HYDROLOGY OF NEW YORK 



425 



the valleys are narrow, with steep slopes, accordingly rendering 

 it impossible for large quantities of water to be stored. 



So far as known, aside from Black river, Raquette river and one 

 or two others in this State, there are no rivers anywhere on which 

 the task assigned to the Roman river conservancy commission 

 could be successfully applied. On Black river it is not difficult to 

 construct a single reservoir, which practically controls 1889 

 square miles of catchment area. The Raquette river can also 

 be thus controlled by a single dam at Tupper lake. If it were 

 not for the location of towns near the water level, the Seneca 

 river could be controlled by a series of dams at the foot of the 

 Finger Lakes; 



River regulation on the Seine. The Seine is the most important 

 river of France, not only on account of its being the highway for 

 a flourishing inland trade, but in consequence of engineering works 

 which have been carried out for its improvement. On this stream, 

 the same as on others, the occurrence of high floods is due to the 

 concentration of the rainfall at special periods of the year. The 

 rainfall is considerably greater in the summer than in the winter 

 months, but owing to evaporation the rains of summer have com- 

 paratively little influence upon the flow of the river, although a 

 heavy rain during the winter months falling upon a saturated 

 soil, when evaporation is inactive, causes a flood of which the 

 hight depends upon the amount of saturation of the basin by 

 previous rains and the duration of the rainfall. Daily readings 

 of the hight of the river have been kept at Paris since 1732. 

 During this time, thirty-one ordinary floods, twelve extraordinary, 

 and two exceptional floods, in December, 1740, and in January, 

 1802, have occurred. A list is also given of five exceptional floods 

 occurring between 1649 and 1732. In 1658 a severe flood followed 

 the breaking up of the ice in the river after severe cold weather 

 lasting five weeks. Of the forty-five large floods recorded since 

 the commencement of the. daily observations in 1732 only three 

 occurred in the warm season, two of them appearing in the month 

 of May and one in the month of September. The foregoing shows 

 that regular floods of the Seine at Paris are almost wholly con- 

 fined to the cold season. 1 



iTlie River Seine, by L. F. Vernon-Harcourt, Proc. Inst. C. E., Vol. 

 LXXXIV, p. 210. 



