29

29

120

124

124

316

20

20

Lawrenceville–Suwanee Road

City limit

City limit

LAWRENCEVILLE

Paper Mill

Road

Fence Road

Creek

Creek

Shoal

Pew

Redland

Alcovy

River

Apalachee

River

Creek

River

Yellow

U.S. Department of the Interior

U.S. Geological Survey

Prepared in cooperation with the City of Lawrenceville

Hydrologic Conditions, Stream-Water Quality, and 

Selected Groundwater Studies Conducted in the 

Lawrenceville Area, Georgia, 2003–2008

Scientific Investigations Report 2010–5032
Cover. Clockwise from top left:

Flowing well 14FF59 near the Alcovy River near Lawrenceville, Georgia. 

 Photo by Alan M. Cressler, USGS.

USGS surface-water station photos by Paul D. Ankcorn, USGS:

02208050, Alcovy River near Lawrenceville, Georgia. 

02218565, Apalachee River at Fence Road near Dacula, Georgia.

02208130, Shoal Creek at Paper Mill Road near Lawrenceville, Georgia. 

02205522, Pew Creek at Patterson Road near Lawrenceville, Georgia.
Hydrologic Conditions, Stream-Water Quality, and 

Selected Groundwater Studies Conducted in the 

Lawrenceville area, Georgia, 2003–2008

By John S. Clarke and Lester J. Williams

Prepared in cooperation with the City of Lawrenceville

Scientific Investigations Report 2010–5032

U.S. Department of the Interior

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

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2010

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natural hazards, and the environment, visit http://www.usgs.gov or call 1-888-ASK-USGS

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U.S. Government.

Although this report is in the public domain, permission must be secured from the individual copyright owners to 

reproduce any copyrighted materials contained within this report.

Suggested citation:

Clarke, J.S., and Williams, L.J., 2010, Hydrologic conditions, stream-water quality, and selected groundwater studies 

conducted in the Lawrenceville area, Georgia, 2003–2008: U.S. Geological Survey Scientific Investigations 

Report 2010–5032, 55 p.
iii

Contents

Abstract...........................................................................................................................................................1

Introduction ....................................................................................................................................................2

City of Lawrenceville Cooperative Water Program.........................................................................2

Purpose and Scope ..............................................................................................................................2

Study Area..............................................................................................................................................2

Water Use ..............................................................................................................................................7

Related Studies .....................................................................................................................................7

Acknowledgments................................................................................................................................8

Methods...........................................................................................................................................................8

Groundwater Levels .............................................................................................................................8

Stream Stage and Discharge..............................................................................................................8

Stream Base Flow.................................................................................................................................9

Precipitation...........................................................................................................................................9

Stream-Water Quality ..........................................................................................................................9

Hydrologic Conditions.................................................................................................................................10

Upper Apalachee River Watershed.................................................................................................10

Monitoring Networks ................................................................................................................10

Hydrologic and Precipitation Trends ......................................................................................11

Upper Alcovy Watershed ..................................................................................................................12

Monitoring Networks ................................................................................................................12

Hydrologic and Precipitation Trends ......................................................................................12

Redland–Pew Creek Watershed ......................................................................................................20

Monitoring Networks ................................................................................................................20

Hydrologic and Precipitation Trends ......................................................................................20

Stream-Water Quality .................................................................................................................................30

Apalachee River..................................................................................................................................30

Redland–Pew Creek ..........................................................................................................................34

Shoal Creek .........................................................................................................................................36

Groundwater Studies ..................................................................................................................................40

Well-Field Expansion in the Upper Alcovy River Watershed .....................................................40

Hydrogeologic Investigation of Ezzard Street Well, Shoal Creek Watershed..........................40

Surface-Water Interconnection..............................................................................................40

Elevated Levels of Radionuclides ...........................................................................................42

Lithology and Water-Bearing Characteristics at Lawrenceville–Suwanee 

No. 2 Test Well, Redland–Pew Creek Watershed............................................................46

Summary........................................................................................................................................................47

Selected References...................................................................................................................................48

Appendix 1. Borehole Geophysical Logs For Wells 14FF62, 14FF63, 14FF64, and 14FF65, 

Lawrenceville Area, Georgia........................................................................................................51
iv

Figures

1. Map showing location of study area and continuous groundwater-level 

monitoring network for the Lawrenceville area, Georgia......................................................3

2. Graph showing mean daily water use by the City of Lawrenceville, 

Georgia, 1985–2007.......................................................................................................................7

3. Map showing surface-water and groundwater monitoring networks, 

upper Apalachee River watershed near Lawrenceville, Georgia, 2008 ....................................10

4. Graph showing total monthly precipitation and mean monthly streamflow 

at surface-water station 02218565, and mean monthly and periodic water 

levels in well 14GG02, upper Apalachee River watershed near 

Lawrenceville, Georgia, 2003–2008..........................................................................................11

5. Map showing surface-water and groundwater monitoring networks, 

upper Alcovy River watershed near Lawrenceville, Georgia, 2008 ...................................13

6–8. Maps showing—

6. Total monthly precipitation and mean monthly streamflow at surfacewater station 02208050, upper Alcovy River watershed near Lawrenceville, 

Georgia, 2003–2008............................................................................................................14

7. Groundwater levels in the regolith in the upper Alcovy River watershed 

near Lawrenceville, Georgia, 2003–2008 .......................................................................16

8. Groundwater levels in the bedrock in the upper Alcovy River watershed 

near Lawrenceville, Georgia, 2003–2008 .......................................................................17

9. Graphs and map showing groundwater seepage along selected reaches in 

the upper Alcovy River watershed near Lawrenceville, Georgia, 2003–2006 ..................18

10. Graph showing stream stage at surface-water station 02208047 and 

groundwater levels in regolith well 14FF60, upper Alcovy River watershed 

near Lawrenceville, Georgia, 2003–2008 ................................................................................20

11. Map showing surface-water and groundwater monitoring networks, Redland–

Pew Creek and Yellow River watersheds near Lawrenceville, Georgia, 2008 .................21

12–14. Graphs showing—

12. Total monthly precipitation and mean monthly streamflow at surface-water 

station 02205522, Redland–Pew Creek watershed near Lawrenceville, 

Georgia, 2003–2008............................................................................................................22

13. Groundwater levels in the regolith in the Redland–Pew Creek and 

Yellow River watersheds near Lawrenceville, Georgia, 2003–2008 ..........................23

14. Groundwater levels in the bedrock in the Redland–Pew Creek and 

Yellow River watersheds near Lawrenceville, Georgia, 2003–2008 ..........................24

15. Map and graphs showing groundwater seepage along selected reaches in 

the Redland–Pew Creek watershed near Lawrenceville, Georgia, 2003–2008................28

16. Graphs showing mean daily streamflow, precipitation, specific conductance, and 

water temperature, and median daily turbidity at surface-water station 02218565, 

Apalachee River at Fence Road near Dacula, Georgia, 2003–2008 ...................................32
v

17–19. Graphs showing—

17. Fecal coliform sampling results for surface-water station 02218565, 

Apalachee River at Fence Road near Dacula, Georgia, 2005–2008 ..........................33

18. Mean daily streamflow, precipitation, specific conductance, and water 

temperature, and median daily turbidity at surface-water station 02205522, 

Pew Creek at Patterson Road near Lawrenceville, Georgia, 2005–2008..................34

19. Fecal coliform sampling results for surface-water station 02205522, 

Pew Creek at Patterson Road near Lawrenceville, Georgia, 2005–2008..................35

20. Map showing surface-water and groundwater monitoring networks, 

Shoal Creek watershed near Lawrenceville, Georgia, 2008................................................36

21–23. Graphs showing—

21. Mean daily streamflow, precipitation, specific conductance, and water 

temperature, and median daily turbidity at surface-water station 02208130, 

Shoal Creek at Paper Mill Road near Lawrenceville, Georgia, 2005–2008 ..............37

22. Fecal coliform sampling results at surface-water station 02208130, 

Shoal Creek at Paper Mill Road near Lawrenceville, Georgia, 2006–2008 ..............38

23. Streamflow, specific conductance, and turbidity at surface-water 

station 02208130, Shoal Creek at Paper Mill Road near Lawrenceville, 

Georgia, June 1–20, 2007..................................................................................................39

24. Geologic map of the upper Alcovy River watershed showing locations 

of test wells drilled in May and July 2003 near Lawrenceville, Georgia...........................41

25. Semilog showing upper and lower packer intervals in relation to 

water-bearing zones in well 14FF55 near Lawrenceville, Georgia, 2005...........................43

26. Photograph showing K-packer system used to modify well 14FF55 

to eliminate the influence of surface water, March 2005 ....................................................43

27. Hydrograph showing water level in the upper portion of well 14FF55 

near Lawrenceville, Georgia, during the packer test, May 10, 2005 ..................................43

28. Hydrograph showing water level responses to pumping the lower zone of 

well 14FF55 near Lawrenceville, Georgia, during packer tests, August 2007...................45

29. Lithology and borehole geophysical log characteristics for test well 13FF34 

near Lawrenceville, Georgia.....................................................................................................46

Appendix

1–1. Borehole geophysical logs for well 14FF62, Lawrenceville area, Georgia .......................52

1–2. Borehole geophysical logs for well 14FF63, Lawrenceville area, Georgia .......................53

1–3. Borehole geophysical logs for well 14FF64, Lawrenceville area, Georgia .......................54

1–4. Borehole geophysical logs for well 14FF65, Lawrenceville area, Georgia .......................55
vi

Tables

1. Construction and site information for selected wells in the Lawrenceville, 

Georgia, area.................................................................................................................................4

2. Stream-site information, Lawrenceville, Georgia, surface-water 

monitoring network ......................................................................................................................6

3. Base-flow measurements along selected stream reaches, upper 

Alcovy River watershed in the Lawrenceville area, Georgia, 2003–2006..........................15

4. Base-flow measurements along selected stream reaches, Redland–Pew Creek 

watershed, Lawrenceville, Georgia area, 2003–2006 ...........................................................26

5. Statistical summary of mean and median daily streamflow, precipitation, 

stream temperature, specific conductance, and turbidity data for 

surface-water sites in the Lawrenceville area, Georgia, October 1, 2005, 

through December 31, 2008.......................................................................................................31

6. Georgia Environmental Protection Division fecal-coliform bacteria standards..............33

7. Summary of radiological testing results for water samples collected from 

Well 14FF55 ..................................................................................................................................42

8. Summary of radiological testing for water samples collected from discrete 

packer intervals in well 14FF55.................................................................................................44

9. Water levels in the upper and lower zones in well 14FF55 during packer test, 

August 1–19, 2007 .......................................................................................................................45
vii

Conversion Factors

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

square mile (mi2) 259.0 hectare (ha)

square mile (mi2) 2.590 square kilometer (km2) 

Volume

gallon (gal) 3.785 liter (L) 

gallon (gal) 0.003785 cubic meter (m3) 

gallon (gal) 3.785 cubic decimeter (dm3) 

million gallons (Mgal) 3,785 cubic meter (m3)

Flow rate

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)

gallon per minute (gal/min) 0.06309 liter per second (L/s)

million gallons per day (Mgal/d) 0.04381 cubic meter per second (m3/s)

Radioactivity

picocurie per liter (pCi/L) 0.037 becquerel per liter (Bq/L) 

Specific capacity

gallon per minute per foot 

[(gal/min)/ft)]

 0.2070 liter per second per meter [(L/s)/m]

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

°F =(1.8 ×°C) + 32

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows:

°C=(°F –32)/ 1.8

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 

(NAVD 88).

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

Altitude, as used in this report, refers to distance above the vertical datum.

Specific conductance is given in microsiemens per centimeter at 25 degrees Celsius (μS/cm at 

25 °C).

Concentrations of chemical constituents in water are given either in milligrams per liter (mg/L) 

or micrograms per liter (μg/L).

Concentrations of bacteria in water are reported in most probable number of colonies per 

100 milliliters (MPN col/100 mL).

