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Rio Grande/Río Bravo del Norte between Ciudad Juárez, Chihuahua, and El Paso,Texas. Photo credit: iose, via Wikimedia Commons.

Treaty between the U.S. and Mexico, there has been no agreement about the sharing of the underlying transboundary aquifers. Extensive pumping of the aquifers has led to a decline in the water table on both sides of the border. Initially, El Paso relied on surface water from the Rio Grande but has started using more groundwater. Juarez relies primarily on groundwater. The City of El Paso implemented a 40-year water plan in 2000 to help ensure future supplies. Juarez, on the other hand, does not have a formal plan to deal with increasing demand. Agricultural water use of the Rio Grande/Rio Bravo has degraded surface water and groundwater quality by increasing salinity. The saline waters seep into the ground, recharging both aquifers and increasing groundwater salinity. Conversely, saline water from the shallow aquifer recharges the Rio Grande via irrigation drains (Walton and Olmacher, 2003). Due to these water quality and potential water quantity issues, a bill (S.B. 214, 2005) was passed by the U.S. Senate that will appropriate money to study the transboundary aquifers. This study may help prevent conflict and lead toward future water sharing agreements. The precursor to this bill was a joint effort by the U.S. and Mexico to create a groundwater database for the El Paso/Juarez area, titled “Transboundary Aquifers and Binational Groundwater Database.” In 1998,

studies completed on both sides of the border were brought into this database by the IBWC to help understand existing data gaps and make recommendations for future studies (IBWC, 1998). This study is an example of cooperation of both countries via the IBWC. By understanding the physical properties of the aquifers, there may be some attempt to minimize future conflict on both sides of the border since both cities will continue to grow and rely on the same source of water. Colorado River Basin The border cities of Nogales, Arizona (U.S.) and Nogales, Sonora (Mexico) along the Santa Cruz River in the Colorado River Basin were the subject

Frog in tributary of Bright Angel Creek, Grand Canyon National Park, Arizona. Photo credit: Keith Davis.

Chapter 5. International Conflicts and Cooperation that Influence Regional Hydropolitical Vulnerability — 49

NORTH AMERICA :Hydropolitical Vulnerability and Resilience along International Waters  
NORTH AMERICA :Hydropolitical Vulnerability and Resilience along International Waters  

This report focuses on the challenges and opportunities facing North America, a continent with about 6.5% of its area covered by surface fre...