GEORGE C. WHIPPLE 



plies of the country on this basis. For this reason the few typical 

 examples given in Table 5 may be more instructive than any attempt 

 at a general classification. 



It will be seen from the above figures that, while the general 

 attractiveness of a water is of less importance than its sanitary quality, 

 yet it is by no means insignificant. For instance, such a water as 

 that now supplied to New York City from the Croton River has a 

 depreciation value of $i i per million gallons, or nearly a million and 

 a half dollars a year for a daily supply of 350 million gallons. At 4 

 per cent this represents the interest on about $35,000,000, a sum several 

 times as large as the cost of filtration. An algae-laden water like that 

 of Ludlow Reservoir at Springfield, Mass., has a depreciation value 

 of more than $20 per million gallons, because of its odor and turbidity. 

 A colored water like that of the Black River at Watertown before 

 filtration has a depreciation value of $11, while a turbid water like 

 that of the Mississippi River at St. Louis gives $25. 



In most surface waters the physical characteristics vary greatly at 

 different times of the year. During the spring and fall, for instance, 

 the color and turbidities may be high on account of rains, while during 

 the summer the water may have bad odors due to microscopic organ- 

 isms. The depreciation value of a certain reservoir water, calculated 

 as above described, serves well to show this seasonal variation, as 

 illustrated by the following figures : 



TABLE 6. 



SEASONAL VARIATION IN THE DEPRECIATION VALUE OF A SURFACE WATER DUE TO SEASONAL 

 CHANGES IN TURBIDITY, COLOR, AND ODOR. 



