U.S. Geological Survey U.S. Geological Survey Open-File Report 00-488 The Setting

The Middle Rio Grande Basin study is a 6-year effort by the U.S. Geological Survey and partner agencies to improve knowledge and understanding of the hydrology, geology, landforms, and land-use characteristics of this region of central New Mexico. The significance of these investigations stems from the geography and demography of this region, and from its features common to populated areas across the southwestern United States. The southwest’s moderate climate, expanding employment opportunities, and abundant recreation activities have stimulated in-migra-tion and population growth. However, these desert environments contain fragile landscapes and finite water resources that limit growth. Making room for more people poses difficult choices among competing options for undeveloped land. In today’s world, those land-use choices are increasingly restricted by recognition of natural hazard potential (flood, subsidence, earthquakes, volcanic eruption, wildfire, etc.), encroachment on wildlife habitat, and the growing demands for construction materials and space to improve the urban infrastructure. Water, the most critical factor for the prosperity of the Middle Rio Grande Basin, remains the key focus of our studies. Surface flow of the Rio Grande was fully appropriated in the early 1900’s to meet needs of irrigation agriculture, Indian tribal lands, and required deliveries to Texas and Mexico. Most residential, industrial, and municipal water needs in the basin today are met by extraction of ground water. Our studies have explored hydrogeological conditions in the urban areas where extraction is currently occurring, and have used diverse methods to infer these condition