|Río Bravo del Norte, Tooh Baʼáadii (Navajo), Kótsoi (Jicarilla Apache)|
The Rio Grande in Texas, c. 1899
|Countries||United States, Mexico|
|States||Colorado, New Mexico, Texas, Chihuahua, Coahuila, Nuevo León, Tamaulipas|
|- left||Red River, Rio Hondo, Rio Pueblo de Taos, Embudo River, Santa Fe River, Galisteo Creek, Alamito Creek, Terlingua Creek, Pecos River, Devils River|
|- right||Conejos River, Rio Chama, Rio Conchos, Rio Salado, Rio Alamo, San Juan River|
|Source||Canby Mountain, Continental Divide|
|- location||San Juan Mountains, Rio Grande National Forest, Colorado, United States|
|- elevation||12,000 ft (3,658 m) |
|Mouth||Gulf of Mexico|
|- location||Cameron County, Texas; Matamoros, Tamaulipas|
|- elevation||0 ft (0 m)|
|Length||1,896 mi (3,051 km) |
|Basin||182,200 sq mi (471,900 km2) |
|Discharge||for Eagle Pass, Texas/Piedras Negras, Coahuila|
|- average||2,403 cu ft/s (68 m3/s) |
|- max||964,000 cu ft/s (27,297 m3/s)|
|- min||24 cu ft/s (1 m3/s)|
The Rio Grande (pronounced /ˈriːoʊ ˈɡrænd/; Spanish: Río Bravo del Norte or Río Bravo, [ˈri.o ˈβra.βo])) is a river that flows from southwestern Colorado in the United States to the Gulf of Mexico. Along the way it forms part of the Mexico–United States border. According to the International Boundary and Water Commission, its total length was 1,896 miles (3,051 km) in the late 1980s, though course shifts occasionally result in length changes. Depending on how it is measured, the Rio Grande is the fourth or fifth longest river system in North America.
The river serves as a natural border between the U.S. state of Texas and the Mexican states of Chihuahua, Coahuila, Nuevo León, and Tamaulipas. A very short stretch of the river serves as the boundary between the U.S. states of Texas and New Mexico. Since the mid–20th century, heavy water consumption of farms and cities along the river has left only 20% of its natural discharge to flow to the Gulf. Near the river's mouth, the heavily irrigated Rio Grande Valley is an important agricultural region. The Rio Grande is one of 19 Great Waters recognized by the America's Great Waters Coalition.
The Rio Grande's watershed covers 182,200 square miles (472,000 km2). Many endorheic basins are situated within, or adjacent to, the Rio Grande's basin, and these are sometimes included in the river basin's total area, increasing its size to about 336,000 square miles (870,000 km2).
The Rio Grande rises in the western part of the Rio Grande National Forest in the U.S. state of Colorado. The river is formed by the joining of several streams at the base of Canby Mountain, just east of the Continental Divide. From there, it flows through the San Luis Valley, then south into New Mexico, passing through Española, Albuquerque, and Las Cruces to El Paso, Texas and Ciudad Juárez, Chihuahua. Below El Paso it serves as part of the border between the United States and Mexico. The official river border measurement ranges from 889 miles (1,431 km) to 1,248 miles (2,008 km), depending on how the river is measured. A major tributary, the Rio Conchos, enters at Ojinaga, Chihuahua, below El Paso, and supplies most of the water in the border segment. Other well-known tributaries include the Pecos and the smaller Devils, which join the Rio Grande on the site of Amistad Dam. Despite its name and length, the Rio Grande is not navigable by ocean-going ships, nor do smaller passenger boats or cargo barges use it as a route. It is barely navigable at all, except by small boats in a few places.
The Rio Grande rises in high mountains and flows for much of its length at high elevation; El Paso is 3,762 feet (1,147 m) 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 El Paso eastward, the river flows through desert. Only in the sub-tropical lower Rio Grande Valley is there extensive irrigated agriculture. 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 of about 7,063 cubic feet per second (200 m3/s).
Millions of years ago, during the Miocene, the Rio Grande ended at the southern end of the Rio Grande rift in Lake Cabeza de Vaca. About one million years ago (mya), the stream was "captured" and began to flow east.
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 US Government and moved to the Rio Grande during the Mexican War in 1846. They provided transport for the U.S. Army, under General Zachary Taylor to invade Monterrey, Mexico, 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 is a large swing bridge that dates back to 1910 and is still in use today by automobiles and railroad trains, connecting Brownsville, Texas with Matamoros, Tamaulipas. It has not been opened since the early 1900s however, when the last of the big steamboats disappeared. The 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. 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.
