The Rio Grande is over-appropriated, that is, there are more users for the water than there is water in the river. In times of severe drought the section from El Paso downstream through Big Bend National Park has been dry. Ecologists fear that unless rainfall returns to normal levels during the next few years and strict water conservation measures are adopted by communities along the river, the Rio Grande may soon become extinct.

The Rio Grande rises in high mountains and flows for much of its length at high elevation; El Paso is 1147 m (3762 ft) 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 in its floodplain. 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 periods of extended dry weather, the river will actually cease flowing into the Gulf.