. Bulletin of the Department of Agriculture. Agriculture; Agriculture. SECT/ON OF EARTH DITCH Fig. 1. The section shown in figure 3 gives a ditch of comparatively small capacity, but the same amount of water flowing in a ditch of this shape will cause less erosion on steep grades than in a very narrow ditch of the cross section shown in figure 1. Another advantage of this wide, flat ditch is that it may be constructed easily and main- 5lope liu. SECT/ON OF EARTH DITCH Fig. 2. tained by means of a road grader, while the other types of ditches require more or less pick-and-shovel work. One
. Bulletin of the Department of Agriculture. Agriculture; Agriculture. SECT/ON OF EARTH DITCH Fig. 1. The section shown in figure 3 gives a ditch of comparatively small capacity, but the same amount of water flowing in a ditch of this shape will cause less erosion on steep grades than in a very narrow ditch of the cross section shown in figure 1. Another advantage of this wide, flat ditch is that it may be constructed easily and main- 5lope liu. SECT/ON OF EARTH DITCH Fig. 2. tained by means of a road grader, while the other types of ditches require more or less pick-and-shovel work. One of its principal dis- advantages is that it must be extremely wide on light grades in order to carry any consideraDle quantity of water, and in deep cuts it may be very expensive to obtain the necessary width. v 1 ^^ '- â â 111 im > Wf7 S/ope li:l '7^/m> SECTION OF EARTH DITCH Fig. 3. Figure 2 shows a modification of the section shown in figure 3, which is intended to meet conditions intermediate between those de- scribed as being suited respectively to the other two sections. From the velocity-quantity tables, pages 7 to 9, it is apparent that for a ditch of given cross section the velocity of flow is de- pendent upon (1) the quantity of water the ditch carries, and (2) the longitudinal slope of the ditch. The velocity which causes erosion. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original United States. Dept. of Agriculture. [Washington, D. C. ?] : The Dept. : Supt. of Docs. , G. P. O.
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