26 



BULLETIN 502, U. S. DEPARTMENT OF AGEICULTURE. 



The wet spot became noticeable in the summer of 1913 and by the 

 following summer had increased considerably. There was not much 

 alkali present, but the ground was very wet. 



A prominent shale ridge outcrops across the north and east sides 

 of this tract. A deep arroyo at one time extended across the tract 



Height of Ground Surface above Datum »o^ ^ 



Fig. 3. — One-acre tract near CaDon City, Colo., showing plan of drainage. 



in the bottom of the shallow draw in which the affected area is 

 located. This was filled in when the land was leveled. It is be- 

 lieved that this had much to do with the development of the seepage, 

 for not only was the natural drainage afforded by the arroyo thus 

 shut off, but the earth filled in became more dense than the natural 

 soil and offered greater resistance to the movement of the ground 

 water. A careful subsoil examination indicated that the seepage 



