U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2006–3114

September 2006

Water Availability for Ecological Needs in 

the Upper Flint River Basin, Georgia

Sustaining the ecological integrity of 

aquatic ecosystems while meeting human 

needs for water resources is a major challenge facing society. In many regions, 

including the Eastern United States, the 

growing demand for water supply and 

changing land use, such as urbanization, are altering hydrologic regimes in 

streams and rivers that society depends 

on for ecological services. These services 

include drinking, irrigation, and industrial 

water supplies; assimilation and removal of 

waste; mitigation of droughts and floods; 

control of river channel erosion; recreation; 

fisheries; and maintenance of biological 

diversity. Meeting the challenge of balancing human needs for water resources with 

protecting aquatic ecosystems requires 

science-based information on what aspects 

of natural, or unaltered, hydrologic conditions are essential for the long-term maintenance of healthy aquatic ecosystems.

The U.S. Geological Survey (USGS) has 

the extensive research background and 

interdisciplinary capabilities that position the agency to take a lead role in 

developing the science needed to improve 

management of water supply and aquatic 

ecosystems, especially in urbanizing landscapes. To accomplish this goal, the USGS 

Director selected “Water availability for 

ecological needs” as a national priority 

science thrust program for 2006– 2008.

UPPER FLINT RIVER BASIN

A number of factors make the upper Flint 

River Basin an appropriate setting for 

developing science to address water and 

ecosystem management issues. The upper 

Flint River flows unimpeded by major 

impoundments for about 195 river miles 

from its Piedmont headwaters onto the 

Coastal Plain Province and harbors habitats 

and biologically diverse communities that 

have been lost from impounded reaches of 

many other eastern rivers. The upper Flint 

River Basin also supplies water to a growing population in the Atlanta metropolitan 

area and is a major recreational resource for 

the region, providing canoeing, white-water 

rafting, and sportfishing opportunities.

Long-term streamflow gaging stations 

have provided flow data for more than 

90 years in the upper Flint River Basin. 

Recently completed investigations of freshwater mussel distributions and fish-habitat 

relations in the upper mainstem, and an 

aquatic Gap Analysis Program (GAP), 

provide baseline data for the system. 

Continued growth in the Atlanta area 

will increase pressure on the ecological 

systems of the Flint River Basin because 

of the potential for increased water 

withdrawals, reservoir construction for 

water storage, urban runoff, and additional 

The Flint River Science Thrust project of the U.S. Geological Survey 

is part of a federally funded program to address key national science 

priorities including landslides/debris flows, fire science, integrated 

landscape monitoring, and water availability. The purpose of the 

project is to advance the science needed to specify the hydrologic 

conditions necessary to support flowing-water ecosystems. This 

information is critical for management of water resources. Specific 

project goals include:

Develop conceptual models that relate hydrology, geomorphology, and water quality to biological management objectives.

Evaluate and determine the major factors driving the 

conceptual models and determine additional data needs.

Use the upper Flint River Basin to demonstrate a spatially

explicit predictive model for evaluating water-supply development options that links watershed conditions to biological 

management objectives.

Identify research and monitoring needed to address critical uncertainties and data gaps determined during model development.

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wastewater loadings. Thus, this setting 

incorporates problems common to many 

regions and rivers in the Eastern United 

States—how to balance water-supply 

development with protection of diverse 

aquatic ecosystem—and provides an 

opportunity for interdisciplinary innovation in providing science-based solutions.

CHARACTERISTICS OF THE 

UPPER FLINT RIVER BASIN

The Flint River begins beneath Hartsfield –Jackson International Airport 

on the south side of Atlanta and flows 

southward across the Georgia Piedmont 

and Coastal Plain to its junction with 

the Chattahoochee River, later forming 

the Apalachicola River. The upper Flint 

River Basin has a drainage area of about 

2,630 square miles. Land use in the basin, 

which includes parts of the upper Coastal 

Plain, consists of about 57 percent forest, 

17 percent agriculture, and 12 percent 

urban, with most of the urban land 

concentrated in the extreme northern 

part of the basin (Georgia Land Use 

Trends, 1998).

