208 SOILS 



with the least amount of digging. He should know 

 the wet spots in the field and if the outlet of the 

 drainage system is to be on the bank of a stream, he 

 should know the high- water mark of the stream. 

 Only the man who tills the field and observes the 

 condition of the soil at all times of the year 

 can locate a drainage system upon it most eco- 

 nomically. 



It may be cheaper and better to have a large 

 job done entirely by a drainage engineer. He has 

 a force of men who are familiar with all the ins and 

 outs of the business, and can dig a ditch, lay tile and 

 finish the work much quicker than men who are 

 unused to the business. It is especially important 

 that the man who lays the tile should be skilled, 

 or if not skilled at least very careful. Cheap help 

 for this work is poor economy. 



In planning a system of under-drainage the 

 various points should be considered in the following 

 order: First, select the best outlet. Second, lo- 

 cate the position of the main or mains. Third, 

 ascertain the difference of level between the out- 

 let and the highest point in the main, and de- 

 termine the grade. Fourth, locate each of the 

 laterals. Fifth, find the difference in level 

 between the highest point in each lateral and 

 the point where it joins the main, and de- 

 termine the fall. Under all circumstances work 

 from the outlet or outlets back to the furthermost 

 laterals. 



Make an exact plan of the system on paper, 

 drawn to a scale. A man usually thinks he can 

 remember just where the drains are located, but 

 in a surprisingly short time all traces of them on the 

 surface are obliterated and recourse must be had 

 to a map. Failure to make a map may cause 



