Outlet of Drains 



453 



THE OUTLET OF DRAINS 



Great pains should be taken to secure a clear fall 

 at the outlet of a drain, placing it, if possible, where 

 it will always be above water, as represented at A, 

 Fig. 142, rather than as at B. If the outlet is beneath 

 water, the checking of the velocity of outflow will 

 cause sediment to be thrown down, and will soon clog 

 the main. Care should also be taken to so guard the 

 outlet from the trampling of animals that they shall 



Fig. 142. Proper and improper outlet of drains. A, proper outlet ; B, improper 

 outlet ; C, proper junction of lateral with main ; D, improper junction. 



not break down the earth about it ; and against the 

 effect of winter frosts and surface rains, tending to 

 throw earth down over the mouth. 



In cold climates it will not do to terminate the 

 main with the ordinary drain tile, as the action of the 

 frost will soon crumble it down. A common plan is 

 to make a wooden outlet, 16 feet long, out of 2 -inch 

 lumber, thus holding the tile back beneath the sur- 

 face sufficiently far to be safe against freezing. A 

 much better termination of the main, however, and 

 one which will be permanent, is glazed sewer tile, 

 using not less than 10 feet of it. Lap -weld iron pipes 



