Water Resources Management at the Mexican Boundary with the USA Javier Aparicio Mexican Institute of Water Technology Ministry of Environment and Natural Resources México

Instituto Mexicano de Tecnología del Agua Deals primarily with water related issues in order to help reaching the sustainable development for the country, by conducting research and technological development (R&D) in collaboration with public and private institutions, universities and other research centers such as NGO’s.

Four main research divisions Hydrology Water Quality Irrigation and drainage Hydraulics Professional development

In the near future, it is expected that conflicts between neighbour municipalities, counties and even countries will be related to water. To avoid that, it is necessary to create transboundary water use policies in which all the parts involved agree to make the efficient use and proper long and short term planning.

3000 km 14 cities 10.6 million in % US, 45% México 14 million in 2020 México/USA Boundary

Watersheds México/USA N WYOMING COLORADO U T A H CALIFORNIA ARIZONA NUEVO MEXICO TEXAS SONORA CHIHUAHUA COAHUILA DURANGO NUEVO LEON GULF OF MEXICO OCEAN PACIFIC NEVADA 1944 Treaty BRAVO/GRANDE RIVER WATERSHED TOTAL = 444,560 km 2 U S A = 229,798 km 2 MEXICO = 214,762 km 2 COLORADO RIVER WATERSHED TOTAL = 634,840 km 2 U S A = 631,000 km 2 MEXICO = 3,840 km 2 TIJUANA RIVER WATERSHED TOTAL = 4,424 km 2 U S A = 1,221 km 2 MEXICO = 3,203 km 2

Colorado River 634,840 km 2 7 USA States: Colorado River compact 2 Mexican States Gulf of California or Gulf of Cortés

Colorado River flows Droughts are shared Hoover Dam Glen Canyon Dam One of the most exploited rivers in the world: 20,700  5,200 hm 3 in 100 years 1,850.2 hm 3 /yr to México; 2097 when there are excedents 1000 acre-ft=1.233 hm 3 Nearly 100% of water is used for agriculture & urban supply

Droughts, Colorado River extraordinary droughtIn case of extraordinary drought or a serious accident in the irrigation system in the USA which would prevent delivering the guaranteed volume, the assigned volumes to Mexico would be reduced in the same proportion as the consumption reduction in the USA.

Colorado River: Salinity Salinity not in the Treaty 1961: Increase in salinity above 2,500 ppm IBWC Negotiations: Act 242 (1973) Bypass channel Salinity < Imperial Dam +121 ppm; higher at San Luis Imperial Valley Mexicali Valley Imperial dam Morelos dam San Luis Río Colorado

Colorado River: Salinity Source: CILA San Luis Morelos Imperial

Delta Region One of the biggest desert estuaries in the world ha Highly diversified collection of plants, birds and marine species Dry and dead system of small wetlands and salt marshes Highly salinized desert Floods, surplus, return flows ha restoration Significant wetland ecosystem in SW USA and NW México in danger 70´s and 80´sLast 2 decades Before 1930

Delta Region Significant population increase Pressure over land, water and other resources Permanent flows vs. Interim Surplus Criteria Legal issues Near future SEA OF CORTÉS LAGUNA SALADA SANTA CLARA SLOUGH ALTAR DESERT IMPERIAL VALLEY SALTON SEA MEXICALI VALLEY

Actions Establishment of the Alto Golfo de California y Delta del Río Colorado Biosphere Reserve Wastewater treatment plants in Border Cities and recycling Efficient water use programs Legal framework modifications: New National Water Law –Ecological priority –Incentives to water consumption reduction Program Border XXI –Public participation –Capacity building –Interinstitutional cooperation Binational workgroups for R&D

Bravo/Grande River Boundary: 2,001 km Total runoff : 11,000 hm 3 /year Total storage capacity: 23,000 hm Treaty: Fort Quitman to mouth

Agricultural use, Bravo Basin

Bravo/Grande River USA Conchos Salado Fort Quitman Gulf of México Gauged rivers Bravo/Grande 1/3 US 2/3 México 74 hm 3 /yr at Juárez (1906) hm 3 /yr in 5-yr cycles : 26 periods Cycle 25 completed in 2001 Deficit in cycle 26 Droughts are not shared Falcón Dam 1/2 La Amistad Dam

Droughts, Bravo/Grande River extraordinary droughtIn case of extraordinary drought or a serious accident in the Mexican hydraulic system which would prevent Mexico to deliver such volume, any undelivered volume at the end of the 5-year period would be distributed in the following period with water from the same tributaries.

Water quality, Bravo/Grande

Actions Wastewater treatment plants in Border Cities Efficient water use programs Binational workgroups for R&D Río Bravo water distribution rule Irrigation modernization and technology improvement in Conchos River Basin

Río Bravo water distribution rule Define Extraordinary drought Distribute US assignment among Mexican tributaries Propose to subject deliveries to US with the same deficit restrictions as Mexican irrigation assignments Consensus building on distribution rule among users

Modernization and technology improvement, Conchos Basin Channels and network lining Control structures and wells rehabilitation Low pressure, drip and sprinkler systems Land leveling Real-time irrigation forecast Efficiency: 33  55% Recover 396 hm 3 /yr in 4 years , US $150 million NADBank Fund and Federal investment

San Diego/Tijuana San Diego Tijuana Water import90%95% Consumption, l/person/day Density, persons/km Population in 2010, millions3.3 (60%) 2.2 (40%)

Water quality, Tijuana 32 hm 3 of treated residual water with organic contaminants to the Pacific Ocean Industrial residuals discharges 8 hm 3 /year. Volumes generated are higher than plant capacity: serious pollution problems

Transboundary aquifers Mapa de la región 1. Mexicali Valley 2. Sonoita River 3. Santa Cruz River 4. San Pedro River 5. Conejos-Médano aquifer 6. Juárez Valley 7. La Amistad observation wells N Chihuahua Coahuila N. León Tamaulipas Sonora Baja California Nte Mexicali: Recharge/ exploitation: 150/ 102 hm 3 ; All-American channel lining? Juárez Valley: Drawdowns > 45 m; quality problems

Boundary with Guatemala Grijalva-Usumacinta and Suchiate Grijalva-Usumacinta: 44,885 km 2 in Guatemala, 83,213 km 2 in México 1961: IBWC Treaty: 1990, still not effective Mapa

Boundary with Belize Hondo River Binational Comission on Boundaries and Cooperation: 1991 No major water consumption nor extensive groundwater exploitation Water quality degradation

Conclusions México and USA share a politically, sociologically and hydrologically complex and rapidly evolving boundary International agreements have been the result of long negotiations made in good will and with the benefits of both countries in mind: examples by other Countries

Conclusions Population growth and comprehensive water use: careful joint water resources management in the boundaries Sustainable development binational plans, including Colorado Delta ecology Integrated international hydrometeorological information system along the Border Efficient water use programs Binational R&D programs