62 The Drainage of Melbourne. 



5. The system of sewers is arranged to convey all the sew- 

 age to the pumping station " in the sandy ground west of 

 Sandridge." Here the sewage " will be pumped up on to a 

 sloping perforated platform, from which the more solid sub- 

 stances can be readity collected and carted away, while the 

 liquid portion of the sewage will pass through the perfora- 

 tions into carriers, which will take it" to the filtering beds. 

 The filtering area is to consist of " three divisions, each of 

 about forty acres, laid out with open drains running in the 

 direction of the out-fall, and drained not less than six feet 

 deep with agricultural tile drains." The area for the present 

 considered sufficient is 120 acres ; but 200 acres more, or 

 320 acres altogether, are provided to meet an increase of the 

 population up to 500,000. For pumping the sewage, "the 

 engine-power required at present will be, including a reserve 

 in case of accident, an engine of 53-horse power, and one of 

 26, and three centrifugal pumps, each capable of throwing 

 6100 gallons per minute 15 feet high." 



6. The localities dealt with are, with the exception of 

 some thinly populated portions, Melbourne City, Fitzroy, 

 Collingwood, Richmond, Prahran, St. Kilda, Emerald Hill, 

 and Sandridge. Provision is made for connecting Haw- 

 thorn, if required. The area included is not stated. The 

 present population of these localities is, probably, about 

 200,000; but it is remarked the main works are sufficient 

 for an increase of the population to 500,000. The pumping 

 machinery is limited to what is required at present, facilities 

 being afforded for connecting additional engine-pow T erwhen 

 required. 



7. The approximate cost of the works to be carried out 

 first, in the streets, at the pumping station, and in preparing 

 the filtering area, is £275,000. The total ultimate cost of the 

 whole scheme sufficient for a population of 500,000, is esti- 

 mated at £336,250. The storm- water culvert in Elizabeth 

 and Little Bourke streets is to cost £26,512 in addition. It 

 is, however, remarked that it is impossible, from the data 

 supplied, to give anything like an exact estimate. The 

 annual cost of pumping is put down at £900 at first, and 

 at £1850 ultimately. No other working expenses are 

 mentioned. 



8. Such is an outline of the scheme proposed in the essay. 

 Reasons are given for coming to certain conclusions on a few 

 main points only, such as — (1) the necessity for subsoil 

 drainage, (2) removing a portion only of the rainfall by the 



