HYDROLOGY OF NEW YORK 



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was 187,255 cubic feet per second. Table No. 45, giving these 

 discharges, has been constructed by substituting the mean 

 monthly elevations of Lake Erie from the preceding table in the 

 formula for discharge of Niagara river. It extends from 1865- 

 1898, inclusive. 



It will be noticed that on a preceding page the writer states that 

 the mean discharge for a year may be as low as 177,700 cubic feet 

 per second, or not exceeding about 6 inches in depth over the entire 

 catchment area. For the year 1895 the mean discharge for the 

 entire year was only 10,000 cubic feet per second in excess of 

 this figure, but it is certain that 1S95, while a low year, was not 

 absolutely the minimum year. In view of the foregoing, it is 

 believed that when properly used, intelligent analysis of rainfall, 

 runoff and evaporation may be sufficient to settle such a question. 



The literature of the discharge of Niagara river and of the 

 probable effect on the lake levels of abstracting 10,000 cubic feet 

 per second at Chicago has grown so extensive as to preclude fur- 

 ther discussion here. Those wishing to pursue the subject may 

 consult the references given in the footnote. 



The following is a summary of the matter: 



1) The studies of the Lake Survey indicate a mean discharge 

 of Niagara river of about 205,000 cubic feet per second, with a 

 range above and below the mean of from 20 per cent to 30 per 

 cent. 



2) The measurements made from December to May, 1891-92, 

 indicate a minimum discharge as low, or even lower, than 141,000 

 cubic feet per second. 



3) The measurements of the Board of Engineers on Deep 

 Waterways, made in 1898-99, indicate a mean discharge from 

 1865-1898, inclusive, of 220,000 cubic feet per second, while for 

 the year 1895 the mean for the whole year is only 187,000 cubic- 

 feet per second. 



4) Based on theoretical considerations purely, the writer in 

 1897 estimated the minimum mean discharge for a series of dry 

 years at 178,000 cubic feet per second, or at the rate of 6 inches 

 in depth over the entire catchment area. The writer considers 

 that this latter figure is more nearly right than any estimate 



