226 SOILS AND SUBSOILS OF SYDNEY AND SUBURBS. 



are several areas within the city boundaries where subsoil drainage 

 would effect immense improvements. The contamination of the 

 soil should be prevented by the systematic collection of all organic 

 refuse and its destruction by fire, or equally well disposed of in 

 some other way which will prevent pollution of the soil, over 

 which population will settle in the future. Sewage farms are 

 admissible for the utilization of sewage. The ground should, 

 however, be carefully prepared so that the organic matters may be 

 destroyed by the combined agencies of oxidation and assimilation 

 by vegetable growths. Some of the municipal authorities located 

 on the clay shale areas, compel residents to dispose of their liquid 

 refuse by casting it on to the surface of their back premises witli 

 the idea, no doubt, of instituting sewage farms on a small scale. 

 Unless the clayey subsoil be drained and the deration of the soil 

 facilitated by frequent movements of the surface by digging it up, 

 most disastrous results will follow. 



The ground surface under all houses, particularly in the western 

 suburbs where the clay shales prevail, should be covered with an 

 impervious layer of concrete or tar pavement, and the space 

 underneath the floor well ventilated. 



The recent wet season has developed unpleasant revelations to 

 many residents on low lying areas, especially in the western 

 suburbs, which are causing them to agitate for relief. There is a 

 general reliance upon the promised sewerage scheme for a remedy. 

 This is a mistake, the proper duty of sewers is now seen to be 

 restricted to the removal of sewage proper and not storm water. 

 The remedy consists in the construction of stormwater drains, 

 combined with subsoil drainage. The importance of separating 

 sewage from rainfall is now being generally recognized by 

 sanitary authorities. 



