HYDROLOGY OF NEW YORK 



441 



March, 1896, was nearly as high. At this time water floAved over 

 the State dam at Tonawanda, with a head of 4.82 feet, indicating 

 a discharge of 9600 cubic feet per second. At the same time there 

 was 3 feet of water having over a waste-weir directly into Niagara 

 river and representing a discharge of about 1000 cubic feet per 

 second, making the total discharge on March 30, 1896, of Tona- 

 wanda creek at Tonawanda 10,600 cubic feet per second (catch- 

 ment, 610 square miles), or at the rate of about 18 cubic feet per 

 second per square mile. This value of the flood discharge is prob- ' 

 ably due to the natural storage in the flat and swampy portions 

 of the creek valley west of Oak Orchard dam, as well as to the 

 diversion of some of its waters through the Oak Orchard cutoff 

 during this flood — probably, the entire flood-flow on March 30, 

 1896, was from 20 to 22 cubic feet per second per square mile. In 

 the upper reaches of this stream the flood-flows may be expected 

 to approximate anywhere from 60 to 80 cubic feet per second per 

 square mile. 



Floods in Niagara river. As shown by table No. 45, the natural 

 regulation of this river is so perfect that floods are unknown. 

 During the entire year 1895 the flow of Niagara river varied from 

 195,578 cubic feet per second to 177,852 cubic feet per second, the 

 extreme variation for the year being only 17.726 cubic feet per 

 second. 



Floods in Genesee river. The following account of early floods 

 in this stream is mostly taken from the report on Genesee river 

 storage surveys, dated January 1, 1897. 



Great floods have occurred in this river in 1815, 1835, 1857, 

 1865 and 1896. At a number of times between 1865 and 1896 the 

 river has also been very high, but at no time since 1865 as severe 

 as in 1896. 



Beyond the mere fact that a very severe flood occurred in 1815, 

 which overflowed the flats in the valley between Avon and Mount 

 Morris and the black ash swamp which then covered the area now 

 included in the first and third wards of the city of Rochester, 

 little is known as to the flood of that year. 



The next great flood of which we have record occurred in 1835. 1 



iSee report of F. C. Mills, relative to the Genesee valley canal, Assembly 

 Document No. 73. 1837, p. 69. 