Abstract

Hydrologic studies conducted during 2003–2008 as part 

of the U.S. Geological Survey Cooperative Water Program 

with the City of Lawrenceville, Georgia, provide important 

data for the management of water resources. The Cooperative 

Water Program includes (1) hydrologic monitoring 

(precipitation, streamflow, and groundwater levels) to quantify 

baseline conditions in anticipation of expanded groundwater 

development, (2) surface-water-quality monitoring to provide 

an understanding of how stream quality is affected by natural 

(such as precipitation) and anthropogenic factors (such as 

impervious area), and (3) geologic studies to better understand 

groundwater flow and hydrologic processes in a crystalline 

rock setting.

The hydrologic monitoring network includes each of 

the two watersheds projected for groundwater development—

the Redland–Pew Creek and upper Alcovy River watersheds—

and the upper Apalachee River watershed, which serves 

as a background or control watershed because of its 

similar hydrologic and geologic characteristics to the other 

two watersheds. In each watershed, precipitation was generally 

greater during 2003–2005 than during 2006–2008, and 

correspondingly streamflow and groundwater levels decreased. 

In the upper Alcovy River and Redland–Pew Creek watersheds, 

groundwater level declines during 2003–2008 were mostly 

between 2 and 7 feet, with maximum observed declines of as 

much as 28.5 feet in the upper Alcovy River watershed, and 

49.1 feet in the Redland–Pew Creek watershed. 

Synoptic base-flow measurements were used to 

locate and quantify gains or losses to streamflow resulting 

from groundwater interaction (groundwater seepage). In 

September 2006, seepage gains were measured at five of nine 

reaches evaluated in the upper Alcovy River watershed, with 

losses in the other four. The four losing reaches were near 

the confluence of the Alcovy River and Cedar Creek where 

the stream gradient is low and bedrock is at or near the land 

surface. In the Redland–Pew Creek watershed, groundwater 

seepage gains were observed at each of the 10 reaches 

measured during September 2008. 

Continuous specific conductance, temperature, and 

turbidity data were collected at gage sites located on Pew 

and Shoal Creeks, which drain about 32 percent of the 

city area, and at a background site on the Apalachee River 

located outside the city boundary. Continuous surface-water 

monitoring data indicate that reduced precipitation during 

2006–2008 resulted in lower turbidity and higher stream 

temperature and specific conductance than in 2003–2005. 

In comparison to the other two stream sites, water at the 

Apalachee River site had the lowest mean and median values 

for specific conductance, and the greatest mean and median 

values for turbidity during October 2005–December 2008.

In addition to continuous water-quality monitoring, 

samples were collected periodically to determine fecalcoliform bacteria concentrations. None of the individual 

samples at the three sites exceeded the Georgia Environmental 

Protection Division (GaEPD) limit of 4,000 most probable 

number of colonies per 100 milliliters (MPN col/100 mL) 

for November through April. In the Redland–Pew Creek 

and Shoal Creek watersheds, the GaEPD 30-day geometric 

mean standard of 200 MPN col/100 mL for May–October 

was exceeded twice during two sampling periods in 

May–October 2007 and twice during two sampling periods 

in May–October 2008.

Groundwater studies conducted during 2003–2007 

include the collection of borehole geophysical logs from 

four test wells drilled in the upper Alcovy River watershed 

to provide insight into subsurface geologic characteristics. A 

flowmeter survey was conducted in a well south of Rhodes 

Jordan Park to help assess the interconnection of the well with 

surface water and the effectiveness of a liner-packer assembly 

installed to eliminate that interconnection. At that same well, 

hydraulic packer tests were conducted in the open-hole section 

of the well, and water samples were collected to assess the 

depth and concentration of gross-alpha radiation detected in 

the well before and after well modification. 

Hydrologic Conditions, Stream-Water Quality, and 

Selected Groundwater Studies Conducted in the 

Lawrenceville Area, Georgia, 2003–2008

By John S. Clarke and Lester J. Williams
2 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

Introduction 

In the metropolitan Atlanta region, demand has increased 

for available surface-water resources as the population 

grows, and downstream users expect minimum streamflow 

requirements to be maintained. This demand has been 

exacerbated by droughts during 1998–2002 and 2006–2008. 

The City of Lawrenceville, Georgia, has a growing need for 

water supply (fig. 1). City population increased from 8,928 in 

1980 to 22,397 in 2000 (Georgia Humanities Council, 2008) 

and by 2007 had risen to 28,969, an increase of 29 percent 

from 2000 (City-Data.com, 2009). These population increases 

resulted in a doubling of water use during 1985–2000 

(Julia Fanning, U.S. Geological Survey, written commun., 

February 19, 2009). 

To meet Lawrenceville’s growing need for water, the city 

currently (2008) is expanding development of its existing 

groundwater supply. During 1995–2007, Lawrenceville 

obtained 4–7 percent of its drinking water from groundwater 

(from a single well), with the remainder from surface 

water (Chattahoochee River). In addition to an existing 

well near the center of town, the city plans to pump 

groundwater from two crystalline bedrock wells—one in 

the Redland–Pew Creek watershed and one in the upper 

Alcovy River watershed (fig. 1). Because the long-term 

effects of groundwater withdrawal in this area are largely 

unknown, the U.S. Geological Survey (USGS), in cooperation 

with the City of Lawrenceville, began a study in 2002 to 

investigate the sustainability of groundwater resources as 

additional municipal wells become operational. The study 

includes establishment of a groundwater level and streamflow 

monitoring network to (1) establish baseline conditions 

prior to the initiation of pumping, and (2) assess effects 

that groundwater development may have on ground- and 

surface-water resources. The data and information developed 

during the study can be used by local resource managers 

to help develop a sustainable groundwater supply that will 

minimize negative effects on surface-water resources. 

In addition to understanding groundwater resources, 

successful watershed management requires an understanding 

of how stream-water quality is affected by watershed 

characteristics. Consistent, long-term, accurate monitoring 

can be used to describe the status and trends in stream-water 

quality and to assess how water quality is affected by natural 

factors (such as precipitation) and anthropogenic factors (such 

as impervious area), and to provide information that is essential 

for successful watershed management. To assist in these efforts, 

the USGS and the City of Lawrenceville established a surfacewater-quality monitoring network in 2005. This network includes 

real-time streamflow and water-quality monitoring via satellite 

telemetry, automated water sampling during storm events, and 

periodic seasonal sampling during high- and low-flow conditions. 

These data provide information needed to meet regulatory 

requirements, while enhancing understanding of how urban 

stream quality is affected by natural and anthropogenic factors.

City of Lawrenceville Cooperative 

Water Program

A Cooperative Water Program (CWP) between the 

USGS and the City of Lawrenceville has been in existence 

since 1994. The studies under this program are conducted 

by the USGS and are supported by funding from the City 

of Lawrenceville and USGS Federal Cooperative Water 

Program. The initial purpose of the CWP was to provide a 

better understanding of the geologic controls on groundwater 

availability in fractured crystalline rock. In 2002, the 

program was modified to incorporate groundwater and stream 

monitoring to assess the effects of groundwater development. 

Stream-water-quality monitoring was added to the program 

in 2005. 

Purpose and Scope

This report presents an overview of hydrologic 

conditions, stream-water quality, and groundwater studies 

based on groundwater, surface-water, and stream-waterquality data collected during 2003–2008 in and around 

Lawrenceville, Georgia (fig. 1). During 2008, 27 wells 

were used to monitor groundwater levels, of which 3 were 

continuously recorded, 21 were measured periodically, and 

2 were continuously monitored during part of the year and 

measured periodically for the remainder of the year (table 1). 

Streamflow and precipitation were continuously recorded at 

four sites, of which three included continuous water-quality 

monitoring of water temperature, specific conductance, and 

turbidity (table 2). In addition to the 4 continuously monitored 

surface-water sites, the network included periodic streamflow 

measurements at 22 other sites (the number of locations 

measured in a given year varied over the reporting period).

Study Area

The 92-square-mile (mi2) study area encompasses 

the 13.6-mi2 City of Lawrenceville and adjacent areas 

in Gwinnett County (fig. 1), located approximately 

26 miles (mi) northeast of Atlanta, Georgia, in the Piedmont 

Physiographic Province. In Georgia, the Piedmont lies 

between the Valley and Ridge and Blue Ridge Physiographic 

Provinces to the north and the Coastal Plain Physiographic 

Province to the south (fig. 1). Topography in the study 

area consists of low hills and moderately entrenched 

stream valleys that range in altitude from about 780 to 

1,170 feet (ft). Lawrenceville is located on a drainage divide 

separating the Yellow River and Alcovy River. To the west, 

the area is drained by Redland Creek, Pew Creek, and 

unnamed tributaries of the Yellow River; to the east, the area 

is drained by Shoal Creek and unnamed tributaries of the 

Alcovy River (fig. 1). 
Introduction 3

Figure 1. Location of study area and continuous groundwater-level monitoring network for the Lawrenceville area, Georgia.

29

29

120

124

124

316

20

20

Upper Alcovy River

EXPLANATION

Watershed

Upper Apalachee 

 River

Redland–Pew Creek

Shoal Creek

Yellow River

Continuous with

 precipitation

Continuous with

 water quality

Base-flow measurement

Periodic with staff gage

River

Chattahoochee

G E O R G I A

GWINNETT Atlanta COUNTY

Groundwater

 monitoring well

 Continuous regolith

 Periodic regolith

 Continuous bedrock

 Periodic bedrock

Surface-water station

OCMULGEE RIVER

BASIN

OCONEE RIVER

BASIN

CHATTAHOOCHEE RIVER

BASIN

0 2 4

0 2 4

6 MILES

6 KILOMETERS

Map area below

Figure 1. Study area showing watersheds and monitoring sites in the City of Lawrenceville area, Gwinnett County, Georgia.

Base from U.S. Geological Survey

1:100,000-scale digital data

N

Buford Dam

Lawrenceville–Suwanee Road

Patterson Road

City limit

City limit

0 1 2 3 MILES

0 1 2 3 KILOMETERS 

Base modified from U.S. Geological Survey

1:24,000-scale digital raster graphics

Lawrenceville, Georgia

LAWRENCEVILLE

DACULA

Paper Mill

Fence Road

Road

N

Existing or proposed 

 bedrock production 

 well—Also used 

 for monitoring

Creek

Creek

Shoal

Pew

Redland

River

Alcovy

Apalachee

Chattahoochee River

River

Yellow

Lake Sidney Lanier

River

Creek

River Yellow
4 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

Table 1. Construction and site information for selected wells in the Lawrenceville, Georgia, area.

[NAVD 88, North American Vertical Datum of 1988; Aquifer: 320CRSL—crystalline rock, 110SFCL—regolith; 2008 network: C—continuous water level, 

P—periodic water level; —, no data]

Basin Well 

identifier

Site 

identification

Lattitude Longitude Altitude1

(feet above 

NAVD 88)

Date 

drilled

(decimal degrees)

