The Rio Grande: Profile of a Border River

The Rio Grande (Río Bravo del Norte) is North America's fourth-longest river system and the defining geographic feature of the U.S.–Mexico border.

Vital Statistics

• Length: ~3,060 km (1,900 mi) – 4th in North America (after Mississippi, Mackenzie, Yukon).
• Source: San Juan Mountains, southern Colorado (Canby Mountain, 3,700 m).
• Mouth: Gulf of Mexico, near Brownsville, TX / Matamoros, TAMPS.
• Basin Area: 470,000 km² (182,000 mi²) – 2% in Mexico, 98% in US (CO, NM, TX).
• Average Discharge: ~85 m³/s (3,000 cfs) at mouth—highly variable, often zero in lower reaches due to diversion.

Major Tributaries

• Pecos River (TX/NM): Largest by length (1,490 km), but often dry.
• Río Conchos (Chihuahua): Largest by volume—delivers 2/3 of lower Rio Grande flow.
• Salado River (Nuevo León/Tamaulipas): Intermittent, flash-flood driven.
• Devils River (TX): Pristine, spring-fed, critical for baseflow.

Engineering & Management

• Dams/Reservoirs: Elephant Butte (NM), Amistad, Falcon (TX/Mexico binational). Store water for irrigation (90% of use), municipal, hydro.
• Treaties: 1906 (US→Mexico 74 MCM/yr), 1944 (Water Treaty: Rio Grande, Colorado, Tijuana). IBWC (International Boundary and Water Commission) manages.
• Bridges: 28+ international crossings (El Paso/Ciudad Juárez, Laredo/Nuevo Laredo, Brownsville/Matamoros).

Ecology & Crisis

Riparian bosque (cottonwood/willow), endangered silvery minnow, ocelot, jaguarundi. Chronic overallocation + climate change → "forgotten river" reaches dry annually. Binational restoration efforts (pulse flows, invasive removal) underway.

The Rio Grande is a river of agreements—and increasing disagreement over a shrinking pie.