Rivers such as the Rio Grande can change course over time, and changes in water depth and topography can alter perceptions of the international boundary's location; treaties governing the U.S.-Mexico boundary require clear demarcation of the national border when such changes occur.
November 17, 2025
high
geopolitical
Natural shifts in river channels affect how international boundaries defined by rivers are perceived and legally demarcated.
Treaties between the United States and Mexico require clear demarcation of the national border when rivers such as the Rio Grande change course.
November 17, 2025
medium
temporal
Border-management principle applied when natural waterways alter the perceived boundary.
Shifting riverbeds, such as sections of the Rio Grande, can complicate precise determination of international land borders when rivers are used as boundary markers.
June 01, 2025
high
geographic
Natural changes in river courses can create uncertainty about the exact location of river-defined borders.