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Transboundary Waters

U.S.-Mexico Transboundary Aquifer Assessment Program

factsheet: English (pdf) | español (pdf)

The TAAP originates from U.S. Public Law 109-448, signed into law by the President on December 22, 2006 as the Transboundary Aquifer Assessment Act. The Act applies to the states of Texas, New Mexico, and Arizona where four transboundary aquifers have been designated for priority assessment; those being the Hueco Bolson and Mesilla Basin aquifers in the greater El Paso / Ciudad Juárez region, and the Santa Cruz and San Pedro aquifers across the Arizona – Sonora border (see map). The TAAP is designated to operate for 10 years, with $50 million authorized for appropriation over that time period.

TAAP-AZ is the Arizona component of assessment activities and is a collaborative effort of the United States Geologic Survey (USGS) and the Water Resource Research Center (WRRC) and the Udall Center for Studies in Public Policy, both at the University of Arizona. A variety of other U.S. and Mexican stakeholders participate in priority setting for the assessment process. TAAP-AZ (the transboundary Santa Cruz and San Pedro aquifers) was recently designated a case study by the UNESCO Internationally Shared Aquifer Resource Management (ISARM) program.

Current Status TAAP-AZ is focused on compilation of scientific and other published materials in a searchable, online, bilingual database on groundwater resources within the binational Santa Cruz and San Pedro aquifers. The collection and synthesis of such materials currently includes 110 sources from a variety of university, governmental, and non-governmental agencies in both the U.S. and Mexico. Priority for database creation was given to the Santa Cruz aquifer, with a similar product focused on the San Pedro to follow.The following agencies or organizations have collaborated in the priority-setting process for TAAP-AZ activities. Many have assisted by contributing materials to the database project: Comisión Nacional del Agua (CONAGUA), Comisión Estatal del Agua (CEA) Sonora, Organismo Operador Municipal de Agua Potable, Alcantarillado y Saneamiento (OOMAPAS) Nogales, Arizona Department of Water Resources (ADWR), United States Bureau of Reclamation (USBOR), City of Nogales, Arizona, Friends of the Santa Cruz River (FOSCR), Sonoran Institute, University of Sonora, Colegio de Sonora, Centro de Estudios Superiores del Estado de Sonora (CESUES), Comisión Internacional de Límites y Aguas (CILA)

Transboundary Aquifer Assessment Program- Arizona (TAAP-AZ)
Timeline and Selected Accomplishments
November 5, 2007- Arizona Dept. of Water Resources (Santa Cruz Active Management Area) hosted first binational meeting to discuss priority setting process, define scope of TAAP – Santa Cruz
January 28, 2008- First meeting of Santa Cruz technical committee, discussed existing data and reports, need to examine groundwater flow and quality data and models on both sides of border
April 30, 2008- TAAP-AZ organized a modeling review meeting between binational stakeholders in Nogales, Arizona. Site visits to upper Santa Cruz River from international boundary north to Tubac Bridge followed the meeting.
June 11, 2008- TAAP personnel participate in meeting convened by the Upper San Pedro Partnership (USPP) in Sierra Vista, Arizona.
June 13, 2008- Site visit to Mexican reach of the Santa Cruz River coordinated by OOMAPAS Nogales, CEA-Sonora and TAAP-AZ (see Photo above).
June 20, 2008- Arizona-Mexico Commission Water Committee meeting in Phoenix with TAAP presentation attended by U.S. and Mexican representatives, and both Commissioners of IBWC and CILA.
September 18, 2008- TAAP-AZ accepted as a case study by the UNESCO Internationally Shared Aquifer Resources Management (ISARM) program.
June 18, 2009- International Boundary and Waters Commission meeting to continue forging an agreement on U.S. – Mexico groundwater data sharing in support of TAAP.

TAAP Contacts:
For more information please visit www.cals.arizona.edu/azwater/taap Sharon B. Megdal, PhD (TAAP Principal Investigator)
Director, Water Resources Research Center,
University of Arizona
Email: smegdal@cals.arizona.edu Phone: (520) 621-9592
Fax: (520) 792-8518

James Callegary, PhD (Co-Principal Investigator)
Hydrologist, USGS Arizona Water Science Center
Email: jcallega@usgs.gov  Phone: (520) 670-6671
Fax: 520-679-5592

Christopher Scott, PhD (Co-Principal Investigator)
Asst. Professor, Udall Center for Studies in Public Policy and Dept. of Geography & Regional Development, University of Arizona
Email: cascott@email.arizona.edu Phone: (520) 626-4393

Prescott Vandervoet
Research Analyst, Udall Center for Studies in Public Policy
University of Arizona
Email: plv@email.arizona.edu Phone: (520) 626-4393

2008 – Transboundary Aquifer Assessment Program (C. Scott, co-PI, 50%).
$167,000, United States Geological Survey.

Pending – Coupling Ecohydrological and Social Interactions in Arid Watersheds:
Building Resilience of the Sonora and San Pedro River Basins (C. Scott, co-PI, 20%, proposal submitted Nov. 2009). $1.5 million requested for 2009-2014. National Science Foundation, Coupled Natural-Human Systems.