Niagara Falls 



1911 The bearing which such facts have upon the question of power 



development is, that the horse-power available at any specified 

 time, at, say, Niagara falls, depends upon the quantity of water 

 flowing in the Niagara river at that time, and, as has just been 

 pointed out, this quantity depends upon the stage, or level, of the 

 water in lake Erie. 



In addition to the monthly, yearly or other periodic changes, 

 variations in the level of the lake's surface, due to winds and to 

 change of barometric pressure, are frequent and irregular, and at 

 times violent. Variations of more than 6 inches are very common, 

 often occurring hourly for many hours in succession, while varia- 

 tions of 2 or 3 feet within an hour are not uncommon. It some- 

 times happens that the stage varies as much as 7 or 8 feet in one 

 day. Storms raise the water level at Buffalo several feet higher 

 than normal, and lower it at Amherstburg, by a like amount; the 

 difference of level between the two ends of the lake in extreme 

 cases having been as great as 1 5 feet. 



Discharge of Niagara River. — The discharge of the Ni- 

 agara river has been determined by measurements taken at the 

 International Bridge located at Buffalo, N. Y., and at a point 

 about 1 ,800 feet down stream at the " Open Section." Measure- 

 ments were begun in 1897 and are being carried on by the 

 engineering staff of the United States Lake Survey. The 

 maximum monthly mean discharge from lake Erie, 257,800 

 cubic feet per second, equivalent to a depth of 2.44 feet on the 

 lake, occurred in June, 1 876. The minimum, 1 68,700 cubic feet 

 per second, equivalent to a depth of 1.60 feet on lake surface, 

 occurred in March, 1 896. The average discharge of the Niagara 

 river during the period 1860-1907 is 212,200 cubic feet per 

 second. 



From 1860 to 1907 the greatest excess average for any one 

 month was for June, 1876, being 45,600 c. f. s., or twenty-one 

 per cent; the greatest excess average for any one year was for 

 1876, being 26,500 c. f. s., or twelve per cent; the greatest 

 deficiency average for any one month was for March, 1896, 

 being 43,500 c. f. s., or twenty-one per cent; the greatest 



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