28 TILE DRAINAGE 



Figure 2. In I 875 feet of four-incli main and 8,1UU feet 

 of three-inch laterals are required to drain ten and one 

 third acres with the lines fifty feet apart. In II the same 

 total length of drains are required as in I, but only 475 

 feet of four-inch main is used. There is thus a saving of 

 about $6.50 in the cost of tile and equally as good drainage 

 obtained. It is seldom that any particular arrangement 

 can be used entirely, as so much depends upon the slope 

 and conformation of the land. It is always important, 

 however, that some systematic arrangement of the drains 

 is made, for thorough drainage in a haphazard way is 

 difficult to obtain and is most expensive. Careful study 

 of the land should first be made and then the drains laid 

 out so as to secure the greatest fall, the least expense for 

 tile, the minimum amount of digging and the most perfect 

 drainage. If at all possible lay all the lines of tile parallel, 

 putting them in through the wettest places first. Then, 

 if your faith and your purse are not strong enough to da 

 thorough work in the beginning you will have your field 

 in such shape that additional lines can be added in the 

 future as your -faith and money increases. Another im- 

 portant matter is to keep an accurate plan or plot of the 

 drains on paper. This will show their exact location and 

 will be valuable for future reference, especially if the land 

 should come into the possession of other parties. 



DETERMINING THE FALL. 



After the main and laterals have been located, with the 

 aid perhaps of a preliminary leveling in case the area is 

 quite flat, their location is marked by stakes driven into the 

 ground every fifty feet, with their tops left four or five 

 inches above the surface. The next step is to determine the 

 total fall of the main. This is done by finding the differ- 

 ence in level between the outlet and the upper end of the 

 main. The leveling can be best done with a surveyor's level 

 and where the grades are slight and require careful work 

 it is usually safest and most economical to hire a competent 



