Water supply and water quality problems facing the City of El
Paso and Ciudad Juarez are complex and interrelated. The twin
cities share the water resources of the Hueco Bolson, a Tertiary
and Quaternary basin fill aquifer that spans the international
border. The binational metroplex is located at the junction
between the western edge of Texas and the northernmost part of
Chihuahua, Mexico. Over-pumping of the Hueco Bolson aquifer has
resulted in drawdown of the water table, encroachment of
brackish groundwater, and the early retirement of wells. In
response to these issues, Mexican and American universities
formed a partnership to study the surface and ground-water
resources of the El Paso/Juarez area. Governmental agencies are
participating in the project by providing existing data, access
to water wells, and other support services. The research team is
applying a suite of isotopic tracers to provide an understanding
of the spatial dynamics of the aquifers by tracing water from
areas of recharge to regions