Niagara Falls 



1894 Owing to the lack in full efficiency of even the best commercial 



turbine wheels, we may take the limit of power that could be 

 developed as about 4,000,000 horse power. 



The average power is not departed from to any great extent at 

 different seasons, as is the case with other water powers, because 

 the spring thaws and summer droughts affect hardly at all the 

 level of Lake Erie, from which the falls get their supply. 



The system of Great Lakes above Ontario would require a 

 year in order to have their level reduced by three feet and a 

 half by even the enormous drain of a thousand million pounds 

 of water per minute above referred to, supposing the system to be 

 entirely cut off from its normal supply. A paper by Mr. R. C. 

 Reid before the Royal Scottish Society of Arts in March, 1885, 

 gives the following data: Total water-shed area down to 

 Niagara, 290,000 square miles; total lake surface, 92,000 square 

 miles; average rain-fall in the lake district, thirty-six inches — 

 and that we may assume twenty inches annually of evaporation 

 and absorption, leaving sixteen inches over the whole area finding 

 its way to the lakes. From the lake surface proper, there occurs 

 evaporation to the extent of twenty-four inches per annum. 

 Further, in reference to the enormous storage capacity of the 

 system, he shows that " it would take six months for the full 

 effect of a flood in Lake Superior to be spent at Niagara Falls." 

 It is easy, therefore, to understand how little fluctuation of level 

 there can be due to seasonal variation in rainfall. Thus we see 

 that quite apart from the fact of the vast volume and head avail- 

 able, and of there being no necessity for building a dam to back 

 up the water, the situation is peculiarly favorable to the develop- 

 ment of a constant power all the year round. 



In spite of the generally equable level of Lake Erie, there are 

 sometimes very considerable fluctuations, not of volume, but of dis- 

 tribution, due to high winds sweeping the length of the lake and 

 causing a considerable banking of water at the end blown into. 

 Sometimes such storms have lasted for days, and have had a very 

 noticeable effect in increasing or diminishing the volume going 



946 



