Quantitative Assessment of the Economic and Institutional Impacts of Climate Change on the Upper Rio Grande Valley Using an Integrated Geographic Information System Framework

University Of New Mexico, Albuquerque NM

Investigators

Abstract

Water availability is a critical issue to the viability of the Rio Grande Basin of the south central U.S. and northern Mexico as well as to many other regions in the world. As in most semi-arid regions, precipitation is highly variable from year to year, and such variability is readily apparent in significant environmental and economic impacts throughout the region. Institutions have evolved to cope with complex water-allocation issues in the Rio Grande Basin and elsewhere. Within Colorado, New Mexico, and Texas, the three states through which the Rio Grande flows, the water-allocation system protects private-property rights while recognizing public rights in the same water, reallocation in times of shortage becomes an especially difficult issue. Although reallocation already is occurring, it will accelerate and become a policy priority if climate variability increases in association with other facets of climate change. With institutional and economic changes already occurring, models of water availability and use must be refined in order to better understand the complex interdynamics of these linked human and natural systems. This interdisciplinary research project will use coupled physical, biological, and human system models in an integrated framework employing a geographic information system (GIS) in order to provide a quantitative assessment of the consequences of climate change and its impacts on water availability in the Rio Grande Valley in Colorado and New Mexico north of Elephant Butte Reservoir. This integrated assessment will operate entirely within a GIS to permit efficient access to and processing of the required spatial data. The modeling framework to be used in this study will be a raster-based distributed water-balance approach in which each raster (an areal unit) will effectively represent a bucket through which inputs and outputs will be routed. The raster structure will permit variable spatial resolution, with smaller cells in some locales and larger cells in others. The four major linked components of the integrated model will deal with water rights, climatologic and vegetation inputs, hydrologic response, and economic use and valuation of water resources. Because water law and economics will be integrated with physical and biological components, the assessment method will be used to evaluate the economic consequences of different kinds of environmental policies as well as physical and institutional changes. In addition to providing valuable new insights into the complex dynamics of human and natural systems, the project also will further knowledge regarding how effectively scale-flexible GIS-based modeling efforts can address critical environmental and resource-management problems.