|
The Bolsón de Mapimí is an endorheic or internal drainage basin in which no rivers or streams drain to the sea but rather toward the center of the basin often terminating in swamps and ephemeral lakes. It is located in the center-north of the Mexican Plateau. The Basin is shared by the states of Durango, Coahuila, Chihuahua, and Zacatecas. It takes its name from Mapimí, a town in Durango. The largest city in the basin is Torreón. Parts of the basin host much industrial and agricultural activity. However, most of the region is sparsely populated. ==Geography== The Bolsón de Mapimí is a large area measuring more than 200 miles (320 km) north to south and the same distance east to west, lying between 25 and 29 degrees north latitude. The total area is about 50,000 square miles (129,000 km2) and the average elevation is 3,000 feet (900 meters).〔"Mapimí Basin", http://www.britannica.com/EBchecked/topic/363554/Mapimi-Basin, accessed 21 Feb 2013〕 The Greater Bolsón de Mapimí covers adjacent areas extending north to the Rio Grande, which are similar in terrain and climate but includes streams which have outlets to the Gulf of Mexico. The Bolsón is bounded on the west by the Sierra Madre Occidental and the Conchos River basin, by the basin of the Rio Grande to the north, and by the mountain ranges of the Sierra del Carmen and Sierra Madre Oriental to the east. At its southern edge, near the state line of Zacatecas, the Bolson shades into another endorheic basin called Llanos El Salado. Major rivers flowing northward into the basin are the Nazas River and its tributaries, which originate in the Sierra Madre Occidental in Durango and the Aguanaval River, which flows north from central Zacatecas. The two rivers terminate in the southern part of the Bolsón in an area called the Comarca Lagunera centered on the city of Torreón, Coahuila which formerly contained large, shallow lakes, now usually dry. The Bolsón de Mapimí consists of desert plains separated by low mountain ranges. Cerro Centinela which rises to 10,269 feet (3130 mts) south of Torreón is at the southern edge. Within the Bolsón most of the mountain ranges are 4,000 to 5,000 feet (1,200-1500 mts) in elevation. Los Alamitos range near the center of the Bolsón reaches 6,516 feet (1,984 mts.)〔Google Earth〕 The Bolsón is the southernmost extension of the Chihuahua Desert. The area receives between 8 and 16 inches (200 to 400 mm.) of precipitation annually, mostly falling in summer. The city of Torreón receives 9.0 inches (228 mm). Summer temperatures are hot. June is the hottest month in Torreón with an average temperature of 82.6 F (28.1 C). Winters are mild with an average temperature of 58 F (14.5 C) in December in Torreón. Freezes are common in winter.〔"Normales Climatologicas 1951-2010" Servicio Meteorológico Nacional, http://smn.cna.gob.mx/climatologia/Normales5110/NORMAL05040.TXT, accessed February 19, 2013〕 The conurbation of Torreón with more than a million inhabitants is the largest city. Most of the Bolsón is sparsely populated with settlements centered on mines and areas where irrigated agriculture is possible. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Bolsón de Mapimí」の詳細全文を読む スポンサード リンク
|