CAUSES INFLUENCING FLOW OF KIVER. 



13 



CAUSES THAT HAVE INFLUENCED THE FLOW OF THE RIVER. 



THE RAINFALL. 



The most obvious explanation for the smaller amount of water 

 annually carried by the Rock River is the diminution of the rainfall. 

 This will appear from the following table, which embraces the drain- 

 age basin in Wisconsin: 



Table of precipitation, in inches, for the ijears 1885 to 1.900, inclusive. " 



Year. 



Jan. 



Feb. 



Mar. 



Apr. 



May. 



June. 



July. 



Aug. 



Sept. 



Oct. , 



Nov. 



Dee. 



An- 

 nual. 



Total for 4-year 

 periods. 



1885... 



1.8 



0.8 



0.4 



3.2 



1.2 



5.9 



4.8 



7. 7 



4.0 



2.7 



1.0 



2.9 



36. 4 



] 



188G... 

 1887... 



4.1 

 2.8 



1.6 



4.2 



4.2 



1.6 



2.9 

 1.0 



2.4 



1.6 



2.2 



1.0 

 4.1 



4.5 



5.0 



2.2 



5.0 



\\ 



1.3 

 1.2 



1.5 

 1.1 



30.3 

 34.2 



[l885-1888, 129. 3. 



1888... 



1.4 



1.1 



2.1 



2.3 



3.9 



3.4 



" 



2.5 



1.5 



1.9 



1.8 



2. 5 



28. 4 



J 



1889... 



1.9 



2.5 



1.3 



2.2 



4.3 



4.7 





1.0 



2.2 



.3 



2.0 



2.5 



27. s 



| 



1890... 

 1891... 



2.4 



i.e. 



1.9 

 1.3 



2.1 

 2.5 



3.1 

 3.2 



4.1 

 1.5 



7.1 

 4.1 



1.2 

 2.9 



3.1 

 1.7 



1.4 

 . 3 



4.4 

 1.8 



2.1 

 3.1 



1.0 

 2. 2 



33. 9 

 25.2 



[1889-1892, 124. 0. 



1892... 



2.4 



1.7 



1.6 



3.2 



7.5 



7.9 



2.4 



3.1 



2.5 



1.5 



1.5 



1.8 



37.1 





1S93... 



1.5 



1.4 



2.6 



5.1 



2.0 



3.9 



3.2 



1.5 



2.7 



2.4 



1.3 



2.3 



29.9 



1 



1894... 

 1895... 



1.6 

 1.6 



.8 



.6 



2.4 



.8 



3.4 



1.2 



4.0 

 4.0 



3.6 



2.0 



1.2 

 2.4 



.9 

 3.2 



5.8 

 1.8 



2. 2 

 . 5 



2.4 

 2.3 



.8 

 2.0 



29.1 

 22. 4 



|l893-1896, 113. 1. 



1896... 



.9 



.8 



1.6 



4.2 



4.9 



2.6 



4.3 



2.2 



6. 4 



1.1 



2.0 



. 7 



31.7 



J 



l c 97... 



2.9 



1.3 



3.2 



4.0 



1.0 



4.7 



2.8 



2.8 



1.5 



1.1 



1.5 



1.7 



28. 5 



1 



1 9\.. 

 1 93... 



2.3 

 .6 



2.0 



3.2 



1.5 



2.1 



3.0 

 5.1 



4.8 

 3.4 



3.1 

 3.1 



3.S 

 2.8 



2.3 



3.0 



3.9 

 1.7 



1.2 



1.7 



. 5 



1.7 



32.2 



27.2 



ll897-1900,119.5. 



1 03... 



1.5 



2.3 



1.6 



2.5 



1.9 



1.9 



6.7 



4.0 





3.6 



2.3 



.6 



31. 6 



J 



1.01''.. 



1.1 



1.2 



2.8 



.5 



2.4 



1.8 



2. 7 



1.0 



3.2 



1.8 



.8 



1.3 



20.6 



1 1901 -1902, 56.1 



1£02&.. 



.4 



1.5 



1.2 



,, 



6.3 



4.9 



9.2 



.8 



4.2 



1.4 



2.3 



2.1 



35. 5 



f | =112. 2c) . 



Aver- 



2.0 



1.6 



2.0 



2.8 



3.3 



3.9 



3.1 



3.1 



2.8 



2.1 



1.8 



1.8 



30.4 





age d 































a Compiled from data furnished by the United States Weather Bureau. 



b The figures for 1901 and 1902 are based upon a more restricted area than the figures for 1885 to 1900. 



c Approximated for a period of four years. 



rfFor the period 1885-1900. 



The most significant figures are those for the years 1893, 1894, and 

 1895, when the annual precipitation averaged only 27.1 inches, or 3.3 

 inches below the average for the entire period, from 1885 to 1900, for 

 which complete records of precipitation are available. The monthly 

 precipitations during these three years were also very irregular, although 

 it can not be said that the deficiency was any greater during the sum- 

 mer, when the rain is most needed, than during other seasons. The 

 departure from the normal during the period from 1S93 to 1895 was 

 preceded by the heavy precipitation of 1892, ,but this precipitation 

 was needed to replenish the supply after the severe drought of 1891; 

 and the same is true in 1890, as well as in the alternate years since 

 1895. If the eighteen years be divided into four and a half 1-year 

 periods, it will be seen from the column at the right that, with the 