Population growth in the six-county 

Upper Flint Water Supply Management 

Area (UFWSMA, shown below) has 

increased more than 200 percent since 

1970, from 133,470 to 302,714 during 

2000 (CH2MHill, 2003). Predictions are 

that more than 550,000 persons will live 

in the six-county UFWSMA by 2030.

Most of the upper Flint River Basin is located in the Piedmont physiographic region of Georgia. The majority of the basin is relatively 

undeveloped; however, development spreading south from Atlanta will increase pressure on the available water in the basin. 

Water-Supply and 

Instream-Flow Issues

Most of the water supply in the upper 

Flint River Basin comes primarily from 

the Flint River or its tributaries. Withdrawal from the 32 permitted municipal 

and industrial water-supply intakes 

totals about 108 million gallons per 

day (Mgal/d) and agricultural interests 

are permitted to remove an additional 

90 Mgal/d from streams in the basin 

(Victoria P. Trent, Georgia Environmental 

Protection Division, written commun., 

2005). Proposals have been submitted 

to increase surface-water supply capacity in the upper Flint River Basin by 

12.7 Mgal/d (about 7 percent) by building 

two additional reservoirs and expanding 

TAYLOR

PIKE

UPSON

TALBOT

MERIWETHER

COWETA

FAYETTE

MACON

CRAWFORD

SPALDING

LAMAR

CLAYTON

FULTON

HENRY

MARION

84°30

84°00'

32°30

33°00'

33°30

EXPLANATION

305b assessed streams

Not supporting (303d listed)

Partially supporting (303d listed)

Supporting (not listed)

Not assessed

Municipal (blue) or industrial 

 (brown) withdrawal—In

 million gallons per day

Wastewater discharge

Less than 0.2

0.2 to 1

1 to 5

5 to 10

10 to 20

20 to 50

Municipal

Industrial

Shoal

0 5 10 MILES

0

Base modified from

U.S. Geological Survey

1:100,000-scale digital data

5 10 KILOMETERS

Upper Flint

Water Supply

Management Area

Upper Flint River Basin

GEORGIA

Atlanta

 Metropolitan

 area

Atlantic Ocean

FLINT

RIVER

BASIN

CHATTAHOOCHEE

RIVER BASIN

APALACHICOLA

RIVER BASIN

FLORIDA

PIEDMONT

COASTAL PLAIN

ALABAMA

Mexico

Gulf of

Fall Line

N

Flint River
an existing reservoir (Georgia Department of Natural Resources, 2003a). 

Under an interim State policy, required 

minimum flows below new reservoirs or 

stream withdrawals must adhere to one of 

three guidelines. Provide a minimum of:

the monthly 7Q10 (the 7-day, 

consecutive low flow with a 

10-year return frequency);

30 percent of the mean-annual 

flow for unregulated streams; or

seasonally adjusted percentage 

of mean-annual flow for 

regulated streams.

The guidelines also suggest that sitespecific studies can be used to determine 

minimum flows.

Stormwater Runoff

Stormwater runoff increases as impervious surface increases. This affects 

stream geomorphology, water quality, 

temperature, aquatic ecosystems, and 

stream baseflows. No statewide policy 

currently exists to manage stormwater 

runoff except related to construction. 

Some municipal and county governments 

have implemented, or are in the process 

of implementing, stormwater-management programs.

Federally and State-Listed 

Aquatic Species

The upper Flint River Basin contains 

extensive shoal habitat that supports 

riverweed (Podostemum ceratophyllum), 

waterwillow (Justicia sp.), and shoal 

lily (Hymenocalis coronaria). At least 

five fish species that are endemic to the 

Apalachicola River Basin occur in the 

upper Flint River Basin. The upper Flint 

River Basin historically supported at least 

25 species of mussels including 6 federally listed species. Recent surveys have 

reported only 20 species of native mussels remaining in the basin.

