Southern Appalachian Digital Collections

Western Carolina University (21) View all

Secretary of Agriculture report on watersheds

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  • 20 APPALACHIAN AND WHITE MOUNTAIN WATERSHEDS. This kind of erosion occurs on close-grained, compact clay soils, the particles of which cling together firmly and resist the downward cutting of small currents of water. Another type of erosion results in parallel gullies extending straight up and down the slopes. As these gullies grow deeper they widen, the smaller ones are obliterated by the larger until they become of huge size, their bottoms sharp, their sides steep, and their edges irregular and jagged. Such erosion results from clay soils of homogeneous texture and somewhat softer and more loamy than the type mentioned above. It is a very common type, and the process once started can be stopped only with great difficulty. It nearly always results in the early abandonment of the field on which it begins. Of all types of erosion, that of gullying, in which rapid down-cutting is accompanied by undercutting and caving, is the most rapid in its progress and the most difficult to check, as well as the most destructive in its effects. This type occurs in soils of relatively soft micaceous subsoil. The surface may be a fairly compact clay that offers moderate resistance to water, but once broken a gully results in the soft subsoil. It rapidly deepens, the micaceous material on the sides is easily undermined and slips in, leaving vertical or overhanging walls. Into such gullies many square yards of soil may cave during a single heavy rain, and as the decomposed micaceous material is usually scores of feet in thickness such gullies frequently become chasms of great depth and width. This kind of erosion when started on cleared land may advance into a forested area and undermine even the largest trees. The rocks which produce soil subject to this kind of erosion are found over a large part of the Southern Appalachian region, and especially in the Blue Ridge Mountains. Still another type of erosion is that started by small landslides, which occur on steep slopes when the soil is saturated during periods of [>rolonged rainfall. Such landslides are often started by the tramping of cattle over the steep slopes during wet weather. One animal in climbing up or down a slope may start a number of such slides, each of which usually grows m width and length and soon makes a great bare scar in the field. The soils subject to serious erosion are very extensive in the Southern Appalachian region. Where on such soils nature has placed a forest that brings about a balance between rainfall and run-off, the danger in widespread clearing is obvious. The loss resulting from erosion means not only the loss of the soil from the fields; it means also the loss which has already been described in the failure of water power and navigation. MINING. While in the Blue Ridge and Great Smokies no valuable coal deposits are known to exist, these mountains have a great variety of mineral resources. Many of them have never been developed, while others have become the basis of important mining operations. Large investments have been made in the mining of copper, marble, mica, corundum, talc, asbestos, slate, kaolin, and other minerals, and the mineral products are said to amount to several million dollars annually. Such mining as is carried on does not require large quantities of timber, since but a small part of it is underground mining, and some
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Object’s are ‘parent’ level descriptions to ‘children’ items, (e.g. a book with pages).