U.S. Department of the Interior a U.S. Geological Survey

U.S. Geological Survey

Programs in Georgia

COASTAL PLAIN

PIEDMONT

BLUE RIDGE

VALLEY AND RIDGE

AND

APPALACHIAN

PLATEAUS

COASTAL PLAIN AQUIFERS

 Floridan aquifer system 

 Claiborne, Clayton, and Providence aquifers

 Cretaceous aquifer systems

PIEDMONT AND BLUE RIDGE AQUIFERS

 Crystalline-rock aquifers

VALLEY AND RIDGE AND APPALACHIAN

 PLATEAUS AQUIFERS

 Paleozoic rock aquifer

 Not a principal aquifer

EXPLANATION

Chattahoochee R

Withlacoochee R

Altamaha R

Satilla R

Ocmulgee R

Oconee R

Suwannee

Alapaha R

F lint R

Savannah R

Ogeechee R

Coosa

Eto wah

Oostanaula

Chattahoochee R

Withlacoochee R

Altamaha R

Satilla R

Ocmulgee R

Oconee R

Suwannee

Alapaha R

F lint R

Savannah R

Ogeechee R

Coosa

Eto wah

Oostanaula

9

7

5

3

1

EXPLANATION

Average annual 

 discharge, in million 

 gallons per minute

Georgia has a rich natural endowment 

in its land, water, biological, and mineral 

resources. The material needs of society 

are ultimately met by these resources. The 

U.S. Geological Survey (USGS) provides 

unbiased earth-science information and 

research that are vital for society to use 

wisely, care for, and live safely within our 

natural environment. This Fact Sheet 

describes a few of the many USGS activities in Georgia.

USGS work in Georgia is pursued in 

partnership with many local, State, and 

other Federal agencies. Examples of these 

partners are the city of Brunswick; the 

Albany Water, Gas, and Light Commission; Gwinnett County; the Georgia Environmental Protection Division; the U.S. 

Army Corps of Engineers; the U.S. 

Department of Energy; and the University 

System of Georgia. 

Supply and Use of Earth 

Resources

Georgia has an abundant supply of 

freshwater, which includes an extensive 

system of rivers, several productive aquifers, and average annual precipitation of 

50 inches (figs. 1, 2). However, population growth and economic development 

have led to competing demands for water 

resources in some areas. In addition, 

surface-water supplies can become critically low during periods of drought, such 

as those Georgia experienced from 1980 

to 1982 and from 1985 to 1989, when 

streamflows in northern Georgia were at 

or near the lowest of this century. The 

USGS responded by making hundreds of 

nonroutine, low-flow discharge measurements and documented the droughts with 

special reports. Drought investigations 

supplement streamflow records routinely 

collected by the USGS in Georgia since 

the early 1890’s and provide the fundamental basis for predictions of low-flow 

discharges. 

Index of Subjects

Supply and Use of Earth Resources

Quality of Water Resources

Natural Hazards

Earth Resources Information

Figure 1. Area of use of principal aquifers and generalized diagram showing aquifers and 

physiographic provinces in Georgia.

Figure 2. Average annual discharge of 

major streams in Georgia.

Ground-water supplies have become 

limited in some areas where demand 

exceeds natural recharge rates. Since 

pumping began in the late 1800’s, the 

ground-water level in the Floridan aquifer 

system at Brunswick has declined as much 

as 65 feet. This water-level decline has 

allowed saline water to migrate upward in 

some areas of the aquifer system. The 

USGS monitors ground-water levels and 

quality in Georgia, and studies are underway in several aquifers to predict water 

levels and potential contamination under 

various climatic and water-withdrawal 

conditions.

Basic water-resources data collected by 

the USGS provide information that is 

essential to water-resources management. 

The USGS operates and collects data at 

134 continuous-record and 102 partialrecord streamflow-gaging stations, 18 reservoir stage and contents gaging stations, 

about 170 continuous-record observation 

wells, and numerous miscellaneous sites. 

These data provide information that is used 

daily by managers to make decisions that 

Earth Science in the Public Service
Total water use, in

million gallons per day

Less than 5

5 to 10

10 to 20

20 to 60

60 to 1,050

EXPLANATION

concern water supply, flood control, hydroelectric power, irrigation, bridge design, 

wildlife management, and pollution abatement. Water-resource management also 

requires information on the use of water 

for public supplies, irrigation, industry, and 

power generation. Water use during 1990, 

excluding use for thermoelectric power 

generation, was 2,290 million gallons per 

day (fig. 3).

