Hydrogeology of the Sells area, Papago Indian Reservation, Arizona.

Abstract

The community of Sells is located in Pima County, Arizona, on the Papago Indian Reservation. The present study was undertaken to determine the water development possibilities of the area. The geology of the Sells area is composed of four basic units: intrusive rock, volcanic rock, cemented Tertiary(?) gravel, and valley fill alluvium. The intrusive rock is essentially dry; the volcanic rock yields small amounts of water to wells; the cemented Tertiary(?) gravel yields small amounts of water to wells (locally saline); and the valley fill alluvium yields from 10 gpm to greater than 200 gpm, depending on local thickness and permeability. Data from geophysical investigations indicate that Sells probably sets on a volcanic plateau, terminated east and west by boundary faults in the basement rocks. The valley fill alluvium is thickest and most permeable in the Baboquivari and Quijotoa valleys east and west of Sells, respectively. Well yields in the thick valley fill alluvium to the west generally exceed 200 gpm, and transmissivity values range from 50,000 to 200,000 gpd/ft. A similar situation probably exists east of Sells; however, more subsurface and pump-test data are needed to evaluate accurately the alluvial aquifer there.