Rio Grande
The Rio Grande, in the United States, or the Río Bravo, in Mexico, also known as Tó Ba'áadi in Navajo, is one of the principal rivers in the Southwestern United States and in northern Mexico. The length of the Rio Grande is, making it the fourth longest river in the United States and in North America by main stem. It originates in south-central Colorado, in the United States, and flows to the Gulf of Mexico. The Rio Grande drainage basin has an area of ; however, the endorheic basins that are adjacent to and within the greater drainage basin of the Rio Grande increase the total drainage-basin area to.
The Rio Grande with its fertile valley, along with its tributaries, is a vital water source for seven U.S. and Mexican states, and flows primarily through arid and semi-arid lands. After traversing the length of New Mexico, the Rio Grande becomes the Mexico–United States border, between the U.S. state of Texas and the northern Mexican states of Chihuahua and Coahuila, Nuevo León and Tamaulipas; a short segment of the Rio Grande is a partial state-boundary between the U.S. states of New Mexico and Texas. Since the mid–twentieth century, only 20 percent of the Rio Grande's water reaches the Gulf of Mexico, because of the voluminous consumption of water required to irrigate farmland and to continually hydrate cities ; such water usages are additional to the reservoirs of water retained with diversion dams. of the river in New Mexico and Texas are designated as the Rio Grande Wild and Scenic River.
Geography
The Rio Grande rises in the western part of Rio Grande National Forest, in the U.S. state of Colorado, and is formed by the joining of several streams at the base of Canby Mountain, in the San Juan Mountains, due east of the Continental Divide of the Americas. From the Continental Divide, the Rio Grande flows through the San Luis Valley, then south into New Mexico, and passes through the Rio Grande Gorge, near Taos, then toward Española, afterwards collecting additional waters from the Colorado River basin via the San Juan-Chama Diversion Project and from the Rio Chama. The Rio Grande then continues southwards, irrigating the farmlands in the Middle Rio Grande Valley through the desert cities of Albuquerque and Las Cruces in New Mexico, to El Paso, Texas and Ciudad Juárez, Chihuahua, in Mexico. In the Albuquerque metropolitan area, the Rio Grande flows by historic Pueblo villages, such as Sandia Pueblo and Isleta Pueblo. South of El Paso, the Rio Grande is the national border between the U.S. and Mexico.The segment of the river that forms the international border ranges from, depending on how the river is measured. The Rio Conchos is a major tributary of the Rio Grande, with its confluence 310 km. southeast of El Paso near Ojinaga, in Chihuahua, Mexico. Downstream, other tributaries include the Pecos River and Devils River, both entering the Rio Grande from the north in the vicinity of Amistad Reservoir in Texas, and the Rio Salado and Rio San Juan both entering from the south with confluences in Tamaulipas, Mexico.
The Rio Grande rises in high mountains and flows for much of its length at high elevation; the valley floor at Albuquerque is, and El Paso above sea level. In New Mexico, the river flows through the Rio Grande rift from one sediment-filled basin to another, cutting canyons between the basins and supporting a fragile bosque ecosystem on its flood plain. From Albuquerque southward, the river flows through desert. Although irrigated agriculture exists throughout most of its stretch, it is particularly extensive in the subtropical Lower Rio Grande Valley. The river ends in a small, sandy delta at the Gulf of Mexico. During portions of 2001 and 2002, the mouth of the Rio Grande was blocked by a sandbar. In the fall of 2003, the sandbar was cleared by high river flows around.
The Rio Grande flows through a valley with diverse animal and plant populations. Conservation of the river and the valley is a recurring theme for people who live in the region.
Navigation
Although the river's greatest depth is, the Rio Grande generally cannot be navigated by passenger riverboats or by cargo barges. Navigation is only possible near the mouth of the river, in rare circumstances up to Laredo, Texas.Navigation was active during much of the 19th century, with over 200 different steamboats operating between the river's mouth close to Brownsville and Rio Grande City, Texas. Many steamboats from the Ohio and Mississippi Rivers were requisitioned by the U.S. government and moved to the Rio Grande during the Mexican–American War in 1846. They provided transport for the U.S. Army, under General Zachary Taylor, to invade Monterrey, Nuevo León, via Camargo Municipality, Tamaulipas. Army engineers recommended that with small improvements, the river could easily be made navigable as far north as El Paso. Those recommendations were never acted upon.