Water Limitations in the 

Apalachicola–Chattahoochee–Flint 

River Basin 

During the period from 1970 to 1990, 

water used for public supply in the 

Apalachicola–Chattahoochee–Flint River 

Basin, which includes the Metropolitan 

Atlanta area, more than tripled to almost 

460 million gallons per day. Severe 

droughts and increased development in the 

area have resulted in shortages and restrictions on limited surface-water supplies. In 

northern Georgia, ground water has not 

been a major source of supply because of 

its sporadic occurrence in the crystalline 

rocks of the Piedmont Physiographic Province (fig. 1). The USGS is using state-ofthe-science geologic and geophysical techniques to address the feasibility of using 

ground water as a supplemental source of 

supply in this region. The USGS also is 

evaluating how changes in surface- and 

ground-water withdrawals affect regional 

water availability, and areas where groundwater resources are overused or underused. 

Preliminary results for the lower part of 

the Basin indicate that pumping increases 

in the Basin could cause a reduction in 

ground-water discharge to streams and 

result in reduced flow to Apalachicola Bay, 

especially during droughts. 

Geology and Geohydrology of 

Northern Georgia 

USGS geologists are providing a base of 

modern geologic mapping for areas of the 

Piedmont and Blue Ridge Physiographic 

Provinces (fig. 1), as part of the Georgia 

Appalachians Project. An inventory of the 

location and size of deposits of mineral 

resources also is being developed. The 

inventory includes industrial minerals, such 

as carbonate rock for paper whitener; industrial chemicals, such as ocher for pigmentation; and many other rock products that are 

widely used for construction of buildings 

and roads in Georgia.

The USGS is developing tools to evaluate 

the availability of ground-water resources 

and the potential transport of ground-water 

contaminants. USGS geologists and hydrologists are mapping subsurface fracture systems to investigate ground-water flow in the 

Piedmont of Georgia and to determine the 

effects of these fracture systems on well 

yield. USGS scientists also are working 

northwest of Atlanta to investigate the processes that control the extent and movement 

of ground water contaminated with chlorinated solvents, which may endanger local 

ground-water resources.

Quality of Water Resources

The quality of water is vital to support 

society’s needs and to sustain rich and 

diverse ecosystems in Georgia. The USGS 

is studying the effects of land use on the 

physical, chemical, and biological quality of 

water. Recent studies have focused on 

water-quality effects of point- and nonpointsources of pollutants from urban watersheds, and nonpoint-sources from agricultural and forested (managed for silviculture) 

watersheds (fig. 6, on back page). 

Phosphorus in the Upper 

Chattahoochee River

During the period from 1980 to 1993, 

Metropolitan Atlanta’s population 

increased by about 43 percent, thus resulting in an increase of about 50 percent in 

wastewater discharge to the Chattahoochee 

River from the six largest Atlanta wastewater-treatment facilities. Treated wastewater 

is a point source of the nutrient phosphorus. 

Increased phosphorus loadings can produce 

rapidly multiplying algal blooms that 

degrade the recreational, water-supply, and 

habitat value of streams and lakes. The 

amounts (loads) of phosphorus discharged 

to the Chattahoochee River increased before 

1989 and then decreased following legislated restrictions on the use of phosphate 

detergents combined with upgrades to 

wastewater-treatment facilities. Even 

though the volume of effluent increased 

from 1988 to 1993, phosphorus loads from 

wastewater-treatment facilities decreased by 

about 83 percent because of reduced phosphorus concentrations in raw sewage and 

improved treatment methods.

The annual phosphorus load at monitoring sites on the Chattahoochee River 

upstream and downstream from Atlanta from 

1980 to 1993 is shown in figure 4. The difference between the two curves shown on the 

graph indicates the effect of point and nonpoint sources from Atlanta on the phosphorus load in the River. Reductions in pointsource phosphorus loads have been documented, and phosphorus loads in the river 

downstream from Atlanta declined by about 

54 percent from 1988 to 1993. However, 

phosphorus loads discharged to the Chattahoochee River from Atlanta wastewatertreatment facilities in 1996 remained higher 

than legislated maximum levels. 

Pesticides From Urban and 

Agricultural Sources

Agricultural land uses (fig. 6, on back 

page) often are assumed to be the primary 

source of pesticides in the environment. 

Water samples collected weekly from 

March 1993 through April 1994 from 

streams that drain urban and agricultural 

watersheds were analyzed for many commonly used pesticides. Twenty-four herbicides and eight insecticides were detected 

in water samples. Preliminary findings 

Figure 3. Water use in Georgia, by 

county, 1990.

