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

对于美国中南部和墨西哥北部的里约热内卢大盆地以及世界上许多其他地区的生存能力来说，水的可用性是一个关键问题。与大多数半干旱地区一样，降水每年变化很大，这种变化在整个地区的重大环境和经济影响中很明显。为了应对大盆地和其他地区复杂的水资源分配问题，相关机构也在不断发展。在科罗拉多、新墨西哥和德克萨斯这三个格兰德河流经的州，水资源分配制度保护私有产权的同时也承认对同一水资源的公共权利，在水资源短缺时重新分配水资源成为一个特别困难的问题。虽然重新分配已经在进行，但如果气候变率与气候变化的其他方面相关联而增加，它将加速并成为一项政策重点。由于体制和经济已经发生变化，必须改进水的可得性和利用模式，以便更好地了解这些相互联系的人类和自然系统之间复杂的相互作用。这个跨学科的研究项目将利用地理信息系统（GIS）在一个综合框架中使用耦合的物理、生物和人类系统模型，以便对气候变化的后果及其对科罗拉多州里约热内卢格兰德河谷和新墨西哥州象顶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进行，以便有效地获取和处理所需的空间数据。本研究中使用的建模框架将是基于栅格的分布式水平衡方法，其中每个栅格（一个面积单位）将有效地代表一个桶，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，在一些区域使用较小的单元，在其他区域使用较大的单元。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价。由于水法和经济学将与物理和生物组成部分相结合，因此将使用评估方法来评价各种环境政策以及物理和体制变化的经济后果。除了为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gis的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.