/ Issued July is, 1911. U. S. DEPARTMENT OF AGRICULTURE, OFFICE OF PUBLIC ROADS— CIRCULAR No. 95. LOGAN WALLER PAGE, DraECTOR. SPECIAL ROAD PROBLEMS IN THE SOUTHERN STATES. D. H. WIXSLOW, Superintendent of Road Construction, Office of rublic Roads. ^^"^ AVA.SIilNti'KJX: f30\T=:RNMENT PRfNirNG OFFICE. 1911. ^oJ^Tiom^ LETTER OF TRANSMITTAL. United States Department of Agriculture, Office of Public Roads, WasJiington, D. C, April 2 J,., 1911. Sir: I have the honor to transmit herewith the manuscript of a cu'cular by ^Ir. D, H. Winslow, a superintendent of road construction in this office, entitled "Special Road Problems in the Southern States." Pubhcations of tliis specific character should have a great interest for the road builders in the section concerned, and it is hoped that much good may be derived from them. I therefore respectfully request that tliis manuscript be issued as Cncular 95 of this office. Respectfully, Logan Waller Page, Director. Hon. James Wilson, Secretary of Agriculture. 3 CONTENTS. Page. Introduction 1 7 Flooded roads and fords 7 Swamp sections and low levels 10 Erosion of the road and ditches 12 Sand and clay stretches 14 Top soil roads 15 5 ILLUSTRATIONS. rage. Fig. 1. Ford on a main road in South Carolina 8 2. A plank bridge in South Carolina one-half mile long 8 3. Crosscut view showing the method of draining a flooded road with logs. . 9 4. Crosscut view showing the method of draining a flooded road with a concrete wall 1^ 5. A swampy mail route in Georgia 10 6. Corduroy road near Lunenbiurg, Va 11 7. Roadbed with V-shaped foundation 12 8. V-shaped drain filled with rock, brickbats, or sand 12 9. Erosion of side ditches on a South Carolina road, causing danger to trafiic 1^ 10. Two-inch plank prepared for use in sandy regions 13 11. Crosscut view of a sandy road protected by planks 14 12. Road ditch prepared with trenches to be filled with logs 14 13. Road ditch with logs in place I'l SPECIAL ROAD PROBLEMS IN THE SOUTHERN STATES. INTRODTJCTION. Wliile the general principles of road construction are nearly the same all over the United States, it will be found necessary to modify them somewhat, owing to climatic conditions, difference in the road materials available, and numerous varying local conditions. Problems ^^'ill be encountered in the Northern States, o^^^ng to frost action and severe winters, that do not concern the southern road builders, and in turn the northern builders do not have to con- tend witli tropical vegetation or the scarcity of free labor. There are certain road problems confined to the Southern States, and it is \\dth these particular cases that this circular will deal, rather than A\4th the general road problems. It will be the aim of this publication to deal as concisely as pos- sible with such difficulties and to offer a simple treatment of them by the use of local materials and labor. FLOODED ROADS AND FORDS. At certain seasons of the 3'ear, in some localities, there arc roads that are entirely covered with water from 1 t(j 10 feet deep, and for a distance varying from a few hundred feet to more than a mile. Such conditions are found in the eastern C'arolinas, and in southern Georgia, Alabama, Mississippi, Florida, and other Staces. At such times, travel is practically cut off or confined to jiorse- back ri(fing, witli a heavy loss to the community. Education is at a standstill; medical service is limited and irregular; church attend- ance becomes impossible; the mails are delayed, if not entirely aban- doned; fire protection is cut off; and life on the farm becomes one of isolation and hardsliip. Tliis is one of the conditions that this cir- cular seeks to refieve by making llie road ])!issable 12 niontlis in the year at a nominal cost. As in otlier cases, the troul)le should be li accd to its source", but iiore, even when the cause is ascertained, tlie road builder is littk^ better off, for the cause for such conditions hardly ever originates on tlic road itself. It is (juit',' likely to ])e a choked channel on private O.'iWiO"'— 1 1 7 8 SPECIAL ROAD PKOIU.EMS TN THE SOUTHERN STATES. land, a swollen slre.uu ovcillowinf; its banks, or a large drainage area emptying over a small area, which limitetl funds will not suffice to remedy, even if nil Ihe lotial objections can be overcome. Fig. 1.— Ford on a main road in South Carolina. The real problem consists in doing the necessary work on the road itself without damage to the property on either side. In some cases Fig. 2.— a plank bridge in South Carolina one-half mile long. a long bridge has been built, but such a bridge is expensive in its construction and is a constant item of maintenance. For most places, indeed, its cost is prohibitive. SPECIAL ROAD PROBLEMS IN THE SOUTHERN STATES. 9 To make a deep fill, with the necessary culverts, wouhl also require a large financial outla}', especially since the slopes would require heavy facing to prevent sUding at flood season. The growth of vegetation is so rapitl in the South that clearance of channels, if permitted by the abutters, would be of little value unless S3'stematicalh^ done at frec^uent intervals. There is, however, scarcely a section in the South where these conditions exist that either timber, brick, stone, or sand can not be obtained. The first solution to the problem lies, then, in the use of timber for making the flooded sections passable, so that, for example, the engine of an automobile may be kept dry while going over the road. On the downstream side of the road logs are placed parallel to the road in the form of a pyramid, with the top of the upper log set as high as the usual water level on the road. The bottom logs are held in place by either sinking them in a shallow trench or b}' driving heavv stakes. The logs are set at the extreme limits of the traveled way- Large-sized logs are used and the largest are placed in the base of the pyramid. These logs lie end to end except that space is left to ' ' ' ^<^^/^Ji Sfi'U^ FILL -|l^<^:^^i^'J CULV/ERT SECTION Fig. :?.