Geohydrologic reconnaissance of the Soquel-Aptos area, Santa Cruz County, California

Open-File Report 67-3
Prepared in cooperation with the Soquel Creek County [Watershed District?], the City of Santa Cruz, and the county of Santa Cruz
By:  and 



This report summarizes existing knowledge on the geohydrology of the Soquel-Aptos area, near, and including the eastern part, of Santa Cruz, California, and outlines work necessary for making a complete appraisal of the water resources of the area.

The area is underlain mostly by marine and continental sedimentary deposits of Tertiary and Quaternary age. A small section in the northeastern part of the area on the eastern side of the San Andreas fault is underlain by sedimentary and metamorphic rocks of Cretaceous or older age. Quartz diorite, probably of Cretaceous age, underlies a considerable part of the area, but crops out only in small exposures along canyon bottom south of the Zayante fault.

The Soquel-Aptos area consists of two main structural blocks?one, downthrown on the northeast side of the Zayante fault; the other, upthrown on the southwest side of the fault. The main water-bearing formations in the southwestern structural block are the Santa Margarita and Purisima Formations. The Purisima, the most widespread of these units in this area, contains water under water-table and artesian conditions and furnishes water to most wells. The water-bearing character of the rocks in the northern structural block is unknown.

Presently available geohydrologic data are too limited for detailed evaluation of the ground-water potential in the Soquel-Aptos area. Work needed for a detailed evaluation includes: (1) Geophysical exploration and test drilling at selected locations, (2) pumping tests of selected existing wells and possibly of specially drilled test wells, (3) study and reconnaissance measurements of spring and streamflow, (4) chemical analysis of water samples from selected wells, and (5) establishment of a program for monitoring water quality and water levels in key wells.

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Geohydrologic reconnaissance of the Soquel-Aptos area, Santa Cruz County, California
Series title Open-File Report
Series number 67-3
DOI 10.3133/ofr673
Year Published 1967
Language English
Publisher U.S. geological Survey
Publisher location Menlo Park, CA
Contributing office(s) California Water Science Center
Description Report: 58 p.; 1 Figure: 27.84 x 32.26 inches
Country United States
State California
County Santa Cruz County
Other Geospatial Soquel-Aptos area
Google Analytic Metrics Metrics page