HYDROLOGY OF NEW YORK 



301 



Milwaukee, the eastern line being for the entire distance nearly 

 parallel to Lake Michigan and in places only 2 or 3 miles distant 

 therefrom. The area drained by the Desplaines river is large 

 enough to give a fair idea of the average yield of streams tribu- 

 tary to Lake Michigan in northern Illinois and Indiana, western 

 Michigan, and southern and central Wisconsin. In 1893, with a 

 mean rainfall on the catchment area of 39.96 inches, the total 

 runoff was 10.14 inches, of which 8.61 inches occurred during the 

 storage period from December to May, inclusive. In 1894, with 

 a total rainfall of 27.94 inches, the total runoff was 7.70 inches, 

 of which 7.54 inches occurred in the storage period. For the year 

 1895 the total rainfall was 27.28 inches. The runoff data of this 

 year are incomplete, but taking into account the sequence of the 

 rainfall it is clear that the total runoff for that year did not 

 exceed about 2.0 to 2.5 inches. The effect of the three dry years 

 1893, 1894, and 1895 in the Desplaines catchment area is shown 

 by the record of 1896, where, with a total rainfall of 39.58 inches, 

 the total runoff was only 6.69 inches, of which 5.39 inches oc- 

 curred in the storage period. These figures indicate that the 

 ground water of the Desplaines area must have been so low at 

 the end of 1895 as to absorb a large portion of the heavier rainfall 

 of 1896 before any great amount could appear as runoff. 1 



*For details of the measurements of the Desplaines river see Data Per- 

 taining to Rainfall and Stream Flow, by Thomas T. Johnston, Journal 

 Western Soc. C. E., Vol. I (June, 1896). 