In the 1800s, the river marked the disputed border between Mexico and the nascent Republic of Texas; Mexico marked the border at the Nueces River. The disagreement provided part of the rationale for the US invasion of Mexico in 1846, after Texas had been admitted as a new state. Since 1848, the Rio Grande has marked the boundary between Mexico and the United States from the twin cities of El Paso, Texas, and Ciudad Juárez, Chihuahua, to the Gulf of Mexico. As such, crossing the river was the escape route used by some Texas slaves to seek freedom. Mexico had liberal colonization policies and had abolished slavery in 1828.
In 1944 the US and Mexico signed a treaty regarding the river, and in 1997 the US designated the Rio Grande as one of the American Heritage Rivers. Two portions of the Rio Grande are designated National Wild and Scenic Rivers System, one in northern New Mexico and the other in Texas, at Big Bend National Park.
In the summer of 2001, a 328-foot (100 m) wide sandbar formed at the mouth of the river, marking the first time in recorded history that the Rio Grande failed to empty into the Gulf of Mexico. The sandbar was subsequently dredged, but it re-formed almost immediately. Spring rains the following year flushed the re-formed sandbar out to sea, but it returned in the summer of 2002. As of the fall of 2003, the river once again reaches the Gulf.
River modifications 
The United States and Mexico share the water of the river under a series of agreements administered by the International Boundary and Water Commission,US-Mexico. The most notable of these treaties were signed in 1906 and 1944. The IBWC traces its institutional roots to 1889, when the International Boundary Committee was established to maintain the border. The IBWC today also allocates river waters between the two nations, and provides for flood control and water sanitation. Once viewed as a model of international cooperation, in recent decades the IBWC has been heavily criticized as an institutional anachronism, by-passed by modern social, environmental and political issues.
Use of that water belonging to the United States is regulated by the Rio Grande Compact, an interstate pact between Colorado, New Mexico, and Texas. The water of the Rio Grande is over-appropriated: that is, there are more users for the water than there is water in the river. Because of both drought and overuse, the section from El Paso downstream through Ojinaga was recently tagged "The Forgotten River" by those wishing to bring attention to the river's deteriorated condition.
There are a number of dams on the Rio Grande, including Cochiti Dam, Elephant Butte Dam, Caballo Dam, Amistad Dam, Falcon Dam, Anzalduas Dam, and Retamal Dam. In southern New Mexico and the upper portion of the Texas border segment, the river's discharge dwindles. Diversions, mainly for agricultural irrigation, have increased the natural decrease in flow such that by the time the river reaches Presidio, Texas, there is little or no water. Below Presidio the Rio Conchos restores the flow of water. Near Presidio the river's discharge is frequently zero. Its average discharge is 178 cubic feet per second (5 m3/s), down from 945 cubic feet per second (27 m3/s) at Elephant Butte Dam. Supplemented by other tributaries the Rio Grande's discharge increases to its maximum annual average of 3,504 cubic feet per second (99 m3/s) near Rio Grande City, Texas. Large diversions for irrigation below Rio Grande City reduce the river's average flow to 889 cubic feet per second (25 m3/s) at Brownsville and Matamoros.
The major international border crossings along the river are at Ciudad Juárez and El Paso; Presidio, Texas, and Ojinaga, Chihuahua; Laredo, Texas, and Nuevo Laredo, Tamaulipas; McAllen, Texas, and Reynosa, Tamaulipas; and Brownsville, Texas, and Matamoros, Tamaulipas. Other notable border towns are the Texas/Coahuila pairings of Del Rio–Ciudad Acuña and Eagle Pass–Piedras Negras.
Names and pronunciation 
Río Grande is Spanish for "Big River" and Río Grande del Norte means "Great River of the North". In English, Rio Grande is pronounced either / / or / /. Because río means "river" in Spanish, the phrase Rio Grande River is redundant.
In Mexico it is known as Río Bravo or Río Bravo del Norte, bravo meaning (among other things) "furious" or "agitated".
Historically, the Pueblo and Navajo peoples also had names for the Rio Grande/Rio Bravo:
- mets'ichi chena, Keresan, "Big River"
- posoge, Tewa, "Big River"
- paslápaane, Tiwa, "Big River"
- hañapakwa, Towa, "Great Waters"
Rio del Norte was most commonly used for the upper Rio Grande (roughly, within the present-day borders of New Mexico) from Spanish colonial times to the end of the Mexican period in the mid-19th century. This use was first documented by the Spanish in 1582. Early American settlers in south Texas began to use the modern 'English' name Rio Grande. By the late 19th century, in the United States, the name Rio Grande had become standard in being applied to the entire river, from Colorado to the sea.
|Tributary||Average discharge||Drainage basin|
|cu ft/s||m3/s||sq mi||km2|
|San Juan River||368||10||12,950||33,500|
|Rio Salado||354||10.0||23,323||60,400 |
|Rio San Rodrigo||130||3.68||1,050||2,720|
|Santa Fe River||10.9||0.31||231||598.3|
See also 
- Chihuahuan Desert
- List of international border rivers
- List of longest rivers of Mexico
- List of longest rivers of the United States (by main stem)
- List of rivers of Colorado
- List of rivers of New Mexico
- List of rivers of Texas
- Rio Bravo, Texas
- Rio Grande border disputes
- Rio Grande dams and diversions
- Rio Grande Gorge
- Rio Grande Trail
- Rio Grande Wild and Scenic River
- West Texas
- Rio Grande from the Handbook of Texas Online
- Metz, Leon C. "Rio Grande". The Handbook of Texas Online. Retrieved 17 July 2010.