Upper Apalachee River 14GG02 340049083551101 34.0137 –83.9198 1,120 — 

Upper Alcovy River 14FF52 335806083581001 33.9684 –83.9698 1,082.25 06/ 1999 

Upper Alcovy River 14FF59 335902083565901 33.9839 –83.9497 952.1 7/20/2001 

Upper Alcovy River 14FF60 335902083565902 33.9839 –83.9497 952.8 8/16/2001 

Upper Alcovy River 14FF62 335843083570101 33.9787 –83.9502 963 5/20/2003 

Upper Alcovy River 14FF63 335851083564701 33.9809 –83.9465 939 5/22/2003 

Upper Alcovy River 14FF64 335846083562401 33.9795 –83.9400 937 7/8/2003 

Upper Alcovy River 14FF65 335905083565101 33.9847 –83.9475 985 7/23/2003 

Upper Alcovy River 14FF66 335905083565102 33.9848 –83.9474 985 7/8/2003 

Upper Alcovy River 14FF67 335908083573701 33.9856 –83.9603 985.17 7/8/2003 

Upper Alcovy River 14FF68 335927083571701 33.9909 –83.9546 1,055 7/8/2003 

Upper Alcovy River 14FF69 335827083565901 33.9741 –83.9500 1,090 7/8/2003 

Yellow River 13FF20 335744084011601 33.9622 –84.0213 990.1 5/14/2001 

Yellow River 13FF21 335641084021101 33.9447 –84.0364 889.4 5/16/2001 

Yellow River 13FF24 335641084021102 33.9447 –84.0364 889.4 8/16/2001 

Yellow River 13FF29 335628084020101 33.9410 –84.0337 1,005 7/9/2003 

Redland–Pew Creek 13FF13 335721084002601 33.9559 –84.0069 972.3 — 

Redland–Pew Creek 13FF14 335741084000801 33.9616 –84.0019 987.86 — 

Redland–Pew Creek 13FF16 335743084003901 33.9625 –84.0109 1,004.68 06 /1999 

Redland–Pew Creek 13FF18 335721084004801 33.9559 –84.0134 953.8 5/9/2001 

Redland–Pew Creek 13FF19 335602084010201 33.9341 –84.0178 921.8 5/10/2001 

Redland–Pew Creek 13FF22 335646084010701 33.9461 –84.0187 929.7 5/17/2001 

Redland–Pew Creek 13FF23 335623084014401 33.9396 –84.0289 906.2 5/30/2001 

Redland–Pew Creek 13FF25 335602084010202 33.9341 –84.0178 921.6 8/16/2001 

Redland–Pew Creek 13FF27 335705084012801 33.9515 –84.0244 1,009 7/15/2003 

Redland–Pew Creek 13FF28 335705084012802 33.9515 –84.0244 1,009.46 7/9/2003 

Redland–Pew Creek 13FF30 335614084010701 33.9372 –84.0186 1,000 7/23/2003 

Redland–Pew Creek 13FF31 335614084010702 33.9371 –84.0185 1,000 7/9/2003 

Redland–Pew Creek 13FF34 335653084010101 33.9480 –84.0170 940 6/25/2008 

Shoal Creek 14FF16 335735083584502 33.9598 –83.9788 994.2 1949 

Shoal Creek 14FF55 335707083582101 33.9519 –83.9726 969.6 4/16/2001 

.
Introduction 5

Table 1. Construction and site information for selected wells in the Lawrenceville, Georgia, area.—Continued

[NAVD 88, North American Vertical Datum of 1988; Aquifer: 320CRSL—crystalline rock, 110SFCL—regolith; 2008 network: C—continuous water level, 

P—periodic water level; —, no data???]

Well 

depth 

(feet)

Casing 

depth 

(feet)

Casing

diameter

 (inches)

Measurement

 date

Depth to 

water below 

land surface3 

(feet)

Aquifer

Date

monitoring

began

2008 

network 

304 42 6 7/7/2003 81.85 320CRSL 7/11/2003 C

624 25 6 8/19/1999 18.80 320CRSL 8/19/1999 P

470 30 8 — — 320CRSL 8/26/2001 —

2

9 24 2 1/23/2003 2.89 110SFCL 1/23/2003 P

600 25 8 6/5/2003 1.83 320CRSL 6/5/2003 P

600 25 8 6/5/2003 0.68 320CRSL 6/5/2003 P

600 26 6 7/24/2003 7.41 320CRSL 7/24/2003 P

465 25 6 7/23/2003 13.49 320CRSL 11/7/2003 C, P

2

20 215 2 7/23/2003 13.10 110SFCL 11/7/2003 C, P

2

41 236 2 7/23/2003 8.81 110SFCL 7/23/2003 P

2

45 239 2 7/23/2003 28.97 110SFCL 10/1/2001 P

2

38 233 2 7/23/2003 16.85 110SFCL 7/23/2003 P

455 72 6 8/2/2001 17.28 320CRSL 8/17/2001 P

505 40 8 8/2/2001 4.12 320CRSL 8/2/2001 P

2

16 212 2 10/31/2001 3.45 110SFCL 10/31/2001 P

26 21 2 7/23/2003 18.90 110SFCL 7/23/2003 P

430 22 6 11/17/1996 4.05 320CRSL 2/5/1998 P

280 23 10 10/6/1998 12.50 320CRSL 7/15/1998 —

627 25 6 8/19/1999 39.17 320CRSL 8/19/1999 P

550 55 8 1/23/2003 –6.47 320CRSL 8/2/2001 —

477 65 8 8/2/2001 8.50 320CRSL 8/2/2001 P

600 60 8 8/2/2001 0.15 320CRSL 8/2/2001 P

— 30 8 — — 320CRSL 10/9/2001 —

2

16 210 2 10/31/2001 6.08 110SFCL 11/1/2001 P

305 34 6 7/23/2003 18.37 320CRSL 7/23/2003 P

2

23 218 2 7/23/2003 17.57 110SFCL 7/23/2003 P

345 36 6 7/23/2003 27.96 320CRSL 11/7/2003 C

2

26 221 2 7/23/2003 19.92 110SFCL 11/7/2003 C

605 21 6 6/26/2008 4.84 320CRSL 6/26/2008 P

302 6 12 12/6/1994 6.24 320CRSL — —

425 65 8 — — 320CRSL — —

1 Accuracy varies based on method of measurement. Values reported to tenths or hundredths of a foot represent measurement made by 

surveying or global positioning techniques.

2 Values rounded to nearest foot.

3 Values reported to hundredth of a foot
6 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

Table 2. Stream-site information, Lawrenceville, Georgia, surface-water monitoring network.

[Site type: S—streamflow, Q—water quality]

Basin USGS site 

identification Site name Drainage area (square miles) Site type Date monitoringbegan

Upper Apalachee River 02218565 Apalachee River at Fence Road, 

near Dacula, GA

5.68 Continuous 

S/Q

7/13/2001

Upper Alcovy River 02208046 Alcovy River Hurricane Shoals Rd, 

near Dacula, GA

4.74 Base flow 8/28/2003

Upper Alcovy River 022080463 Alcovy River below Hurricane Sh Rd 

below confluence

4.90 Base flow 9/6/2006

Upper Alcovy River 02208047 Alcovy River at GA 316, near 

Lawrenceville, GA

5.01 Staff gage 4/23/2003

Upper Alcovy River 022080475 Alcovy River above Cedar Creek 

near Lawrenceville, GA

5.11 Base flow 8/28/2003

Upper Alcovy River 022080477 Cedar Creek above Progress Center 

Ave, Lawrenceville, GA

0.620 Base flow 9/6/2006

Upper Alcovy River 022080478 Cedar Creek below Hurricane Shoals 

Road, Lawrenceville, GA

1.50 Base flow 9/6/2006

Upper Alcovy River 022080479 Cedar Creek below GA 316, 

at Lawrenceville, GA

3.24 Base flow 8/28/2003

Upper Alcovy River 0220804795 Cedar Creek below airport 

near Lawrenceville, GA

0.630 Base flow 9/6/2006

Upper Alcovy River 02208048 Cedar Creek at Cedars Rd, 

near Lawrenceville, GA

4.08 Staff gage 7/19/2007

Upper Alcovy River 02208049 Cedar Creek above Alcovy River 

at Lawrenceville, GA

4.10 Base flow 8/28/2003

Upper Alcovy River 022080495 Alcovy River tributary at sewer cut 

near Lawrenceville, GA

0.630 Base flow 9/6/2006

Upper Alcovy River 02208050 Alcovy River near 

Lawrenceville, GA

10.0 Continuous S 4/23/2004

Redland–Pew Creek 02205450 Pew Creek at Sarah Lane, 

at Lawrenceville, GA

1.82 Base flow 8/29/2003

Redland–Pew Creek 02205500 Pew Creek near Lawrenceville, GA 2.23 Base flow 10/26/1953

Redland–Pew Creek 02205508 Pew Creek at Sugarloaf Pkwy, 

near Lawrenceville, GA

3.43 Staff gage 2/10/2003

Redland–Pew Creek 022055082 Redland Creek at Maltbie St 

near Lawrenceville, GA

0.470 Base flow 8/29/2003

Redland–Pew Creek 022055085 Redland Creek below GA 120 

at Lawrenceville, GA

0.950 Base flow 8/29/2003

Redland–Pew Creek 02205520 Redland Creek at GA 29, near 

Lawrenceville, GA

3.11 Staff gage 9/10/1952

Redland–Pew Creek 02205522 Pew Creek at Patterson Rd, 

near Lawrenceville, GA

7.00 Continuous 

S/Q

3/28/2003

Redland–Pew Creek 335602084010401 Pew Creek tributary below 

Johnston Rd, Lawrenceville, GA

0.600 Base flow 9/6/2006

Redland–Pew Creek 335629084013801 Redland Creek tributary near 

Monfort Rd, Lawrenceville, GA

0.240 Base flow 9/5/2006

Redland–Pew Creek 335645084010701 Redland Creek at Lawrenceville

Suwanee Rd, Lawrenceville, GA

2.57 Base flow 9/5/2006

Redland–Pew Creek 335646084010702 Redland Creek tributary at Lville 

Suwanee Rd, Lawrenceville, GA

0.090 Base flow 9/5/2006

Redland–Pew Creek 335658084010001 Redland Creek at Lawrenceville 

Suwanee Rd No 2, Lawrenceville, GA

2.38 Base flow 9/5/2006

Shoal Creek USGS 02208130 Shoal Creek at Paper Mill Rd, 

near Lawrenceville, GA

3.90 Continuous 

S/Q

10/1/2005
Introduction 7

The Lawrenceville area is underlain by igneous and 

metamorphic rocks (bedrock) of the Piedmont Physiographic 

Province that have very little primary porosity and 

permeability. The Redland–Pew Creek, upper Apalachee, 

and southern part of the upper Alcovy River watersheds are 

characterized by compositionally layered rocks, whereas the 

northern part of the upper Alcovy River watershed is underlain 

by granitic gneiss. Groundwater in igneous and metamorphic 

rock aquifers occurs in joints, fractures, and other secondary 

openings in the bedrock. The bedrock in most areas is overlain 

by a mantle of soil, saprolite, alluvium, and weathered rock, 

collectively referred to as regolith, that provide much of 

the recharge to the igneous and metamorphic rock aquifers 

in areas where the aquifers and regolith are hydraulically 

connected. Under natural, unstressed conditions, the amount of 

groundwater discharged to streams (base flow) and available 

to be withdrawn by wells is approximately equal to the amount 

of water recharging the aquifer. 

Wells in the area have a wide range of yield and depth, 

and derive water mainly from the fractures and other 

discontinuities in the igneous and metamorphic bedrock that 

underlie the entire study area (Williams and others, 2004). The 

reported yield of wells ranges from about 1 to 600 gallons per 

minute (gal/min). Most of the bedrock wells range from about 

100 to 600 ft in depth. 

In a recent report on watersheds in Gwinnett County, 

Landers and others (2007) characterize the climate near 

Lawrenceville as humid subtropical with warm, humid 

summers and cool, wet winters. The average high monthly 

temperature of about 88 degrees Fahrenheit (°F) is in July, 

and the average low monthly temperature of about 32 °F is 

in January. Average annual precipitation in Gwinnett County 

during 1998–2003 was 53.6 inches, with most precipitation 

occurring December through April. Consequently, the 

greatest groundwater recharge and subsequent contribution to 

streamflow occurs during the cooler months when rainfall is 

highest and evapotranspiration is lowest. Summer precipitation 

is usually of short duration and unevenly distributed. Summer 

storms generally produce less cumulative rainfall than 

winter storms; however, they tend to have greater intensity 

and may result in more erosion and wash off of constituents 

(Landers and others, 2007).

Water Use

Water supply in the Lawrenceville area is provided 

mostly by surface water (Chattahoochee River ) purchased 

from Gwinnett County, with a smaller amount derived from 

city-owned supply wells (fig. 2). During 1985–2000, total 

water use more than doubled from 1.37 million gallons per 

day (Mgal/d) in 1985 to 2.81 Mgal/d in 2000 (Julia Fanning, 

U.S. Geological Survey, written commun., February 19, 

2009). Since 2000, water use decreased as the result of water 

conservation, leak detection, and improvements in metering 

equipment (Mike Bouie, City of Lawrenceville, oral commun., 

February 2009). 

During 1985–95, supply was exclusively provided by 

surface water. In 1995, groundwater from a single well located 

near the center of the city in the Shoal Creek watershed 

began to supply a small percentage of the total withdrawal 

(well 14FF16, table 1). Between 1995 and 2007, groundwater 

from this well contributed 4–7 percent of the water supply, 

with a maximum annual production of 0.19 Mgal/d in 2000. 

