HYDROLOGY OF NEW YORK 



443 



Tlie flood commission of 186-5. Following the great flood the 

 Legislature passed an act appointing commissioners to inquire 

 into and ascertain the cause or causes of the inundation of the 

 city of Rochester by the waters of the Genesee river in the month 

 of March, 1865, and also to ascertain whether any, and, if any, 

 what obstructions had been placed in said river which tended to 

 cause or increase the extent of such inundation, and the nature 

 and extent of such obstructions, and what measures, proceedings 

 and remedies were necessary or proper for the purpose of guard- 

 ing against or preventing a recurrence of such an inundation. 

 The commissioners were Addison Gardner, Amos Bronson, Levi 

 A. Ward, George J. Whitney and George E. Mumford. General 

 I. F. Quinby was engineer to the commission. 



The commission begins its report by stating that there is no 

 record in the previous history of Rochester of any serious damage 

 from overflows of the river, no former flood having to any im- 

 portant extent spread beyond the banks of the river. In view of 

 this state of things the citizens of Rochester had felt it to be of 

 the highest importance to ascertain the cause of the unprecedented 

 extent of the 1865 flood, and, as far as possible, to guard against 

 its recurrence. 



As to the first cause, it is stated that by reason of a sudden 

 change of temperature from winter to almost summer heat an 

 immense body of snow, which had accumulated during the pre- 

 vious winter weather, was suddenly melted and thrown at once 

 into the river channel within the space of three or four days 

 instead of occupying a week or more, as in ordinary floods. Sec- 

 ondly, the effect of the flood was increased in consequence of the 

 obstruction to free flow caused by the bridge and embankment of 

 what is iioav the Xew York, Lake Erie & Western Railway at 

 Avon. The openings in the embankment across the river valley, 

 while adequate for ordinary floods, were entirely too small for 

 the quantity of water flowing in March, 1865. The consequence 

 was that at the time of greatest flow the water stood at least 

 three feet higher on the upper side of the embankment than on 

 the lower side. The embankment finally gave way, thus allowing 

 a large quantity of ponded water to flow suddenly down the river, 

 filling the channel at Rochester beyond its carrying capacity. As 



