ELEVATION, IN FEET ABOVE NATIONAL GEODETIC VERTICAL DATUM OF 1929

West Point

Lake

Walter F

George

Reservoir

Lake Seminole

(Jim Woodruff)

Allatoona

Lake

Carters 

Lake Hartwell 

 Lake

Richard B 

 Russell Lake

J Strom Thurmond

 Lake

Lake

Sidney

Lanier

Full summer pool 840 feet

Full winter pool 823 feet

820

825

830

840

845

835

Lake Allatoona

O N D J F M A M J J A S

Top of conservation

Water level

1,050

1,055

1,060

1,065

1,070

1,075

1,080

Carters Lake

O N D J F M A M J J A S

Full summer pool 1,071 feet

Full winter pool 1,070 feet

1,058

1,060

1,062

1,064

1,066

1,068

1,070

1,072 Lake Sidney Lanier

O N D J F M A M J J A S

O N D J F M A M J J A S

2006 2007

75.5

75.0

76.0

76.5

77.0

77.5

78.0

Lake Seminole

Lakes and Reservoirs

Reservoirs in Georgia are multipurpose lakes that provide flood protection, power 

generation, water supply, navigation, recreation, and fish and wildlife management. 

Reservoirs operate at the highest level possible for all these purposes when water 

levels are close to the top of conservation or “full pool,” which may vary from summer 

to winter. Reservoir levels declined with low streamflow conditions during the 2007 water 

year, and by August and September some of the major water-supply reservoirs receded 

towards historic low pool elevations. These reservoirs—most operated by the 

U.S. Army Corps of Engineers 

and the Southern Company—

had water levels that were 

among the lowest recorded 

since the impoundments were 

constructed. Lake Lanier, for 

example, experienced 12 percent 

more outflow than inflow 

during the 2007 water year (http://lanier.sam.usace.

army.mil/ accessed on 

June 13, 2008). Lake Lanier’s 

historic low occurred during 

December 1981, at a pool 

elevation of 1,052.66 feet. By 

the end of September 2007, 

Lake Lanier was at a pool 

elevation of 1,058 feet, more than 

12 feet below full pool. Precipitation deficits and shortages of surface-water supplies 

resulted in emergency water-conservation efforts by both State and local authorities, 

similar to those during the drought of 1986. Sustained droughts in Georgia have further 

emphasized the necessity for having accurate water-resources information to aid in 

watershed management, conservation efforts, and reservoir operations.

Reservoir

Full pool elevation Lowest observed 

pool elevation during Winter Summer water year 2007

Feet above National Geodetic Vertical Datum of 1929

Apalachicola–Chattahoochee–Flint River Basin

Lanier Sidney Lanier 1070.0 1,071.0 1,058.84

West Point Lake 628.0 635.0 623.36

Walter F. George Reservoir 188.0 190.0 184.90

Lake Seminole 77.5 77.5 75.78

Alabama–Coosa–Tallapoosa River Basin

Allatoona Lake 823.0 840.0 822.92

Carters Lake 1072.0 1,074.0 1,051.80

Savannah River Basin

Hartwell Lake 656.0 660.0 651.66

Richard B. Russell Lake 475.0 475.0 472.63

J. Strom Thurmond Lake 326.0 330.0 320.30

References

Precipitation maps modified from National Oceanic and Atmospheric Administration, accessed 

on June 2, 2008, at http://water.weather.gov/index.php?layer%5B%5D=0&layer%5B%5D=

1&layer%5B%5D=3&layer%5B%5D=4&timetype=YM&loctype=STATE&units=engl&timeframe=

current&timeYYYY=2007&timeMM=13&timeDD=1&product=per_normal&loc=stateGA

Seven-day-hydrograph data from U.S. Geological Survey, accessed on August 1, 2008, at 

http://water.usgs.gov/waterwatch/?m=sitedur&r=ga&w=pa07d_dry%2Cmap

Hydrologic drought map from U.S. Geological Survey, accessed on September 27, 2007, at 

http://water.usgs.gov/waterwatch/?m=dryw&r=ga

Runoff data from U.S. Geological Survey, accessed on August 1, 2008, at 

http://water.usgs.gov/waterwatch/?m=statesum&r=ga&w=statesum%2Cmedian

Reservoir data from U.S. Army Corps of Engineers, accessed on June 13, 2008, at 

http://water.sam.usace.army.mil/ 

by Andrew E. Knaak and John K. Joiner

Design and layout by Bonnie J. Turcott 

 and Caryl J. Wipperfurth

For more information contact:

Director, USGS Georgia Water Science Center

3039 Amwiler Road, Suite 130

Atlanta, Georgia 30360

770-903-9100

Or visit the following Web sites:

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

http://www.usgs.gov
100

10

1

1,000

10,000

100

10

1

1,000

10,000

50 years of record

SEVEN-DAY AVERAGE DISCHARGE, 

IN CUBIC FEET PER SECOND

O N D J F M A M J J A S

2006 2007

DAILY DISCHARGE,

IN CUBIC FEET PER SECOND

1,000

100

10,000

100,000

1,000

100

10,000

100,000

62 years of record

O N D J F M A M J J A S

2006 2007

SEVEN-DAY AVERAGE DISCHARGE, 

IN CUBIC FEET PER SECOND

DAILY DISCHARGE,

IN CUBIC FEET PER SECOND

Mu

Mu

Abo

No

Bel

Hist

Peachtree River

Creek

Satilla 

Chattahoochee

Al

Ocmulgee River

Oconee River

Flint River

0 30 60 MILES

0 30 60 KILOMETERS

Peachtree Creek at Atlanta 

Flint River near Newton 

The Flint River joins the Chattahoochee River at Lake Seminole in southwestern Georgia to form 

the Apalachicola River. “Much below normal” streamflow was observed from March 2007 to 

September 2007. New historic low daily discharge was recorded in May and August, and runoff 

was about half of the annual average. Rainfall recorded at the gaging station was about 15 inches 

less than average annual rainfall for the watershed. (Photo by Brian E. McCallum, USGS.)

Hydrographs: Daily Discharge

Hydrographs shows 2007 daily mean stream

flow as compared to historical minimum and 

median streamflow for the entire period of 

record, in cubic feet per second. 

Peachtree Creek is highly urbanized with 30 percent impervious area. The daily discharge hydrograph shows high peak discharges during storm events due to urbanization. Summer showers did 

not bring enough relief to overcome several months of “much below normal” streamflow. A new 

historic low daily discharge was recorded in August, and runoff was about half of the annual average. 

Rainfall recorded at the gaging station was about 20 inches less than average annual rainfall for the 

watershed. (Photo by Christopher A. Smith, USGS.)

Hydrographs show the 7-day 

average for 2007 as compared 

to historical 7-day averages. 

Data are categorized in ranges 

from “much above normal” to 

“much below normal.”

Runoff 

Runoff is average streamflow per unit 

area, or streamflow yield. Runoff for 

2007 was computed from 167 streamflow 

gages in Georgia. The median runoff 

average is shown for several drought 

years. The median runoff for 2007 was 

one-half of the average of the medians 

from 1955 to 2007.

Hydrographs: Seven-Day Average 
100

10

1

1,000

10,000

100

10

1

1,000

10,000

50 years of record

SEVEN-DAY AVERAGE DISCHARGE, 

IN CUBIC FEET PER SECOND

O N D J F M A M J J A S

2006 2007

DAILY DISCHARGE,

IN CUBIC FEET PER SECOND

1,000

100

10,000

100,000

1,000

100

10,000

100,000

62 years of record

O N D J F M A M J J A S

2006 2007

SEVEN-DAY AVERAGE DISCHARGE, 

IN CUBIC FEET PER SECOND

DAILY DISCHARGE,

IN CUBIC FEET PER SECOND

Mu

Mu

Ab

No

Be

His

Peachtree River

Creek

Satilla 

Chattahoochee

A

Ocmulgee River

Oconee River

Flint River

0 30 60 MILES

0 30 60 KILOMETERS

Peachtree Creek at Atlanta 

Flint River near Newton 

The Flint River joins the Chattahoochee River at Lake Seminole in southwestern Georgia to form 

the Apalachicola River. “Much below normal” streamflow was observed from March 2007 to 

September 2007. New historic low daily discharge was recorded in May and August, and runoff 

was about half of the annual average. Rainfall recorded at the gaging station was about 15 inches 

less than average annual rainfall for the watershed. (Photo by Brian E. McCallum, USGS.)

Hydrographs: Daily Discharge

Hydrographs shows 2007 daily mean stream

flow as compared to historical minimum an

median streamflow for the entire period of 

record, in cubic feet per second. 

Peachtree Creek is highly urbanized with 30 percent impervious area. The daily discharge hydrograph shows high peak discharges during storm events due to urbanization. Summer showers did 

not bring enough relief to overcome several months of “much below normal” streamflow. A new 

historic low daily discharge was recorded in August, and runoff was about half of the annual average. 

Rainfall recorded at the gaging station was about 20 inches less than average annual rainfall for the 

watershed. (Photo by Christopher A. Smith, USGS.)

Hydrographs show the 7-day 

average for 2007 as compared 

to historical 7-day averages. 

Data are categorized in ranges 

from “much above normal” to 

“much below normal.”

Runoff 

Runoff is average streamflow per unit 

area, or streamflow yield. Runoff for 

2007 was computed from 167 streamflow 

gages in Georgia. The median runoff 

average is shown for several drought 

years. The median runoff for 2007 was 

one-half of the average of the medians 

from 1955 to 2007.