Additional production wells are planned for the Redland–Pew 

Creek and upper Alcovy River watersheds. An additional 

production well in the Redland–Pew Creek watershed was 

brought online during the fall of 2008. The city would like 

to develop a groundwater system capable of delivering 

2 Mgal/d (Mike Bowie, City of Lawrenceville, oral commun., 

February 2009).

Related Studies

The USGS, in cooperation with the Gwinnett County 

Department of Water Resources, established a water-quality 

monitoring program during late 1996 to collect streamflow 

and stream-water-quality data (Landers and others, 2007). 

The overall purpose of the monitoring program is to provide a 

long-term record of hydrologic and water-quality data that can 

be used by county and State watershed managers to protect 

and enhance the streams in the county. This water-quality 

monitoring program provides comprehensive measurements 

of stream hydrology and constituent concentrations and loads. 

The program includes:

• Monitoring water-quantity and water-quality status,

• Monitoring long-term and seasonal water-quantity and 

water-quality trends,

• Providing flood warning data for emergency managers,

• Providing data to water managers to evaluate and 

meet regulatory monitoring requirements of permits 

for water-supply withdrawals, wastewater discharges, 

stormwater, source-water watersheds, and total 

maximum daily load studies, and

• Providing data for computation of constituent loads. 

Figure 2. Mean daily water use by the City of 

Lawrenceville, Georgia, 1985–2007.

0

0.5

1.0

1.5

2.0

2.5

3.0

1985

Groundwater

Surface water

1990 1995 2000 2005 2006 2007

MEAN DAILY WATER USE,

IN 

MILLION GALLONS PER DAY

Figure 2. Mean daily water use by the City of 

Lawrenceville, Georgia, 1985–2007.
8 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

The scope of data-collection activities for the surfacewater-quality component of the Lawrenceville CWP is 

similar to the Gwinnett County study, including continuous 

monitoring of temperature, specific conductance, and turbidity, 

and periodic sampling for bacteria and water quality.

Landers and Ankcorn (2008) conducted a reconnaissancelevel investigation in cooperation with the Georgia 

Environmental Protection Division and the Gwinnett County 

Department of Water Resources to compare stream base 

flow in watersheds with low and high densities of onsite 

septic wastewater-treatment systems (OWTS). Base flow 

was measured during October 2007 in 24 watersheds in an 

area of consistent geologic setting (massive granitic rocks) 

in southeastern Gwinnett County that included watersheds 

in the southwestern and southeastern parts of the City of 

Lawrenceville. The resulting report provides a description of 

the method used to evaluate groundwater recharge and base 

flow from OWTS, and to determine if OWTS density can be 

used to explain changes in base-flow quantity.

Acknowledgments

This study was conducted in cooperation with the City 

of Lawrenceville, and we wish to thank the continued support 

of the City Council members and Mayor Rex Millsaps. 

Mike Bowie, City of Lawrenceville Water Department 

Superintendent, has provided enormous support to this 

program and provided day-to-day assistance when needed. 

Robert Paul and Steve Stubblefield, Water-Treatment Plant 

Operators, helped with logistical support, clearing roads to 

drilling sites, and assisting with the packer tests.

Many U.S. Geological Survey employees assisted with 

this project. Phil Albertson and Michael Hamrick maintained 

the groundwater level monitoring network and assisted in 

collection of stream base flow synoptic events. Alan Cressler 

also assisted by helping with the 2006 base-flow measurement 

event. Paul Ankcorn and Mark Landers provided all of the 

support for maintaining and interpreting the surface-water 

component of this study. Chris Leeth provided quality 

assurance and data verification of much of the data presented 

in this report.

Methods

A variety of methods have been used to monitor the 

hydrologic conditions in the Lawrenceville area, including 

groundwater monitoring, surface-water monitoring, and waterquality sampling. Groundwater data consist of continuous 

and intermittent water-level measurements in wells. Surfacewater data consist of continuous precipitation, continuous 

and intermittent stage and discharge, and continuous and 

intermittent water quality. Information about well datacollection sites is listed in table 1; information about stream 

sites is listed in table 2. 

A crucial element of the study was to determine 

baseline conditions for groundwater levels and streamflow 

before increasing groundwater withdrawal for public 

supply. The baseline data collected as part of this study can 

be compared with new data collected after the initiation 

of pumping to determine the amount of drawdown in the 

aquifer and reductions in base flow that may be attributed 

to pumping. Data were evaluated using linear regression 

to establish trends during the study period. The following 

sections describe the various data-collection components.

Groundwater Levels

Water-level measurements from observation wells are 

the principal source of information about the hydrologic 

stresses on aquifers and how these stresses affect groundwater 

recharge, storage, and discharge. Long-term, systematic 

measurements of water levels provide essential data needed to 

evaluate changes in the resource over time, develop groundwater models and forecast trends, and design, implement, and 

monitor the effectiveness of groundwater management and 

protection programs (Taylor and Alley, 2001). 

In the Lawrenceville area, continuous and intermittent 

water-level measurements are collected according to USGS 

standard procedures (Brunett and others, 1997). Continuous 

water-level measurements were recorded hourly in selected 

wells using a pressure transducer and data logger. These data 

were manually retrieved, typically at 6-week intervals, from 

the data loggers and uploaded to the USGS National Water 

Information System (NWIS; available at http://waterdata.

usgs.gov/ga/nwis/gw). Intermittent water levels typically are 

measured using a graduated steel tape or electric tape following 

procedures described in Garber and Koopman (1968).

Stream Stage and Discharge

Stage represents water height above an arbitrary datum 

and is used to compute streamflow—the total volume of water 

that flows past a specific point on a river during a period of 

time. Stream stage (or gage height) is continually measured at 

selected sites in the Lawrenceville area. Values are recorded 

to the nearest 0.01 foot using an air bubbler system. Discharge 

measurements are routinely made to define and verify a stage-todischarge relation at each site, so that both stage and discharge 

are known. A bubbler gage also is verified against an outside 

reference gage routinely (at least every 6 weeks), and levels 

are run periodically from established reference points to verify 

gage datums. These sites continuously record data at 15-minute 

intervals and transmit the data via satellite to be incorporated 

into the USGS National Water Information System database. 

These data are automatically posted to the USGS Web site for 

public dissemination (http://waterdata.usgs.gov/ga/nwis/nwis). 

Discharge for periods of missing or unreliable stage data 

were estimated using hydrographic comparisons with nearby 

watersheds having similar characteristics (Rantz, 1982b). 

Stage also is measured at several non-recording staff gages 

during site visits. Staff gages are installed and maintained in 

accordance with the methods of monitoring stream stage and 
Methods 9

computing streamflow further described in Rantz (1982a, b) 

and in the Surface-Water Quality-Assurance Plan of the USGS 

Georgia Water Science Center (Gotvald and Stamey, 2005).

Stream Base Flow

Synoptic base-flow measurement events are used to 

locate and quantify gains or losses to streamflow resulting 

from groundwater interaction (groundwater seepage). 

Gain or loss in streamflow is calculated by subtracting an 

upstream streamflow measurement from a downstream 

measurement. In Lawrenceville, base-flow discharge was 

periodically measured along selected stream reaches 

using (1) current meter (Pygmy-type) measurements 

(Rantz, 1982b), (2) acoustic Doppler velocity meter 

(ADVM) measurements (Laenen, 1985), or (3) volumetric 

measurements (Rantz, 1982b) based on the time for the 

flow to fill a container of known volume. Streamflow 

measurements have an error which may affect reported values 

for seepage and whether a stream reach is characterized 

as gaining or losing. Of the three methods, volumetric 

measurements are most accurate; ADVM measurements 

have been shown to have an uncertainty of 4.5 percent or 

less (Oberg and Mueller, 2007), and current meters have 

standard errors ranging from 3 to 6 percent (Sauer and Meyer, 

1992). Sources of error include error contributed by the 

current meter, measurement of depth, the pulsation of flow, 

the vertical distribution of velocities, the measurement of 

horizontal angles, and computations involving the horizontal 

distribution of velocity and depth (insufficient number of 

or inadequate measuring subsections). Poor measuring 

conditions (such as very slow water velocities or shallow 

depths similar to those in the Lawrenceville study area) or 

improper procedures of meter use, however, can result in 

much larger errors. For this reason, stream seepage estimates 

are conservatively reported with a ±25-percent error bracket 

to account for errors in streamflow measurements. Improved 

accuracy of streamflow measurements using volumetric or 

acoustic Doppler current meters could provide more accurate 

seepage estimates. 

Precipitation

Precipitation data are collected at real-time streamgaging stations operated by USGS following procedures 

described in Gotvald and Stamey (2005). In general, 

precipitation is measured using a calibrated tipping bucket 

rain gage that records and transmits data via satellite to the 

USGS NWIS database every 15 minutes. Periodic inspection 

of the rain gage occurs every 6 weeks, and calibration occurs 

yearly using a constant-head bottle. 

Stream-Water Quality

Stream-water quality is monitored at streamgage sites 

in the Apalachee River, Pew Creek, and Shoal Creek. At 

each site, water-quality meters are deployed to continuously 

measure and record streamwater temperature, specific 

conductance, and turbidity every 15 minutes. Specific 

conductance is directly related to the total dissolved solids in 

water. Turbidity provides an indicator of the total suspended 

solids in water. Turbidity to suspended solids concentration 

relations, however, may be unreliable because turbidity 

readings vary with suspended solids size, gradation, and color, 

as well as concentration (Gray and Glysson, 2003). Waterquality meters are cleaned and calibrations are checked at least 

every 4 weeks following the quality-assurance procedures 

described in Wagner and others (2000).

In addition to continuous stream-water quality 

monitoring, discrete water-quality samples were collected during 

storms to characterize nonpoint-source pollution in storm 

flow. To improve the ability to collect discrete samples during 

rainfall runoff, pumping point samplers were installed at all 

water-quality monitoring stations. These data can be used 

to characterize stream-water quality and develop relations 

between continuously-monitored parameters and laboratoryanalyzed concentrations. Eight samples are collected annually 

from each of these water-quality sampling sites, four samples 

per site collected during each of the two sampling seasons 

(November–April, May–October). During each season, samples 

were collected during three storm events and one dry event.

Storm composite water-quality samples are collected 

with in situ “automatic” point samplers, which are cleaned 

and prepared prior to each sampled storm. The sampler is 

programmed to begin sampling based on precipitation and (or) 

stream-stage thresholds and to collect subsamples each time 

a specified volume of water flows by the station at variable 

time intervals. This method of sampling provides a composite 

sample of the storm that is discharge-weighted, and accounts 

for pollutant concentration differences throughout the storm 

hydrograph. All storm samples were collected in accordance 

with the applicable standards for stormwater monitoring 

(Metropolitan North Georgia Water Planning District, 2007) 

which require that wet-weather samples follow a minimum 

precipitation event of 0.3 inch Additionally, a minimum time of 

72 hours is required between each wet-weather event to ensure 

that the events are discrete and that the measured water-quality 

properties are associated with the sampled event. The samples 

are refrigerated at about 4 degrees Celsius until the sample is 

removed and processed. Sampler cleaning and maintenance 

procedures are followed as described in the USGS Georgia 

Water Science Center, water-quality-assurance plan (Steven J. 

Lawrence, U.S. Geological Survey, written commun., 2009).

Base-flow samples were collected with a USGS DH-81 

manual sampler, or open bottle method as hydrologic conditions permit, using depth and width integrating techniques as 

outlined in Wilde and others (1998). Base-flow samples were 

collected after no more than 0.1 inch of precipitation had 

fallen during the previous 72 hours. Base-flow and stormflow 

samples were processed and preserved following USGS field 

methods (Wilde and others, 1998), and analyzed in USGSapproved laboratories.
10 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

Hydrologic Conditions

The collection of groundwater-level, streamflow, base 

flow, and precipitation data are necessary to provide the City 

of Lawrenceville a means to estimate the sustainability of 

the hydrologic system under normal or anticipated pumping 

conditions. A monitoring network was established in two areas 

projected for groundwater development—the Redland–Pew 

Creek and upper Alcovy River watersheds, and the upper 

Apalachee River watershed, which serves as a background 

or control watershed because of its similar hydrologic 

characteristics to the pumped watersheds (fig. 1). In addition, 

sites in the Yellow River watershed are monitored to provide 

an indication of changes along the northern boundary of the 

Redland–Pew Creek watershed.

