Treaty relating to the utilization of waters of the Colorado and Tijuana Rivers and of the Rio Grande

The International Boundary and Water Commission (Spanish: Comisión Internacional de Límites y Aguas) is an international body created by the United States and Mexico in 1889 to apply the rules for determining the location of their international boundary when meandering rivers transferred tracts of land from one bank to the other, as established under the Convention of November 12, 1884.

The organization was created as the International Boundary Commission by the Convention of 1889 between the United States and Mexico. It was given its present name under the 1944 Treaty relating to the Utilization of Waters of the Colorado and Tijuana Rivers and of the Rio Grande. Under these agreements, the IBWC has a U.S. section and a Mexican section, headquartered in the adjoining cities of El Paso, Texas, and Ciudad Juárez, Chihuahua. The U.S. section is administered by the Department of State; the Mexican part by the Secretariat of Foreign Relations.

Some of the rights and obligations administered by the IBWC include:

The U.S. and Mexican commissioners meet at least weekly, alternating the place of meetings and are in almost daily contact with one another. Each section maintains its own engineering staff, a secretary and such legal advisers and other assistants as it deems necessary.

The Treaty of Guadalupe Hidalgo of 2 February 1848 fixed the international boundary between El Paso – Ciudad Juárez and the Gulf of Mexico. The Gadsden Purchase Treaty of 30 December 1853 extended the southern boundary of New Mexico and Arizona southwards to enable the United States to construct a railroad to the west coast along a southern route and to resolve a question arising from the 1848 Treaty as to the location of the southern boundary of New Mexico. Temporary commissions were formed by these boundary treaties to perform the first joint mission of the governments of the United States and Mexico, which was to survey and demarcate the boundary on the ground in accordance with the treaties. Another temporary commission was created by the 1852 Boundary Convention (29 July), which surveyed and increased the number of monuments marking the land boundary westward from El Paso and Ciudad Juárez. As settlements sprang up along the boundary rivers and the adjoining lands began to be developed for agriculture in the late 19th century, questions arose as to the location of the boundary when the rivers changed their course and transferred tracts of land from one side of the river to the other. The two governments, under the 1884 Border Convention (12 November), adopted certain rules designed to deal with such questions.

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