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The Rio Grande (Río Bravo del Norte) has changed course several times in recorded history, leading to a number of border disputes, both international (involving Mexico and the United States) and between individual U.S. states:
- The Horcón Tract was a parcel of land surrounded by an oxbow bend of the Rio Grande, including the village of Rio Rico, Texas, that inadvertently defaulted to Mexican administration with the passage of time after an irrigation company in 1905 dug an unapproved cut across the oxbow to change the course of the river. This issue, which was not technically a dispute as both sides were in agreement about its legal status upon its discovery, was resolved by treaty ceding the land to Mexico in 1970, but the official handover did not take place until 1977.
Numerous border treaties are jointly administered by the International Boundary and Water Commission, which was established in 1889 to maintain the border, allocate river waters between the two nations, and provide for flood control and water sanitation. Once viewed as a model of international cooperation, in recent decades the IBWC has been heavily criticized as an institutional anachronism, by-passed by modern social, environmental and political issues.