The Río Grande is the 5th longest river in North America and the 20th longest in the world. Before humans subdued it with dams and reservoirs, the Río Grande ran wild. Spring run off created flood zones along its path, spreading rich sediment and carving amazing geologic features, like the 50-mile-long Río Grande Gorge in northern New Mexico and the 1,500-foot walls of Santa Elena Canyon in Big Bend National Park, Texas.
The river creates a unique and extensive riparian corridor. The cottonwoods that flank the bank of the Rio Grande form the largest contiguous cottonwood forest in the world. The Río Grande’s floodplains, which extend between one and three miles wide, are home to more than 400 species of native fish, wildlife, and plants. Tens of thousands of sandhill cranes still overwinter each year at Bosque del Apache National Wildlife Refuge, south of Socorro.
The bounty of wildlife near the river attracted ancient hunters. Later, as the Puebloan culture spread throughout the region, hamlets and villages were established on most of New Mexico’s waterways. As the largest, most reliable, source of water, the Río Grande was lined with hundreds of settlements relying on the water for sustenance.
Based on thousands of petroglyphs pecked into boulders on the edge of the river, and the remains of stone tools found by archaeologists, the Río Grande valley has been inhabited since at least the Archaic period. Archaeologists have also recovered potsherds, projectile points, and the remains of pit houses. The Jicarilla Apache, Utes, Taos Pueblo and Picuris Pueblo have inhabited the area for hundreds to thousands of years (Taos).
Spanish conquistadors discovered the mouth of the Río Grande River in 1519. The Spaniards established numerous settlements on the river over the following century. They called the waterway El Río Grande, or ‘the Great River.’ However, the river arrived before humans. It has been called many names, most of which reflect reverence and respect for the power and importance of water.
Wild & Scenic River
The Río Grande starts as a snow-fed stream 12,000 feet above sea level in Colorado’s San Juan Mountains, part of the Rocky Mountain range. It is formed by several streams merging at the base of Canby Mountain, just east of the Continental Divide in Colorado.
After winding through southern Colorado, the Río Grande descends into New Mexico. The river follows the Río Grande Rift, from one sediment-filled basin to another, carving canyons between the basins, and supporting a fragile bosque ecosystem in its floodplain. Ultimately, the river crosses 1,900 miles of deserts, plains and steppes, before draining into the Gulf of Mexico.
As it flows through the cities of Albuquerque, Las Cruces, and El Paso, the environment changes from a cold steppe climate, with juniper, piñon, and sagebrush, to a hot steppe and desert climate, with cactus, creosote bush, mesquite, and yucca.
Conservation and Preservation
Segments of the Río Grande remain among the most spectacular stretches of river in America. Congress designated the Río Grande as a Wild and Scenic River in 1968, making it one of the first eight rivers to be protected.
Protected landscapes along the river include the Río Grande del Norte National Monument, Valle del Oro, and Bosque del Apache National Wildlife Refuge in New Mexico, as well as Big Bend National Park, the Santa Ana, Laguna Acosta, and Lower Río Grande National Wildlife Refuges in Texas. Three additional protected regions exist in Mexico, south of the Big Bend region, including Cañon de Santa Elena, Ocampo and Maderas del Carmen Flora and Fauna Protection Areas. Additionally, the U.S. Congress designated two sections of the Río Grande for protection as wild and scenic rivers, including the Río Grande from the Colorado-New Mexico state line to Velarde, New Mexico and the Río Grande through Big Bend National Park.
Flowing Down the Río
The Río Grande gains momentum as it flows south, with numerous smaller rivers merging with it on the way to the Gulf of Mexico. The main tributaries are the Pecos, Devils, Chama, and Puerco rivers in the United States, and the Conchos, Salado, and San Juan rivers in Mexico. The Río Conchos, which enters at Ojinaga, Mexico, is responsible for most of the water in Texas’ stretch.
The Río Grande forms the border between the United States and Mexico in El Paso. The international boundary is in the middle of the river, established as part of the 1848 Treaty of Guadalupe Hidalgo, which ended the Mexican-American war. As the river flows east from El Paso, it carved three canyons between 1,500 and 1,700 feet deep across the faulted area known as the “big bend.” Big Bend National Park is on the Texas side of the river. The river’s pace is more subdued on this stretch. Less water. It meanders slowly through the desert to the fertile delta where it merges with the Gulf of Mexico.
Overall, the Río Grande’s watershed encompasses 336,000 square miles. However, most of the basin is arid or semiarid. Only 176,000 square miles contribute water to the river’s flow. Peak flow occurs between April and October, depending on the snow melt in Colorado, spring precipitation, and the stretch of river. In the upper reaches of the Río Grande, peak flow is usually May or June. Travel Tip: This is prime time for rafting the Taos Box outside of Taos, New Mexico.
The southern portion of the river, providing water to Las Cruces, Texas, and Mexico, usually peaks between June and September. It depends on summer monsoon activity. During dry years, the river slows to a trickle. For example, a 330-foot wide sandbar formed at the mouth of the Río Grande during the summer of 2001. It was the first time in recorded history that the river failed to empty into the Gulf of Mexico. They removed it, but it has reformed repeatedly.
Greater Demand, Less Water
The river is the heart of the economy in the Río Grande Basin, which encompasses 10 million people and two million acres of land. Although these cities’ do not rely economically on agriculture, farming and ranching absorbs 87% of the surface water. As annual snowfall decreases and evaporation rates increase, the U.S. Bureau of Reclamation estimates the upper Río Grande watershed will collect 30% less water by the end of the century. Yet, the number of people relying on the river continues to increase.
Water is precious. Water is scarce. The Río Grande is a vital artery that brings life to the desert. However, the water supply available within the Río Grande drainage is dwindling. Diversions for municipal and agricultural use claim approximately 95 percent of the Río Grande’s annual flow (on average). Elephant Butte’s gates only open for a short irrigation season. Furthermore, the reservoir was at less than 10% capacity in 2018. Prolonged drought and growing urban populations around Albuquerque and El Paso exacerbate the problem. Scientists have recommended that communities along the river implement strict water conservation measures.