THE DRAINAGE OF FARM SOILS 207 



matter how tight a joint is made, water will pass in 

 freely. In laying tile, therefore, the object should 

 be to make as tight a joint as possible, so that dirt 

 will not enter and clog the tiles. 



PLANNING THE DRAINAGE SYSTEM 



The attempt to drain a piece of land, no matter 

 how small, should be preceded by careful planning. 

 The direction of the drains, the distance between 

 them and the grade should be plotted on paper. 

 The aim should be to lay out the system so as to 

 secure sufficient fall ana give adequate drainage 

 with the least digging and the least amount of tile. 

 To this end it is necessary to make few outlets and 

 junctions and not to lay two lines of tiles so close 

 together that they both drain an area that could be 

 drained by one line. 



On small areas having a noticeable fall, the 

 drains may be located by eye and the planning may 

 be done without the aiu of a surveyor; but much 

 land that requires draining is quite flat and it is 

 extremely difficult to give the drains the right grade 

 without the assistance of an instrument. It does 

 not pay to go to the expense of buying tile and dig- 

 ging ditches only to make a botch of the job by 

 trying to save the cost of the services of a competent 

 drainage engineer. Nine times out of ten the work 

 of laying out the drainage system on a large area 

 should DC entrusted to a surveyor. 



The owner of the field should, however, con- 

 tribute his knowledge of local conditions. He 

 should know, for instance, the source of the 

 water it is expected the drain will remove whether 

 it comes from overflow, springs or otherwise so 

 that the drains may be laid to cut off the supply 



