DRAINAGE 



281 



TILE DRAINAGE 



Underdrainage. Because of the objections made to 

 open ditches, methods of eliminating them have been 

 developing for many years. The most satisfactory way is 

 by the use of circular drain tile laid in a trench and then 

 covered so that there is no waste land and no inconvenience 

 in cultivation. If it is properly constructed, there is no main- 

 tenance cost. 



At the present time there is no means of determining the 

 drainage properties of a soil except by actual experiment 

 and comparison with soils in a region which has been under- 

 drained. The depth and width of tile drains depend on 



After University of Minnesota 



Fig. 230. Clay tile, sewer pipe, concrete tile 



the rapidity with which water will pass through the soil 

 and on the crops to be raised. In light, open soil, drains 

 can be laid deep and wide apart. In heavy soil they should 



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