HYDROLOGY OF NEW YORK 



473 



large volume, although part of the water was discharged through 

 the aqueduct to the waste-weir at Mill river, fifteen miles below 

 Croton dam. The water rose in Croton lake at the rate of four- 

 teen inches per hour. The earthen bank remained intact until the 

 water nearly reached its top, when it flowed between the frozen 

 and unfrozen earth, twenty inches below its crest, forming a 

 breach. The large amount of ice in the river demolished the pro- 

 tection wall and the whole embankment was washed away. At 

 the time of the accident, on January 8, the water flowed over the 

 weir to a depth of 15 feet. 



Another severe flood occurred in November, 1853, while in 

 April, 1854, after unprecedented rains, the worst freshet was 

 experienced which has yet been recorded. The depth on the crest 

 of the Croton dam was 8.25 feet. 



Floods in Fishkill creek. This stream is subject to severe floods, 

 although there is not a great deal known about them. The follow- 

 ing tabulation, calculated from high-water marks observed for a 

 number of years at the Groveville dam, embodies practically all 

 the information. The dam is of masonry faced with plank, with a 

 straight horizontal crest, 4 feet wide and 134 feet long. The dis- 

 charge has been calculated by coefficients derived from Cornell 

 University experiment No. 11. 



Year 



(1) 



1882 

 1888 

 1888 

 1891 

 1891 

 1891 

 1891 

 1893 

 1893 

 1893 

 1893 

 1893 

 1896 

 1896 

 1896 

 1902 



Month 



(2) 



September 24 . 



March 22 



December 18 . . 

 January 12. . . . 

 January 13. . . . 

 January 22. . . . 

 January 23. . . . 



March 10 



March 11 



March 12 



March 13 



March 14 



February 7. . . . 



March 1 



March 20 



March 1 



Depth on 

 crest, feet 



(3) 



5 

 4 

 6 

 4 

 4 



5 

 4 

 5 

 5 

 4 



6.7 

 4.5 



Discharge 



Cubic feet 

 per second 



(4) 



7, 700 

 5,200 

 4,400 

 7, 700 

 3, 650 

 3. 650 

 8,800 

 5.200 

 4, 000 

 6,100 

 5,200 

 3,650 

 8,300 

 4, 400 

 8,300 

 13, 700 



