HYDROLOGY OF NEW YORK 



1S7 



it may be fixed at $100 per acre. At this rate the catchment area 

 of 339 square miles would cost $21,696,000. The planting out of 

 trees could hardly cost less than $20 per acre additional, but in 

 order to make the estimate as reasonable as possible we will take 

 it at $10 per acre, which makes an additional sum of $2,169,900, 

 or a total of $23,865,900. 



If we assume the annual interest at 3 per cent, and place this 

 sum at compound interest for 120 years, we have at the end of 

 that time the sum of $779,510,000. The present safe yield of the 

 Croton catchment, with all available storage, is about 280,000,000 

 gallons per day. We would pay, therefore, this large sum for, 

 perhaps, 75,000,000 gallons additional per day at the end of 120 

 years. It is true there would be some increase in water supply 

 after about 30 years, and the supply might be expected to go on 

 increasing until the average increase of yield was attained in 120 

 years. But the increase in water supply would not be at all 

 commensurate with the increase of capitalization. It is very 

 evident that an expenditure of this sum of money would procure 

 a far greater quantity of water from other sources. Hence it 

 does not seem expedient to suggest the forestation of the Croton 

 catchment area as a method of obtaining an increased water 

 supply. As to whether it is desirable to reforest this area as a 

 forestry investment is another question which is not discussed 

 here. 



Another objection to the forestation of the Croton catchment 

 as a remedy for the water difficulties of New York city may be 

 found in the fact that a considerably increased water supply is 

 wanted at once; it is entirely out of the question to wait 120 years 

 for such increased supply. 



As a broad proposition, however, catchment areas from which 

 municipal water supplies are drawn should be in forests, and 

 undoubtedly as time goes on this condition will be more and more 

 attained. Already various European and American municipali- 

 ties have recognized the advisability of owning the catchments 

 from which their municipal water supplies are drawn. From 

 this point of view it is desirable to reforest the Croton catchment. 



