth rates of each category of consumer, gleaned from population estimates, building programmes, etc., a picture of future demand can be built up from the estimates of its various parts. Estimates of this sort were prepared by the Water Resources Survey, and statistics to revise these are currently being gathered by the Waterworks Planning Division.
3.27. When demand is estimated, the possible resources can be matched to it, taking account of practical time-tables for investigation, design, and construction of large civil engineering works. This work, carried out by the Water Resources Survey, showed the need to proceed with works to increase the capacity of the Plover Cove system, and to begin investigations on a new reservoir at High Island. It was also shown that desalting will be needed in Hong Kong, sooner or later. As a result, plans are at present in hand to construct a pilot desalting plant, so that information may be gathered for the design of large-sized plants and on the chemical treatment required to render the desalted water suitable for distribution.
3.28. Planning of the supply facilities necessary to deliver water to the consumers is carried out by the Waterworks Planning Division. In newly developing areas, this involves assessment of the best physical subdivision of the area into supply zones, limited in extent and level, calculation of probable demand in these zones, based on estimates of use, population, and unit demand rates, and selection of suitable sites for pumping stations, pipelines, and service reservoirs. The process is the same in established but growing areas, with the added guidance of a record of demand growth. All of this planning is duplicated for salt water flushing supplies.
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