128 



SEWER DESIGN 



the variation of flow from hour to hour. Evidently more water 

 is used and the flow to the sewers is greater during the day 

 than during the night, and if the size of the sewer was based 



Aug. 25-26 

 1890 



Aug. 10-11 



WATER CONSUMPTION 



FROM 



HEMLOCK LAKE 



AT 



ROCHESTER, N. Y., 

 1890. 



\ 



\V 



\f\ 



450000 



400000 



350000 



300000 



250000 



200000 



150000 



100000 



50000 



FIG. 34. 



only on the average flow through the twenty-four hours, it 

 would be too large at some times and altogether too small 

 at others. To fulfil its purpose, the sewer must plainly be 

 large enough to readily carry off the water, at that time of 

 the day when the rate of flow is largest, even if it requires 