In the 4 watersheds, 26 wells were monitored during 

2008, of which 10 are completed in the regolith, and 16 are 

completed in bedrock (table 1). Twelve of these wells 

are located at cluster sites, with each including a bedrock 

well and a regolith well. At the beginning of 2008, 

five wells were equipped with continuous recorders; 

however, a funding shortage required conversion of two 

of these sites (wells 14FF65 and 14FF66; table 1) to 

periodic measurements in February 2008, leaving three 

continuously recorded wells at the end of the year.

In addition to an existing real-time continuous stream 

stage recorder at the outlet of the upper Apalachee River 

control watershed, new installations were established at the 

outlet of the upper Alcovy River, Redland–Pew Creek, and 

Shoal Creek watersheds during 2004–2005 (table 2). Each of 

the four sites includes a precipitation gage. Additional periodic 

streamflow measurements were made at 22 locations during 

the study period. 

Upper Apalachee River Watershed

The upper Apalachee River watershed covers a 5.68-mi2

area in the northeastern part of the study area (fig. 3) and is 

similar in size and has similar geology and topography as 

the upper Alcovy River and Redland–Pew Creek watersheds, 

located to the southwest. Examination of land use maps 

reported by Landers and others (2007) indicate the upper 

Apalachee River has less transportation land use and high 

and low density development than the other two watersheds. 

Because this watershed has no known major groundwater 

withdrawal wells and because of its proximity to the pumped 

watersheds, it was selected as the most suitable background or 

control site for comparison to data from the other watersheds 

in the study area. 

Monitoring Networks

To assess hydrologic conditions and trends in the upper 

Apalachee River watershed, streamflow and precipitation data 

have been recorded at surface-water station 02218565 since 

July 2001, and groundwater levels have been recorded at 

observation well 14GG02 since July 2003 (fig. 3; tables 1 and 2). 

In addition to streamflow and precipitation data, specific 

conductance, temperature, turbidity, and precipitation data are 

collected; intermittent water-quality samples also are collected 

for quality assurance and for characterization of storm events. 

Water-quality information for this site is described in the 

“Stream-Water Quality” section of this report.

Figure 3. Surface-water and groundwater monitoring 

networks, upper Apalachee River watershed near 

Lawrenceville, Georgia, 2008.

Base modified from U.S. Geological Survey

1:24,000-scale digital raster graphics

EXPLANATION

0 0.5 1 MILE

0 0.5 1 KILOMETER

Watershed

Upper Apalachee River

Surface-water station and number

Groundwater monitoring well and name

Continuous with water quality

Continuous bedrock

Figure 3. Surface-water and groundwater monitoring 

networks, upper Apalachee River watershed near 

Lawrenceville, Georgia, 2008.

GWINNETT

COUNTY

Lawrenceville

124

324

River

Apalachee

02218565

14GG02

N

Dacula

City

limit
Hydrologic Conditions 11

Figure 4. Total monthly precipitation and mean monthly streamflow at surface-water station 02218565, 

and mean monthly and periodic water levels in well 14GG02, upper Apalachee River watershed near 

Lawrenceville, Georgia, 2003–2008. (See fig. 3 for location.)

Hydrologic and Precipitation Trends

Precipitation is the main control on streamflow and 

groundwater levels in the Apalachee River watershed. Increased 

precipitation generally results in increasing streamflow and 

groundwater levels; decreased precipitation results in decreased 

streamflow and groundwater levels (fig. 4). Although there 

are gaps in the record, precipitation was generally greater 

during 2003–2005, than in 2006–2008, with an average 

monthly rainfall of 5 inches and 3.3 inches, respectively. Lower 

precipitation during 2006–2008 resulted in a corresponding 

decrease in streamflow and groundwater levels. At surfacewater station 02218565, the lowest mean monthly streamflow 

during 2003–2008, was 1.03 cubic feet per second (ft3/s) in 

September 2008 (fig. 4). The lowest groundwater level of 

88.9 ft below land surface was measured in October 2008.

Average 2006–2008 (3.3 inches)

Average 2003–2005 (5 inches)

0 

2 

4 

8 

6 

10 

12 

14 

16 

78 

80 

82 

84 

86 

88 

90 

Periodic

2003 2004

Figure 4. Total monthly precipitation and mean monthly streamflow at surface-water station 02218565, and 

mean monthly and periodic water levels in well 14GG02, upper Apalachee River watershed near 

Lawrenceville, Georgia, 2003–2008. (See fig. 3 for location.)

MEAN MONTHLY

GROUNDWATER LEVEL BELOW

LAND SURFACE, IN FEET

Jan

Apr

July

Oct

July

Oct

Jan

Apr

Jan

Apr

July

Oct

July

Oct

Jan

Apr

July

Oct

Jan

Apr

July

Oct

2005 2006 2007 2008

Blank where 

 data are missing

Trend

0

5

10

15

20

25

30

MEAN MONTHLY

STREAMFLOW, IN MILLION

GALLONS PER DAY

MONTHLY PRECIPITATION,

IN INCHES
12    Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

Upper Alcovy Watershed 3.3 inches, respectively. Lower precipitation during 2006–

2008 resulted in a corresponding decrease in streamflow and 

The upper Alcovy River watershed covers a 9.97-mi2 groundwater levels. At surface-water station 02208050, the 

area in the north-central portion of the study area (fig. 5). lowest mean monthly flow during 2003–2008, was 0.7 Mgal/d 

Examination of land use maps reported by Landers and others in September 2008 (fig. 6). 

(2007) indicate the watershed has a greater amount of high During 2003–2008, water levels declined in each of the 

density land use than the upper Apalachee River watershed to 10 wells monitored in the upper Alcovy River watershed, with 

the northeast. Currently (2008) there are no known ground- the exception of well 14FF63, which showed little change 

water withdrawal sites in the upper Alcovy River watershed; (figs. 7 and 8). The declining water levels corresponded 

however, two production wells have been identified by the to decreased precipitation and changes in pumping. The 

city for possible future use. One of these wells (14FF59) magnitude of decline was similar in regolith and bedrock wells,

is a flowing artesian well and discharges 40 to 50 gallons ranging mostly between 2.4 and 6.9 ft, with a considerably 

per minute (gal/min) into the upper Alcovy River. The current greater decline of 28.5 ft in bedrock well 14FF52, located 

(2008) main production well for the city (14FF16) is located near the basin divide between the upper Alcovy River and 

in the adjacent Shoal Creek watershed, about 1-mi southwest Shoal Creek. During January 2003–December 2007, water 

of the watershed boundary. levels in well 14FF52 showed little change until a pronounced 

water-level decline of 23.7 ft beginning in December 2007 

through September 2008. This accelerated rate of decline Monitoring Networks may be related to the initiation of periodic pumping from well 

14FF55, located about 1.2 mi southwest, near the center of the To assess hydrologic conditions and trends in the upper city in the Shoal Creek watershed. Alcovy River watershed, streamflow and precipitation To assess changes in base-flow conditions in selected data have been continuously recorded at surface-water stream reaches in the Alcovy River watershed, periodic station (02208050) since April 2004 (table 2; fig. 5). Eleven streamflow measurements were made during periods of low additional surface-water sites were visited periodically during rainfall in August 2003, August 2004, September 2005, and 2004–2006 for measurement of base-flow conditions. The September 2006 (table 3, figs. 6 and 9). Net gain or loss of periodic streamflow measurement program for this area was streamflow (seepage) during these dry or base-flow periods discontinued after September 2006 to enable the shifting of is representative of the interaction between surface and resources to the Redland–Pew Creek watershed where ground- groundwater—when positive, there is a net gain in ground- water development is anticipated in the near future. water inflow; when negative, there is a net loss of streamflow In addition to streamflow and precipitation data, specific to the groundwater system. Seepage was calculated for the conductance, temperature, turbidity, and precipitation data are following stream reaches: continuously monitored at surface-water station 02208050 

with intermittent water-quality samples collected for quality • Reach AL-1: intermediate area between 

assurance and for characterization of storm events. Water- sites 02208046 and 02208047;

quality information for this site is described in the “Stream- • Reach AL-2: intermediate area between Water Quality” section of this report. sites 02208047 and 022080475; During 2008, groundwater levels were monitored in 

11 wells in the upper Alcovy River watershed, of which 6 • Reach AL-3: area above site 022080477;

are completed in the bedrock and 5 are completed in the 

regolith (table 1, fig. 5). At the beginning of 2008, water • Reach AL-4: intermediate area between 

levels were continuously recorded in three observation wells; sites 022080477 and 022080478;

however, this number was reduced to one well by the end • Reach AL-5: intermediate area between of the year. Wells 14FF65 (bedrock) and 14FF66 (regolith) sites 022080478 and 022080479; were continuously monitored from November 2003 until 

March 2008, when the recorders were removed due to a • Reach AL-6: intermediate area between 

shortage of funding. sites 022080479 and 02208048;

• Reach AL-7: intermediate area between Hydrologic and Precipitation Trends sites 02208048 and 02208049;

During 2003–2008, streamflow and precipitation in the • Reach AL-8: intermediate area between 

upper Alcovy River watershed showed a general downward site 02208050 and combined flow at sites 

trend (fig. 6). Although there are gaps in the record, 022080475, 02208049, and 022080495; and

precipitation was generally greater during 2003–2005 than in 

2006–2008, with average monthly rainfall of 5.4 inches and • Reach AL-9: area above site 022080495.
Hydrologic Conditions 13

Figure 5. Surface-water and groundwater monitoring networks, upper Alcovy River watershed near 

Lawrenceville, Georgia, 2008. Figure 5. Surface-water and groundwater monitoring networks, upper Alcovy River watershed near 

Lawrenceville, Georgia, 2008.

N

0 0.5 1 MILE

0 0.5 1 KILOMETER

EXPLANATION

Surface-water station and number Groundwater monitoring well

 and name

Continuous regolith

Periodic regolith

Continuous bedrock

Periodic bedrock

Continuous with precipitation

Periodic with staff gage

Base-flow measurement

Base modified from U.S. Geological Survey

1:24,000-scale digital raster graphics

Shoal Creek

Upper Alcovy River

Watershed

Continuous with water quality

316

120

124

124

20

20

City limit

Airport

29

Paper Mill Road

Ezzard St Existing or proposed bedrock

 production well and name—

 Also used for monitoring

Cedar Creek

Alcovy

River

River Yellow

Shoal

Creek

14FF69

02208048

02208049

14FF67

14FF68

14FF62

14FF66

14FF65

02208047

022080463

02208046

02208050

14FF63

14FF64

14FF59

14FF60

14FF52

0220804795

022080479

022080478

022080477

022080475

022080495

14FF55

14FF16

02208130

14FF42

Lawrenceville

GWINNETT

COUNTY
14 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

Figure 6. Total monthly precipitation and mean monthly streamflow at surface-water station 02208050, 

upper Alcovy River watershed near Lawrenceville, Georgia, 2003–2008. (See fig. 5 for location.)

Average 2006–2008 (3.3 inches) Average 2003–2005 (5.4 inches)

Figure 6. Total monthly precipitation and mean monthly streamflow at surface-water station 02208050, 

upper Alcovy River watershed near Lawrenceville, Georgia, 2003–2008. (See fig. 5 for location.)

0 

5 

10 

15 

20 

Blank where 

 data are missing

Trend

Jan

Apr

July

Oct

Jan

Apr

July

Oct

Jan

Apr

July

Oct

Jan

Apr

July

Oct

2003 2004 2005 2006

Jan

Apr

July

Oct

Jan

Apr

July

Oct

2007 2008

Groundwater

seepage

measured

0

10

20

30

40

MEAN MONTHLY

STREAMFLOW, IN MILLION

GALLONS PER DAY

MONTHLY PRECIPITATION,

IN INCHES
Hydrologic Conditions 15

Table 3. Base-flow measurements along selected stream reaches, upper Alcovy River watershed in the Lawrenceville area, 

Georgia, 2003–2006. 

