The Transboundary Aquifer Assessment Act: Program Objectives and Status Dr. Karl Wood New Mexico Water Resources Research Institute Dr. Sharon Megdal Arizona Water Research Center Dr. Ari Michelsen Texas A&M Research Center at El Paso James Stefanov U.S. Geological Survey – Austin, Texas

Problems? Human population growth along US-Mexico border is among the highest nationally Average per capita income is far below the U.S. average Economic develop is restricted by lack of adequate water Availability of water is a key issue in the U.S. – Mexico border region Groundwater is used for all the drinking water in southern New Mexico, all of Juarez, and half of the El Paso area Groundwater is probably the only source of new water as the drought continues and new desalting technology develops

How extensive are the aquifers? How deep are the aquifers? How thick are the aquifers? Which directions are the aquifers flowing? What is the quality of the aquifers at various depths? How fast are they declining in supply and quality? What is the long-term availability? What is the relationship between surface supplies and aquifer recharge? Many questions concerning the aquifers remain:

borderborder Water Resources in the New Mexico Border Region

 Mined basin with water-level drawdowns exceeding 250 feet  Sole source of water for Ciudad Juarez  Major source of water for El Paso  Quality generally <1,000 mg/L TDS, but deteriorating  Very little natural recharge  Extensive modeling in El Paso/Ciudad Juarez area  Artificial recharge program by El Paso  Water Use 2000: El Paso = 126,420 acre-feet Ciudad Juarez = 124,000 acre-feet Distrito de Riego 009 = 57,000 acre-feet Hueco Bolson

Mesilla Basin Largest rechargeable reservoir in region Southern boundary in Mexico poorly defined Connected with overlying semi- confined alluvium aquifer Quality <1,000 mg/L TDS Use: Domestic & Supplemental to Rio Grande for Irrigation Quantity pumped = ? Quantity in storage = ~60 million af - ? Number of modeling efforts, none bi- national

The Act Conceived by Senator Jeff Bingaman of New Mexico from U.S. Senate field hearing in Las Cruces August 14, 2001 Authorization bill written by Senator Bingaman’s staff Sponsored by Senator Bingaman of New Mexico and Co-Sponsored by Senator Domenici of New Mexico and Senator Kyl of Arizona Supported by other Senators from Arizona and Texas Passed U.S. Senate in 2005

The Act continued Sponsored in U.S. House by Congressman Kolbe of Arizona and co-sponsored by Congressmen Grijalva of Arizona and Reyes of Texas in 2006 Supported by Congressmen from Arizona, New Mexico, and Texas Not supported by Congressmen from California Passed Congress in December 2006 Signed by President in December 2006

The Act - Objectives Collect new and existing data Improve existing and develop new computer models to: –Characterize transboundary aquifers for: Horizontal extents Depth to aquifers Thickness of aquifers Anomalies of aquifers Water qualities of aquifers including salinity, nutrients, toxics, and pathogens Movement of water in aquifers Assess interaction with surface waters Sources and amounts of depletion of aquifers –Develop high-quality, comprehensive, binational groundwater quantity and quality data bases –Develop hydrogeologic maps of both surficial and bedrock deposits –Apply the new data and models to evaluate strategies to protect water quality and enhance supplies.

The Act – Some Bumps International Boundary and Water Commission’s (IBWC) Commissioner supported the Act to gain information to write a groundwater treaty with Mexico State Engineers in Arizona, New Mexico, and Texas opposed the bill because groundwater in U.S. belongs to the states and not to the federal government IBWC backed off of treaty ambitions State Engineers eventually supported the bill California’s congressmen felt the information could complicate issues surrounding the All-American Canal

The Act continued Bill was authorized for $5 million per year for 10 years Appropriation now needed Budget for 2007 is a continuing resolution Budget request for 2008 is $2 million for startup

Who Gets The Money? 50% to the Arizona, New Mexico, and Texas Water Resources Research Institutes to provide funding to appropriate entities including: 1.Universities 2.State agencies 3.The Tri-Regional Planning Group 4.Sandia National Laboratory 5.Other relevant organizations and entities in Mexico 50% to the U.S. Geological Survey to work in partnership with the above organizations

Priority Aquifers Hueco Bolson – Texas, New Mexico, & Chihuahua Mesilla Bolson - Texas, New Mexico, & Chihuahua Santa Cruz River Valley – Arizona & Sonora San Pedro Aquifer – Arizona & Sonora Additional aquifers to be added i.e Mimbres, etc.

Programs Already Started Development of a bibliography in English and Spanish Determining existing data sources, extent, & form Developing a relationship Mexico’s new Office of Transboundary Basins established in the National Water Commission Updating colleagues in: –International Boundary & Water Commission U.S. Division Mexico Division (CILA) –University of Ciudad Juarez –Juarez campus of Monterrey Tech –El Colegio de la Frontera Norte (COLEF)

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