HYDROLOGY OF NEW YORK 



203 



In all of the foregoing statements as to minimum runoff, it 

 should be understood that the actual quantity appearing in the 

 stream as runoff from a given precipitation will vary, depending 

 on whether ground water is high or low at the beginning of the 

 period considered. All such statements, therefore, are necessarily 

 approximate— they may have a plus or minus variation from the 

 diagram of one or two inches. Possibly the maximum variation 

 may be more than this. 



HIVEK SYSTEMS 



Classification of rivers. The rivers of the State may be classi- 

 fied into seven general systems, whose relative position is shown 

 by the accompanying map. fig. 17. These are: 



Fig. 17 Map of rivers of New York. 



