The Impact of Climate Change on the Upper Rio Grande Basin

Author: Ed Hamlyn

Dissertation School: University of Texas at El Paso

Abstract:

The purpose of the research is to determine the potential impact of global climate change on the upper Rio Grande basin. Geographically, the study encompasses the Rio Grande basin upstream of its confluence with the Rio Conchos. The basin is estimated to be the home of more than 3.1 million people. Included in this basin are the cities of Alamosa, Colorado; Los Alamos, Santa Fe, Albuquerque and Las Cruces, New Mexico; El Paso, Texas; and Cd. Juárez, Chihuahua. Temporally, the investigation extends to an 80-year time horizon, broken down into 20-year increments. Impacts to be analyzed consist of temporal and quantitative variations in surface water flows. A parallel aspect of the impact study will be changes in water demand based on population growth.

Initially, a basin-wide water balance will be developed based on inputs from precipitation, storage, evapotranspiration, diversions and return flows sufficient to predict stream flow at critical reaches of the river. This information will be drawn from existing models.

One or more General Circulation Models (GCM) will be selected and applied to the basin. GCMs are three-dimensional models that predict climate on a regional, seasonal and annual basis. The selection specific GCMs to use will be based on a comparison of the models’ predicted temperature and precipitation values relative to current climatic conditions in the basin. Selected GCMs will be used to "bracket" the extent of probable temperature and precipitation change.

The third task will be a sensitivity analysis based on hypothetical variations in climatic conditions. The purpose of this part of the investigation is to identify areas where climatic change may have the greatest impact.

The fourth task will be to evaluate water demand based on anticipated population change. Initially, population will be projected using estimates prepared by the states and localities within the basin. Population will be further projected based on trends in fertility and mortality, and based on assumptions regarding migration dynamics. Nested within this evaluation will be an assessment of the age stability of populations within sub-regions to provide a measure of their relative propensity for growth due to natural increase.

The fifth task will be an evaluation of the adaptability of the water management system. A review of the existing legal framework of water allocation will be made, noting categories of senior and junior water rights holders. This will enable an assessment of the types of uses and sub-regions likely to experience the greatest impacts if net surface flows diminish.

The eligibility criteria of the HUD Office of University Partnerships are met in terms of both my acceptance into candidacy in the ESE doctoral program and my successful defense of my dissertation proposal. My research topic addresses the HUD principal objective of, "regionalism and smart growth." This objective embodies the concept of sustainable growth, which is particularly relevant in an environment of diminishing water resources. By studying the entire upper Rio Grande basin, different impacts of potential climate change can be better understood and form a basis of regional problem solving.

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