10 



AGRICULTURAL ENGINEERING 



Gridiron System 



ig. 



47. The gridiron system 

 laying out tile drains. 



of 



The single line system is 

 one in which the outlet for 

 tile lines is an open ditch. 

 Tile lines in this case are 

 independent of one another, 

 and each must have its own 

 outlet. 



Large Drainage Systems. 

 In laying out a large drainage 

 system it may be necessary 

 to use several of the various 

 methods or systems of ar- 

 rangement. There are no 

 hard and fast rules for any 

 one system, though short 



laterals should be avoided 

 whenever possible, because 

 mains will drain the land for 

 some distance on each side, 

 and, the part of the laterals 

 extending across the drained 

 area of the main is largely 

 useless as far as adding to 

 the drained area is con- 

 cerned. 



Straight Tile Lines. Tile 

 lines should be as straight as 

 possible, and when curves 

 are required they should not 

 be sharp. In addition to the 

 fact that the flow of water is 

 hindered to a greater extent 

 in tile lines with sharp turns 





Single-Lmc System 



Fig. 48. The single-line system of 

 laying out tile drains. 



