Water Resources Project
Title: Sustainable water resources for irrigated agriculture in a desert river basin facing drought and competing demands: From characterization to solutions
Rationale. The Middle Rio Grande basin from Elephant Butte reservoir to the entrance of the Rio Conchos from Mexico is a highly managed system with competing demands. Over the past 100 years, the Middle Rio Grande has been the primary source of water for irrigated agriculture in the region. However, due to increasingly frequent and severe periods of drought and growing demand, the river alone no longer meets regional water needs, leading to increased groundwater extraction and dropping water tables. A better understanding of the conjunctive water system, the competing demands for water, and a changing climate, is prerequisite to identifying alternative futures that will result in sustainable water supplies for irrigated agriculture, not only locally but regionally in the Southwest. Water resources sustainability for agriculture faces a number of drivers of change, including: 1) agricultural practices and trends, especially increasing production of perennial tree crops (pecans), and greater reliance on groundwater of marginal quality for irrigation; 2) urban growth and per capita usage, impacting land use and water demand and quality; 3) climate change that is impacting both water supply (especially reduced snowpack in the headwaters) and demand (through increasing temperatures and greater evapotranspiration demand); and 4) growing demand for environmental services such as riparian habitat for endangered species and environmental flows. The core question is how can water be managed so that the three competing sectors—agricultural, urban, and environmental—can simultaneously thrive in a shared water system challenged by climate change, dwindling supply, and competing demands? This region exemplifies an important category of agricultural water sustainability challenges: it is an arid/semi-arid river basin relying on conjunctive use of surface water and regional groundwater in order to sustain irrigated agriculture. Significant areas of the southwestern U.S. fall into this category, as do other intensively used desert-river basins around the world. Thus, the Middle Rio Grande basin is a compelling site to explore solutions for long-term water sustainability for agriculture in relationship to urban and ecosystems uses.
Hypothesis and Goals. Our hypothesis is that, in spite of dwindling supplies, competing demands, and changing climate, sufficient water supplies can be achieved and managed to sustain irrigated agriculture in the desert Southwest through innovative technologies, collaborative decision making, and improved policies. Our overall goals are to: 1) characterize key components of this complex system including: a) changing climate as a key driver of water supply and demand; b) the hydrological connections between surface and groundwater; and c) the dynamic competing demands for water in a bi-national setting with a large metropolitan area (El Paso/Ciudad Juarez) sandwiched between irrigated agriculture both upstream and downstream, and surrounded by the Chihuahuan desert; and 2) use our improved characterization and understanding of the system to develop and test technologies and policies that will: a) augment useable water supplies; b) optimize allocation of water to competing demands; and/or c) improve water use efficiency, conservation, and environmental impacts.
Objectives: 1) Model medium to long-term climate change, and short-term climate variability for the region. 2) Improve and integrate existing hydrology models, including upstream demands and flows, groundwater supplies and demands, surface-subsurface interactions, and water quality dynamics. 3) Recruit a robust set of stakeholders, representing the range of interests in the basin, and obtain their effective participation in modeling activities and reflection/synthesis meetings. 4) Develop a spatially explicit, dynamic systems model with a front interface of variables and outputs that can be used in participatory stakeholder meetings. (This will require integration of biophysical, economic, and social dimensions). 5) With stakeholders, identify and formulate technologies and policies that can potentially: a) augment water supplies available to agriculture; b) optimize water allocations among competing demands; and c) improve water use efficiency, conservation, and environmental impacts. 6) Disseminate selected agricultural technologies through traditional extension methods and outreach campaigns. 7) Strengthen our capacity to train water professionals by developing and implementing a problem-based graduate education course to be offered across our respective institutions; engaging graduate students in our participatory modeling approach; and develop a strong experiential learning component to environmental science training at UTEP.
Approach. Our approach will have three characteristics: (1) a dynamic systems approach to water quantity and quality at the regional scale, with interacting subcomponents (e.g., agriculture, urban, and ecosystems; surface and subsurface; climate); (2) a stakeholder-participatory approach to future scenario development, testing, and modeling; (3) integration of solutions within the participatory process and dissemination by extension and participant-leaders. Our approach to participatory modeling is particularly innovative, since it will promote the development, diffusion, and use of water quality and quantity solutions. While researcher-based modeling of the basin is vital, stakeholder participation in model scenario design, outcomes, and adaptive solutions is crucial in three ways (1) agricultural, urban, and ecosystem-advocacy water users develop a dialogue around shared understandings of water futures, even as they deepen understanding of their own needs; (2) participatory modeling diminishes barriers presented by international and other jurisdictional boundaries; and (3) agricultural users develop increased “buy-in” for key challenges (such as climate stresses) that makes innovative management and technological solutions more appealing. We see the latter as crucial in an effective extension initiative to improve water quality and efficiency. By engaging stakeholders and involving them directly in the identification and testing of solutions, our aim is that solution technologies and policies will be more readily adopted. Examples of “solution” technologies that we will consider include: storm water capture and retention for irrigation use; improved treatment and reuse of wastewater; improved treatment of agricultural return flows from flood irrigation; alternative crop mixes; improved irrigation methods, such as drip irrigation; improved irrigation scheduling; improved soil and land management to reduce salinization; and others. Important policy solutions include water pricing, water trading, re-allocation of water rights and others. Our team includes a robust suite of disciplines and experiences that range across biophysical, economic, policy, and social sciences.
Expected Outcomes and Potential Impacts. (1) Our participatory approach will result in an improved understanding for both stakeholders and researchers of the drivers of water supply and demand and solutions that are acceptable and workable at a local and regional level. (2) An enduring systems dynamic model that can be consulted, improved, and recalibrated. (3) Transferrable approaches and solutions aimed at alternative futures for arid/semi-arid basins in which irrigated agriculture faces challenges from climate change, competing demands, and salinization. 4) A cadre of well-trained water professionals, the majority of whom will be Hispanic. 5) Strengthening of our institutions to train and develop water professionals.