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

水的可获得性对美国中南部和墨西哥北部的格兰德盆地以及世界上许多其他地区的生存能力来说是一个关键问题。与大多数半干旱地区一样，降水量每年变化很大，这种变化很容易在整个区域的重大环境和经济影响中显现出来。为了应对格兰德盆地和其他地方复杂的水资源分配问题，各机构都在不断演变。在科罗拉多州、新墨西哥州和德克萨斯州，格兰德河流经的三个州，水资源分配制度在保护私有财产权的同时承认同一水域的公共权利，在水资源短缺时重新分配成为一个特别困难的问题。虽然重新分配已经在进行，但如果气候变异性与气候变化的其他方面一起增加，重新分配将加速并成为政策优先事项。在体制和经济已经发生变化的情况下，必须改进水的可获得性和使用模型，以便更好地理解这些相互关联的人类和自然系统的复杂相互作用。这一跨学科研究项目将在一个综合框架内使用物理、生物和人类系统的耦合模型，利用地理信息系统(GIS)对气候变化的后果及其对科罗拉多州格兰德河谷和新墨西哥州大象巴特水库以北的水资源供应的影响进行定量评估。这一综合评估将完全在地理信息系统内运行，以便能够有效地获取和处理所需的空间数据。这项研究中使用的建模框架将是基于栅格的分布式水量平衡方法，其中每个栅格(一个面积单位)将有效地表示一个桶，输入和输出将通过该桶进行路由。栅格结构将允许可变的空间分辨率，一些地区的像元较小，另一些地区的像元较大。综合模式的四个主要组成部分将涉及水权、气候和植被投入、水文反应以及水资源的经济利用和评估。由于水法律和经济学将与物理和生物成分相结合，因此该评估方法将用于评估各种环境政策以及物理和制度变化的经济后果。除了对人类和自然系统的复杂动态提供有价值的新见解外，该项目还将进一步了解基于地理信息系统的灵活比例建模工作如何有效地解决关键的环境和资源管理问题。

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.