98 OPERATIONS OF DRAINING. 



ty. If there is one to whom it is not familiar, let hihi 

 make the trial, and he will be astonished at the result, 

 and at his own want of forethought in not having made it 

 before. 



CHAPTER XII. 



OPERATIONS OF DRAINING. 



For the purpose of illustrating the operations of dram- 

 ing, we shall consider the effect of, 



1 . Draining the surface ; 



2. Draining the soil ; and, 



3. Draining the subsoil. 



1. Draining the surface. Surface-water wants only 

 a suitable channel, and a moderate inclination, to readily 

 pass off. In case of heavy rains, it is seen that tenacious 

 soils, upon a level or slightly-inclined surface, are liable 

 to be flooded with surface-water, which often stands for 

 some time in pools, destroys the seed or growing crops, 

 and renders the soil, when dry, compact and hard. Again, 

 in ravines, or depressed surfaces, the like evils are liable 

 to occur, from the sudden accumulations of water, with- 

 out a proper gradation of surface, and a sufficient drain to 

 carry it off. 



In the first case, the evil may be corrected by throw- 

 ing the land into ridges ; the modes of doing which we 

 shall prescribe under the article, ploughing. 



In the second case, when large quantities of surface- 

 water are liable to concentrate from heavy rains, an open 

 drain or ditch is the only resort. This should be capa- 

 cious enough to carry off, in its channel, all the waters 

 that may thus accumulate. It should be from two to four 

 feet deep, to give a sufficient descent to drain off the 

 waters from the contiguous grounds. Its banks should 

 have a slope of 45 degrees, that they may resist the pres- 

 sure from the surface, and the action of the water ; and 

 in digging, the sides should be left sohd, without being 



