8 



BULLETIN 447, U, S. DEPARTMENT OF AGRICULTUEE. 



ferences between the cracked, and uncracked layers as to the time 

 required for the water to disappear. In all parts of the uncracked 

 area water disappeared very slowly. 



Water penetrated to practically the same depth from the surface 

 in all the holes except the first and the last. In all the holes except 

 the first, water evidently penetrated to a point where further move- 

 ment took place with difficulty. That the water applied at the sur- 

 face did not reach the depth where movement was difficult was 

 doubtless due to the fact that the quantity of water was not sufficient 

 to reach that depth. The fact that the water from most of the holes 

 penetrated to a depth of from 21 to 25 inches below the surface 

 would indicate that a layer of impervious soil exists at that depth 



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Fig. 3. — Diagram showing the depth of soil penetrated and the total distance from the 

 surface reached when water was kept standing for 10 days in holes 8 inches in 

 diameter bored to different depths. The heavy lines indicate the lowest points reached 

 by the water from the different holes. 



were it not for the fact that water added at about this depth pene- 

 trated through as many inches of soil as did that introduced 9 inches 

 higher. The depth to which the water penetrated in all holes in the 

 compact layer indicates that the water movement throughout this 

 portion of the soil was very uniform. 



A second experiment was made to determine the distance to which 

 water introduced into the soil at various depths would penetrate in 

 a given length of time. For this purpose a set of borings duplicating 

 those in the previous experiment was made, and water was kept 

 standing in each of them for a period of 10 days. At the end of that 

 time the depth to which the water had penetrated was measured. 

 The results of this experiment are shown in Table III and figure 3. 