Water Quality and Aquatic 

Biological Integrity

Urban development in the upper Flint 

River Basin has resulted in water-quality 

problems in the headwaters. Studies in 

the early 1970s noted severe waterquality problems due to high levels of 

bacteria and nutrients in many of the 

tributaries and the mainstem reaches of 

the upper Flint River. During the period 

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Advancing the science of linking hydrology and stream ecology

More than 200 methods for deriving “environmental” flow requirements have been 

developed to meet the needs of water managers (Tharme, 2003). Many of these 

methods focus on the minimum flows needed to support survival of aquatic organisms. Because flow conditions that drive ecosystem functions are complex, current 

emphasis in flow management is to identify hydrologic regimes necessary to 

protect and maintain differing levels of ecological integrity (Arthington and Pusey, 

2003; King and others, 2003; Postel and Richter, 2003; Annear and others, 2004). 

Current limitations on quantifying the linkages between flow regimes and ecosystem processes underlie much of the uncertainty in predicting ecological effects of 

flow-regime alteration (Castleberry and others, 1996; Irwin and Freeman, 2002; 

Tharme, 2003). The USGS and its partners can advance the science underlying 

environmental flow specifications by applying multidisciplinary expertise and data 

from other studies of riverine processes to build and evaluate alternative hypotheses regarding flow-regime effects on geomorphic and ecological processes—in 

this case, for a Piedmont river system. Through this process, the USGS anticipates 

addressing questions such as: 

What are the appropriate spatial scales for identifying geomorphic variation 

in hydrologic-ecologic linkages?

What are the relative roles of changes in sediment transport, water quality, 

and habitat conditions in altering ecological communities? 

How does altering the flow regime (magnitude, duration, frequency of 

occurrence, seasonality, rate of change) influence persistence of native aquatic 

species and communities?

How are direct effects of flow regulation and water diversion on physi­cal and 

biological processes altered by different land uses within the watershed?

Results of this effort will contribute to the global effort to improve the understanding of the effects of hydrologic alteration on the ecological integrity of 

flowing-water ecosystems, as well as supporting the development of a modelbased framework for adaptively applying current scientific understanding to 

address stream-management issues.

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between 1972 and 1990, ammonia, dissolved nitrate, and phosphorous decreased 

in the mainstem reaches due to improvements in the quality of wastewater discharges. A study conducted during 1992 

found that nutrient levels in the mainstem 

of the Flint River decreased by almost 

an order of magnitude from those found 

during the mid-1980s (Frick and others, 

The upper Flint River 

contains numerous 

shoal areas that 

provide habitat for 

endangered species 

(photograph by 

Jonathan Kennen, 

USGS).

1996). From 1998 to 2002, 28stream segments in the Flint River Basin were listed 

as not supporting or only partially supporting their designated water uses. Of the 

28 stream segments, 14 are located in the 

upper Flint River Basin and were listed as 

having poor or very poor fish and invertebrate communities (Georgia Department 

of Natural Resources, 2003b).
SELECTED REFERENCES 

Annear, T.C., Chisholm, I.M., Beecher, H.A.,

Locke, A.G.H., Aarestad, P.A., Coomer, C.C.,

Estes, C.E., Hunt, J.G., Jacobson, R.B.,

Jobsis, G.J., Kauffman, J.B., Marshall, J.H.,

Mayes, K.B., Smith, G.L., Wentworth, Rod,

and Stalnaker, C.B., 2004, Instream flows for 

riverine resource stewardship, revised edition: 

Instream Flow Council: Cheyenne, Wy., 268 p.

Arthington, A.H., and Pusey, B.J., 2003, Flow 

restoration and protection in Australian 

rivers: River Research and Applications 

v. 19, p. 377–395.

