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NEW YORK STATE MUSEUM 



nary flood-flows are at the rate of about 30 to 35 cubic feet per 

 second per square mile. 



Floods in Blade river. Heavy floods have occurred in Black 

 river in 1807. 1833, 1850, 1857. 1862, 1866, 1869 and 1896. The 

 flood of April 20-21, 1869, was specially heavy, there being a 

 heavy snowfall over nearly the entire catchment area, which 

 melted rapidly that year. In addition to the ground being heavily 

 covered with snow, about 2.2 inches of rain fell in some parts of 

 Black river catchment basin from April 17-23, though this quan- 

 tity of rain, which was only over a portion of the catchment area, 

 hardly explains the severity of the flood. The greater portion of 

 the water evidently came from rapid melting of snow. 



Flood in Black river in April, 1869. On April 21, 1869. the 

 banks of North lake reservoir, a structure maintained by the Stale 

 for the purpose of storing water for the Black river and Erie 

 canals, gave way, precipitating into the heavily swollen stream 

 about 350,000,000 cubic feet of water. This accident was made 

 the basis of large claims for damages against the State, which 

 were tried before the Canal Appraisers in the summer and fall of 

 1869. The testimony in this case, which included two large octavo 

 volumes of over twelve hundred pages, is the source of the follow- 

 ing information as to flood-flows of Black river and its tributaries 

 in the spring of 1869 : 



The Black river flood of April, 1869, was studied by David M. 

 Green, Samuel MeElroy. William J. McAIpine, L. L. Xichols and 

 other hydraulic engineers of that day. The testimony may, there- 

 fore . be referred to as furnishing unusually good flood data. 



Mr Nichols stated that he not only measured the lengths of 

 the crests of the dams on the several streams for which flood- 

 flows were given, but that he also instrumental ly determined 

 the hight of flood marks above the crests. This work was done 

 within a few months after the flood while the matter was fresh 

 in the minds of everybody. He further stated that the tabulated 

 flood-flows were obtained by computing with Francis's formula 

 for discharge over sharp-crested weirs with clear overfall. The 

 dams, however, on which the flood-flows were measured were <>f 

 such a form as to indicate the use of Cornell experiments Nos. 



