These maps represent hydrologic conditions in 

the context of available historical data. The colors 

represent current 7-day average streamflow as 

a percentile class of long-term averages. Only 

stations having at least 30 years of record were 

used (U.S. Geological Survey, 2010b). Because of 

persistent drought conditions that began in spring 

2006, streamflow conditions at the beginning of the 

2009 WY in the State were “much below normal” 

(map A). Steady rainfall and spring flooding in south 

Georgia brought much-needed relief, and 7-day 

average streamflow conditions improved from 

1

Water year is the period October 1 through 

September 30 and is designated by the year in 

which it ends. For example, the 2009 water year 

began on October 1, 2008, and ended on 

September 30, 2009.

Extreme Drought to Extreme Floods: Summary of Hydrologic 

Conditions in Georgia, 2009

The United States Geological Survey 

(USGS) Georgia Water Science Center 

(WSC) maintains a long-term hydrologic 

monitoring network of more than 317 realtime streamgages, more than 180 groundwater wells of which 31 are real-time, and 

10 lake-level monitoring stations. One of 

the many benefits of data collected from 

this monitoring network is that analysis 

of the data provides an overview of the 

hydrologic conditions of rivers, creeks, 

reservoirs, and aquifers in Georgia. 

Hydrologic conditions are determined 

by statistical analysis of data collected 

during the current water year1 (WY) and 

comparison of the results to historical data 

collected at long-term stations. During the 

2009 WY Georgia experienced a dramatic 

change from drought conditions to abovenormal streamflows. Maps A–D indicate 

that during the first half of the 2009 WY, 

most streams in Georgia had flows much 

below normal, but by the end of the year, 

the majority of streams had flows much 

above normal. At the start of the 2009 WY, 

new historic minimum streamflows were 

recorded at several streamgages with 20 

or more years of record, and reservoirs 

approached historic low elevations. South 

Georgia received drought relief as a result 

of historic flooding from March 27–April 3, 

2009. North Georgia experienced historic 

flooding during September 16–22, 2009. 

During these flood events, Georgia WSC 

hydrographers verified peak streamflows 

and flood levels, and this information 

was shared with Federal, State, and local 

agencies for use in protecting life and 

property. New record peak flows were 

observed in many creeks and rivers throughout the State during these epic floods, and 

reservoir and lake elevations approached 

full pool. Extreme hydrologic conditions, 

both drought and floods, in the 2009 WY 

emphasizes the need for accurate, timely 

data to help make informed decisions by 

state and local authorities regarding the 

management and conservation of Georgia’s 

water resources for the protection of life.

On June 10, 2009, Governor Perdue 

met with the State Drought Response 

Committee and announced that the 

Environmental Protection Division issued 

a non-drought schedule for outdoor water 

use for the first time since June 2006 (State 

of Georgia, 2010). This announcement was 

made as a result of substantial rainfalls and 

improved water supplies in Georgia. Under 

a non-drought schedule, household outdoor 

water use is allowed 3 days a week. 

Streamflow And Groundwater Data

Daily, monthly, and yearly streamflow 

and groundwater statistics from the 2009 

USGS Annual Data Report (ADR; U.S. 

Geological Survey, 2010a) were used to 

develop this summary. The ADRs for 

WYs 1999–2009 can be accessed online 

at http://ga.water.usgs.gov/publications/

pubswdr.html. A digital map is available 

at this site to interface with current and 

historical data, graphics, and photographs 

from the Georgia WSC monitoring network.

“below normal” to “above normal” (map B, C). 

By September 30, 2009, the end of the water year, 

the 7-day average streamflows throughout most of 

Georgia were “much above normal” (map D).

Lake Lanier reached an all-time historic low elevation of 1,050.79 feet on December 26, 2007, nearly 21 feet 

below full pool. From December 2008 through September 2009 the lake elevation increased more than 18 feet 

after Georgia received above normal precipitation and experienced two historic flood events. Photos by USGS.