1980

19811982

1983

1984

1985

1986

1987

1988

1989

1990

199119921993

0

200

400

600

800

1,000

1,200

1,400

1,600

1,800

PHOSPHORUS LOAD, IN TONS PER YEAR

CHATTAHOOCHEE

RIVER DOWNSTREAM

OF ATLANTA

CHATTAHOOCHEE

RIVER UPSTREAM 

OF ATLANTA

Voluntary

restriction

on use of

phosphate

detergents

Mandatory

restriction

on use of

phosphate

detergents 

Figure 4. Phosphorus loads in the 

Chattahoochee River upstream and 

downstream from Atlanta, 1980 to 1993.
indicate that more pesticides are present in 

water from urban watersheds, generally at 

higher concentrations and for a greater part 

of the year, than in water from agricultural 

watersheds. In general, the trace concentrations of pesticides detected do not exceed 

U.S. Environmental Protection Agency 

(USEPA) drinking-water standards for 

human health. However, concentrations of 

several insecticides detected in urban 

watersheds exceed guidelines for the protection of aquatic life. 

Fish Communities in Urban Streams

Because aquatic organisms respond 

directly to the quality of the water they 

inhabit, they are useful indicators of the 

cumulative effects of water quality. The 

USGS surveyed fish communities in Chattahoochee River tributaries and compared 

streams that receive runoff from the Metropolitan Atlanta area with a stream in a forested basin. In general, the urban basins 

had fewer than one-half the number of fish 

in the forested basins, and about 90 percent 

of the fish in urban basin were nonnative 

species. Fish that live in urban streams 

generally are tolerant of a wide range of 

water-quality conditions, and after such 

mishaps as chemical or sewage spills that 

decrease fish populations, these fish types 

are opportunistic and can repopulate urban 

streams rapidly.

Water Quality During Tropical Storm 

Alberto

Tropical Storm Alberto in 1994 caused 

record flooding. In Georgia, the flood provided a unique opportunity to measure the 

nutrients, suspended sediments, and pesticides transported during extreme floods. 

Twenty pesticides commonly used in agricultural and urban areas were detected in 

floodwaters. Pesticide concentrations were 

well below USEPA standards for drinking 

water. However, concentrations of the 

insecticides chlorpyrifos, carbaryl, and 

diazinon approached or exceeded USEPA 

guidelines for protection of aquatic life. 

Pollutants flushed from the land surface 

during storm runoff tended to reach streams 

during the first portion of a flood. The highest herbicide concentrations were measured 

4 to 6 days before the flood peak in the 

Flint River at Newton (fig. 5). Concentrations decreased as flooding progressed 

because of the combined effects of dilution 

and the passing of the “first flush” pollutants. This information can be used to evaluate potential pollution characteristics of 

future extreme floods.

CONCENTRATION, IN MICROGRAMS PER LITER

DISCHARGE, IN THOUSANDS OF 

CUBIC FEET PER SECOND

0.15

0.10

0.05

0

110

100

90

80

70

60

50

40

30

20

10

0 5 10 15 20 25 31

July 1994

Discharge

Cyanazine

Atrazine Metolachlor Simazine

Water Quality in a Major Aquifer

The Floridan aquifer system is one of the 

most productive in the United States and is 

the source of water supply for the city of 

Valdosta and much of the surrounding area 

in southeastern Georgia. Water quality in 

the Upper Floridan aquifer is affected by 

direct recharge from Withlacoochee River 

water (fig. 2) through sinkholes in and near 

the streambed north of Valdosta. The river 

water contains naturally occurring organic 

matter and receives little filtration as it 

recharges the aquifer, which results in high 

concentrations of organic carbon, hydrogen 

sulfide, and methane in ground water downgradient from the recharge area. The USGS 

measured and characterized water quality in 

the Upper Floridan aquifer. Concentrations 

of naturally occurring constituents in 

ground water from several locations were 

used to trace the movement of recharge 

water in the Upper Floridan aquifer. Findings from this investigation were used by 

water-resource managers and planners to 

assess the contamination potential of the 

aquifer by recharge from the Withlacoochee 

River and to delineate areas suitable for new 

public water-supply wells. 

Natural Hazards

Natural hazards cause losses that average 

about $52 billion per year in the United 

States. In Georgia, the USGS provides 

information on natural hazards, which 

include floods, droughts, earthquakes, sinkholes, and coastal storm surges.

Flood Hazards

 In July 1994, parts of central and southwestern Georgia in the Flint and the Ocmulgee River Basins were inundated by floods 

that resulted from as much as 28 inches of 

rainfall produced by Tropical Storm 

Alberto. The floods caused 33 deaths and 

property damage estimated to be nearly $1 

billion as highways, water systems, crops, 

and homes were inundated. Damage from 

such a severe flood cannot be averted completely, but with reliable estimates of river 

stages and discharge, communities can be 

warned of impending danger. The USGS 

operates data transmitters at 56 of its continuous stage-monitoring stations Statewide. 

Fifteen of these stations in the affected 

basins provided near-realtime tracking of 

flood conditions during Tropical Storm 

Alberto. Personnel of the USGS worked 

throughout the flood to maintain stream 

gages, to measure peak-flow rates and 

flood-elevation profiles, and to provide critical information to emergency management 

personnel and the public. 

