Rio Grande

• 1. Introduction

  ›

  In mid-2001, the Rio Grande did something no one had recorded it doing before. A sandbar 328 feet wide rose at its mouth and kept the river from reaching the Gulf of Mexico. Crews dredged the bar, and it reformed almost at once. A river 1,896 miles long, central to life across the Southwest and northern Mexico, had been cut off from the sea. How does a river fall short of its own finish line? The answer starts in the high mountains of Colorado and runs through deserts, border cities and a long argument over who may take how much water. It also involves a river that carries one name on its northern bank and another on its southern bank. That puzzle of names is the place to begin.

  338654

• 2. A River of Many Names

  ›

  Río Grande is Spanish for Big River, and the longer Río Grande del Norte means Big River of the North. In Mexico the same water is called the Río Bravo, and bravo can mean furious, agitated or wild. One stretch of water, two very different moods.

  The Pueblo peoples had their own names long before either. The Keresan name, mets'ichi chena, means Big River. Tewa speakers say Pʼoesóˀon, Big Water, or Pʼoesógeh, Place of the Big Water. In Tiwa it is paslápaane, Big River, and in Towa it is hañapakwa, Great Waters. All four names likely predate the Spanish entrada by several centuries.

  The Navajo call it Tó Baʼáadi, which means Female River. South is the female direction in Navajo cosmology.

  Spanish usage shifted over time. Rio del Norte was the common name for the upper river, roughly the area of present-day New Mexico, from colonial times until the mid-19th century. The Spanish first documented that use in 1582. By 1602, Río Bravo had become the standard Spanish name for the lower river, below its meeting with the Rio Conchos.

  Early American settlers in South Texas began using the English name Rio Grande. By the late 19th century, across the United States, that name covered the entire river from Colorado to the sea. The river those names describe begins as a handful of mountain streams.

  495051652

• 3. Source to Sea

  ›

  Several small streams meet at the base of Canby Mountain, in the San Juan Mountains of Colorado, and together they become the Rio Grande. The place lies inside Rio Grande National Forest, just east of the Continental Divide of the Americas. From there the water crosses the San Luis Valley and turns south into New Mexico. It passes near Taos and then Española, where it gains water from the Rio Chama and from the Colorado River basin through the San Juan-Chama Diversion Project.

  By main stem, the river is the fourth longest in both the United States and North America. Its drainage basin covers 182,200 square miles. Counting the neighboring basins that have no outlet to the sea, the total grows to 336,000 square miles.

  Elevation shapes everything along the way. The valley floor at Albuquerque sits 5,312 feet above sea level, and El Paso lies at 3,762 feet. Near Albuquerque the river flows past historic Pueblo villages such as Sandia Pueblo and Isleta Pueblo. In New Mexico it runs through the Rio Grande rift, passing from one sediment-filled basin to the next and cutting canyons between them. Its flood plain supports a fragile woodland ecosystem called the bosque. South of Albuquerque, the land becomes desert.

  Below El Paso and Ciudad Juárez, the river turns into the national border. Depending on how it is measured, that border stretch runs from 889 to 1,248 miles. The Rio Conchos joins near Ojinaga, in Chihuahua, about 310 kilometers southeast of El Paso. It carries almost twice as much water as any other tributary, though the Pecos River drains the largest basin. The Pecos and the Devils River enter from the north near Amistad Reservoir in Texas. The Rio Salado and Rio San Juan enter from the south, in Tamaulipas.

  Farming follows the water almost everywhere, and it is especially extensive in the subtropical Lower Rio Grande Valley. The river finally ends in a small, sandy delta. Spring rains in 2002 flushed out the reformed sandbar, but it returned by mid-2002. Only in the fall of 2003 did flows of about 7,063 cubic feet per second clear it for good.

  612105447

• 4. Before the Maps

  ›

  Thirteen million years ago, the Rio Grande was not yet one river. The basins opened by the Rio Grande rift were closed bowls with no outlet, each holding a dry lake bed called a playa. An axial river already ran in the Espanola Basin by then and reached the Santo Domingo Basin by 6.9 million years ago. Even so, it emptied into a playa in the southern Albuquerque Basin.

  By 5 million years ago, an ancestral Rio Grande draining the eastern San Juan Mountains had joined the ancestral Rio Chama. The combined river linked basin after basin to the south. It reached the Mesilla Basin 4.5 million years ago and the Palomas basin 3.1 million years ago, where it formed Lake Palomas. A tributary of the Pecos River then captured it, and the river flowed to Texas by 2.06 million years ago. It joined the Pecos itself 800,000 years ago. In the north, volcanism on the Taos Plateau had starved the San Luis Basin of drainage. Then, 440,000 years ago, a spillover drained Lake Alamosa, carved the Rio Grande Gorge and reconnected that basin to the watershed.

