1. INTERNATIONAL BOUNDARY AND WATER COMMISSION
MEXICO AND THE UNITED STATES
SHARED WATERS
OF NORTH AMERICA
TRANSBOUNDARY AQUIFERS BETWEEN MEXICO AND USA
Science and Policy
XVI World Water Congress
Cancún Quintana Roo, 2017
Luis Antonio Rascón Mendoza

2. WATER TREATIES (1906, 1944)

3. TRANSBOUNDARY AQUIFERS

4. INTERNATIONAL LEGAL FRAMEWORK
GENERAL ASPECTS
There is no Groundwater Treaty between Mexico and the USA.
Groundwater issues are addressed by IBWC in a case by case basis.
Different legal framework in each country.
Jurisdiction is different in each country ( In Mexico is federal; in USA is non federal with variations in each state).
Interest in both sides of the border in improving the knowledge of the shared aquifers.

5. INTERNATIONAL LEGAL FRAMEWORK
LEGAL INSTRUMENTS ON TRANSBOUNDARY GROUNDWATERS
Minute 242
Consultations.
Distribution of groundwater
Minute 289
Water Quality studies.
Includes surface water and groundwater.
2009 agreement
Develop transboundary aquifer assesments.
Starting with the Mesilla Bolson, Rio San Pedro and Rios Santa Cruz aquifers.

6. Joint selection of the aquifers and the scope of the studies.
INTERNATIONAL LEGAL FRAMEWORK
BINATIONAL COORDINATION CONCEPTS (2009 AGREEMENT)
Creation of Binational Technical Groups.
Joint selection of the aquifers and the scope of the studies.
Focus in improving the knwoledge of the aquifers.
Topics like water rights and water management should not be discussed.
Respect each country legal framework.
Not contravene what is stipulated in the Boundary and Water Treaties.
Costs and works distribution.

7. TRANSBOUNDARY AQUIFERS.
JOINT EFFORTS
Exchange of information.
Joint reports
Joint assesments ( Quantity and quality )
Joint Models.
Consultation. Conflict resolution.
Contingencies (with aquifer contamination potential)

8. TRANSBOUNDARY AQUIFERS. JOINT STUDIES
1) Hueco Bolson Aquifer (Valle de Juárez )
Exchange of information since the 1970´s
Binational Report in 1998
Binational Flow Model
Ongoing Talks to update the Binational Model

9. TRANSBOUNDARY AQUIFERS. JOINT STUDIES
2) Río San Pedro Aquifer
Exchange of Information
Joint Assessment under the 2009 agreement
Joint Report published in 2017
Emergency response to potential contamination
Ongoing Talks to develop a binational Flow Model

10. TRANSBOUNDARY AQUIFERS. JOINT STUDIES
3) Río Santa Cruz Aquifer
Exchange of Information
Joint Assessment under the 2009 agreement
Joint Report to be published in 2017
Ongoing talks to develop a binational Flow Model

11. TRANSBOUNDARY AQUIFERS. JOINT STUDIES
4) Arroyo Nogales Aquifer
Arroyo Nogales is within the Santa Cruz River Watershed.
In the 1990´s, concerns regarding potential contamination of the aquifer.
Binational groundwater quality study developed under minute 289.
Monitoring wells were built in both countries (7 in MX, 6 in USA; 10 cm diameter, 12 m depth).
Binational Report published in 2002.
Some parameters of concern were found.
Intensive exchange of information and actions were undertaken to address potential contamination sources.
A binational workgroup continues to meet quarterly to exchange information and address potential sources.

12. TRANSBOUNDARY AQUIFERS. JOINT STUDIES
5) Mesilla Bolson Aquifer (Conejos Médanos)
Exchange of Information in 2010 under the 2009 agreement.
Domestic assesments and reports prepared by each country and exchanged.
A binational Joint Report was not prepared for this aquifer
Ongoing Talks to develop a binational Flow Model

13. TRANSBOUNDARY AQUIFERS. JOINT STUDIES
6) Mexicali Valley Aquifer
All American Canal Lining Project.
Sistematic exchange of information in the Yuma area (water levels, pumping volumes)

14. RESEÑA DE LOS ESTUDIOS DE ACUÍFEROS TRANSFRONTERIZOS REALIZADOS
7) Middle segment of the Río Grande/Bravo:

15. TRANSBOUNDARY AQUIFERS.
FUTURE ACTIONS
Continue the exchange of information and the develompent of joint studies and models to improve the konwledge of the transboundary aquifers.
Build trust.
Address contingencies and aquifer protection.
Water rights and water management should not be discussed at this moment