South Mesa | Site Hydrogeology

The site is located within the East Salt River Valley Sub-Basin of the Salt River Basin. The basin is in a broad alluvial filled valley overlying crystalline and extrusive rock. The sedimentary deposits are divided into three stratigraphic units: the upper unit, middle unit, and the lower unit. These units consist of primarily unconsolidated to semi-consolidated deposits of gravels, sands, silts, and clays. The middle unit is the principal water bearing unit in the site area.