Hydrographs: Seven-Day Averag
ELEVATION, IN FEET ABOVE NATIONAL GEODETIC VERTICAL DATUM OF 1929

West Point

Lake

Walter F

George

Reservoir

Lake Seminole

(Jim Woodruff)

Allatoona

Lake

Carters 

Lake Hartwell 

 Lake

Richard B 

 Russell Lake

J Strom Thurmond

 Lake

Lake

Sidney

Lanier

Full summer pool 840 feet

Full winter pool 823 feet

820

825

830

840

845

835

Lake Allatoona

O N D J F M A M J J A S

Top of conservation

Water level

1,050

1,055

1,060

1,065

1,070

1,075

1,080

Carters Lake

O N D J F M A M J J A S

Full summer pool 1,071 feet

Full winter pool 1,070 feet

1,058

1,060

1,062

1,064

1,066

1,068

1,070

1,072 Lake Sidney Lanier

O N D J F M A M J J A S

O N D J F M A M J J A S

2006 2007

75.5

75.0

76.0

76.5

77.0

77.5

78.0

Lake Seminole

Lakes and Reservoirs

Reservoirs in Georgia are multipurpose lakes that provide flood protection, power 

generation, water supply, navigation, recreation, and fish and wildlife management. 

Reservoirs operate at the highest level possible for all these purposes when water 

levels are close to the top of conservation or “full pool,” which may vary from summer 

to winter. Reservoir levels declined with low streamflow conditions during the 2007 water 

year, and by August and September some of the major water-supply reservoirs receded 

towards historic low pool elevations. These reservoirs—most operated by the 

U.S. Army Corps of Engineers 

and the Southern Company—

had water levels that were 

among the lowest recorded 

since the impoundments were 

constructed. Lake Lanier, for 

example, experienced 12 percent 

more outflow than inflow 

during the 2007 water year (http://lanier.sam.usace.

army.mil/ accessed on 

June 13, 2008). Lake Lanier’s 

historic low occurred during 

December 1981, at a pool 

elevation of 1,052.66 feet. By 

the end of September 2007, 

Lake Lanier was at a pool 

elevation of 1,058 feet, more than 

12 feet below full pool. Precipitation deficits and shortages of surface-water supplies 

resulted in emergency water-conservation efforts by both State and local authorities, 

similar to those during the drought of 1986. Sustained droughts in Georgia have further 

emphasized the necessity for having accurate water-resources information to aid in 

watershed management, conservation efforts, and reservoir operations.

Reservoir

Full pool elevation Lowest observed 

pool elevation during Winter Summer water year 2007

Feet above National Geodetic Vertical Datum of 1929

Apalachicola–Chattahoochee–Flint River Basin

Lanier Sidney Lanier 1070.0 1,071.0 1,058.84

West Point Lake 628.0 635.0 623.36

Walter F. George Reservoir 188.0 190.0 184.90

Lake Seminole 77.5 77.5 75.78

Alabama–Coosa–Tallapoosa River Basin

Allatoona Lake 823.0 840.0 822.92

Carters Lake 1072.0 1,074.0 1,051.80

Savannah River Basin

Hartwell Lake 656.0 660.0 651.66

Richard B. Russell Lake 475.0 475.0 472.63

J. Strom Thurmond Lake 326.0 330.0 320.30

References

Precipitation maps modified from National Oceanic and Atmospheric Administration, accessed 

on June 2, 2008, at http://water.weather.gov/index.php?layer%5B%5D=0&layer%5B%5D=

1&layer%5B%5D=3&layer%5B%5D=4&timetype=YM&loctype=STATE&units=engl&timeframe=

current&timeYYYY=2007&timeMM=13&timeDD=1&product=per_normal&loc=stateGA

Seven-day-hydrograph data from U.S. Geological Survey, accessed on August 1, 2008, at 

http://water.usgs.gov/waterwatch/?m=sitedur&r=ga&w=pa07d_dry%2Cmap

Hydrologic drought map from U.S. Geological Survey, accessed on September 27, 2007, at 

http://water.usgs.gov/waterwatch/?m=dryw&r=ga

Runoff data from U.S. Geological Survey, accessed on August 1, 2008, at 

http://water.usgs.gov/waterwatch/?m=statesum&r=ga&w=statesum%2Cmedian

Reservoir data from U.S. Army Corps of Engineers, accessed on June 13, 2008, at 

http://water.sam.usace.army.mil/ 

by Andrew E. Knaak and John K. Joiner

Design and layout by Bonnie J. Turcott 

 and Caryl J. Wipperfurth

For more information contact:

Director, USGS Georgia Water Science Center

3039 Amwiler Road, Suite 130

Atlanta, Georgia 30360

770-903-9100

Or visit the following Web sites:

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

http://www.usgs.gov