The State of the Aquifers The Transboundary Santa Cruz and San Pedro River basins Prescott Vandervoet Christopher Scott Sharon Megdal The University of Arizona 2010 AHS Annual Symposium: "Dryland Hydrology: Global Challenges, Local Solutions Co-hosted with the International Association of Hydrogeologists 9/2/10 AHS Annual Symposium 1
Overview What is the status of water resources and management of the transboundary Santa Cruz and San Pedro aquifers? What factors determine the status? Natural Environment Use (pumping) Governance Water quality 9/2/10 AHS Annual Symposium 2
Variability Monthly Mean Discharge (cfs) 1000 900 800 700 600 500 400 300 200 100 0 July April January October 800 700 Nogales Gage, USGS 600 500 400 300 200 100 0 Palominas Gage, USGS July April January October 9/2/10 AHS Annual Symposium 3
350000 300000 250000 200000 150000 100000 50000 Nogales, Sonora Santa Cruz, Sonora Cananea, Sonora Naco, Sonora Population Drivers of Future Demand Continued growth (projections from 2005) 0 2005 2007 2009 2011 2013 2015 2017 2019 2021 2023 2025 2027 2029 Municipio-level population, CONAPO, 2010 200,000 180,000 160,000 140000 140,000 120000 100000 80000 60000 Cochise County Santa Cruz County Sierra Vista 120,000 100,000 80,000 60,000 Cochise County Santa Cruz County Sierra Vista Nogales 40000 Nogales, AZ 40,000 20000 20,000 0 0 1950 1960 1970 1980 1990 2000 2010 2012 2014 2016 2018 2020 2022 2024 2026 2028 2030 US Census Bureau, 2010 AZ Dept. of Commerce, 2010 9/2/10 AHS Annual Symposium 4
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Water Use Demand and changing sectoral water use 25000 25000 20000 20000 15000 15000 Municipal 10000 10000 Industrial Agricultural 5000 5000 0 1985 1990 1995 2000 2005 0 2000 2005 2010 2020 2030 Af/yr in Santa Cruz AMA, ADWR Af/yr in Sierra Vista subwatershed, ADWR 9/2/10 AHS Annual Symposium 6
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Drivers of future scenarios Demand and changing sectoral water use Water use in Santa Cruz basin, Mexico (not including Nogales Wash) Scott et al., in review 9/2/10 AHS Annual Symposium 8
Groundwater Balance Recharge and pumping Acre-Feet Santa Cruz Million Cubic Meters Acre-Feet San Pedro Million Cubic Meters Supply 39,600 142,900 48.8-176 18,000 22.2 US Demand 21,105 26.0 16,920 20.9 Supply?????? 33,200 41.0 Mex Demand 23300 28.7 23,595 29.1 Sources: USPP 2007 321 Report, ADWR, Conagua Estudios de Disponibilidad 9/2/10 AHS Annual Symposium 9
Regional use/availability breakdown water withdrawn by basin/nation per year San Pedro Basin Santa Cruz Basin 16920 AF 20.9 MCM 23595 AF 29.1 MCM 21105 AF 25.0 MCM 23300 AF 28.7 MCM 309 AF 0.38 MCM Santa Cruz, Arizona Nogales Wash, Sonora Santa Cruz, Sonora San Pedro, Sonora San Pedro, Arizona Sources: ADWR, CONAGUA, USPP 9/2/10 AHS Annual Symposium 10
Upper Santa Cruz Groundwater Balance and SCAMA tasked with maintaining sustainable yield Nogales, Sonora has at times been forced to purchase water from Nogales, AZ Upper San Pedro In 2004 local actors charged with restoring and maintaining sustainable yield in Arizona Drawdowns noted of up to 3 meters between 1995-2000 along river channel in Mexico Management 9/2/10 AHS Annual Symposium 11
Management Important to recognize differing nature of water management How do unique management regimes interact across the border within shared basins? 9/2/10 AHS Annual Symposium 12
Differing management regimes Source: Milman and Scott, 2010 9/2/10 AHS Annual Symposium 13
Description of Management Responsibilities for Agencies within Basins Arizona Arizona Department of Water Resources Administers and enforces State groundwater code US Geological Survey collects information needed to understand water resources. US Bureau of Land Management manages the nation's public lands and resources. balancing recreational, commercial, scientific and cultural interests and strives for long-term protection of renewable and nonrenewable resources. Utilities Sonora National Water Commission Administer and preserve national waters to achieve their sustainable use. State Water Commission Promote the coordinated development and efficiency of water resources in Sonora. Municipal Utilities Provisioning and supply to urban users 9/2/10 AHS Annual Symposium 14
Binational Cooperation and Initiatives Arizona Mexico Commission State-level work group since 1959 with 13 binational committees (including water) Border Environmental Cooperation Commission Preserve, Protect, Enhance human health and environment along border Transboundary Aquifer Assessment Program Transboundary Aquifer Assessment Program (TAAP) U.S. Federal Law 109-448 Secretary of Interior to systematically assess priority transboundary aquifers Santa Cruz and San Pedro identified on Arizona/Sonora border Approval for appropriation of 50 million dollars over 10-year period Collaborative project between USGS and Water Resource Centers within Texas, New Mexico, and Arizona 9/2/10 AHS Annual Symposium 15
Transboundary Aquifer Assessment Program Goals and Achievements Formation of binational work group to prioritize assessment activities Engagement of stakeholders throughout basins and administrative areas. Interaction at regional and binationally-focused meetings regarding groundwater issues. 9/2/10 AHS Annual Symposium 16
Transboundary Aquifer Assessment Program Goals and Achievements Design of work plans for assessment of shared groundwater resource Beginning stages of binationally coordinated aquifer studies in Mexico Collaborators include: ADWR, CONAGUA, CEA- Sonora, USPP, FOSCR, among others. 9/2/10 AHS Annual Symposium 17
Contacts and Webpage Prescott Vandervoet plv@email.arizona.edu Christopher Scott cascott@email.arizona.edu Sharon Megdal smegdal@cals.arizona.edu James Callegary jcallega@usgs.gov www.cals.arizona.edu/azwater/taap 9/2/10 AHS Annual Symposium 18