Quarterly Hydrologic Conditions in Georgia for 2009, Based on 7-Day Average Streamflows 

U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2010–3101

October 2010 Printed on recycled paper

A. Oct. 1, 2008 B. Mar. 1, 2009 C. June 1, 2009 D. Sept. 30, 2009

GEORG IA

Much above normal, > 90

Much below normal < 10

Above normal, 76 to 90

Normal, 25 to 75

Below normal, 10 to 24

EXPLANATION

Percentile classes

Tree Tree

Sign

Sign
2

Daily Discharge and 7-Day Average 

Streamfow Conditions, 2009 Water Year

The Ocmulgee River flows 

out of Jackson Lake and joins 

the Oconee River to form the 

Altamaha River (U.S. Geological 

Survey, 1975). In 2009, new 

record daily low streamflows 

were observed for the month 

of February. During the historic floods in March–April and September 2009, 

however, record high streamflows were observed when 7-day average 

streamflows were “much above normal” and daily streamflows were near 

record maximum.

The Chattooga River flows 

in the northwest corner of 

Georgia into Alabama and 

is an inflow to Wiess Lake 

in Alabama (U.S. Geological 

Survey, 1975). At the beginning 

of the 2009 WY, the 7-day 

average streamflow was “much below normal,” and near-historic minimum 

daily values were observed. In December 2008, 7-day average streamflow 

conditions changed from “much below normal” to “normal.” During the 

September 2009 flood in northern Georgia, streamflow conditions were 

“much above normal,” and the annual peak flow exceeded the 2-percent 

annual exceedance probability (50-year recurrence interval).

Hydrographs show 2009 daily-mean streamflow, in cubic 

feet per second, as compared to historical maximum, 

median, and minimum streamflow for the entire period 

of record (U.S. Geological Survey, 2009a).

Hydrographs show the 7-day averages for 2009 as 

compared to historical 7-day averages. Data are 

categorized in percentile ranges from “much above 

normal” (greater than the 90th percentile) to “much 

below normal” (less than the 10th percentile; 

U.S. Geological Survey, 2009b).

7-Day Average Discharge

Daily Discharge

Ocmulgee River at Macon, Georgia. 

Photo by USGS.

Chattooga River at Summerville, 

Georgia. Photo by USGS.

Ocmulgee River at Macon 02213000

Chattooga River at Summerville 02398000

C O A S T A L P L A I N

PIEDMONT

Satilla–Suwannee–

St Marys–Ochlockonee

Oconee–

Ocmulgee–Altamaha

Savannah–Ogeechee

Chattahoochee–Flint

Coosa–Tallapoosa–Tennessee

Base modified from U.S. Geological Survey

1:2,000,000-scale digital data

N

0 30 60 MILES

0 30 60 KILOMETERS

Chattahoochee

Altamaha River

Ogeechee River

Atlantic Ocean

Savannah River

Flint River

Oconee River

River

River

Ocmulgee

Wi ht lacoochee R

Chattooga RChattooga R

Jackson

Lake

Atlanta

02213000

02318500

02337000

02398000

02398000 Chattooga River at Summerville, Georgia

7-day average discharge, 

in cubic feet per second

10 

1 

100 

1,000 

10,000 

100,000 

Daily discharge,

in cubic feet per second

10 

1 

100 

1,000 

10,000 

100,000 

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

2008 2009

7-day average discharge, 

in cubic feet per second

Daily discharge,

in cubic feet per second

100 

1,000 

10,000 

100,000 

02213000 Ocmulgee River at Macon, Georgia 

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

2008 2009

10,000

1,000

100

100,000

Historical daily flow

2009 daily mean

EXPLANATION

Minimum

Median

Maximum

2009 water year

Much above normal, ≥ 90

Much below normal ≤ 10

Above normal, 76 to 89

Normal, 25 to 75

Below normal, 11 to 24

Historical (percentile)

EXPLANATION

Streamgage 

 and number

EXPLANATION

02213000
3

The Withlacoochee River flows in 

the Ochlockonee River basin in the 

southern coastal plain of Georgia 

(U.S. Geological Survey, 1975). For 

most of the 2009 WY, 7-day average 

streamflow conditions were “normal.” The March–April 2009 flood produced 

a record high 7-day average streamflow, and the highest annual peak flow 

at this site since 1948. During the flood peak, the water surface was flowing 

5 to 6 feet above U.S. Highway 84 when USGS field crews measured the 

streamflow by boat.

