TAAP

TAAP-Transboundary Aquifer Assessment Program
Background
Para la versión en español, haz clic aquí
TAAP-A/S (the transboundary Santa Cruz and San Pedro aquifers) is a federally funded program co-hosted between the USGS Arizona Water Science Center in Tucson, Arizona and the Water Resources Research Center (WRRC) at the University of Arizona. The program originates from U.S. Public Law 109-448, signed 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). TAAP-A/S is designated to operate for 10 years, with $50 million authorized for appropriation over that time period.
TAAP-Official Binational Reports
The International Boundary and Water Commission, United States and Mexico (IBWC) have completed the Binational Study of the Transboundary San Pedro Aquifer. The study marks the first time researchers from both countries have collaborated to collect data and jointly prepare binational maps of the San Pedro River aquifer, which spans the border between the States of Arizona and Sonora near the communities of Sierra Vista, Arizona and Cananea, Sonora. The binational database and bilingual maps created for this study, and the resulting technical analysis, are an important contribution to scientists’ understanding of the aquifer.
The report is the result of a dedicated group of scientists from both countries that worked with IBWC according to an IBWC-approved binational cooperative framework to allow them to exchange ideas and information to improve the state of knowledge in the basin.
Recent Publications






- Elia M. Tapia-Villaseñor, Eylon Shamir, Sharon B. Megdal, Jacob D. Petersen-Perlman - Impacts of Variable Climate and Effluent Flows on the Transboundary Santa Cruz Aquifer - 2020
- Jacob D. Petersen-Perlman - Ambos Nogales Effluent. Institutional Frameworks for Effluent Water Use in the Ambos Nogales Region - 2019
- Sharon B. Megdal - Reflections on the 10th Anniversary of the Transboundary Aquifer Assessment Program and the Importance of its Joint Cooperative Process - 2019
- Callegary, J.B., Megdal, S.B., Tapia Villaseñor, E.M., Petersen-Perlman, J.D., Minjárez Sosa, I., Monreal, R., Gray, F., Grijalva Noriega, F. Findings and lessons learned from the assessment of the Mexico-United States transboundary San Pedro and Santa Cruz aquifers: The utility of social science in applied hydrologic research. Journal of Hydrology: Regional Studies. -2018
- Sharon B. Megdal and Jacob D. Petersen-Perlman - Groundwater Governance and Assessment in a Transboundary Setting (book chapter in Velma I. Grover and Gail Krantzberg (eds.) Lake Governance. CRC Press) - 2018
- Sharon B. Megdal - Public Policy - The Cooperative Framework for the Transboundary Aquifer Assessment Program: A Model for Collaborative Transborder Studies - 2017
- Callegary, J.B., Minjárez Sosa, I., Tapia Villaseñor, E.M., dos Santos, P., Monreal Saavedra, R., Grijalva Noriega, F.J., Huth, A.K., Gray, F., Scott, C.A., Megdal, S.B., Oroz Ramos, L.A., Rangel Medina, M., Leenhouts, J.M., 2016, Binational Study of the Transboundary San Pedro Aquifer: International Boundary and Water Commission.
- Five-year interim report of the United States-Mexico Transboundary Aquifer Assessment Program: 2007--2012
- Localizing Decision-Making in the Bi-National US-Mexico upper San Pedro River-July 12-14, 2011
- The Importance of Institutional Asymmetries to the Development of Binational Aquifer Assessment Programs: The Arizona-Sonora Experience
- Institutional Assessment of the Transboundary Santa Cruz and San Pedro Aquifers on the United States-Mexico border (p. 453)
- Joint Report of the Principal Engineers Regarding the Joint Cooperative Process United States-Mexico for the Transboundary Aquifer Assessment Program
- Front-row view of federal water lawmaking shows process works-U.S. Mexico Transboundary Aquifer Assessment Act pondered, passed, and signed (p. 11)
- Deadline Looms for Transboundary U.S.-Mexico Water Management: Experts weigh in on the potential for conflict and cooperation, 2020
- Climate Change and Water Resources Management in the Upper Santa Cruz River, Arizona - Journal of Hydrology, 2015
- Water Resources Vulnerability to Climate Change in the Upper Santa Cruz River, Arizona - Proceedings of the 7th International Congress on Environmental Modelling and Software, 2014
- Groundwater Use and Re-use in the Transboundary Santa Cruz River Basin - World Water Development Report, 2012
- Climate Change and Popluation Impacts on the Transboundary Santa Cruz Aquifer - Climate Research, 2012
TAAP News and Events

A 20-minute presentation, Tackling Wicked Water Problems in the Transboundary Colorado River Basin, is available for viewing on the WRRC website.

The Upper Santa Cruz River Basin (USCRB) stretches across the US-Mexico border in Southern Arizona.

The WRRC recently held a Zoom meeting to discuss issues related to water use and climate uncertainties in the Transboundary Santa Cruz Aquifer. The meeting, held on September 17, 2020, was organized by the WRRC as part of the Transboundary Aquifer Assessment Program (TAAP). The TAAP is a joint effort between the United States and Mexico to evaluate shared aquifers. Sharon B. Megdal, WRRC Director and Principal Investigator on this project, welcomed the audience, which included members of the Mexican and U.S.