130 



SEWER DESIGN 



per capita, and the average 115, for the maximum rate is only 

 24 per cent more than the average. If, however, 65 gallons 

 of waste were to be eliminated, so that the average rate would 

 be 50 gallons and the maximum 78 gallons, the latter would 

 then be 56 per cent greater than the average. 



TABLE XIX. 



GAGINGS OF DRY-WEATHER FLOW OF SEWAGE AT DES MOINES 

 AND ELSEWHERE 



* Estimated. 



The variation shown in the next to the last column is evidence of the effect of 

 ground-water flow. The larger the minimum flow, the smaller the effect of the 

 daily variation. The last column shows the percentage by which the maximum 

 is greater than the average if the minimum flow be made zero and the average 

 and maximum flows reduced by the same amount. 



Fig. 35 * shows the hourly variations in the cities of Chicago 

 and Fall River. In the former, the leakage is very large, 

 and the maximum rate of consumption only 15 per cent more 



* Fuertes' Report, p. 123. 