Sweetwater Creek is a major 

tributary of the Chattahoochee 

River (U.S. Geological Survey, 

1975). For most of the 2009 WY, 

7-day average streamflow 

fluctuated between “much below 

normal” and “normal” conditions. New record daily low streamflows were 

observed for the month of February. During the September 2009 flood, a new 

annual peak flow for the period of record was recorded on Sweetwater Creek. 

This peak flow exceeded the 0.2-percent annual exceedance probability 

(500-year recurrence interval). During the peak of this historic flood, the 

Interstate 20 bridge crossing over Sweetwater Creek 300 feet downstream 

from the USGS streamgage was inundated and closed to traffic.

Well 07H003 

is in Miller 

County in 

southwestern 

Georgia and 

is completed 

in the surficial 

aquifer. The 

water level 

in this well 

generally rises 

rapidly during 

wet periods 

and declines 

slowly during 

dry periods. 

The water 

level in 

well 07H003 

responds 

to seasonal 

change 

similarly to streamflow at the nearby streamgage on 

Spring Creek near Iron City (02357000), which indicates 

atmospheric, surface-water, and groundwater 

interactions. During the March–April 2009 flood, the 

streamgage on Spring Creek recorded the second 

highest peak flow in 65 years of record (18,500 cubic 

feet per second, ft3/s) at this site, and water levels in 

well 07H003 increased above the historic median and 

remained there for the remainder of the 2009 WY.

The USGS maintains a network of groundwater wells to monitor the effects of droughts and 

other climate variability on groundwater levels. 

These wells are part of the Climate Response 

Network, which is designed to measure the effects 

of climate on groundwater levels in unconfined 

aquifers or near-surface confined aquifers where 

pumping or other human influences on groundwater 

levels are minimal (U.S. Geological Survey, 2007, 

2009a). The national network consists of about 

130 wells, of which 15 are located in Georgia. 

Information obtained for the 2009 WY from four 

of these wells is summarized in this section. These 

wells are monitored as part of the USGS Groundwater Resources and Cooperative Water Programs. 

Current conditions of groundwater wells in the 

Climate Response Network can be accessed online 

at http://groundwaterwatch.usgs.gov.

Climate Response Network

Withlacoochee River at U.S. 84 near 

Quitman, Georgia. Photo by USGS.

Sweetwater Creek near Austell, Georgia. 

Photo by USGS.

Sweetwater Creek near Austell 02337000

Withlacoochee River at US 84 near Quitman 02318500

Groundwater Watch

Climate Response Network

Daily mean water level

below land surface, in feet

Daily mean discharge,

in cubic feet per second

0 

2 

4 

6 

8 

10 

12 

14 

16 

4,000

2,000

8,000

12,000

16,000

20,000

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

2008 2009

Precipitation,

in inches

0 

2 

4 

6 

8 

10 

Well_07H003_Miller

25

20

15

10

5

0

–5

 Daily mean water level above (–) 

and below land surface, in feet

02357000

02357000

07H003

1 

10 

100 

1,000 

10,000 

100,000 

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

2008 2009

Daily discharge,

in cubic feet per second

7-day average discharge, 

in cubic feet per second

02337040 Sweetwater Creek Below Austell, Georgia

100

10

1

1,000

10,000

7-day average discharge, 

in cubic feet per second

Daily discharge,

in cubic feet per second

10 

1 

100 

1,000 

10,000 

100,000 

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

2008 2009

10 

1 

100 

1,000 

10,000 

100,000 

02318500 Withlacoochee River at US 84, near Quitman, Georgia
4

Well 16MM03 is in White 

County in northeastern Georgia 

and is completed in the 

crystalline-rock aquifer. Water 

is stored in the regolith and 

fractures, and the water level 

is affected by precipitation and 

evapotranspiration (Cressler 

and others, 1983). Precipitation 

can cause a rapid water-level 

rise in wells tapping aquifers 

overlain by thin regolith (Peck 

and others, 2009). The water 

level in well 16MM03 responds 

to seasonal change similarly 

to streamflow at the nearby 

streamgage Chattahoochee 

River at Helen (02330450), which 

indicates atmospheric, surfacewater, and groundwater 

interactions. The water level 

in well 16MM03 rarely rose above the historic daily median during 

the 2009 WY. The highest water level below land surface occurred 

in September 2009 when the area received more than 12 inches of 

precipitation during the month, most of which occurred near the end 

of September and contributed to the flooding.

