HYDROLOGY OF NEW YORK 



693 



square miles amounted to 16.81 inches on the catchment, equiva- 

 lent to 800,191 gallons per square mile, or to 1.24 cubic feet per 

 second per square mile. The water drawn from the new catch- 

 ment of 88.5 square miles that year amounted to 3.67 inches 

 equivalent to 174,776 gallons per square mile per day, or to 0.27 

 of a cubic foot per second per square mile. In 1895, with a 

 total rainfall of 35.64 inches, the original catchment of 65.6 

 square miles yielded 12.62 inches, equivalent to 600,723 gallons 

 per square mile per day, or to 0.93 of a cubic foot per second 

 per square mile. The new catchment of 88.5 square miles fur- 

 nished in that year 8.64 inches, equivalent to 411.558 gallons 

 per square mile per day, or to 0.64 of a cubic foot per second 

 per square mile. 



Summarizing the information in regard to the water yield of 

 the sand plains of Long Island, it may be stated that the avail- 

 able data indicate a large yield. The streams of* eastern New 

 York can not be relied upon in their natural condition to yield 

 more than about 0.15 to 0.25 of a cubic foot per second per 

 square mile, while with an ordinary development of storage, 

 the limit may be usually placed at from 0.7 to 0.8 of a cubic 

 foot per second per square mile, or at any rate at not much 

 exceeding one cubic foot per second per square mile. The sand 

 deposits of Long Island may therefore be considered as great 

 natural reservoirs from which, with proper development, large 

 water supplies may be drawn, the same as from reservoirs 

 artificially created on the earth's surface, these natural under- 

 ground reservoirs possessing the advantage of furnishing a 

 filtered water of high purity. This fact was recognized by the 

 New York Water Supply Commission of 1903, who have recom- 

 mended the further development of this supply. This commis- 

 sion made extensive observations as to the hight of ground 

 water, etc. 



Recent Projects for Water Supply of Greater New York 

 The rapid growth of Greater New Y^ork has compelled a gen- 

 eral extension of the water supply, and a number of able reports 

 have been made, which will be briefly referred to. 



The first of these is in relation to the Ramapo Water Com- 

 pany, which was organized in 1887 under an act which per- 

 mitted companies organized under it to supply with water any 



