129—Sand Mountain

This MLRA (shown in red in the figure above) is in Alabama (96 percent), Georgia (3 percent), and Tennessee (1 percent). It makes up about 8,030 square miles (20,805 square kilometers). The towns of Jasper, Cullman, and Fort Payne, Alabama, are in this MLRA. Interstate 65 crosses this area from north to south, and Interstates 24 and 59 join in the area just west of Chattanooga, Tennessee, which is just outside the northeast tip of the MLRA. Areas of the Redstone Arsenal Military Reservation are in the northern part of the MLRA. The William B. Bankhead National Forest and the Sipsey National Forest Wilderness are in the western part.

Physiography

Most of this area is in the Cumberland Plateau Section of the Appalachian Plateaus Province of the Appalachian Highlands. This MLRA is deeply dissected and consists mainly of a series of rather narrow valleys, steep escarpments, and broad plateaus that are underlain by consolidated bedrock. Elevation ranges from 330 to 2,300 feet (100 to 700 meters). Valley floors are commonly about 100 to 400 feet (30 to 120 meters) below the adjacent plateau summits, but local relief may be as much as 1,200 feet (365 meters).

The extent of the major Hydrologic Unit Areas (identified by four-digit numbers) that make up this MLRA is as follows: Mobile-Tombigbee (0316), 50 percent; Middle Tennessee-Elk (0603), 25 percent; Alabama (0315), 21 percent; and Middle Tennessee-Hiwassee (0602), 4 percent. The Sipsey Fork, Locust Fork, and Mulberry Fork Rivers, headwaters of the Black Warrior River, are in this area. The Tennessee River forms part of the northern boundary of the area.

Geology

The bedrock in this area consists of alternating beds of limestone, dolomite, shale, and sandstone of early Paleozoic age (mostly Mississippian and Pennsylvanian age). The summits of ridges and plateaus are capped with the more resistant carbonate and sandstone layers, and valleys have been eroded into the less resistant shale beds. These mostly level-bedded sedimentary rocks are at the southernmost extent of the Appalachian Mountains. The narrow river valleys are filled with unconsolidated deposits of clay, silt, sand, and gravel.

Climate

The average annual precipitation in most of this area is 53 to 60 inches (1,345 to 1,525 millimeters). It is as much as 68 inches (1,725 millimeters) at the higher elevations in the northern tip of the area. The precipitation is somewhat unevenly distributed throughout the year. The maximum occurs in midwinter, and the amount decreases gradually from spring to autumn and increases slightly in midsummer. Winter rainfall occurs as moderate-intensity, tropical storms that can produce large amounts of rain. During the rest of the year, rainfall occurs as high-intensity, convective thunderstorms. Snowfall is rare in winter, and the snow does not remain on the ground for long periods. The average annual temperature is 55 to 63 degrees F (13 to 17 degrees C). The freeze-free period averages 225 days and ranges from 200 to 255 days. The longer freeze-free periods occur in some of the valleys.

Water

Following are the estimated withdrawals of freshwater by use in this MLRA:

Public supply—surface water, 8.3%; ground water, 2.5%
Livestock—surface water, 0.8%; ground water, 0.7%
Irrigation—surface water, 0.1%; ground water, 0.4%
Other—surface water, 86.6%; ground water, 0.6%

The total withdrawals average 1,225 million gallons per day (4,635 million liters per day). About 4 percent is from ground water sources, and 96 percent is from surface water sources. In most years precipitation is adequate for crops and pasture. Droughts are short and infrequent. Streams, springs, and ponds provide water for livestock. Most streams flow intermittently and are often dry in summer and autumn, except after rainstorms. A few large reservoirs on the Elk and Tennessee Rivers are in the area. The surface water is suitable for almost all uses. Rivers below the reservoirs in this area commonly have water with low levels of dissolved oxygen because of the release of water from the bottom of the reservoirs.

Deep wells provide an adequate supply of water for most domestic, municipal, and industrial uses. Good-quality ground water occurs in solution channels in limestone and dolomite and in fractures and partings along bedding planes in shale and sandstone bedrock layers. The ground water is very hard, and the median level of total dissolved solids is about 150 parts per million (milligrams per liter). This Paleozoic aquifer system is susceptible to contamination from surface sources because of the vertical fractures and the cavernous limestone and dolomite layers. The median level of nitrates, 1.3 parts per million (milligrams per liter), is about four times greater than the median level in any other aquifer in this area.

Soils

The dominant soil orders in this MLRA are Ultisols and Inceptisols. The soils in the area dominantly have a thermic soil temperature regime, a udic soil moisture regime, and mixed or siliceous mineralogy. They are shallow to very deep, generally well drained, and loamy. Hapludults (Albertville, Hartsells, Gorgas, Linker, Nauvoo, Sipsey, Sunlight, and Townley series), Fragiudults (Wynnville series), Dystrudepts (Bankhead, Hector, and Montevallo series), and Eutrudepts (Limrock series) formed in residuum on hills, ridges, and plateaus and in residuum and colluvium on mountainsides.

Biological Resources

This area supports mixed oak, hickory-pine, and oak-hickory forests. Shortleaf pine, loblolly pine, Virginia pine, sweetgum, yellow-poplar, hickory, American beech, red oak, and white oak are the major overstory species. Dogwood and redbud are the major midstory species. Japanese honeysuckle, greenbrier, low panicums, bluestems, and native lespedezas are the major understory species.

Some of the major wildlife species in this area are white-tailed deer, fox, bobcat, raccoon, skunk, opossum, mink, rabbit, gray squirrel, quail, and mourning dove.

Land Use

Following are the various kinds of land use in this MLRA:

Cropland—private, 7%
Grassland—private, 14%; Federal, 1%
Forest—private, 60%; Federal, 3%
Urban development—private, 9%
Water—private, 3%
Other—private, 3%

Almost two-thirds of this area is forestland, less than one-tenth is cropland, and more than one-tenth is pasture. About three-fifths of the forestland is privately owned, about one-tenth is industry owned, and less than one-tenth is federally owned. Timber production occurs mostly in the western half of the area. The poultry industry, which produces broilers and eggs, is the major farm enterprise. Corn, soybeans, tomatoes, and potatoes are the major cash crops. Pastures are grazed mainly by beef cattle and are important disposal areas for poultry waste. Haying provides feed during the long winters. Some areas are used for coal mining or urban development.

The major soil resource concerns are water erosion, maintenance of the content of organic matter and productivity of the soils, and management of soil moisture. Conservation practices on cropland generally include crop residue management, cover crops, crop rotations, water disposal, pest management, and nutrient management. The most important conservation practice on pasture is prescribed grazing. Critically eroding areas and areas of livestock concentration must be monitored regularly and treated promptly.

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