- U.S. Geological Survey Geographic Names Information System: Rio Grande
- "Rio Grande NASQAN Program". United States Geological Survey. Retrieved 17 July 2010.
- "Water Bulletin Number 75: Flow of the Rio Grande and Related Data; From Elephant Butte Dam, New Mexico to the Gulf of Mexico". International Boundary and Water Commission. 2005. Retrieved 17 July 2010.
- National Wildlife Federation (August 18, 2010). "America's Great Waters Coalition". Retrieved 2011-18-20.
- Benke, Arthur C.; Colbert E. Cushing (2005). Rivers of North America. Academic Press. pp. 186–192. ISBN 978-0-12-088253-3.
- The Chihuahuan Desert Through Time
- Tom Lea (1957) The King Ranch writes that Richard King made his fortune as a riverman on the Rio Grande before he proposed marriage to Henrietta and started his cattle ranch.
- "The UGRR on the Rio Grande"
- "Bibliography on Water Resources and International Law: Rio Grande". Peace Palace Library. Retrieved 2010-12-23.
- IBWC: Treaties Between the U.S. and Mexico
- Thompson, Olivia N., "Binational Water Management: Perspectives of Local Texas Officials in the U.S.-Mexico Border Region" (2009). Applied Research Projects. Texas State University. Paper 313.[specify]
- Robert J. McCarthy, Executive Authority, Adaptive Treaty Interpretation, and the International Boundary and Water Commission, U.S.-Mexico, 14-2 U. Denv. Water L. Rev. 197(Spring 2011) (also available for free download at http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1839903).
- "Rio Grande Sucked Dry for Irrigation, Industry", CNN SATURDAY MORNING NEWS, (Aired June 9, 2001)]
- Source for historical names: Carroll L. Riley, 1995, Rio del Norte, University of Utah Press. ISBN 0-87480-496-5
- For the spelling of Navajo terms: Young, Robert W & William Morgan, Sr. The Navajo Language. A Grammar and Colloquial Dictionary. University of New Mexico Press. Albuquerque, NM: 1987.
- "Devils River Protection Campaign, Devils River Conservation Easements". The Nature Conservancy. Retrieved 22 July 2010.
- Largest Rivers of the United States, USGS
- "The Rio Conchos: An Essential Ribbon of Life". Environmental Defense Fund. Retrieved 20 July 2010.
- "Water resources data for the United States, Water Year 2009; gage 08353000 Rio Puerco near Barnardo, NM". USGS. Retrieved 21 July 2010.
- "Water resources data for the United States, Water Year 2009; gage 08329000, Jemez River below Jemez Canyon Dam, NM". USGS. Retrieved 20 July 2010.
- "Water resources data for the United States, Water Year 2009; gage 08317200 Santa Fe River above Cochiti Lake, NM". USGS. Retrieved 21 July 2010.
- "Water resources data for the United States, Water Year 2009; gage 08290000, Rio Chama near Chamita, NM". USGS. Retrieved 21 July 2010.
- "Water resources data for the United States, Water Year 2009; gage 08249000, Conejos River near Lasauses, CO". USGS. Retrieved 21 July 2010.
- Coker, Caleb (1992). The News from Brownsville: Helen Chapman's Letters from the Texas Military Frontier, 1848-1852. Austin, Tex: Texas State Historical Association. ISBN 0-87611-115-0.
- Horgan, Paul (1991). Great River: The Rio Grande in North American History (4th ed.). Hanover, NH: Wesleyan University Press. ISBN 0-8195-6251-3.
- Kearney, Milo; Anthony K. Knopp (1995). Boom and Bust: The Historical Cycles of Matamoros and Brownsville. Austin, Tex: Eakin Press. ISBN 978-0-89015-815-9.
- Kelley, Pat (1986). River of Lost Dreams: Navigation on the Rio Grande. Lincoln: University of Nebraska Press. ISBN 978-0-8032-2712-5.
- Lea, Tom (1957). The King Ranch. Boston: Little, Brown. ISBN 978-0-316-51745-4.
|Wikimedia Commons has media related to: Rio Grande (river)|
- Border Stories: the only hand pulled ferry on the Rio Grande (video)
- 1854 map of Rio Grande entrance (hosted by the Portal to Texas History).
- Rio Grande Cam - in Mission Texas. Mexico is on the left and the US is on the right.