Well 21T001 is in Laurens 

County in east-central 

Georgia and is completed 

in a semiconfined part of 

the Upper Floridan aquifer. 

Water levels in semiconfined 

parts of the aquifer fluctuate 

seasonally in response to 

variations in precipitation, 

evapotranspiration, and 

natural drainage or discharge 

(Peck and others, 2009). The 

water level in well 21T001 

responds to seasonal change 

similarly to streamflow at 

the nearby streamgage on 

Oconee River near Dublin 

(02223500), which indicates 

atmospheric, surfacewater, and groundwater 

interactions. At the beginning 

of WY 2009, water levels in well 21T001 were well below the historic 

daily median. During the March–April 2009 flood, the streamgage on 

the Oconee River recorded the second highest peak flow in 10 years 

(46,400 ft3/s), and water levels in well 21T001 increased above the 

historic median and remained there until June 2009 before dipping 

below the historic daily median for the remainder of the water year. 

Well 35P094 is in 

Chatham County 

in southeastern 

Georgia and is 

completed in the 

surficial aquifer. 

Water levels in this 

well generally rise 

rapidly during wet 

periods and decline 

slowly during dry 

periods. The water 

level in well 35P094 

responds to seasonal 

change similarly to 

streamflow at the 

nearby streamgage 

on Peacock Creek at 

McIntosh (02203559), 

which indicates 

atmospheric, 

surface-water, and groundwater interactions. During the 

March–April 2009 flood, the Peacock Creek streamgage 

recorded the highest peak flow at this site for the 2009 WY 

(210 ft3/s), and water levels in well 35P094 increased above 

the historic median and remained there for the remainder of 

the 2009 WY. 

Georgia’s Climate Response Network

Hydrographs are presented on the Climate Response 

Network Web site for wells with at least 5 years of continuous 

data. The 2009 WY data are shown here for selected wells.

0 

5 

10 

15 

20 

25 

30 

35 

40 

0 45 

10,000 

20,000 

30,000 

40,000 

50,000 

0 

1 

2 

3 

4 

5 

6 

Daily mean water level

below land surface, in feet

Daily mean discharge,

in cubic feet per second Precipitation,

in inches

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

2008 2009

Well_21T001_Laurens

26

40

38

34

30

22

 Daily mean water level 

 below land surface, in feet

02223500

02223500 21T001

0 

50 

100 

150 

200 

250 

0 

02198980

02203559 35P094

2 

4 

6 

8 

10 

12 

Precipitation,

in inches

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

2008 2009

Daily mean water level

below land surface, in feet

Daily mean discharge,

in cubic feet per second

0 

1 

2 

3 

4 

5 

6 

7 

8 

Well_35P094_Chatham

2

12

10

8

6

4

0

 Daily mean water level 

 below land surface, in feet

0 

16MM03

1 

2 

3 

4 

5 

0 6 

200 

400 

600 

800 

1,000 

1,200 

0 

4 

8 

12 

16 

Daily mean water level

below land surface, in feet

Daily mean discharge,

in cubic feet per second Precipitation, in inches

Well_16MM03_White

7

2

1

6

5

3

4

 Daily mean water level 

 below land surface, in feet

0

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

2008 2009

02331000

02330450

Range of historical daily 

 minimum and maximum 

Daily mean Daily mean water level

Historical median

2009 groundwater level

EXPLANATION

Stream discharge

Groundwater level

EXPLANATION

16MM03

21T001

35P094

07H003

07H003 Helen

Dublin

McIntosh

Iron City

02203559

02198980

02198980

02357000

02223500

02330450

02331000

Peacock Cr

Chattahoochee

Ocmulgee River

Ogeechee

Oconee River

Savannah River

Flint River

Spring Cr

River

River Altamaha

River

Atlantic Ocean

Streamgage

 and number

Monitoring well

 and identifier

EXPLANATION

Base modified from U.S. Geological Survey

1:2,000,000-scale digital data

N

0 30 60 MILES

0 30 60 KILOMETERS
5

Major lakes and reservoirs 

throughout Georgia are managed 

primarily by the U.S. Army Corps 

of Engineers and Georgia Power 

Company to provide water for 

public and industrial use, flood 

protection, power generation, 

wildlife management, and 

recreation. Managing lakes and 

reservoirs requires computer models 

that predict changes in climate and 

water demands and rely on USGS 

data. During the first half of the 

2009 WY, lakes and reservoirs in 

Georgia continued to have record 

minimum levels as a result of the 

lengthy drought that began in 2006. 