Castleberry, D.T., Cech, J.J., Jr., Erman, D.C., 

Hankin, D.G., Healey, M.C., Kondolf, G.M.,

Mangel, Marc, Mohr, M.S., Moyle, P.B., 

Nielsin, J.L., Speed, T.P., and Williams, J.E., 

1996, Uncertainty and instream flow standards: Fisheries, v. 21, no. 8, p. 20 –21.

CH2MHill, 2003, North Georgia regional 

water supply needs assessment, prepared for 

Georgia Department of Natural Resources: 

Atlanta, Ga., 221 p. 

Frick, E.A., Buell, G.R., and Hopkins, E.A., 

1996, Nutrient source and analysis of 

nutrient water-quality data, Apalachicola–

Chattahoochee–Flint River basin, Georgia, 

Alabama, and Florida, 1972–90: U.S. GeoSpecies of concern in the 

upper Flint River Basin

Endemic species

Undescribed Halloween darter 

 (Percina sp.)

Shoal bass 

 (Micropterus cataractae)

Bluestripe shiner 

(Cyprinella callitaenia)

Undescribed Greyfin redhorse 

(Moxostoma sp.)

Greater jumprock (M. lachneri)

Endangered species (Georgia)

Shoal lily 

(Hymenocallis coronaria)

Threatened species (Federal)

Purple bankclimber 

(Elliptoideus sloatianus)

Endangered species (Federal)

Shinyrayed pocketbook 

(Hamiota subangulata)

Oval pigtoe 

(Pleurobema pyriforme)

logical Survey Water-Resources Investigations Report 96-4101, 120 p.

Georgia Department of Natural Resources,

2003a, Regional Reservoir Plan, Final 

Report, 221 p.

Georgia Department of Natural Resources, 

2003b, TMDL evaluation for twenty-eight 

stream segments in the Flint River basin for 

sediment (Biota impacted): Georgia Environmental Protection Division, Atlanta, 

Georgia, 76 p.

Georgia Land Use Trends, 1998, Land cover 

of the upper Flint watershed: Natural 

Resources Spatial Analysis Laboratory, 

Institute of Ecology, Athens, Ga., accessed 

July 11, 2006, at http://narsal.ecology.uga.

edu/glut.html

Irwin, E.R., and Freeman, M.C., 2002, A 

proposal for adaptive management to 

conserve biotic integrity in a regulated 

segment of the Tallapoosa River, Alabama, 

USA: Conservation Biology, v. 16, 

p. 1,212–1,222.

King, J.M., Brown, C.A., and Sabet, Hosein,

2003, A scenario-based holistic approach to 

environmental flow assessments for rivers: 

River Research and Applications, v. 19, 

p. 619–639.

By M. Brian Gregory, Mary C. Freeman,

 and W. Brian Hughes

Design and layout by Caryl J. Wipperfurth

Edited by Patricia L. Nobles

For more information contact: 

Thrust Project Coordinator

3039 Amwiler Road, Suite 130

Atlanta, Georgia 30360

770-903-9162

Or visit the following Web sites:

http://ga.water.usgs.gov and

http://www.usgs.gov

U.S. Department of the Interior

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

P. Patrick Leahy, Acting Director

Postel, S.L., and Richter, B.D., 2003, Rivers for 

life: Managing water for people and nature: 

Island Press, Washington, D.C., 264 p.

Tharme, R.E., 2003, A global perspective on 

environmental flow assessment: Emerging 

trends in the development and application 

of environmental flow methodologies for 

rivers: River Research and Applications, 

v. 19, p. 397– 441.

Mussels from top, purple bankclimber, 

shinyrayed pocketbook, and oval pigtoe, 

threatened or endan­gered species in 

the upper Flint River Basin (photographs 

courtesy of Sean Kelly and Stephen W. 

Golladay, J.W. Jones Ecological 

Research Center, Newton, Georgia).

Shoal lily (photograph by 

Mary C. Freeman, USGS).

Halloween darter and shoal bass (photographs by Noel M. Burkhead, USGS)