to6 ENGINEERING FOR LAND DRAINAGE 



men do not have *' a good eye " for this kind of work 

 and cannot use it. 



These methods of grading ditches are simple, prac- 

 tical, and accurate, and in the hands of competent \^ork- 

 men drains can be constructed with as great accuracy 

 as our city sewers are laid when done under the most 

 rigid supervision. 



Digging the Ditches and Laying the Tile, 



Not every laborer can dig a creditable ditch for tile, 

 but perhaps any man can learn. An apprenticeship of 

 greater or less duration is required to develop a skilful 

 ditcher. This work is rapidly passing into the hands 

 of those who by their skill merit a premium in wages 

 readily accorded them by those who appreciate thor- 

 ough and economical work. 



The work of constructing a tile drain should begin 

 at the outlet, be it a main or branch. The general 

 method that should be followed may be described, but 

 only practice will give that swing and ease of motion 

 with which the trained workmen digs the ditch and lays 

 the tile. The ditch should be started straight at the 

 top and the curves should be smooth, not uneven and 

 crooked. Let no one think that he can dig such a 

 ditch without first drawing a line for cutting one side 

 of it. This should be a J-inch rope which can be drawn 

 tight or be laid to form a suitable curve. The top 

 width of the ditch should be proportioned to the depth 

 to which it must be made, lo or 12 inches be- 

 ing a common width for a 3 -foot lateral ditch. A 

 ditching spade with blade 18 or 20 inches long, slightly 