Emergency water-conservation efforts 

by both State and local authorities 

were in place at the beginning of the 

2009 WY. After an extremely wet 

spring, however, State climatologists 

declared an end to the drought and the 

entire State returned to a non-drought 

outdoor watering schedule in June 

2009 as lake and reservoir elevations 

approached 

full pool.

Lake Sidney Lanier (Lake 

Lanier) on the Chattahoochee River 

is the primary drinking-water source 

for the Atlanta metropolitan area. 

Lake Lanier is the most upstream 

reservoir in a series of reservoirs that 

include West Point Lake, Walter F. 

George Lake, and Lake Seminole. 

Lake Lanier had 80 percent more 

inflow than outflow during the 2009 

WY, and lake elevation increased 

more than 18 feet from December 2008 

through September 2009. Flooding in the 

watershed in September 2009 contributed 

a large amount of inflow—50 percent 

more than in June, July, and August 

combined, and the lake elevation increased 

4.5 feet from September 19 to September 30.

Approximately 150 river miles downstream, the elevation of West Point Lake 

also increased 4 feet during the September 

floods, but released discharge was nearly 

equal to the inflow, which resulted in the 

lake elevation being maintained at preflood levels. The volume of Lake Lanier is 

nearly 14 times greater than the volume of 

West Point Lake, which remains near full 

pool elevation even in times of drought. 

West Point Dam provides flood protection 

and hydroelectric power to Troup County, 

and construction was authorized by the 

Flood Control Act of 1962 (U.S. Army 

Corps of Engineers, 2009b).

Lakes and Reservoirs

Hartwell Lake is on the border 

between Georgia and South Carolina 

on the Savannah and Tugaloo Rivers. 

Hartwell is the most upstream reservoir 

on the Savannah River. Water is released 

to the downstream reservoirs, Richard 

B. Russell and J. Strom Thurmond. 

These three lakes on the Savannah River 

are managed by the U.S. Army Corps 

of Engineers for water supply, power 

generation, and water-quality needs of 

the Savannah River from below Thurmond 

Dam all the way to Savannah, Georgia, and 

the Atlantic Ocean (U.S. Army Corps of 

Engineers, 2009c). On December 9, 2008, 

Hartwell Lake reached an all-time historic 

low elevation of 637.49 feet. Shortly 

thereafter, however, lake elevation began 

to rise (from December 2008 through 

June 2009), and Hartwell Lake had nearly 

2.6 times more inflow than outflow; lake 

elevation increased more than 20 feet.

Allatoona Lake is on the Etowah River 

and is managed by the U.S. Army Corps of 

Engineers. During the 2009 WY, Allatoona 

Lake had 20 percent more inflow than outflow, and lake elevation increased more 

than 27.5 feet from December 2008 through 

September 2009. The September 2009 flooding 

in the watershed contributed a large amount of 

inflow. Nearly 50 percent more inflow occurred 

in September than in May, June, July, and 

August combined, and lake elevation increased 

13 feet from September 19 to September 30.

Hartwell Lake

640 

635 

645 

650 

655 

660 

0 

20,000 

40,000 

60,000 

80,000 

100,000 

120,000 

140,000 

160,000 

O N J

2008 2009

D F M A M J J A S

Inflow and outflow, in cubic feet per second

Water level elevation, in feet above National

 Geodetic Vertical Datum of 1929

Lake Sidney Lanier

1,050 

1,052 

1,054 

1,056 

1,058 

1,060 

1,062 

1,064 

1,066 

1,068 

1,070 

1,072 

0 

20,000 

40,000 

60,000 

80,000 

100,000 

120,000 

O N J

2008 2009

D F M A M J J A S

Inflow and outflow, in cubic feet per second

Water level elevation, in feet above National

 Geodetic Vertical Datum of 1929

West Point Lake

628 

630 

632 

634 

636 

638 

640 

Inflow and outflow, in cubic feet per second

0 

50,000 

100,000 

150,000 

200,000 

250,000 

300,000 

350,000 

400,000 

O N J

2008

(Data from U.S. Army Corps of Engineers, 2009a)

