DRAINAGE METHODS FOR COUNTY ROADS. 29 



by tile drains; and fonrth, by V-drain foundations. Each of these 

 methods will be discussed briefly. 



OPEN DITCHES. 



Open ditches have been used frequently in some of the Southern 

 States for subdraining roads through low flat sections. Ordinarily 

 only one ditch is used, and it is located a few feet outside of and 

 parallel to the road. This ditch usually is made about 2 feet wide 

 and 3 or 4 feet deep, with the banks vertical. The material ex- 

 cavated from the ditch is used to build up the roadbed, and the 

 surface water from the side ditches is turned into the deep ditch at 

 convenient intervals. 



The use of such ditches should be decided upon with care. There 

 are ditches in the South, within the coastal plain, where sand clays 

 and indurated clays occur a few inches underground, that have stood 

 with vertical sides since the middle of the last century. They have 

 been cleaned repeatedly and no doubt have become somewhat en- 

 larged, but considering the cost of maintenance and the service given 

 they have been entirely satisfactory. In other soils of a gravelly 

 nature, however, the sides of such ditches would not stand, and the 

 cost of keeping them clean would be excessive. 



The open ditch is not to be selected for use in all locations. At 

 best, when used near roads, it is dangerous and often unsightly. To 

 keep it far enough from the traveled way to reduce danger to pass- 

 ing traffic to a minimum, it has to be deepened or lose somewhat its 

 effectiveness. In general, this method gives fairly satisfactory re- 

 sults for a short time, provided the ditch be dug to a uniform grade 

 and supplied with a suitable outlet. But a ditch of this kind, under 

 ordinary conditions, soon will become obstructed by the banks break- 

 ing away and by the growth of vegetation, and is very seldom 

 economical in the long run. There are few cases where a tile drain 

 would not perform the work equally as well as an open ditch, and 

 a tile drain possesses the advantage that when once completed, it 

 will last indefinitely with practically no attention. 



If open ditches are used for subdrainage they should be located 

 carefully and constructed so they will perform their intended func- 

 tion. It is almost impossible to locate such a ditch that will not act 

 somewhat as a surface drain, and in this event the possibilities must 

 be considered. Frequently the ditches are designed to act in both 

 capacities, but this practice is distinctly faulty if the depth of ditch 

 is increased thereby much over what would be required for surface 

 drainage alone. 



DITCHES FILLED WITH STONE. 



Ditches filled with broken stone or gravel sometimes are used as a 

 substitute for tile drains to be described later. These have been used 



