The Chamizal dispute was caused by a shift in which one of the principal rivers in the southwest United States and northern Mexico?
Rio Grande The Rio Grande ( or ; Spanish: Río Bravo del Norte , ] or simply Río Bravo) is one of the principal rivers in the southwest United States and northern Mexico (the other being the Colorado River). The Rio Grande begins in south-central Colorado in the United States and flows to the Gulf of Mexico. Along the way, it forms part of the Mexico–United States border. According to the International Boundary and Water Commission, its total length was 1896 mi in the late 1980s, though course shifts occasionally result in length changes. Depending on how it is measured, the Rio Grande is either the fourth- or fifth-longest river system in North America.
Boundary Treaty of 1970 The 1970 Boundary Treaty between the United States and Mexico settled all then pending boundary disputes and uncertainties related to the Rio Grande (Río Bravo del Norte) border. The most significant dispute remaining after the Chamizal Settlement in 1963 involved the location of the boundary in the area of Presidio, Texas, and Ojinaga, Chihuahua. The river channel was jointly relocated to approximate conditions existing prior to the dispute which arose from changes in the course of the river in 1907. The International Boundary and Water Commission was charged with its implementation. The American-Mexican Treaty Act of October 25, 1972 authorized the United States Section's participation. The project was undertaken in 1975 and completed in 1977.