HYDROLOGY OF NEW YORK 



39 



265,000 cubic feet per second. The recent studies indicate that 

 the extreme low flow of a cycle of minimum years may not be 

 more than 60 per cent to TO per cent of this figure. From this 

 point of view, the people of the State of New York have great 

 interest in any project which would tend to decrease the low- 

 water runoff of that stream. The figures obtained by the Deep 

 Waterways Survey, substantiate this statement. Such interest is 

 equally pronounced in the case of the St Lawrence river. 



The measurements of discharge of a number of inland streams 

 of New York indicate considerable variation in the water yield 

 in different parts of the State. Genesee river, in 1895, gave, with 

 a rainfall of 31 inches, a minimum flow for the year of only 6.67 

 inches. The catchment area of this stream is, as already stated, 

 mostly deforested, whence it results that serious floods are 

 frequent. 



The lowest annual runoff thus far measured in the State of New 

 York is that of the Hemlock lake catchment area, where, in 1880, 

 the total runoff from an area of 18 square miles was only about 

 3.35 inches. 



Oswego, Mohawk, and Hudson rivers and their tributaries in 

 this State all have large pondage on natural lakes, which, with 

 other conditions, tend to maintain the low-water flow. Croton 

 river presents surface geologic conditions which tend to increase 

 its low-water flow. Without going into detail, we may say that 

 these streams will yield a minimum flow of about 0.2 of a cubic 

 foot per second per square mile. Variations from this limit are 

 given in the chapters specially discussing minimum flow. 



As a typical flood stream of the State we have Chemung river, 

 where serious floods, due to deforestation of a mountainous catch- 

 ment area, have become so common as to necessitate the carrying 

 out of extensive protection works at the large towns on that 

 stream. 



Value of water to industries. Water power is extensively sold 

 at Oswego, Cohoes, and Niagara Falls, and to some e^tenit at 

 Rochester. It will also be extensively sold at Massena when the 

 development there is completed. 