[mi2, square miles; see figure 9 for reach locations; shaded cells represent reaches evaluated for groundwater seepage; —, no data]

Site 

identification

Station 

name

Intermediate 

drainage area 

(mi2)

Drainage 

area 

(mi2)

Base flow, in million gallons per day, and date measured

8/28/2003 8/31/2004 9/12/05–9/13/05 9/5/06–9/6/06

02208046 Alcovy River Hurricane Shoals 

Rd, near Dacula, GA

4.74 2.19 1.49 1.53 0.790

Reach AL-1 Intermediate area between sites 

02208046 and 02208047

0.270 — 0.680 –0.370 –0.260 –0.090

02208047 Alcovy River at GA 316, 

near Lawrenceville, GA

5.01 2.87 1.11 1.27 0.700

Reach AL-2 Intermediate area between sites 

00208047 and 022080475

0.100 — 0.170 0.060 0.220 –0.110

022080475 Alcovy River above Cedar Creek 

near Lawrenceville, GA

5.11 3.04 1.17 1.49 0.590

Reach AL-3 Area above site 022080477 0.624 — — — — 0.070

022080477 Cedar Creek above Progress 

Center Ave, Lawrenceville, GA

0.624 — — — 0.070

Reach AL-4 Intermediate area between sites 

022080477 and 022080478

0.880 — — — — 0.350

022080478 Cedar Creek below Hurricane 

Shoals Road, Lawrenceville, GA

1.50 — — — 0.430

Reach AL-5 Intermediate area between sites 

022080478 and 022080479

1.74 — — — — 0.34

022080479 Cedar Creek below GA 316 

at Lawrenceville, GA

3.24 1.73 1.02 0.710 0.760

Reach AL-6 Intermediate area between sites 

022080479 and 02208048

0.840 — 0.120 0.210 0.050 0.070

02208048 Cedar Creek at Cedars Rd, 

near Lawrenceville, GA

4.08 1.85 1.23 0.760 0.830

Reach AL-7 Intermediate area between sites 

02208048 and 02208049

0.020 — 0.160 –0.010 0.180 –0.180

02208049 Cedar Creek above Alcovy River 

at Lawrenceville, GA

4.10 2.01 1.23 0.940 0.650

Combined flow at sites 022080475, 02208049, and 022080495 compared to flow at site 02208050

022080475 Alcovy River above Cedar Creek 

near Lawrenceville, GA

5.11 3.04 1.17 1.49 0.590

02208049 Cedar Creek above Alcovy River 

at Lawrenceville, GA

4.10 2.01 1.23 0.940 0.650

022080495 Alcovy River tributary at sewer 

cut near Lawrenceville, GA

0.630 — — — 0.060

Combined 9.22 — — — 1.31

Reach AL-8 Intermediate area between site 

02208050 and combined flow 

at sites 022080475, 02208049, 

and 022080495

0.760 — — — — –0.210

02208050 Alcovy River near 

Lawrenceville, GA

10.0 5.36 3.43 1.62 1.10

Reach AL-9 Area above site 022080495 0.630 — — — 0.060

022080495 Alcovy River tributary at sewer 

cut near Lawrenceville, GA

0.630 — — — 0.060

Minimum 0.120 –0.370 –0.260 –0.210

Maximum 0.680 0.210 0.220 0.350

Median 0.160 0.030 0.120 0.060
16 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

Figure 7. Groundwater levels in the regolith in the upper Alcovy River watershed near Lawrenceville, 

Georgia, 2003–2008. (See fig. 5 for location.)

WATER LEVEL BELOW LAND SURFACE, IN FEET

Well 14FF60 (periodic)

Well 14FF67 (periodic)

Well 14FF68 (periodic)

Well 14FF69 (periodic)

Well 14FF66 (mean monthly)

Figure 7. Groundwater levels in the regolith in the upper Alcovy River watershed near Lawrenceville, 

Georgia, 2003–2008. (See fig. 5 for location.)

0 

1 

2 

3 

4 

5 

6 

7 

7 

8 

9 

10 

11 

12 

13 

14 

28 

29 

30 

31 

32 

33 

34 

35 

17 

16 

18 

19 

20 

21 

22 

23 

24 

11 

12 

13 

14 

15 

16 

17 

18 

Jan

Apr

July

Oct

Jan

Apr

July

Oct

Jan

Apr

July

Oct

Jan

Apr

July

Oct

2003 2004 2005 2006

Jan

Apr

July

Oct

Jan

Apr

July

Oct

2007 2008

Trend

Blank where 

 data are missing
Hydrologic Conditions 17

Figure 8. Groundwater levels in the bedrock in the upper Alcovy River watershed near Lawrenceville, 

Georgia, 2003–2008. (See fig. 5 for location.)

WATER LEVEL ABOVE (–) AND BELOW LAND SURFACE, IN FEET

Jan

Apr

July

Oct

Jan

Apr

July

Oct

Jan

Apr

July

Oct

Jan

Apr

July

Oct

2003 2004 2005 2006

Jan

Apr

July

Oct

Jan

Apr

July

Oct

2007 2008

Figure 8. Groundwater levels in the bedrock in the upper Alcovy River watershed near Lawrenceville, 

Georgia, 2003–2008. (See fig. 5 for location.)

Well 14FF52 (periodic)

Well 14FF62 (periodic)

Well 14FF63 (periodic)

Well 14FF64 (periodic)

Well 14FF65 (mean monthly )

10 

15 

20 

25 

30 

35 

40 

45 

–3 

–2 

–1 

0 

1 

2 

3 

4 

–3 

–2 

–1 

0 

1 

2 

3 

4 

2 

4 

6 

8 

10 

12 

14 

11 

12 

13 

14 

15 

16 

17 

18 

Trend

Blank where 

 data are missing
18 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

Seepage values in this report are in million gallons per 

day, rather than in the more commonly used cubic feet per 

second, to facilitate comparison to groundwater pumping rates.

Multiple-year records of seepage data are available 

for reaches AL-1, AL-2, AL-6, and AL-7 (fig. 9). During 

August 2003—a period of relatively high precipitation 

(fig. 6)—each of the four reaches showed seepage gains 

(fig. 9). In September 2006, three of the four reaches 

showed seepage loss corresponding to a period of reduced 

precipitation as effects of the drought began to take effect. 

During the summers of 2004–2006 reach AL-6 remained 

gaining, with seepage ranging from 0.05 to 0.21 Mgal/d. 

The largest change in seepage during 2003–2006 occurred 

at reach AL-1, where a seepage gain of 0.68 Mgal/d in 2003 

changed to seepage losses ranging from 0.09 to 0.37 Mgal/d 

during 2004–2006. The reason for this large change is unclear 

but may be related to decreased precipitation and changes in 

drainage patterns or impervious area that reduce recharge and 

(or) runoff.

The most extensive monitoring effort was conducted 

in September 2006, when seepage in all nine reaches was 

measured, as shown on the map in figure 9. During this period, 

seepage gains were measured at five of the nine reaches 

evaluated, with losses measured at the other four reaches. 

The four losing reaches were near the confluence of the 

Alcovy River and Cedar Creek where the stream gradient is 

low, regolith is thin, and bedrock is at or near land surface, 

limiting the amount of storage available to replenish streamflow. 

September 2006 was a period of low precipitation resulting in 

low streamflow and groundwater levels.

In losing reaches, it is likely the water table fell near or 

beneath stream stage, resulting in a decrease or reversal of the 

hydraulic gradient between groundwater and the stream. A 

decreased gradient would result in a decrease in groundwater 

discharge to the stream; a gradient reversal would result in 

movement of water from the stream into the aquifer. Head 

relations between Alcovy River stage and groundwater are 

shown with hydrographs for surface-water station 02208047 

and regolith well 14FF60 during 2003–2008 (fig. 10). 

Altitudes of stream stage and groundwater levels are similar, 

with groundwater levels slightly higher than stream levels, 

indicating a gradient from the aquifer into the stream. Because 

altitudes are similar, a slight change in stage or head could 

change the magnitude and direction of flow, as were apparent 

during dry conditions in the summer and fall of 2006–2008 

when stream stage and groundwater levels were nearly 

coincident. Lowering of the water table can sometimes be 

caused by nearby groundwater pumping; however, the nearest 

groundwater pumping is in the Shoal Creek watershed, greater 

than 2.5 mi to the southwest. 

Figure 9. Groundwater seepage along selected reaches in the upper Alcovy River watershed near Lawrenceville, 

Georgia, 2003–2006.

+25 percent error

Estimated groundwater seepage

–25 percent error

EXPLANATION

Figure 9. Groundwater seepage along selected reaches in the upper Alcovy River watershed near Lawrenceville, 

Georgia20032006

Reach AL-7

Reach AL-6

Reach AL-2

Reach AL-1

0.5

1.0

–1.0

–0.5

0

0.5

–1.0

–0.5

0.5

1.0

0

1.0

–1.0

–0.5

0

0.5

1.0

–1.0

–0.5

0

08/28/2003 08/31/2004 9/12–13/2005 9/5–6/2006 08/28/2003 08/31/2004 9/12–13/2005 9/5–6/2006

GROUNDWATER SEEPAGE, IN MILLION GALLONS PER DAY
Hydrologic Conditions 19

Figure 9. Groundwater seepage along selected reaches in the upper Alcovy River watershed near Lawrenceville, 

Georgia, 2003–2006.—Continued

Cedar Creek

River

Alcovy

Airport

City limit

29

316

Base modified from U.S. Geological Survey

1:24,000-scale digital raster graphics

Stream reach with net gain

 in seepage

Stream reach with net loss 

 in seepage

EXPLANATION

Groundwater seepage, September 2006— Surface-water station and number Pattern shown to differentiate between 

 stream reaches. Number is stream-reach

 identifier listed in table 3

Continuous with precipitation

Periodic with staff gage

Base-flow measurement

Upper Alcovy River watershed

Groundwater monitoring well

 and name

Figure 9. Groundwater seepage along selected reaches in the upper Alcovy River watershed near Lawrenceville, 

Georgia, 2006, and trends in selected reaches 2003–2006.—Continued

AL-2

N

0 0.5 1 MILE

0 0.5 1 KILOMETER

Periodic regolith

AL-5

14FF60

0220804802208048

0220804902208049

0220804702208047

0220804602208046

0220805002208050

0220804795

022080479

022080478

022080477

022080475 022080495

14FF62

AL-3

AL-4

AL-1

AL-2 AL-5

AL-6 AL-7 AL-8

AL-9

Existing or proposed bedrock

 production well and name—

 Also used for monitoring

Lawrenceville

Map

area
20 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

Redland–Pew Creek Watershed

The Redland–Pew Creek watershed covers a 7.49-mi2

area in the southwestern part of the study area (fig. 11). The 

watershed is part of the larger Yellow River watershed, and is 

the most urbanized of the watersheds included in this study, 

with a greater proportion of high density land use according 

to maps presented by Landers and others (2007). Several 

well sites in this area have been identified for development 

of groundwater supplies for the city, including well 13FF18, 

which was brought online in the fall of 2008.

Monitoring Networks

To assess hydrologic conditions and trends in the 

Redland–Pew Creek watershed, streamflow and precipitation 

data have been continuously recorded at Pew Creek at 

Patterson Road (02205522) since March 2003 (table 2, fig. 11). 

Eleven additional surface-water sites were visited periodically 

during 2003–2008 for measurement of base-flow conditions.

Streamflow, precipitation, specific conductance, 

temperature, and turbidity data are continuously monitored 

at surface-water station 02205522. Intermittent water-quality 

samples are collected for quality assurance and for 

characterization of storm events. Water-quality information for 

this site is described in the “Stream-Water Quality” section of 

this report.

During 2008, groundwater levels in the Redland–Pew 

Creek watershed were continuously monitored in wells 

13FF30 (bedrock) and well 13FF31 (regolith) at a multi-well 

cluster to provide insight into vertical head relations between 

the bedrock and overlying regolith (table 1, fig. 11). In 

addition to continuously recording wells, periodic water-level 

measurements were made in 7 wells in the Redland–Pew 

Creek watershed, and 4 wells in the adjacent Yellow River 

watershed, for a total of 11 wells. Of the 11 wells with 

periodic measurements, 7 are completed in bedrock, and 4 

are completed in regolith.

