This aerial survey of the flooding at Presidio, Texas on September 29, 1978 includes footage of the Rio Grande over its banks, flooded fields and submerged bridges. In late September of 1978, unusually heavy rainfall in the Sierra Grande Mountains caused record flooding both in Presidio, Texas and on the other side of the border, just south of Presidio, in Ojinaha, Mexico. The rainfall caused the Rio Grande River to swell, spilling over the 29 foot levees in Presidio. The Pecos River in Texas and the Rio Conchos in Mexico also flooded due to more than ten inches of rain in four days in the region. Citizens of Presidio, a town of about 1,000 in 1978, piled sandbags on their levees in anticipation of the crest of the flood. The levees were designed to hold back 42,000 cubic feet of water per second, but the flood still overtopped the levees with a crest of 28 to 29 feet, filling about 1,000 acres of farmland with water. In Ojinaga, the Rio Grande also collapsed the 27 foot levee; the Rio Conchos and Rio Grande converged, putting the Rio Grande at more than ten feet above its 14-foot flood stage. The flood left about 10,000 Ojinaja residents homeless, two dead, and five missing.
The International Boundary and Water Commission (IBWC) has its roots in the 1848 Treaty of Guadalupe Hidalgo and the Gadsen Treaty of 1853, both of which established (and re-established) the U.S.-Mexico border, and also established commissions to survey and map the new U.S.-Mexico border, designating landmarks to mark the border. As the rivers that created the borders changed their courses naturally, land changed jurisdiction, and the International Boundary Commission (IBC), the IBWC's predecessor, was established in 1889 to apply rules that resulted from the Rio Grande and Colorado Rivers' roles as the boundaries between the two countries. In 1906, the two countries signed their first water distribution treaty, the Convention of March 1, 1906, which designated portions of the rivers to each country. In 1933, the two countries began joint river projects to stabilize the Rio Grande, and in 1944, the countries formed the IBWC to enforce allocations of the river and began work on dams that would be operated and maintained by both countries. The IBWC has been integral in resolving boundary disputes for the two countries over the following decades and in constructing dams and reservoirs that stabilize the boundary rivers, keeping them on course to maintain consistent borders and benefits for the U.S. and Mexico.