12 



BTJT.TiETIH 675, V. S. DEPARTMENT OF AGRICULTURE. 



fact that area A received loss than one-half as much rainfall as 

 area B. 



The other 25 rainstorms of the year 1915, with the possible excep- 

 tion of one or two in June, produced no run-off, because they were of 

 a much gentler nature, so that the soil was able to absorb the moisture 

 as it fell. Exception is made to certain storms occuring during 

 June, since there was at that time a continual flow from the melting 



WINTER 

 SNOW 



PRECIPITATION! 



W A'^^^^^ 



(AREft-A *)I6 



lyAREA-B 1<?16< 



STREAM FLOW^^^^^^I 



EROSION I 



10 



PRECIPITATION ■■ 

 STREAM FLOW^f 

 lEROSION IZD 



fPRECIPITATlONH 



fAREA-B \q\i< 



SUMMER 

 RAINS * 



STREAM FLOW PNW\\> 



Tn ov 5 an DS or 



Qu I VAi_ E.NT 



OO'j OF CwFt, 



Alll FALL - INCH 



\\\\K\\\^ 



Hur^DRCO) O? < u. F* 



Fir,. 



kEROSION 



'PRECIPITATION 

 AREA-B Iqi5< STREAM FLOW 



,EROSION [ 



(PRECIPITATION 

 AREA-A tfllfrC STREAM FLOW 



Ierosion 

 (precipitation 



.AREA-B iqifr< STREAM Fl0wL2\23 



Ierosion I I 

 -Erosion and run-off from molting of accumulated winter snow and from rainstorms. 



of snow on the areas. The effect of rainfall upon the stream flow 

 during the presence of melting snow could not be ascertained. 



On July 4 a fall of 0.36 and 0.34 of an inch, respectively, were 

 recorded from the two rain gauges on area A, and 0.43 and 0.40 of 

 an inch on area B, over a. period of 3 hours and 25 minutes. This 

 resulted in no run-off. On September 2 and 3 there was a fall of 

 0.65 and 0.65 of an inch on area A and 0.62 and 0.63 of an inch on 

 area B, covering a period, of 8 hours and 45 minutes. This produced 

 no run-off. These latter two cases, in which the rain fell at an 



