Georgia Water Science Center

USGS Water-Resources Investigations Report 98-4202

Hydrogeology of the Upper Floridan aquifer in the vicinity of the Marine Corps Logistics Base near Albany, Georgia

This report is available online in pdf format (2.8 MB): USGS WRIR 98-4202 (Opens the PDF file in a new window. )

Kristen Bukowski McSwain

U.S. Geological Survey Water-Resources Investigations Report 98-4202, 49 pages (Published 1999)

ABSTRACT

In 1995, the U.S. Navy requested that the U.S. Geological Survey conduct an investigation to describe the hydrogeology of the Upper Floridan aquifer in the vicinity of the Marine Corps Logistics Base, southeast and adjacent to Albany, Georgia. The study area encompasses about 90 square miles in the Dougherty Plain District of the Coastal Plain physiographic province, in Dougherty and Worth Counties—the Marine Corps Logistics Base encompasses about 3,600 acres in the central part of the study area.

The Upper Floridan aquifer is the shallowest, most widely used source of drinking water for domestic use in the Albany area. The hydrogeologic framework of this aquifer was delineated by description of the geologic and hydrogeologic units that compose the aquifer; evaluation of the lithologic and hydrologic heterogeneity of the aquifer; comparison of the geologic and hydrogeologic setting beneath the base with those of the surrounding area; and determination of ground-water-flow directions, and vertical hydraulic conductivities and gradients in the aquifer.

The Upper Floridan aquifer is composed of the SuwanneeLimestone and Ocala Limestone and is divided into an upper and lower water-bearing zone. The aquifer is confined below by the Lisbon Formation and is semi-confined above by a low-permeability clay layer in the undifferentiated overburden. The thickness of the aquifer ranges from about 165 feet in the northeastern part of the study area, to about 325 feet in the southeastern part of the study area. Based on slug tests conducted by a U.S. Navy contractor, the upper water-bearing zone has low horizontal hydraulic conductivity (0.0224 to 2.07 feet per day) and a low vertical hydraulic conductivity (0.0000227 to 0.510 feet per day); the lower water-bearing zone has a horizontal hydraulic conductivity that ranges from 0.0134 to 2.95 feet per day.

Water-level hydrographs of continuously monitored wells on the Marine Corps Logistics Base show excellent correlation between ground-water level and stage of the Flint River. Ground-water-flow direction in the southwestern part of the base generally is southeast to northwest; whereas, in the northeastern part of the base, flow directions generally are east to west, as well as from west to east, thus creating a ground-water low. Groundwater flow in the larger study area generally is east to west towards the Flint River, with a major ground-water-flow path existing from the Pelham Escarpment to the Flint River and a seasonal cone of depression the size of which is dependent upon the magnitude of irrigation pumping during the summer months.

Calculated vertical hydraulic gradients (based upon data from 11 well-cluster sites on the Marine Corps Logistics Base) range from 0.0016 to 0.1770 foot per foot, and generally are highest in the central and eastern parts of the base. The vertical gradient is downward at all wellcluster sites.


CONTENTS

Abstract

Introduction

Purpose and scope

Description of study area and Marine Corps Logistics Base

Well-numbering system

Methods of investigation

Previous investigations

Acknowledgments

Geology

Lisbon Formation

Ocala Limestone

Suwannee Limestone

Undifferentiated overburden

Hydrogeology of the Upper Floridan aquifer

Hydraulic characteristics of the undifferentiated overburden

Hydraulic characteristics of the Upper Floridan aquifer

Ground-water levels

Vertical hydraulic gradients

Ground-water flow in the Upper Floridan aquifer

Upper water-bearing zone

PSC areas 1, 2, 3, and 26

PSC areas 6, 10, 12, 13, and 22

Lower water-bearing zone

Summary

Selected references

Appendixes

Appendix A—Records of wells in the study area

Appendix B—Records of wells drilled by ABB Environmental Services, Inc., on the Marine Corps Logistics Base, Albany, Georgia

Appendix C—Lithologic logs of selected wells drilled in the Upper Floridan aquifer in the vicinity of the Marine Corps Logistics Base near Albany, Georgia

 


REPORT AVAILABILITY

This report is available online in pdf format (2.8 MB): USGS WRIR 98-4202 (Opens the PDF file in a new window. )
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