396 ROADS AND PAVEMENTS 



5. The Depth. The drains should be placed at a sufficient 

 depth to accomplish the object sought. A deep drain will be 

 more effective than a shallow one. 



6. The Inlet and Outlet. The ends of the drain should be 

 such as to allow free passage of the water, and should be well 

 protected. 



CONSTRUCTION OF ROADS 



Natural Roads. Earth, or natural, roads consist of either 

 clay or loam or sand and gravel. They form the larger part 

 of the country roads of the United States, and under favorable 

 conditions, furnish a sufficiently satisfactory wheelway for 

 light traffic. By reason, however, of improper location, neglect, 

 and insufficient drainage, the average country road is in a 

 condition far from satisfactory during a large part of the year. 

 By changing the location and providing drainage where neces- 

 sary, and by prompt and systematic repairs, the condition of 

 natural roads may be greatly improved without much additional 

 expenditure. In the formation of natural roads, each soil 

 requires different treatment to produce satisfactory results. 



Sandy roads are in best condition when moist. Side-ditching, 

 beyond a slight depth to carry away the surface water in long 

 rainy spells, is not desirable, as it tends to facilitate the drying 

 of the sand. When clay is available, a coating 6 in. thick, 

 spread over the sand and mixed with it by harrowing, will pro- 

 duce a good roadway. 



Sand roads should be as narrow as practicable, and the 

 sides should be lined with as much vegetation as possible. 

 Trees along the sides will aid in keeping the surface moist, 

 and the falling leaves will assist in binding the sand together. 

 The spreading of straw, hay, or sawdust over the surface 

 will greatly improve the road. 



In clay soils, the first essential is thorough drainage of the 

 subsoil by either subsoil drains, deep side ditches, or both. The 

 surface of the portion intended for the wheelway should be 

 cleared of all vegetable matter, then graded and formed to a 

 suitable cross-section by means of a road grader. If sand is 

 available, the clay surface should be plowed, then covered with 

 a layer of sand 6 in. thick, then harrowed and finally rolled. 

 This will provide a good wheelway during -iry weather. If sand 



