LOSS BY PERCOLATION 



193 



The rainfall and relative loss through gages of differ- 

 ent depths is shown in the following curves, based upon 



the above figures. 



30 

 28 

 26 

 24 

 22 



CO 



20 

 o 



S IS 



Z 



-i 16 



< 



< 



* 12 

 < 

 o 10 



8 



C 



JAU. rtO. MAK. APHIL MAT JUNL JULY UU. OCri. UU I . NUV. UtL. 



Fig. 61. Curves representing the annual rainfall and percolation through 

 20, 40 and 60 inches of soil by months. Rothamsted, England. Average of 34 

 years. 



It appears from these figures and curves that about 

 50 per cent of the rainfall is lost by percolation, under 

 the climate of England. It also appears that the loss 

 is slightly less from the sixty-inch than from the twenty- 

 inch gage. Under a climate less humid, this difference 

 is greater. This is illustrated in two ways: (1) In the 

 above table 1 it is clear that the proportion of water lost 

 by drainiage is much less in summer than in winter. 

 ^(See page 195.) The saving is somewhat larger in the 

 deep than in the shallow gage, as the proportionate 



M 



