Subsurface Geology of the Easternmost Phoenix Basin, Arizona: Implications for Groundwater Flow

Water is the lifeblood of the Southwest, and much of the region’s water resources occur in the large sedimentary basins that underlie the modern valleys of the Basin and Range Province. One such basin encompasses most of the city of Phoenix in central Arizona (Figure 1). This subsurface basin, herein called the Phoenix basin, underlies the western part of the Salt River Valley; many hydrologists use the term western Salt River Valley synonymously with the Phoenix basin. In the geologic literature, valley refers to a modern physiographic feature, whereas basin refers to a subsurface feature. The Phoenix basin is a major source of groundwater for the large growing metropolitan area, and in some parts of the basin the groundwater contains municipal and industrial contaminants. To understand the directions and flow rates of the groundwater requires knowledge of the geometry of the basin, the internal stratigraphic of the basin-filling units, and the ability of these units to hold and transmit groundwater. It is within this context that the present study was undertaken.Documents in the AZGS Document Repository collection are made available by the Arizona Geological Survey (AZGS) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact azgs-info@email.arizona.edu