100 



AGRICULTURAL ENGINEERING 



Trouble with Roots of Trees. Tile drains laid near 

 aquatic, or water-loving, trees, are sometimes partially, if 

 not entirely, obstructed by roots of these trees. The willow 

 and water elm are among those that give the most trouble in 

 this respect. Fruit trees give very little trouble, and drains 

 may be laid in orchards with impunity. 



If a drain must pass within 30 or 40 feet of any of the 

 trees that are aquatic by nature, the trees should be cut down 



Fig. 65. A tile drain which became completely obstructed by roots 

 from a willow tree. 



and killed, or sewer pipes with cemented joints should be 

 used near the trees, which will prevent the roots from getting 

 into the drains. 



Drainage Wells, or Sinks. Wells are occasionally used 

 as outlets for tile drains. It is known that about as much 

 water may be discharged into a well as may be pumped from 

 it. An investigation of the success of wells as drainage out- 



