Geology topics

Research about Soquel-Aptos area

Source-linked reports with geographic coverage including Soquel-Aptos area.

3 recordsLinked to original sources

USGS1981

Approximate ground-water-level contours, April 1981, for the Soquel-Aptos area, Santa Cruz County, California

Ground-water levels in selected wells were measured in the Soquel-Aptos, Calif., area in April 1981. On the basis of these measurements approximate ground-water-level contours were constructed. The general direction of ground-water movement in the Soquell-Aptos area is from the ridges in the northern part of the area, toward the adjacent canyons, and then southward toward the ocean. Ground-water pumping has caused ground-water levels to decline below sea level in the Capitola area, in the area just to the west and northwest of aptos, and in isolated local areas southwest of Rio Del Mar. Ground-water levels in the northern part of the area away from the seacoast have not declined much over time. (USGS)

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USGS1980

Seawater intrusion and potential yield of aquifers in the Soquel-Aptos area, Santa Cruz County, California

Seawater has intruded the Purisima Formation in the interval 0-100 feet below sea level in the Soquel-Aptos area. It occurs in the central part of the area and extends inland about half a mile. The potential yields of the two principal aquifers in the Soquel-Aptos area are 4,400 acre-feet per year from the Purisima Formation and 1,500 acre-feet per year from the Aromas Sand. Pumping from the Purisima Formation, averaging about 5,400 acre-feet per year since 1970, has caused water levels along the coast to decline below sea level and has allowed seawater to enter the aquifer. Seawater intrusion and ground-water storage could be monitored in all depth zones by expanding the observation-well network to include a number of shallow wells, one deep well inland from the coast, and three deep wells along the coast.

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USGS1967

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

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.

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