H53G-01 INVITED
A Physical Assessment of the Opportunities for Improved Management of the Water Resources of the Bi-National Rio Grande/Rio Bravo Basin
The hydro-physical opportunities for expanding the beneficial uses of the fixed water supply in the Rio Grande/Bravo Basin to better satisfy an array of water management goals are examined. These include making agriculture more resilient to periodic conditions of drought, improving the reliability of supplies to cities and towns, and restoring lost environmental functions in the river system. This is a comprehensive, outcome-neutral, model- based planning exercise performed by some 20 technical, primarily non-governmental institutions from both countries, aimed at proposing strategies that can reduce future conflicts over water throughout the entire basin. The second track consists in generating a set of future water management scenarios that respond to the needs and objectives of the basin stakeholders in each segment and each country. An array of scenarios for improved water management has been developed for the lower Rio Grande/Rio Bravo basin in Texas and the Mexican state of Tamaulipas. Another set under development will focus on the Rio Conchos and the El Paso/Juarez region. Eventually, scenarios will be generated such that will comprehend the entire basin on both sides of the border. These scenarios are the product of consultations with agricultural water districts, governmental organizations and environmental NGOs. They include strategies for reducing the physical losses of water in the system, conservation transfers, improvements in the operations of the Mexican and international reservoirs, improvements in environmental flow conditions, improvements in reliability of water supplies, and drought coping strategies.These scenarios will be evaluated for hydrologic feasibility by the basin-wide model and the gaming exercises. Modeling is necessary to understand how these options will affect the entire system and how they can be crafted to maximize the benefits and avoid unintended or uncompensated effects. The scenarios that have the potential to provide large mutual benefits to all stakeholders in the basin will then be subjected to an economic feasibility analysis, and, finally, a legal and political feasibility analysis. The scenario development, hydrologic modeling, economic and institutional analysis will culminate in the presentation of technical recommendations to policy-makers on both sides of the border on the potential for improved water management in the basin.
H53G-02
Water and Development along the US-Mexico Border
The US-Mexico Border agenda is full of complexities. Water is part of this complex picture and the Lower Rio Grande/Rio Bravo is a case in point. The drought that affected this bintaional region since the early 1990s to very recently, showed that water and development in this geostrategic region have to do with a wide variety of affairs that go grom hydrology to estimation of human impacts. It is concluded that in an agenda so complex like this one, water demonstrates that cooperation is possible. This requires, among different matters, the best scientific knowledge.
H53G-03
Institutions and Societal Impacts of Climate in the Lower Colorado and San Pedro Basins of the U.S.-Mexico Border Region
The U.S. Southwest and Mexico border region feature two prominent river basins, the Colorado and Rio Grande, and ecologically important sub-basins such as the San Pedro. The area within which these transboundary basins lie is characterized by overall aridity and high climatic variability over seasonal to decadal and longer time scales. Throughout human occupation, numerous and diverse strategies for buffering climate impacts have emerged. The most notable response has been an increasingly complex system of institutions and structures designed to buffer water scarcity. The Colorado River Compact, and the laws governing allocation of waters from the Rio Grande River, together with the dams, hydropower generators, canals and other engineered features, represent two of the most complex systems. Drought nevertheless remains a looming specter across much of the binational border region. Institutional mechanisms for responding to drought range from awareness-raising and capacity-building efforts, to implementation of formal drought plans, to storing water to make up for deficits, and water conservation rules that become increasingly stringent as drought intensifies. A number of formal and informal binational institutions operate in the region. Some are venerable, like the century-old International Boundary and Water Commission (IBWC) and its Mexican counterpart the Comision Internacional de Limites y Agua (CILA). Others, like the Border Environment Cooperation Commission and the North American Development Bank, were created in the mid-1990s with the North American Free Trade Agreement. These institutions, both domestic and transnational, operate in a complex binational, bicultural environment with contrasting legal and administrative traditions. Under such constraints, they manage water resources and ecosystems and attempt to improve water and sanitation infrastructure in the context of deep and extended drought. But in spite of their efforts, society and natural habitat along the border remains highly vulnerable to changes driven by high population growth rates, migration and border enforcement, expansion into fire prone wildland-urban interface areas, invasions of exotic ecosystem-altering species, and climate changes. This is especially true for rural populations lacking alternatives to their usual water sources or to alternative means of earning a living when, for example crops fail. The paper will examine the impacts of transborder water- management institutions in the San Pedro and Lower Colorado basins, including the Delta region. In particular, the authors will assess the palpable trend toward (1) more transboundary institutional cooperation (e.g., CRICA, the Colorado River International Conservation Area effort), and (2) more community-based conservation and research efforts (e.g., the University of Arizona, NOAA-supported Climate Assessment for the Southwest project; in conjunction with new projects by the Arizona-based Sonoran Institute and Pronatura in Mexico to do restoration in particular zones, working closely with communities and local groups, such as the Asociacion Ecologica de Usuarios del Rio Hardy y Colorado (AHEURYC). Finally, the paper will seek to identify new climate-related responsibilities and actions that may be needed to respond to likely climatic change.
