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The Gulf Coastal Plain covers southern and eastern Texas and includes about 40 percent of the state's area. Along the coast are many long barrier beaches, such as Padre Island, separated from the mainland by lagoons. Galveston is the largest of the bays. The plain extends 150 to 250 miles (240 to 400 kilometers) inland to a series of hills that sweep across Texas from Denison on the Red River to Del Rio on the Rio Grande. The western part of this line (between Austin and Del Rio) is called the Balcones Escarpment.
The Gulf Coastal Plain may be divided into five distinct sections. They are: the Rio Grande plain, in the south; the coastal prairies, from the San Antonio River to the Sabine River; the Pine Belt, or Piney Woods, from the Louisiana line westward about 100 miles (160 kilometers); the Post Oak Belt, west of the Pine Belt; and the Blackland Prairies, along the western edge of the Gulf Coastal Plain from the Red River to a point near San Antonio.
e Peak in Culberson County. Within the state are four large natural regions.
The Central Lowland covers the eastern edge of the Panhandle and the north-central part of the state. It extends southward to include Fort Worth, Abilene, and Colorado City. The eastern part of this region includes the Grand, or Fort Worth, Prairie, sandwiched between the East and West Cross Timbers belts. The remainder of the Central Lowland consists of rolling plains.
The Great Plains extend over most of the Panhandle and west-central and central Texas. This vast tableland ranges in elevation from 2,500 to 4,700 feet (760 to 1,430 meters). In the Panhandle are the High Plains, or Llano Estacado (Staked Plain), a dry, flat, treeless area. To the east the central Texas section extends almost as far as Waco and Austin. The southeastern extension of the Great Plains is the Edwards Plateau. Across the lower Pecos River the plain continues westward as the Stockton Plateau. This section is sometimes called the Trans-Pecos.
The Basin and Range Region covers the extreme western part of the state. It has a series of rugged mountain ranges and dry, sandy basins. In Hudspeth County is the Diablo Plateau, or Bolston, between the Guadalupe and Hueco mountains. In a southward loop of the Rio Grande is a rugged area that includes Big Bend National Park. The Chisos Mountains lie within the park. Thousands of acres in the upper Rio Grande valley near El Paso are irrigated from Elephant Butte Reservoir in New Mexico.
Most of the rivers of Texas flow in a southeasterly direction into the Gulf of Mexico. From the state's eastern border to its western border, the largest of these rivers are the Sabine, Neches, Trinity, Brazos, Colorado (of Texas), Guadalupe, San Antonio, Nueces, and Rio Grande with its chief branch, the Pecos. The northern edge of the state lies in the Mississippi River basin. Within this section are the Canadian River, which flows across the Panhandle, and the Red River, on the Texas-Oklahoma border.
Climate
Texas has three main types of climate. A narrow strip along the coast has a marine climate tempered by winds from the Gulf of Mexico. Here temperatures are fairly uniform, with pleasant summers and mild winters. The Gulf coast area, from Brownsville northward, can experience severe ocean-borne storms, including destructive hurricanes. The mountain climate of western Texas brings dry, clear days with dramatic dips in temperature at nightfall. The rest of the state has a continental climate with cold winters and hot summers. Quick temperature changes are common in this area. The warmest part of the state is the lower Rio Grande valley, which has an average annual temperature of 74° F (23° C). The coldest is the northwest Panhandle, with a 54° F (12° C) average.
Average annual precipitation (rain and melted snow) varies from 58 inches (147 centimeters) in the extreme eastern part of the state to less than 10 inches (25 centimeters) near El Paso. In most parts of the state, the greatest amount of rainfall occurs between April and July and is especially heavy during May. Snowfall is generally limited to the northern plains area, where it averages about 15 inches (38 centimeters) annually.
Реферат опубликован: 29/01/2010