Colony by the Traffic & Transport Survey Division, are used by the Traffic Engineering Divisions and the Works Divisions of the Highways Office to formulate programmes of works considered desirable and feasible to undertake over the next five years. This programme is revised annually and approved by Colonial Secretariat and the Transport Advisory Committee, a body with official and unofficial membership.
Stormwater Drainage and Sewage Systems
3.14. Of the 3.1 million (1971) urban population about 90% are served by a sewerage system. The 'Sewer Duplication Report' written in 1965 will be updated in the light of the forward projections of population by the Planning Division of the Crown Lands and Survey Office on the basis of the 1971 Census reports. As and when the need arises to construct a project recommended in the Report the basic data are checked and up-dated as necessary. Comprehensive sewerage layouts are prepared for all the new towns. The field work for the Hydrological Surveys of Victoria and Tolo Harbours has been completed and the final report from the Consulting Engineers is awaited. Monitoring tests are continuing to check the capacity of the water surrounding the Colony to accept sewage either raw or treated. Also, by means of a pilot plant now being designed, the best methods under varying conditions will be investigated to achieve the required quality of effluent.
3.15. Intensive development in the past decade has urbanized many areas thereby gradually changing the pattern of stormwater flow. To cope with this persistent trend, investigations have been started to formulate a more accurate criterion of stormwater drainage design. Based on past records of stream gauging a general unit hydrograph has been found suitable for calculating surface water flow due to rainfall on undeveloped hilly areas. Measurements are being carried out to obtain the time of concentration for typical urban catchments, in order to be able to evaluate the urban run-off in a similar way. Knowledge of these run-off processes will be used with the relationship between the maximum rainfall depth, the duration and the probability of recurrence, to derive the maximized flow to be used in designing the stormwater drainage system for a general catchment.
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Colony by the Traffic & Transport Survey Division, are used by the Traffic Engineering Divisions and the Works Divisions of the High- ways Office to formulate programmes of works considered desirable and feasible to undertake over the next five years. This programme is revised annually and approved by Colonial Secretariat and the Trans- port Advisory Committee, a body with official and unofficial member- ship.
Stormwater Drainage and Sewage Systems
3.14. Of the 3.1 million (1971) urban population about 90% are served by a sewerage system. The 'Sewer Duplication Report' written in 1965 will be updated in the light of the forward projections of population by the Planning Division of the Crown Lands and Survey Office on the basis of the 1971 Census reports. As and when the need arises to construct a project recommended in the Report the basic data are checked and up-dated as necessary. Comprehensive sewerage layouts are prepared for all the new towns. The field work for the Hydrological Surveys of Victoria and Tolo Harbours has been completed and the final report from the Consulting Engineers is awaited. Monitoring tests are continuing to check the capacity of the water surrounding the Colony to accept sewage either raw or treated. Also, by means of a pilot plant now being designed, the best methods under varying conditions will be investigated to achieve the required quality of effluent.
3.15. Intensive development in the past decade has urbanized many areas thereby gradually changing the pattern of stormwater flow. To cope with this persistent trend, investigations have been started to formulate a more accurate criterion of stormwater drainage design. Based on past records of stream gauging a general unit hydrograph has been found suitable for calculating surface water flow due to rainfall on undeveloped hilly areas. Measurements are being carried out to obtain the time of concentration for typical urban catchments, in order to be able to evaluate the urban run-off in a similar way. Knowledge of these run-off processes will be used with the relation- ship between the maximum rainfall depth, the duration and the prob- ability of recurrence, to derive the maximized flow to be used in designing the stormwater drainage system for a general catchment.
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