— Crosscut view showing the method of draining a flooded road with logs. permit a culvert \\dth a head wall to pass through. The purpose of this culvert will be explained later. Sand is dumped against the logs on the side toward the traveled wa}- imtil it is level witli tlie top k)g and wide enough for a vehicle to travel on. The logs act as a re- taining wall, or as a dam, and practically aU sediment is retained, so as to form a grathial sh)pe from the top of the logs to the opposite side of the road. By (h'iving close to the logs a wagon or automobile encounters but a few inches of water. After the flood season and as the water recedes, the purpose of the culvert is apparent. The logs and sand act as a dam and, without tlie culvert, would keep the land flooded on the side of the road opposite tlie logs. A culvert is placed at right angles to the road at the natural grade of the ground and protected with head walls at both ends. As the water recedes, it runs away from tiie logs down the incline to the inlet of the culvert and through tliis under the road. Every flood adds sediment and compacts the material. If stone, brick, or sand can be had, a moic pennanent structure can be obtained by making it of concrete, brick, stone, or cement 10 SPECIAL EOAD PROBLEMS IN THE SOUTHERN STATES. mortar. If stone is the only available material, it is necessary only to lay the stone, like a wall, parallel to the road, similar to the arrange- ment of the logs as shown in figure 3. Where brick is used, the top of the wall should be at least 8 inches thick, while the thickness at the base depends upon the height of the wall. In some sections con- FiG. 4.— Crosscut view showing tlie method of draining a flooded road with a concrete wall. Crete or cement mortar can be obtained, and in such places a neat pemianent w^all can be laid. SWAMP SECTIONS AND LOW LEVELS. There are roads on wdiich the water stands throughout the whole year and, while they do not become impassable like the flooded areas, Fig. 5.— Swampy mail ronte in Georgia. they are a nuisance to all who are obliged to use them. Pedestrians are sometimes able to cross these sections on plank walks, which, however, are generally neglected. They are impassable for automo- biles because of the danger of flooding the engines. SPECIAL ROAD PROBLEMS IN THE SOUTHERN STATES. 11 In cases of this description the trouble is caused by the fact that the water can not be 'drawn away from the road because the road is lower than the level of the adjacent land. It is, therefore, necessary to elevate the road above the water to secure proper drainage. "Wliile a bridge would remedy the trouble in some cases, it must be remembered that this circular is describing those sections which are financially unable to build bridges at present. Moreover, unless the bridge is built of something more permanent than wood, there must be a constant outlay for the maintenance of the bridge floor. On the other hand, to make a fill that would raise the road entirely out of the water would cost a large amount of money, and such a fill would require heavy protection on it^ slopes, in order that the water might not undermine them. Where a small fill has been made, the local authorities have usu- ally resorted to the corduroy road, which is one of the roughest and most unsatisfac- tory roads in use. If the material used can absorb moisture to any extent, the fill nat- urally becomes gradu- ally saturated. As the water must remain on or around the road, it Fig. 0.— Corduroy loaii iioar Luueubuij,', \'a. is necessary to use a material that holds as lilth' nioistuiv as possible, and to use it in such a manner as to give a dry road with Ihc least amount of materials. There is scarcely a section in the South where either rock, clay, or sand can not be obtained. "WTierever there is clay, brick will prob- ably be made, and wherever there is a brick kiln, it is ])ossible to secure old brickbats, or at any rate they can generally be found around the sites of ohl brick buildinirs. 12 SPECIAL ROAD PROBLEMS IN THE SOUTHERN STATES. The method ol" eonst ruction for roads of this description is the same, whether rock, brickbats, or sand are used. The road is first formed in a V-shape by cither excavating in the center and throwing tlie material to the sides or ])y fiUing the materials in at the sides of the roadbed to form the sides of the "V." Tliis " V " is next filled with either rock, brickbats, or sand. If it is filled with rock, the largest- sized pieces are kept at the point of the "V," while the smallest are used at the top. For a lo-foot roadbed the rock is placed from 18 to 24 inches thick in the center and to a depth of about 6 inches at a point 7h feet on each side of the center. The top is then dressed oft' with natural soil and a road drag is used. SECTION Fig. 7.— Roadbed with V-shaped foundation. If it is filled with brickbats or sand, the same methotl is used. The sand section will remain damp and, since sand supports a load better when damp than when dry, this is an advantage. This type of road is more satisfactory than the old corduroy road, and far less expensive to maintain, because the use of the road drag and an occasional renewal of material when settlement takes place will be the only items of expense. In some sections the *'V" has been filled wdth logs laid parallel with the road, but this method is not recommended except as a temporary measure. 1 ^ -"-Mm^i^^^^^^^^^^^^^^^^ 'o (0 15- O" SECTION Fig. 8.— V-sliaped drain filled with rock, briclibats, or saud. EROSION OF THE ROAD AND DITCHES. After hard or prolonged rains, roads which have been constructed with a flat surface are often gullied in the center, or, if the road was well crowned, the gutters or ditches are usually badly washed. As a rule the damage is more extensive on grades than on level stretches. This is because the damage in general depends upon the velocity of the water, and this of course is controlled by the steep- ness of the slope. If the water cuts the ditches very deep, it might SPECIAL ROAD PROBLEMS IN THE SOUTHERN STATES. 13 be advisable to reduce the grade of the road, if j)ossil)le, either by cutting down the summit or filhng at the foot of the hill, or both. It must be remembered that this is likely to be economical in the end even if the first cost seems high, since it will not only save on future maintenance, but will decrease the tractive force required to Fig.