THE PRINCIPLES OF DRAINAGE. 



CHAPTER XXIII. 



HOW TO DRAIN LAND. 



The manner of draining land necessarily depends upon 

 several conditions such as the character of the soil; the 

 amount of water; the manner in which the water exists in 

 the soil or in which it arrives there, the kind of materials 

 at hand ; the outlet for the water and others which may 

 present themselves in any particular case. A few general 

 principles however will enable the farmer to adapt his 

 methods to his circumstances without difficulty. 



The soil. Whenever, in early spring, the water appears 

 on the surface, or in the furrow after the plow, or remains 

 upon the surface after rain and interferes with the cultiva- 

 tion, the land requires drainage. It may be that the water can 

 be carried off by open surface ditches; or that the sources 

 of the water may be tapped by a few converging drains 

 meeting in one main ditch by which the whole of the water 

 may be carried off from the land. It may be on the other 

 hand that the subsoil is full of springs which are supplied 

 from distant sources and that in this case deep drains are 

 necessary to cut off the water and carry it away. Or the 

 soil may be of stiff impervious clay under the surface, or an 

 impermeable hardpan prevents the surface water from pas- 

 sing down and making its way from the land. All this 

 must be studied and known before any work is done, lest a 

 costly job of draining may be done unnecessarily or without 

 useful effect. To learn this, it is proper that the subsoil 

 should be examined by digging with the spade 3 or 4 feet 

 deep. 



Springs, frequently fill a large area of low land with 

 water, which flows under the surface and immediately upon 

 a hard bed of clay or gravel hardpan. To understand 

 clearly how this occurs, it may be well to explain the na- 

 ture and action of springs. 