Geologic Hazards

Earthquakes and ground failures are 

uncommon events in Georgia; however, 

they can pose a threat to human life and 

property. Although Georgia has experienced 

only small to moderate earthquakes in 

recorded history, nearby States experienced 

large seismic events during the 1800’s. 

Shock waves from earthquakes anywhere in 

the Southeastern United States can affect 

Georgia. The USGS National Earthquake 

Information Center World Wide Web 

(WWW) site 

http://wwwneic.cr.usgs.gov/

documents earthquakes through the U.S. 

National Seismograph Network with such 

stations as the one near Eatonton. In addition, the USGS investigates the causes of 

earthquakes and delineates possible earthquake faults. Ground failures, such as landslides, are a common byproduct of seismic 

shaking and also can be caused by unstable 

surface conditions. The USGS has supported projects to identify areas of potential 

ground failure to ensure the stability of 

large structures such as dams. 

Earth-Resources Information

Hydrologic and Geologic Information

The USGS provides hydrologic information on stream stage and discharge, water 

quality, and ground-water levels. The USGS 

also provides interpretative information 

about water and geologic earth resources to 

describe the availability, use, quality, prospective and retrospective trends, and potential impacts from various factors such as 

land use. Investigative techniques and computer models developed by the USGS are 

used daily by resource managers, engineers, 

hydrologists, geologists, educators, and 

others who serve the citizens of Georgia. 

Figure 5. Herbicide concentrations and 

discharge in the Flint River at Newton.
For More

Information

Urban or built-up land

Agricultural land

Forest land

Water

Wetland

EXPLANATION

Information is available in annual data 

reports, special investigative reports, fact 

sheets, and on the USGS WWW site for 

Georgia 

http://wwwga.usgs.gov/

which describes hydrologic conditions, 

current investigations, and the availability 

of other information products.

Biological Resources Information

 The USGS Biological Resources Division (formerly the National Biological Service) provides information to improve the 

understanding of priority species, fisheries, 

songbirds, and forests in Georgia. At the 

request of Federal and State agencies, scientists conduct investigations of forest and 

aquatic habitats and species in Georgia. 

For example, scientists are studying the 

effects of pine timberland management on 

habitats required by migratory birds and 

woodpeckers. The USGS has provided 

essential information for management of 

important game fish such as the striped 

bass. Other investigations are assessing the 

effects of streamflow regulation on the 

spawning and foraging habitats necessary 

to sustain diverse fish populations. 

Mapping the Earth

Among the most popular and versatile 

products of the USGS are its 1:24,000-scale 

topographic maps—1 inch represents 2,000 

feet on the ground. These maps show basic 

natural and cultural features of the landscape, such as mountains and valleys, lakes 

and streams, towns, and highways; contour 

lines on these maps show the elevation and 

shape of terrain. Georgia is covered by 

1,017 topographic maps at this scale. These 

maps are used for civil engineering, naturalresource monitoring, hiking, camping, 

exploring, and many other purposes. 

The USGS also provides extensive 

digital-mapping data that are widely used 

in geographic information system (GIS) 

data bases. The USGS National Geospatial 

Data Clearinghouse WWW site

http://nsdi.usgs.gov/nsdi/

contains additional information on these 

digital-mapping products. The USGS 

Earth Resources Observation Systems Data 

Center near Sioux Falls, South Dakota, 

WWW site 

http://edcwww.cr.usgs.gov/

distributes a variety of aerial photographs 

and satellite-image data products that cover 

the entire State. The Center for Spatial 

Analysis Technology, which is a joint 

research effort of the USGS, the Georgia 

Environmental Protection Division, and the 

Georgia Institute of Technology, performs 

GIS analysis and research. 

USGS State representative

3039 Amwiler Road, Suite 130

Atlanta, GA 30360-2824

(770) 903-9100

Fax: (770) 903-9199

Email: info@wwwga.usgs.gov

HomePage: http://wwwga.usgs.gov

Additional earth science

information can be found by

accessing the USGS Home Page

on the World Wide Web at

http://www.usgs.gov/

For more information on

all USGS reports and products

(including maps, images,

and computerized data), call

1-800-USA-MAPS

The USGS provides maps,

reports, and information to help

others meet their needs to manage,

 develop, and protect America’s water,

energy, mineral, biological, and land

resources. We help find the natural

resources needed to build tomorrow,

and supply the scientific understanding needed to help minimize or mitigate the effects of natural hazards

and environmental damage caused

by natural and human activities. The

results of our efforts touch the daily

 life of almost every American.

U.S. Geological Survey

Fact Sheet FS-010-96

Figure 6. Major land uses in Georgia.