2009

D F M A M J J A S

Water level elevation, in feet above National

 Geodetic Vertical Datum of 1929

Walter F

George

Lake

Hartwell Lake

J Strom 

 Thurmond

 Lake

Lake

Sidney

Lanier

West

Point

Lake

Lake Seminole

(Jim Woodruff)

Allatoona

Lake

Lake

Sinclair

Richard B 

 Russell Lake

Atlantic Ocean

Tagaloo R

EtowahR

Savannah River

Chattahoochee R

Savannah

Atlanta

820 

825 

830 

835 

840 

845 

850 

855 

0

140,000

40,000

60,000

20,000

100,000

120,000

160,000

180,000

80,000

O N J

2008 2009

D F M A M J J A S

Inflow

Outflow

Top of 

conservation

Water pool

level

Inflow and outflow, in cubic feet per second

Alatoona Lake

Water level elevation, in feet above National

 Geodetic Vertical Datum of 1929
6

September 25, 2009, accessed March 15, 2010, 

at http://www.ajc.com/news/atlanta/six-morecounties-added-147169.html.

U.S. Army Corps of Engineers, 2009a, Lake 

elevations, inflows and outflows, accessed May 

1, 2010, at http://www.sas.usace.army.mil/.

U.S. Army Corps of Engineers, 2009b, West Point 

Lake: U.S. Army Corps of Engineers, Mobile 

District, accessed May 1, 2010 at http://westpt.

sam.usace.army.mil/.

U.S. Army Corps of Engineers, 2009c, Hartwell 

Dam & Lake: U.S. Army Corps of Engineers, 

Savannah District, accessed May 1, 2010 at 

http://www.sas.usace.army.mil/lakes/hartwell/

intro.htm#funfacts. 

U.S. Geological Survey, 1975, Hydrologic unit 

map 1974, State of Georgia: U.S. Geological 

Survey, scale 1:500,000, 1 sheet.

U.S. Geological Survey, 2007, U.S. Geological 

Survey Ground-Water Climate Response 

Network: U.S. Geological Survey Fact Sheet 

2007–3003, 4 p., accessed July 1, 2009, 

at http://pubs.usgs.gov/fs/2007/3003/.

U.S. Geological Survey, 2009a, U.S. Geological 

Survey Groundwater Watch, Climate Response 

Network, accessed May 1, 2010, at 

http://groundwaterwatch.usgs.gov/.

References

Cressler, C.W., Thurmond, C.J., and Hester, W.G., 

1983, Groundwater in the greater Atlanta region, 

Georgia: Georgia Geological Survey Information 

Circular 63, 144 p.

National Weather Service, 2010a, Advanced Hydrologic Prediction Service, precipitation maps for 

Georgia, accessed June 24, 2009, at http://www.

srh.noaa.gov/rfcshare/precip_analysis_new.php.

National Weather Service, 2010b, Southeast United 

States floods, September 18–23, 2009: Silver 

Spring, MD, U.S. Department of Commerce, 

National Oceanic and Atmospheric Administration, 

Service Assessment, accessed March 15, 2010, 

at http://www.nws.noaa.gov/os/assessments/

pdfs/se_floods10.pdf.

Peck, M.F., Painter, J.A., and Leeth, D.C., 2009, 

Ground-water conditions and studies in Georgia, 

2006–2007: U.S. Geological Survey Scientific 

Investigations Report 2009–5070, 86 p.; 

at http://pubs.usgs.gov/sir/2009/5070/.

State of Georgia, 2010, Governor, EPD Ease 

Outdoor Water Use Schedules, accessed 

May 1, 2010, at http://gov.georgia.gov/00/press/det

ail/0,2668,78006749_141938033_143196762,00.html.