Hydrologic and Precipitation Trends

During 2003–2008, streamflow and precipitation in the 

Redland–Pew Creek watershed showed a general downward 

trend (fig. 12). Although there are gaps in the record, 

precipitation was generally greater during 2003–2005 than in 

2006–2008, with average monthly totals of 4.42 inches and 

3.25 inches, respectively. Lower precipitation during 2006–

2008 resulted in a corresponding decrease in streamflow and 

groundwater levels. At surface-water station 02205522, the 

lowest mean monthly flow during 2003–2008, was 1.09 Mgal/d 

in September 2008 (fig. 12).

During 2003–2008, water levels declined in 12 of the 

13 wells monitored in the Redland–Pew Creek and Yellow 

River watersheds, corresponding to decreased precipitation 

and changes in pumping (figs. 13 and 14). The magnitude of 

decline was similar in regolith and bedrock wells, ranging 

mostly between 2.8 and 6.5 ft, with considerably greater 

declines in bedrock wells 13FF16 (40.4 ft) and 13FF13 

(49.1 ft). The water-level change in well 13FF16 represented 

a temporary decline during a water-sampling event in 

September 2008. In well 13FF13, water levels showed little 

decline (0.34 ft) during January 2003–July 2008; however, 

a pronounced water-level decline of 36.8 ft was observed 

beginning in August through December 2008. This accelerated 

decline corresponded to the initiation of pumping in well 

13FF18, located about 0.3 mi west of well 13FF13 (fig. 11).

This decline is due to the pumping drawdown that extends 

out in an east-west direction along the trend of foliationparallel partings identified in well logs collected in these 

wells (Williams and others, 2004). The amount of drawdown 

observed at well 13FF13 is similar to the drawdown observed 

during an aquifer test conducted at well 13FF18 (Williams and 

others, 2005).

Not all of the wells in the area showed a decreasing trend. 

Water levels in bedrock well 13FF20 generally rose during 

2003–2008 (fig. 14). The well is located in an upland area of 

the adjacent Yellow River watershed. The reason for rising 

Figure 10. Stream stage at surface-water station 02208047 and groundwater levels in regolith well 14FF60, 

upper Alcovy River watershed near Lawrenceville, Georgia, 2003–2008. (See fig. 9 for location.)

Well 14FF60 (periodic)

Stream stage at station 02208047

Figure 10. Stream stage at surface-water station 02208047 and groundwater levels in regolith well 14FF60, 

upper Alcovy River watershed near Lawrenceville, Georgia, 2003–2008. (See fig. 9 for location.)

947 

948 

949 

950 

951 

952 

953 

WATER LEVEL

ABOVE NAVD 88, IN FEET

Jan

Apr

July

Oct

Jan

Apr

July

Oct

Jan

Apr

July

Oct

Jan

Apr

July

Oct

2003 2004 2005 2006

Jan

Apr

July

Oct

Jan

Apr

July

Oct

2007 2008
Hydrologic Conditions 21

Figure 11. Surface-water and groundwater monitoring networks, Redland–Pew Creek and Yellow River watersheds near 

Lawrenceville, Georgia, 2008.

120

124

20

29

Redland

Creek

Yellow

River

Creek

Pew

13FF29

13FF24

02205522

02205508

02205520

13FF25 13FF19

02205450

02205500

13FF23

13FF31 13FF30

13FF27

13FF28

13FF22

13FF18

13FF34

13FF20

13FF16

022055085

13FF13

13FF14

022055082

335646084010702 3356465084010701

335658084010001

335629084013801

335602084010401

13FF21

Patterson Road

Lawrenceville–Suwanee Road

EXPLANATION

Groundwater monitoring well and number

Continuous regolith

Periodic with staff gage Periodic regolith

Base-flow measurement

N

0 1 MILE

0 0.5 1 KILOMETER

0.5

Continuous bedrock

Periodic bedrock

Base modified from U.S. Geological Survey

1:24,000-scale digital raster graphics

Watershed

Existing or proposed bedrock

 production well and name—

 Also used for monitoring

Figure 11. Surface-water and groundwater monitoring networks, Redland–Pew Creek and Yellow River watersheds 

near Lawrenceville, Georgia, 2008.

City limit

City limit

Surface-water station and number

Continuous with water quality

Lawrenceville

GWINNETT

COUNTY

Redland–Pew Creek

Yellow River
22 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

• Reach RP-8: area above site 335629084013801;

• Reach RP-9: area above site 335646084010702;

• Reach RP-10: intermediate area between 02205522 

and combined flow at 02205520 and 02205508;

• Reach RP-11: intermediate area between 02205508 

and combined flow at 02205500 and 

335602084010401; and

• Reach RP-12: intermediate area between 

02205520 & combined flow at 335646084010701, 

335646084010702, and 335629084013801.

Seepage measurements collected during 2003–2008 

indicate that with the exception of reach RP-10, most stream 

reaches were gaining throughout the period (fig. 15). Multipleyear records of seepage data are available for all reaches 

except for RP-6, RP-7, and RP-8. For sites with multipleyear records, net seepage was positive during each of the 

measurement periods, with the exceptions of reach RP-10, 

which was negative during 2003–2005 and in 2007, and reach 

RP-9, which was zero during 2007 and near zero during 2006 

and 2008. Maximum seepage gains during 2003–2008 were 

observed in reaches RP-1, RP-2 and RP-10, ranged from 

0.23 to 1.17 Mgal/d. 

During September 2008, seepage measurements were 

made at 10 of the 12 reaches. Although each of the 10 sites 

was gaining water, median seepage was 0.03 Mgal/d, the 

lowest observed during 2003–2008 (table 4). September 2008 

was a period of low precipitation (fig. 12) that resulted in low 

streamflow and groundwater levels. 

water levels in this well is not clear at this time, although it 

may be related to new landscaping and runoff controls that 

may have affected recharge to the bedrock. 

To evaluate changes in base-flow conditions in selected 

stream reaches in the Redland–Pew Creek watershed, periodic 

streamflow measurements were made during periods of low 

rainfall in September 2003, October 2004, September 2005, 

September 2006, October 2007, and September 2008 (table 4; 

figs. 12 and 15). Net gain or loss of streamflow (seepage) 

during these dry or base-flow periods is representative of the 

interaction between surface and groundwater—when positive, 

there is a net gain in groundwater inflow; when negative, there 

is a net loss of streamflow to the groundwater system. Seepage 

was evaluated for the following stream reaches:

• Reach RP-1: area above site 02205450;

• Reach RP-2: intermediate area between sites 

02205450 and 02205500;

• Reach RP-3: area above site 335602084010401;

• Reach RP-4: area above site 022055082;

• Reach RP-5: intermediate area between sites 

022055082 and 022055085;

• Reach RP-6: intermediate area between sites 

022055085 and 335658084010001;

• Reach RP-7: intermediate area between sites 

335658084010001 and 335646084010701;

Figure 12. Total monthly precipitation and mean monthly streamflow at surface-water station 02205522, 

Redland–Pew Creek watershed near Lawrenceville, Georgia, 2003–2008.

Blank where 

 data are missing

Average 2006–2008

 (3.25 inches)

Average 2003–2005

 (4.42 inches)

Trend

Jan

Apr

July

Oct

Jan

Apr

July

Oct

Jan

Apr

July

Oct

Jan

Apr

July

Oct

2003 2004 2005 2006

Jan

Apr

July

Oct

Jan

Apr

July

Oct

2007 2008

MEAN MONTHLY

STREAMFLOW, IN MILLION

GALLONS PER DAY

MONTHLY PRECIPITATION,

IN INCHES

0 

5 

10 

15 

20 

25 

0 

2 

4 

6 

8 

10 

12 

Figure 12. Total monthly precipitation and mean monthly streamflow at surface-water station 02205522, 

Redland–Pew Creek watershed near Lawrenceville, Georgia, 2003–2008.

Groundwater

seepage

measured
Hydrologic Conditions 23

Figure 13. Groundwater levels in the regolith in the Redland–Pew Creek and Yellow River watersheds near 

Lawrenceville, Georgia, 2003–2008. (See fig. 11 for location.)

16 

17 

18 

19 

20 

21 

22 

23 

18 

19 

20 

21 

22 

23 

24 

25 

26 

1 

2 

3 

4 

5 

6 

7 

8 

1 

2 

3 

4 

5 

6 

7 

8 

19 

20 

21 

22 

23 

24 

25 

26 

Well 13FF28 (periodic, Redland–Pew Creek watershed)

Well 13FF29 (periodic, Yellow River watershed)

Well 13FF25 (periodic, Redland–Pew Creek watershed)

Well 13FF24 (periodic, Yellow River watershed)

Trend

Well 13FF31 (monthly mean, Redland–Pew Creek watershed)

WATER LEVEL BELOW LAND SURFACE, IN FEET

Jan

Apr

July

Oct

Jan

Apr

July

Oct

Jan

Apr

July

Oct

Jan

Apr

July

Oct

2003 2004 2005 2006

Jan

Apr

July

Oct

Jan

Apr

July

Oct

2007 2008

Figure 13. Groundwater levels in the regolith in the Redland–Pew Creek and Yellow River watersheds near 

Lawrenceville, Georgia, 2003–2008. (See fig. 11 for location.)

Blank where 

 data are missing
24 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

Figure 14. Groundwater levels in the bedrock in the Redland–Pew Creek and Yellow River watersheds near 

Lawrenceville, Georgia, 2003–2008. (See fig. 11 for location.)

Figure 14. Groundwater levels in the bedrock in the Redland–Pew Creek and Yellow River watersheds near 

Lawrenceville, Georgia, 2003–2008. (See fig. 11 for location.)

Well 13FF30 (monthlymean, Redland–Pew Creek watershed)

Well 13FF13 (periodic, Redland–Pew Creek watershed)

Well 13FF16 (periodic, Redland–Pew Creek watershed)

Well 13FF19 (periodic, Redland–Pew Creek watershed) Jan Apr July Oct Jan Apr July Oct Jan Apr

July

Oct

Jan

Apr

July

Oct

2003 2004 2005 2006

Jan

Apr

July

Oct

Jan

Apr

July

Oct

2007 2008

23 

24 

25 

26 

27 

28 

29 

30 

–10 

0 

10 

20 

30 

40 

50 

60 

–10 

0 

10 

20 

30 

40 

50 

60 

6 

7 

8 

9 

10 

11 

12 

13 

Trend

Drawdown due to

water sampling

WATER LEVEL ABOVE (–) AND BELOW LAND SURFACE, IN FEET

Blank where 

 data are missing
Hydrologic Conditions 25

Figure 14. Groundwater levels in the bedrock in the Redland–Pew Creek and Yellow River watersheds near 

Lawrenceville, Georgia, 2003–2008. (See fig. 11 for location.)—Continued

Figure 14. Groundwater levels in the bedrock in the Redland–Pew Creek and Yellow River watersheds near 

Lawrenceville, Georgia, 2003–2008. (See fig. 11 for location.)––Continued

Well 13FF20 (periodic, Yellow River watershed)

Well 13FF21 (periodic, Yellow River watershed)

Well 13FF22 (periodic, Redland–Pew Creek watershed)

Well 13FF27 (periodic, Redland–Pew Creek watershed)

1

2

3

4

5

6

7

8

13

14

15

16

17

18

19

20

–4

–3

–2

–1

0

1

2

3

16

17

18

19

20

21

22

23

Jan

Apr

July

Oct

Jan

Apr

July

Oct

Jan

Apr

July

Oct

Jan

Apr

July

Oct

2003 2004 2005 2006

Jan

Apr

July

Oct

Jan

Apr

July

Oct

2007 2008

Trend

WATER LEVEL ABOVE (–) AND BELOW LAND SURFACE, IN FEET

Blank where 

 data are missing
26 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

Table 4. Base-flow measurements along selected stream reaches, Redland–Pew Creek watershed, Lawrenceville, Georgia area, 

2003–2006.—Continued 

[mi2, square miles; see figure 15 for reach locations; shaded cells represent reaches evaluated for groundwater seepage; <, less than; —, no data]

Site 

identification Station name

Intermediate 

drainage 

area (mi2)

Drainage 

area 

(mi2)

