When determining borders, a river is often the clearest delineation between sovereign nations. But that clarity abruptly ends when countries must decide how to use the water that the river provides. Even managing rivers that do not determine borders, but rather travel through multiple countries, is precarious at best. The Rio Grande, which partly establishes the U.S.-Mexico border, is no exception. It has been and will continue to be vital to economic growth in the region, especially in Mexico, where the river and its tributaries are crucial to supporting new opportunities for manufacturing and energy.
But growing demands and environmental pressures will increase tension over water resources in the coming decades. Unlike the waters of the Colorado River, which originate entirely in the United States, the watershed of the Rio Grande is more evenly split between the United States and Mexico. Although Mexico depends on the water resources far more than the United States does, both nations are vulnerable to increasing water stress, making it difficult for them to meet anticipated water treaty obligations… Read more from Stratfor.com