The Brownsville & Matamoros International Bridge, a large swing bridge, dates back to 1910 and is still in use today by automobiles connecting Brownsville with Matamoros, Tamaulipas. The swing mechanism has not been used since the early 1900s, though, when the last of the big steamboats disappeared. At one point, the bridge also had rail traffic. Railroad trains no longer use this bridge. A new rail bridge connecting the U.S. and Mexico was built about 15 miles west of the Brownsville & Matamoros International Bridge. It was inaugurated in August 2015. It moved all rail operations out of downtown Brownsville and Matamoros. The West Rail International Crossing is the first new international rail crossing between the U.S. and Mexico in over a century. The Brownsville & Matamoros International Bridge is now operated by the Brownsville and Matamoros Bridge Company, a joint venture between the Mexican government and the Union Pacific Railroad.
At the mouth of the Rio Grande, on the Mexican side, was the large commercial port of Bagdad, Tamaulipas. During the American Civil War, this was the only legitimate port of the Confederacy. European warships anchored offshore to maintain the port's neutrality, and managed to do so successfully throughout that conflict, despite occasional stare-downs with blockading ships from the US Navy. It was a shallow-draft river port, with several smaller vessels that hauled cargo to and from the deeper-draft cargo ships anchored off shore. These deeper-draft ships could not cross the shallow sandbar at the mouth of the river. The port's commerce was European military supplies, in exchange for bales of cotton.
History
Ancestral Rio Grande
The sedimentary basins forming the modern Rio Grande Valley were not integrated into a single river system draining into the Gulf of Mexico until relatively recent geologic time. Instead, the basins formed by the opening of the Rio Grande rift were initially bolsons, with no external drainage and a central playa. An axial river existed in the Espanola Basin as early as 13 million years ago, reaching the Santo Domingo Basin by 6.9 million years ago. However, at this time, the river drained into a playa in the southern Albuquerque Basin where it deposited the Popotosa Formation. The upper reach of this river corresponded to the modern Rio Chama, but by 5 million years ago, an ancestral Rio Grande draining the eastern San Juan Mountains had joined the ancestral Rio Chama.The ancestral Rio Grande progressively integrated basins to the south, reaching the Mesilla Basin by 4.5 million years and the Palomas basin by 3.1 million years ago, forming Lake Palomas. River capture by a tributary of the Pecos River then occurred, with the Rio Grande flowing to Texas by 2.06 million years, and finally joining the Pecos River 800,000 years ago, which drained into the Gulf of Mexico. Volcanism in the Taos Plateau reduced drainage from the San Luis Basin until a spillover event 440,000 years ago that drained Lake Alamosa, forming the Rio Grande Gorge, and fully reintegrated the San Luis Basin into the Rio Grande watershed.
Prior to European contact
Archeological sites from the earliest human presence in the Rio Grande Valley are scarce, due to traditional Indigenous nomadic culture, Pleistocene and Holocene river incision or burial under the Holocene floodplain. However, some early sites are preserved on West Mesa on the west side of the Rio Grande near Albuquerque. These include Folsom sites, possibly dating from around 10,800 to 9,700 BCE, that were probably short-term sites such as buffalo kill sites. Preservation is better in flanking basins of the Rio Grande Valley, where numerous Folsom sites and a much smaller number of earlier Clovis sites have been identified. Later Paleo-Indian groups included the Belen and Cody cultures, who appear to have taken advantage of the Rio Grande Valley for seasonal migrations and may have settled more permanently in the valley.The Paleo-Indian cultures gave way to the Archaic Oshara tradition beginning around 5450 BCE. The Oshara began cultivation of maize between 1750 and 750 BCE, and their settlements became larger and more permanent.
Drought induced the collapse of the Ancestral Puebloan culture, at Chaco Canyon and elsewhere across the Four Corners region, at around 1130 CE. This led to a mass migration of the Ancestral Puebloans to the Rio Grande and other more fertile valleys of the Southwest, competing with other indigenous communities such as the Apache with territory in the Rio Grande Valley. This led to decades of conflict, the eventual merging of cultures, and the establishment of most of the Tanoan and Keresan pueblos of the Rio Grande Valley. This was followed by the Classic Period, from about 1325 CE to 1600 CE and the arrival of the Spanish. The upper Rio Grande Valley was characterized by occasional periods of extreme drought, and the human inhabitants make extensive use of gridded gardens and check dams to stretch the uncertain water supply.