DRAINING. 19 



other matters connected with it. The drains should 

 only have sufficient fall to enable them to discharge 

 the water sufficiently, which one in every 300 will 

 enable them to do. 



A difficulty of an opposite extreme is, however, 

 sometimes met with in the levelness of the ground 

 and excessive wetness combined. In such cases the 

 most practical thing to do is to lay the ground up in 

 narrow ridges, and by means of the excavations thus 

 taken out of the drains or ditches, the surface can be 

 raised 2 feet or 3 feet above the water-level. The 

 ridges should not be broad, seldom exceeding 20 feet, 

 and 12 feet is sometimes even more suitable. 



The fall required for open drains is considerably 

 more than that for underground tile-drains. If open 

 drains require one in 300, underground drains will do 

 well with only one in 500. 



Covered drains, though the best, are difficult to 

 keep clear of roots, and the only safe method is to 

 put in as large pipes as possible. In cases where a 

 3- or 4-inch pipe would sufficiently carry all the 

 water, I would put in a 12- or 14-inch pipe or cor- 

 respondingly large culvert ; and where this has been 

 done the drains have stood well for over forty years, 

 no tree roots choking them. 



Annexed are prices which I have paid for planta- 

 tion drains in Banffshire and Morayshire within the 

 last twenty years : 



Dimensions 30 inches wide, 20 inches deep, 8s. 4d. per 100 yards. 

 Do. do. do. 6s. Od. do. 



Do. do. do. 5s. Od. do. 



varying according to state and condition of ground ; 

 but in some districts the work can now be done 20 

 per cent cheaper. 



