50 



TRANSPORTATION ON LAND BY VEHICLES:— THE ROADS 



REMARK: -The Southern logging superintendents, at a recent meeting, gave the following as the 

 figures, in cents per 1,000 feet b. m. of logs handled over the railroad, for expenses incurred by their 

 concerns when cutting right of way, breaking ground, grading, and building bridges :- 



Arkansas ... from 14"6 to 16 cents 



Texas from 30 to 47 cents 



Louisiana ... from 27 to 59 cents 



Mississippi ... from 32 to 75 cents 



(H) DRAINAGE OF FOREST ROADS. 



I. Water is the chief enemy of roads. The following means of defense may be adopted :- 



1. Curvature of the crown. 



2. Sloping the road bed toward the valley side. 



3. Shelving or terracing the slope above the road. 



4. Side ditches in connection with cross runs or culverts. 



5. Covering the slope with stones, brush work, or sods of grass. 



6. Ditches of about 10 per cent grade some 35 feet above the road emptying just above culvert. 



7. Removal of shading trees, especially on South slopes, and fostering dense and low underbrush 

 above roads. 



The number of protective measures and their construction depends on grade, ground, local precipi- 

 tation, &c. 



II. Side ditches secure drainage in the most efficient manner provided that they have sufficient depth, 

 width, and pitch. They intercept the waters streaming, superficially or subterraneously, down the hillside 

 above the road; they convey these waters rapidly to outlets; they draw the ground water out of the roadbed 

 itself. A road without a ditch on the hillside "soon becomes a ditch itself." Ditch -cutting along the 

 road, however, in a mountainous section, is extremely expensive. 



Theoretically speaking, a ditch should gradually increase in cross section toward the lower culvert, 

 through which it empties. 



The cross section of a ditch depends on:- 



1. Maximum cross section of water apt to pass through it after a cloud burst. 



2. The grade of the road. 



3. Distance between culverts or outlets. If this distance is halved the cross section of ditch might 

 be reduced to one fourth. 



The standard ditch measures 3 feet at the top, 1 foot at the bottom, 1 foot in depth ; its sides are inclined 

 at an angle of 45 degrees. 



In clay soil, ditches of steeper sides are permissible. 



The common ditch found along the railroads is 2 feet wide. 



III. Cross runs. By "cross runs" are understood drainage arrangements built across the road, their 

 purpose being either to carry water from the side ditch across the road, or to intercept the water found 

 in the roadbed itself. The capacity of a cross run, like that of a ditch, should be sufficient to meet a 

 cloud burst. 



Main rule for all cross runs: -Pitch secures drainage better than size. 



Cross runs are either "open" or "covered." 



(a) Open cross runs. Water running down the ruts of a waggon road will never get out of the rut 

 unless there are maintained either shallow side ditches leading to right and left from rut; or paved cross 

 runs (saucer shaped) falling at least one foot across the road; or cross poles (thank -you -ma'ms) of the 

 same fall, placed above the roadbed; or culverts, the tops of which are raised about 6 inches above the surface 

 of the road. An impediment to the run of water in ruts must necessarily be an impediment to traffic. 

 On dirt roads it is wise to secure drainage rather by the inclination of the open cross runs than by the 

 depth of open cross runs. 



