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Geohydrology of the Aguirre and Pozo Hondo areas, southern Puerto Rico

Water-Resources Investigations Report 91-4124

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Abstract

The subsurface geology of the Aguirre and Pozo Hondo areas in southern Puerto Rico is primarily a fractured igneous volcanic rock (andesite) with three distinct zones: regolith, transition zone, and bedrock. Alluvial deposits are present, locally in each area, as well as weathered low- grade metamorphosed volcanics with a schistose texture and a vertical plane of foliation. A thin, water-table aquifer exists in the study areas. Ground water in this aquifer occurs primarily in the regolith and transition zone. The depth to the water table ranges from less than 1 foot to 75 feet below land surface. Ground- water flow out of the study areas is to the south into the southern coastal plain. The results of 2 multiple-well aquifer tests and 21 single-well slug injection and removal tests indicate that transmissivities range from 175 to 5,700 feet squared per day; hydraulic conductivities, from 0.02 to 160 feet per day; and storage coefficients from 0.02 to 0.2. The ground water in the study areas is of the calcium carbonate type. With the exception of dissolved solids, which were as much as 1,110 milligrams per liter, concentrations of common constituents in ground water did not exceed the U.S. Environmental Protection Agency's drinking water criteria.

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Geohydrology of the Aguirre and Pozo Hondo areas, southern Puerto Rico
Series title:
Water-Resources Investigations Report
Series number:
91-4124
Edition:
-
Year Published:
1992
Language:
ENGLISH
Publisher:
U.S. Geological Survey ; Books and Open-File Reports Section [distributor],
Description:
vi, 43 p. :ill. ;28 cm.