Part 18

PHYSICAL ENVIRONMENT OF THE GRAND CANYON AND THE SOUTHWEST REGION

Physical, chemical, and comparable aspects of land, water, and atmospheric environments of the Grand Canyon region; interdisciplinary research of the environment in the Grand Canyon region and the Colorado River corridor through the Grand Canyon; and atmospheric and climatological investigations relating to the Colorado River Basin or the American Southwest that embrace the Grand Canyon and the hydrographically defined Lower Colorado River Basin

OVERVIEW. This part includes environmental studies that are not organismically specific and publications that address general environmental issues, including water-quality studies, atmospherics, climatology, and astronomy. Broadly based investigations embracing the Southwest are included here so as to accommodate the hydrographically defined Lower Colorado River Basin. Documents that are Environmental Impact Statements, and similar administrative and guidance documents, are included in PART 13. ADMINISTRATIVE AND MANAGEMENT ISSUES because they usually embrace multiple areas of administrative oversight, are not solely focused on ecological concerns as might be inferred from the title, and may offer a variety of management alternatives. Exceptions are those documents that are specifically biological in perspective. Items that relate to astronomical observations, and the science of astronomy generally, are included in Part 18. Items that relate to the scientific study of ambient noise and the natural soundscape of Grand Canyon are included in Part 18; items that relate specifically to non-environmental management issues of “noise” are relegated to Part 13, or items that relate specifically to sociological responses to these issues are consolidated with PART 14 (SOCIOLOGY, RECREATION, EDUCATION, ECONOMICS, AND RELATED SUBJECTS). Items relating to environmental responsibility particularly by government agencies, such as the use of hybrid electric vehicles, are included in Part 18.