  The first people left little behind. Nomadic life, deep river cutting and burial under the floodplain hid most early sites. Some survive on West Mesa, west of the river near Albuquerque. They include Folsom sites, possibly dating from around 10,800 to 9,700 BCE, that were probably short-term buffalo kill sites. The flanking basins hold numerous Folsom sites and a much smaller number of earlier Clovis sites. Later Paleo-Indian groups, including the Belen and Cody cultures, used the valley for seasonal migrations.

  The Archaic Oshara tradition began around 5450 BCE. Between 1750 and 750 BCE, the Oshara started growing maize, and their settlements grew larger and more permanent. Around 1130 CE, drought collapsed the Ancestral Puebloan culture at Chaco Canyon and across the Four Corners region. Many migrated to the Rio Grande and other fertile valleys, where they competed with communities such as the Apache. Decades of conflict, called the Coalition Period, ended in merged cultures and most of the Tanoan and Keresan pueblos. The Classic Period ran from about 1325 CE to 1600 CE. Through periodic extreme drought, the valley's people stretched scarce water with gridded gardens and check dams.

  The Spanish arrived next. In 1519, a naval expedition along the northeastern coast of Mexico charted the mouths of several rivers, including the Rio Grande. In 1536 the river first appeared on a map of New Spain by a royal Spanish cartographer. In the autumn of 1540, Francisco Vásquez de Coronado, Governor of Nueva Galicia, led a military expedition to the Tiwa pueblos along the river. On the 12th of July 1598, Don Juan de Oñate y Salazar founded the colony of Santa Fe de Nuevo Méjico at San Juan de los Caballeros, beside Ohkay Owingeh Pueblo, where the Rio Chama meets the Rio Grande.

  1819202324

• 5. Steamboats and Cotton

  ›

  More than 200 different steamboats worked the lower Rio Grande in the 19th century, running between the mouth near Brownsville and Rio Grande City, Texas. Today that traffic is almost unimaginable. The river's greatest depth is 60 feet, yet passenger riverboats and cargo barges generally cannot navigate it. Boats can travel only near the mouth, and rarely as far as Laredo.

  In 1846, during the Mexican-American War, the United States government requisitioned many steamboats from the Ohio and Mississippi Rivers and sent them to the Rio Grande. They carried the army of General Zachary Taylor toward an invasion of Monterrey, Nuevo León, by way of Camargo, Tamaulipas. Army engineers argued that small improvements could make the river navigable as far north as El Paso. Nobody acted on that recommendation.

  At the river's mouth, on the Mexican side, stood the commercial port of Bagdad, Tamaulipas. During the American Civil War it was the only legitimate port of the Confederacy. European warships anchored offshore to keep the port neutral, and they succeeded throughout the war, despite occasional stare-downs with blockading US Navy ships. Deeper-draft cargo ships could not cross the shallow sandbar at the river's mouth. Smaller vessels carried goods between those ships and the shore. The trade swapped European military supplies for bales of cotton.

  The Brownsville & Matamoros International Bridge dates to 1910, and it still carries automobiles. It is a large swing bridge, but its swing mechanism has sat idle since the early 1900s, when the last big steamboats disappeared. The bridge once carried trains as well. In August 2015, the West Rail International Crossing opened about 15 miles to the west, and it was the first new international rail crossing between the two countries in over a century. Today a joint venture between the Mexican government and the Union Pacific Railroad operates the older bridge.

  6417626360

• 6. The Contested Line

  ›

  In the late 1830s and early 1840s, the river marked a disputed border between Mexico and the young Republic of Texas. Mexico placed the border at the Nueces River instead. After Texas was admitted as a state, the disagreement helped supply a rationale for the Mexican-American War of 1846. Since 1848, the Rio Grande has marked the boundary between the two countries from the twin cities of El Paso, Texas, and Ciudad Juárez, Chihuahua, to the Gulf.

  The border also had a human meaning. Mexico had abolished slavery in 1828 and had liberal colonization policies, so crossing the river became an escape route for some enslaved Texans seeking freedom.

  Today the major international crossings pair Ciudad Juárez with El Paso, Ojinaga with Presidio, Nuevo Laredo with Laredo, Reynosa with McAllen and Matamoros with Brownsville. Del Rio and Ciudad Acuña, and Eagle Pass and Piedras Negras, are other notable pairs.

  A river that serves as a border can also move. In 1899, after the channel had gradually shifted, workers dug a new channel for flood control. It moved the river and created Cordova Island, which became the center of the Chamizal dispute. Resolving that dispute took many years, and it is tied in the record to a 1909 combined assassination attempt on the American and Mexican presidents.

  6244616

• 7. Dividing the Water

  ›

  In 1905, federal lawmakers approved the Rio Grande Project, which divided the river's water between New Mexico and Texas according to each state's irrigable land. It also granted Mexico 60,000 acre-feet every year, answering that country's demands. The aim was to end years of disagreement over a dam and reservoir, which pitted the farmers of the Mesilla Valley against those of El Paso and Juárez. The agreement provided for the Elephant Butte dam on public lands. It was the first congressionally directed allocation of an interstate river, although New Mexico did not become a state until 1912.