The Atlanta Journal-Constitution, 2009, Six more 

counties added to federal disaster list: The 

Atlanta Journal-Constitution Cox Media Group, 

By Andrew E. Knaak, Timothy K. Pojunas, and 

 Michael F. Peck

For more information contact:

Director, USGS Georgia Water Science Center

3039 Amwiler Road, Suite 130

Atlanta, Georgia 30360

770-903-9100

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

U.S. Geological Survey, 2009b, Historic Flooding 

in South Georgia, March 27–April 3, 2009: 

U.S. Geological Survey Fact Sheet 2009–3079, 

2 p., accessed June 1, 2010, at http://pubs.usgs.

gov/fs/2009/3079/.

U.S. Geological Survey, 2010a, U.S. Geological 

Survey annual data report for Georgia, water 

year 2009, accessed May 1, 2010, at http://

ga.water.usgs.gov/publications/pubswdr.html. 

U.S. Geological Survey, 2010b, Water Watch—

Current water resources conditions, accessed 

May 1, 2010, at http://waterwatch.usgs.gov.

U.S. Geological Survey, 2010c, Historic Flooding 

in Northern Georgia, September 16–22, 

2009: U.S. Geological Survey Fact Sheet 

2010–3061, 2 p., accessed August 10, 2010, 

at http://pubs.usgs.gov/fs/2010/3061/.

Flooding in South Georgia, 

March–April 2009

Flooding in South Georgia during 

March–April 2009 resulted in the highest 

streamflows recorded since 1948 on several 

rivers and since 1929 on a few others. Rainfall 

totals ranged from 5.6 to 14.0 inches during the 

6-day event across southern Georgia (National 

Weather Service, 2010a). Seven USGS field 

crews worked extensively for 10 days and 

made 84 flood measurements in south Georgia. 

These measurements were used to extend 

or verify the highest streamflow ratings. 

Six streamgages in the flooded area had peak 

streamflows that exceeded the 1-percent annual 

exceedance probability (100-year recurrence 

interval). The Federal Emergency Management 

Agency declared 46 counties in Georgia as 

disaster areas as a result of the flooding (U.S. 

Geological Survey, 2009b). 

Flooding in North Georgia occurred over 

several days, during September 18–22, 2009, 

as a result of precipitation totals that were 

as high as 20 inches in some areas. Georgia 

WSC field crews were mobilized and made 

118 discharge measurements before, during, and 

after (September 16–30, 2009) the flood. These 

measurements were made in a timely manner 

sometimes during perilous peak-flow or close to 

peak-flow conditions and were used to extend or 

verify streamflow ratings. Although 20 USGS 

streamgages throughout the northern part of 

the State were destroyed during the flood, all 

were restored to active status within 5 days. At 

several streamgages, temporary instrumentation 

was installed hundreds of feet away from the 

main channel. Peak flows that exceeded the 

0.2-percent annual exceedance probability 

(500-year recurrence interval) were recorded 

at 15 streamgages throughout the flooded area 

(U.S. Geological Survey, 2010c).

The Federal Emergency Management 

Agency reported that nearly $220 million in flood 

damage claims were submitted as a result of this 

flood event, and 14 counties declared Federal 

disaster areas (The Atlanta Journal-Constitution, 

2009). Eleven fatalities were attributed to this 

flood, many of which occurred during early 

morning hours when drivers attempted to cross 

flooded roads. Significant damage to hundreds 

of roads and bridges across the region severely 

affected traffic conditions for months after the 

event (National Weather Service, 2010b). 

Flooding in North Georgia, September 2009

GEORGIA

March 27, 2009

April 1, 2009 April 2, 2009 April 3, 2009

March 28, 2009 March 29, 2009

0.50

0.25

0.10

0.01

2.0

1.5

1.0

0.75

0.50

5.0

4.0

3.0

2.5

2.0

10

8.0

6.0

5.0

Observed daily precipitation, in inches

EXPLANATION

33°30'

84°30'

Base modified from 

U.S. Geological Survey

1:2,000,000-scale digital files

34°

85° 84°

0 30 MILES

0 15

15

30 KILOMETERS

Atlanta

0 to 2

2 to 4

4 to 6

6 to 8

8 to 10

10 to 12

12 to 14

14 to 16

16 to 18

18 to 20

Real-time streamgage

Crest-stage streamgage

EXPLANATION

Precipitation—September 18–22, 2009, 

in inches

Flood discharge—Measurement made 

between September 16–30, 2009