222 



FARM DEVELOPMENT 



Figure 117. Reversible road machine making lateral ditches which run into a large 

 drainage canal made beyond by the elevating grader. 



tile drains, there are other forms of drains which are 

 useful for special conditions. Drainage wells are useful 

 where vertical drains can be made cheaply through 

 impervious layers of clay or stone which hold the water 



in the saucer-shaped 

 area, thus carrying the 

 water downward into 

 the nonwater-bearing 

 stratum of gravel or 

 sand below. In Figure 

 131 the hills surround- 

 ing the low area are so 

 high that a horizontal 

 drain under the ad- 

 joining hill would be 

 very expensive. A well 

 is sunk at one side, or if a dry time can be found when 

 the low area is dry, the well can be sunk in the midst of 

 the wet area. Drain tiles, laid from I to 3 feet under- 



Figure 118. Showing forms of ditch beside a 

 fence line, as at the side of a public highway. 

 A-D, ditch made with steep bank and dirt left in 

 high ridge. B-F, ditch made with slanting outer 

 bank and ridge rounded down. C-E, ditch 

 rounded and earth spread out so that land can be 

 mowed or even cultivated to the roadway, as at P. 



