140 SEWER DESIGN 



Rochester, August 10 ..................... gj 



" 25 ..................... 8J 



Canton .................................. gi 



Schenectady .................... ......... 1 1 



Hospital, Weston ......................... 9 



Chautauqua, July 24 ..................... 8^ 



August 16 ................... pi 



18 ................... 9l 



indicating that to assume that one-half of the daily flow will 

 flow off in 8 hours is a safe assumption. It further indicates 

 that a capacity of twice the average flow is a larger allowance 

 than necessary. 



What the daily average will be must be left to the judgment 

 of the engineer. By Table XII it varies from 19 to 222 gallons 

 per capita per day, according to published records. Mr. 

 Brackett shows that for the vicinity of Boston from- 11.2 gallons 

 to 44.3 gallons per capita per day are legitimately used for 

 domestic purposes, and that these amounts must be increased 

 for public purposes and for manufacturing and trade. 



Mr. Whitney of Newton shows that the amount of water 

 for domestic use varies with the number of fixtures in the 

 house, from 7 gallons per capita per day for one faucet to 22.8 

 gallons for two faucets, two water-closets, and two baths, and 

 that other uses increase the amounts as given in Table XVIII. 



It remains for the engineer, after studying the character of 

 the population and the possibility of manufacturing interests, 

 to fix such a per capita allowance as is appropriate for that 

 community. 



PROBLEMS 



42. From Fig. 24 determine the ratio of the sewage flow to the water- 

 consumption for the months of July and September. 



43. From Table XIII, plot points showing the relation between total 

 population and per capita consumption. See if the relation follows any 

 law. 



