The 2nd longest river in the United States, its basin is more than 30% arid and drains an area greater than the size of California.
The Rio Grande flows from the San Juan Mountains of Colorado, south through New Mexico. Turning to the southeast, it forms the border between the United States (Texas) and Mexico for approximately two thirds of its course, opening into a small sandy delta at the Gulf of Mexico.
Through the stretch from Laredo/Nuevo Laredo to the mouth, the river constitutes the primary source of drinking water for communities in both Mexico and the United States.
Despite the rapidly growing economy, the basin is one of the poorest regions in the US, where many live in shanties without access to running water. The basin is facing per capita water scarcity, and by 2025, will likely descend into further water scarcity.
The Rio Grande basin is a globally important region for freshwater biodiversity. The Rio Grande supports 121 fish species, 69 of which are found nowhere else on the planet. There are 3 areas supporting endemic bird species as well as a very high level of mollusk diversity.
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