H53G-04
The San Pedro Basin: A Case Study of US and Mexican Strategies to Connect Science to Societal Needs
The San Pedro River originates in northern Sonora near the town of Cananea and spans the U.S. - Mexico border into southeastern Arizona. The San Pedro Basin and perennial portions of its river support one of the most ecological diverse regions in the world. The regional groundwater aquifer which largely supports perennial flow and the associated riparian ecosystem is the primary water source for a number of communities, and for the Cananea copper mine in Sonora, which produces roughly two to three percent of the world's copper, and Ft. Huachuca, a major military installation in Arizona and the largest employer of southern Arizona. This presentation will discuss strategies and efforts over the past decade on both sides of the border to link hydrological, ecological and social sciences to aid elected officials and decision-makers in managing the basin, its growing population, and the water it so vitally depends upon. The disparate legal, cultural, economic and scientific environments, as well as the unequal degrees of decentralization and regional autonomy on the two sides of the border have resulted in distinct concerns and approaches to water resource management and varying rates of success. In the Sonoran portion of the basin water quality is the primary concern and in Arizona, water quantity is the major concern. The paper will report on sustained binational efforts and constraints encountered by researchers at the University of Arizona's NSF-funded SAHRA project and several NOAA-supported efforts in the basin region.
H53G-05
A Groundwater flow Model of the Colorado River Delta to Support Riparian Habitat Restoration in Northern Mexico
Quantification of groundwater flow dynamics and of the interactions among groundwater, surface water, and riparian vegetation, represent key components in the development of a balanced restoration plan for functional riparian ecosystems. A groundwater model was developed using MODFLOW 2000 to support of riparian restoration along the Colorado River Delta (Mexico: Baja California, Sonora). The Colorado River is widely recognized as one of the most modified and allocated rivers in the United States. For over 50 years flows into the Delta were severely reduced by the requirements of an emergent American West. However, subsequent to discharge pulses associated with the filling of Lake Powell, and the increased precipitation that accompanied ENSO cycles, a semblance of a native riparian habitat has been observed in the Delta since the 1980's (Zamora- Arroyo et al. 2001). The Delta and the riparian ecosystems of the region have since become the focus of a substantial body of multidisciplinary research. The research goal is to understand water table dynamics with particular attention to stream-aquifer interactions and groundwater behavior in the root zone. Groundwater reliant transpiration requirements were quantified for a set of dominant native riparian species using the Riparian ET (RIP-ET) package, an improved MODFLOW evapotranspiration (ET) module. RIP-ET simulates ET using a set of eco-physiologically based curves that more accurately represents individual plant species, reflects habitat complexity, and deals spatially with plant and water table distribution. When used in conjunction with a GIS based postprocessor (RIP-GIS.net), RIP-ET provides the basis for mapping groundwater conditions as they relate to user-specified plant groups. This explicit link between groundwater and plant sustainability is a driver to restoration design and allows for scenario modeling of various hydrologic conditions. Groundwater requirements determined in this research will be used by the international non-profit organizations, The Sonoran Institute and Environmental Defense, to implement large-scale planting activities within the riparian corridor, and to secure instream flow rights for the Colorado River Delta from the Mexican Government.
H53G-06
Identification and Mapping of the Edwards Stratigraphic Sequence in the State of Chihuahua Assisted by ten ArcMap Based Layers
Edwards Formation is a reef limestone that hosts one of the largest aquifers of the State of Texas. In 2004 the United States and Mexico signed an agreement intended to characterize and identify the shared binational underground resources. Texas Water Development Board Report 360 established for the Edwards Aquifer an area of more than 31,000 km2, half of which is in the State of Coahuila, Mexico (the agreement did not include the State of Chihuahua). This led to the idea that Chihuahua may also have hydrologic potential in the Edwards equivalent, where numerous large cavern systems are already recognized (Naica's Sword Cavern, and the Coyame, Nombre de Dios and Bocagrande Caverns). The objective of this study is to establish the existence, in the State of Chihuahua, of the stratigraphic sequence and geohydrologic properties such as faulting, sinkholes, and springs, within the Edwards equivalent. The Consejo de Recursos Minerales geologic map, INEGI's hydrologic study, petroleum, mining and hydrogeology studies of Chihuahua, and many others, constitute the database used. ArcMap is used to define the geologic framework and construct different thematic layers (structural, lithological, hydrological) that would aid in the identification of the stratigraphic sequence. The results show that all the Edwards Stratigraphic Sequence (ESS) exists in Chihuahua; that there are isolated areas of groundwater production in eastern Chihuahua possibly from ESS but this is not well established. Overall the ESS presents an unusual opportunity as a potentially productive aquifer in the State of Chihuahua.