Stormwater Drainage and Sewerage Systems
3.13 Since the preparation of the 'Sewer Duplication Report' in 1965, the pattern of urban development has changed significantly. A complete review of the recommendations of that Report has been started, based on the latest forward projections of population by the Planning Division of the Crown Lands and Survey Office. Sewer gaugings are also being carried out to check typical data used in the previous Report and to formulate new design criteria.
3.14 The final report for the Hydrological Surveys of Victoria and Tolo Harbours has been received and the implications of the recommendations for maintaining or improving the level of pollution at various points are being studied. Monitoring tests are continuing to check the possible changing situation of the surrounding harbour water in connection with the effects of the continuous discharge of sewage either raw or treated. Water pollution control is maintained by planning and implementing sewage treatment works with reference to the Report on the Hydrological Surveys of Victoria and Tolo Harbours. Also, by means of a pilot plant now being constructed, the best treatment methods under varying conditions will be investigated to achieve the required quality of effluent.
3.15 Investigations are continuing on the formulation of a more accurate criterion of stormwater drainage design in order to cope with the persistent trend towards urbanization. The essential part of the remaining investigations is to arrive at a reliable method of designing road pavement drainage and a practicable way of predicting the run-off process from a general catchment.
Port Works and Reclamation
3.16 The construction of seawalls, piers and other marine structures is not normally carried out to a comprehensive programme but undertaken as and when required.
3.17 Reclamation schemes usually come into being to provide land from the sea when this is required for development. Their programming is planned to tie in with the date that the land is needed and with the availability of suitable reclamation material to complete it. Engineering feasibility studies are carried out to determine the optimum size and layout for the larger schemes. In the planning of reclamation the interested Government departments and offices are consulted.
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