  The 1938 Rio Grande Compact took far longer to reach. Colorado and New Mexico were eager to negotiate at first, but talks broke down in 1928 over whether Texas should be allowed to join, though it had representatives present. A provisional agreement in 1929 promised to resume talks once a reservoir stood on the New Mexico-Colorado line. The Market Crash of 1929 delayed its construction. In 1935 Texas sued New Mexico, and the president responded by setting up the Rio Grande Joint Investigation. Its findings helped lead to the final deal.

  The compact created a commission and gaging stations along the river. These measure the flow Colorado owes New Mexico at the state line and the flow New Mexico owes Elephant Butte Reservoir. Once water reaches the reservoir, the Rio Grande Project governs it and guarantees supplies to Texas and Mexico. A system of debits and credits tracks the yearly variations. The compact has been amended twice and remains in effect.

  Between the two countries, the International Boundary and Water Commission administers the main agreements, notably the treaties of 1906 and 1944. Its roots go back to 1889, when the International Boundary Committee was set up to maintain the border. Today it also allocates river water between the nations and handles flood control and water sanitation.

  Some of the water in the Rio Grande never belonged to its basin. The San Juan-Chama Project, begun under legislation signed by President John F. Kennedy in 1962 and completed in 1971, carries water under the continental divide. It draws from the Navajo, Little Navajo and Blanco Rivers, which are tributaries of the San Juan River. The water flows into Heron Reservoir and on to the Rio Chama. The Upper Colorado River Basin Compact allots 62,780 acre-feet a year to New Mexico municipalities, and Albuquerque owns 48,200 of them, about three-quarters.

  Albuquerque held these rights for years but began using the water only in 2008, when the San Juan-Chama Drinking Water Project was completed. An adjustable-height diversion dam skims the imported water from the river, and pumps send it to a treatment plant on the city's north side. Diversions are restricted when the river runs low, to protect the riparian ecosystem and endangered species such as the Rio Grande silvery minnow. Treated effluent returns to the river south of the city. The utility's long-term plan, named WATER 2120, does not include buying native pre-1907 water rights.

  2728444647

• 8. Running Dry

  ›

  Since the mid-twentieth century, only 20 percent of the river's water has reached the Gulf of Mexico. Irrigation of farmland, such as the Mesilla and Lower Rio Grande Valleys, takes much of it. Cities such as Albuquerque take more, and reservoirs behind diversion dams hold back the rest. Dams on the river include Rio Grande Dam, Cochiti, Elephant Butte, Caballo, Amistad, Falcon, Anzalduas and Retamal.

  The flow numbers show the toll. Near Presidio the discharge is frequently zero, and its average of 178 cubic feet per second compares with 945 at Elephant Butte Dam. Below Presidio, the Rio Conchos restores the flow. The annual average peaks at 3,504 cubic feet per second near Rio Grande City. Large irrigation diversions then cut it to 889 at Brownsville and Matamoros.

  The river is over-appropriated, meaning more users hold claims on its water than the water in it. From Las Cruces downstream to Ojinaga, it frequently runs dry. Campaigners have tagged this section The Forgotten River. Since water rights arrived in the 1890s, the river flowed through Las Cruces from February to October. In 2020 it flowed only from March to September. As of January 2021, the Elephant Butte Irrigation District expected it to flow only from June through July. The shortage endangers cottonwood trees and the southwestern willow flycatcher. Texas, with the least control over the waterway, has seen under-delivery of its water since 1992, and locals in three states have called for a fresh look at the 1944 treaty.

  Protection exists alongside depletion. In 1997 the United States designated the Rio Grande an American Heritage River. Two portions are National Wild and Scenic Rivers, one in northern New Mexico and one at Big Bend National Park in Texas. In all, 260 miles in New Mexico and Texas carry the Wild and Scenic designation.

  In 2022, the water debt owed to Texas jumped from 31,000 acre-feet in 2021 to over 130,000 acre-feet. That happened despite what officials called "very significant efforts that were done on the river this year to keep water flowing downstream." New Mexico expanded its program paying farmers to leave fields unplanted. Albuquerque had already shut off its domestic supply diversion in 2021 and switched fully to groundwater pumping. Work on El Vado Dam began in 2022 and cut system storage capacity by about 180,000 acre-feet. The Middle Rio Grande Conservancy District asked to store its native water downstream at Abiquiu Reservoir, which normally holds only imported water. Elephant Butte Reservoir stood at 13.1 percent of capacity on the 1st of May 2022. By October 2022 it held only 6.4 percent.

  In late July 2022, the river ran dry for about 50 miles of the middle valley, including five miles in Albuquerque. It was the first time in over 40 years. Heavy winter snow then drove very high flows in spring 2023 and flooded tributaries including the Jemez and Pecos Rivers. By summer, a failed monsoon season and record heat dried the river in Albuquerque for a second year in a row.

  3435404332