Base flow, in million gallons per day, and date measured

9/8/2003 10/28/2004 9/12/2005 9/5/2006 10/17/2007 9/8/2008

Reach RP-1 Area above site 02205450 1.82 — 0.58 0.83 — 0.32 0.23 0.25

02205450 Pew Creek at Sarah Lane, 

at Lawrenceville, Ga

1.82 0.58 0.83 — 0.32 0.23 0.25

Reach RP-2 Intermediate area between 

sites 02205450 and 

02205500

0.410 — — — — 0.37 0.11 0.03

02205500 Pew Creek near 

Lawrenceville, GA

2.23 — — — 0.69 0.34 0.28

Reach RP-3 Area above site 

335602084010401

0.599 — — — — 0.17 0.12 0.10

335602084010401 Pew Creek tributary 

below Johnston Rd,

Lawrenceville, GA

0.599 — — — 0.17 0.12 0.10

Reach RP-4 Area above site 

022055082

0.471 — 0.22 0.21 0.10 0.06 0.06 0.08

022055082 Redland Creek at 

Maltble St near 

Lawrenceville, GA

0.471 0.22 0.21 0.10 0.06 0.06 0.08

Reach RP-5 Intermediate area between 

sites 022055082 

and 022055085

0.480 — 0.33 0.29 0.35 0.12 0.02 0.01

022055085 Redland Creek below 

GA 120 at Lawrenceville, GA

0.954 0.56 0.49 0.45 0.19 0.08 0.10

Reach RP-6 Intermediate area between 

sites 335658084010001 

and 022055085

1.43 — — — — 0.30 — —

335658084010001 Redland Creek at Lville 

Suwanee Rd No 2, 

Lawrenceville, GA

2.38 — — — 0.49 — —

Reach RP-7 Intermediate area between 

sites 335658084010001, 

335645084010701

0.190 — — — — 0.09 — —

335645084010701 Redland Creek at Lville 

Suwanee Rd,

Lawrenceville, GA

2.57 — — — 0.57 0.30 0.32

Reach RP-8 Area above site 

335629084013801

0.241 — — — — 0.06 — 0.03

335629084013801 Redland Creek tributary 

near Monfort Rd, 

Lawrenceville, GA

0.241 — — — 0.06 — 0.03

Reach RP-9 Area above site 

335646084010702

0.093 — — — — 0.02 dry < 0.01

335646084010702 Redland Creek tributary 

at Lville Suwanee Rd, 

Lawrenceville, GA

0.093 — — — 0.02 dry < 0.01
Hydrologic Conditions 27

Table 4. Base-flow measurements along selected stream reaches, Redland–Pew Creek watershed, Lawrenceville, Georgia area, 

2003–2006.—Continued 

[mi2, square miles; see figure 15 for reach locations; shaded cells represent reaches evaluated for groundwater seepage; <, less than]

Site 

identification Station name

Intermediate 

drainage 

area (mi2)

Drainage 

area 

(mi2)

Base flow, in million gallons per day, and date measured

9/8/2003 10/28/2004 9/12/2005 9/5/2006 10/17/2007 9/8/2008

Combined flow at sites 02205520 and 02205508

02205520 Redland Creek at GA 29, 

near Lawrenceville, GA

3.11 1.25 1.36 0.96 0.80 0.41 0.37

02205508 Pew Creek at Sugarloaf 

Pkwy, near Lawrenceville, GA

3.43 3.10 2.04 1.74 1.17 0.49 0.45

Combined 6.54 4.35 3.39 2.70 1.97 0.90 0.83

Reach RP-10 Intermediate area between 

site 02205522 and 

combined flow at sites 

02205520 and 02205508

0.950 — –1.03 –0.61 –0.50 0.29 –0.13 1.17

Combined flow at sites 02205522, 02205500, and 335602084010401

02205522 Pew Creek at Patterson Rd, 

near Lawrenceville, GA

7.49 3.32 2.78 2.20 2.26 0.78 2.00

02205500 Pew Creek near 

Lawrenceville, GA

2.23 — — — 0.69 0.34 0.28

335602084010401 Pew Creek tributary 

below Johnston Rd, 

Lawrenceville, GA

0.60 — — — 0.17 0.12 0.10

Combined 2.83 — — — 0.86 0.46 0.38

Reach RP-11 Intermediate area between 

site 02205508 and 

combined flow at 

sites 02205500 and 

335602084010401

0.601 — — — — 0.31 0.03 0.08

Combined flow at sites 02205508, 335629084013801, 335645084010701, and 335646084010702

02205508 Pew Creek at Sugarloaf 

Pkwy, near Lawrenceville, GA

3.43 2.13 2.04 1.74 1.17 0.49 0.45

335629084013801 Redland Creek tributary 

near Monfort Rd, 

Lawrenceville, GA

0.24 — — — 0.06 0.00 0.03

335645084010701 Redland Creek at 

Lville Suwanee Rd, 

Lawrenceville, GA

2.57 — — — 0.57 0.30 0.32

335646084010702 Redland Creek tributary 

at Lville Suwanee Rd, 

Lawrenceville, GA

0.09 — — — 0.02 dry 0.00

Combined 2.90 — — — 0.65 — 0.35

Reach RP-12 Intermediate area between 

site 02205520 and 

combined flow at sites 

335645084010701, 

335646084010702, 

335629084013801

0.207 — — — — 0.15 — 0.03

02205520 Redland Creek at GA 29, 

near Lawrenceville, GA

3.11 1.25 1.36 0.96 0.80 0.41 0.37

Minimum –1.03 –0.61 –0.50 0.02 –0.13 0.00

Maximum 0.58 0.83 0.35 0.37 0.23 1.17

Median 0.28 0.25 0.10 0.16 0.06 0.05
28 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

Figure 15. Groundwater seepage along selected reaches in the 

Redland–Pew Creek watershed near Lawrenceville, Georgia, 2003–2008.

29

120

20

124

LAWRENCEVILLE

City limit

City limit

13FF21

13FF29

13FF24

02205522

02205508

02205520

13FF25

13FF19

02205450

02205500

13FF23

13FF31 13FF30

13FF27

13FF28

13FF22

13FF18

13FF20

13FF16

022055085

13FF13

022055082

13FF14

335646084010702

335646084010701

335658084010001

335629084013801

335602084010401

RP-3

RP-10

RP-11

RP-12

RP-8

RP-9

RP-7

RP-6

RP-4

RP-5

RP-1

RP-2

Redland

Creek

Pew

Patterson Road

Lawrenceville–Suwanee Road

Creek

0 1 MILE

0 0.5 1 KILOMETER

0.5

Existing or proposed bedrock

 production well and name—

 Also used for monitoring

Yellow

River

City limit

City limit

Lawrenceville

GWINNETT

COUNTY

RP-1

Figure 15. Groundwater seepage along selected reaches in the 

Redland–Pew Creek watershed near Lawrenceville, Georgia, 2003–2008.

EXPLANATION

Continuous with water quality

Periodic with staff gage

Base-flow measurement

N

Base modified from U.S. Geological Survey

1:24,000-scale digital raster graphics

Groundwater seepage, 2008— Watershed

 Pattern shown to differentiate between 

 stream reaches. Number is stream-reach

 identifier listed in table 4

Continuous regolith

Periodic regolith

Continuous bedrock

Periodic bedrock

Surface-water station and number Groundwater monitoring well

Stream reach with net gain and name

 in seepage

Redland–Pew Creek

Yellow River
Hydrologic Conditions 29

Figure 15. Groundwater seepage along selected reaches in the Redland–Pew Creek watershed near 

Lawrenceville, Georgia, 2003–2008.—Continued

–0.25

0.25

0.50

–0.5

0

–0.25

0.25

0.50

–0.5

0 0

2

1

–1

–2

0

3

1

–1

–2

–3

2

–0.25

0.25

0.50

–0.5

0

Reach RP-9 Reach RP-10

Reach RP-11 Reach RP-12 

Reach RP-2

Reach RP-4 Reach RP-5

Reach RP-1

–0.25

0.25

0.50

–0.5

0

–0.25

0.25

0.50

–0.5

0

–0.25

0.25

0.50

–0.5

0

9/8/2003 10/28/2004 9/12/2005 9/5/2006 10/17/2007 9/8/2008 9/8/2003 10/28/2004 9/12/2005 9/5/2006 10/17/2007 9/8/2008

GROUNDWATER SEEPAGE, IN MILLION GALLONS PER DAY

+25 percent error

Estimated groundwater seepage

–25 percent error

EXPLANATION

Figure 15. Groundwater seepage along selected reaches in the Redland–Pew Creek watershed near 

Lawrenceville, Georgia, 2003–2008.—Continued
30 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

Stream-Water Quality

Continuous water-quality data are collected at gage 

sites located on Pew Creek and Shoal Creek inside the city 

limits and at a background site on the Apalachee River 

located outside the city boundary (fig. 1). These sites provide 

long-term data for various water-quality properties to help 

better characterize stormwater runoff. These sites are used 

to continuously monitor precipitation, water temperature, 

specific conductance, and turbidity. In addition, water samples 

are collected at the sites to monitor fecal bacteria at Pew 

and Shoal Creeks, using the geometric mean method for 

comparison with State water-quality regulations. Because 

streamflow characteristics are a primary control of nonpointsource-associated water quality (Hirsch and others, 2006), 

continuous stream stage and discharge are continuously 

monitored at the stream-water-quality sites. The sites are

• 02218565—Apalachee River at Fence Road 

near Dacula (fig. 3), 

• 02205522—Pew Creek at Patterson Road, about 

0.8 mi southwest of Lawrenceville (fig. 11), and 

• 02208130—Shoal Creek at Paper Mill Road, about 

0.3 mi east of Lawrenceville (fig. 5). 

Monitoring at the Pew and Shoal Creek sites is funded 

through the Lawrenceville CWP, and monitoring at the 

Apalachee River site is funded by the Gwinnett County CWP. 

A statistical summary of mean and median daily streamflow, precipitation, water temperature, specific conductance, 

and turbidity is listed in table 5. Additional data are summarized 

for each site in the USGS Annual Water Data Reports for 

Georgia (http://wdr.water.usgs.gov/). These archival products 

supplement direct access to current and historical water data 

provided by the USGS National Water Information System 

(http://waterdata.usgs.gov/ga/nwis/). Beginning with water 

year 2006 (defined as the period from October 1, 2005 through 

September 30, 2006), Annual Water Data Reports are available 

as individual electronic Site Data Sheets for retrieval, 

download, and localized printing on demand.

Apalachee River

Based on comparison of land-use maps presented in 

Landers and others (2007), the 5.68-mi2 upper Apalachee 

River watershed in the northeastern part of the study area 

(fig. 3) has less transportation land use and less high and 

low density development than the upper Alcovy River and 

Redland–Pew Creek watersheds located to the southwest. 

Water-quality monitoring at the Upper Apalachee station 

(02218565) began in July 2001, and includes real-time 

monitoring of discharge, specific conductance, water 

temperature, turbidity, and precipitation, and collection of 

intermittent water-quality samples for quality assurance and 

to characterize water quality during storm events. 

 In comparison to the water quality at the other two 

stream sites, water at the Apalachee River site had the lowest 

mean and median values for specific conductance and water 

temperature and the greatest mean and median values for 

turbidity during October 2005–December 2008 (table 5). 

Continuous surface-water monitoring data indicate that 

changes in stream water-quality properties may be related to 

decreased streamflow during the 2006–2008 drought (fig. 16). 

During this drought period, streamflow and values of turbidity 

were generally lower than during 2003–2005, whereas water 

temperature and specific conductance were generally higher. 

Water temperature varies seasonally in response to air 

temperature, with highest values in the summer months. 

In addition to water-quality monitoring, 29 fecal coliform 

samples were collected at the Apalachee River site during 

October 2005 through July 2008 (fig. 17). Bacteria counts 

ranged from a low of 44 most probable number of colonies 

per 100 MPN col/100 mL in December 2006, to a high of 

31,000 MPN col/100 mL in October 2005. Fecal coliform 

standards for drinking-water supply, fishing, and recreation 

are listed in table 6. None of the samples at the Apalachee 

River site during November–April were above the Georgia 

Environmental Protection Division (GaEPD) single sample 

limit of 4,000 MPN col/100 mL for November–April.
Stream-Water Quality 31

Table 5. Statistical summary of mean and median daily streamflow, precipitation, stream 

temperature, specific conductance, and turbidity data for surface-water sites in the Lawrenceville 

area, Georgia, October 1, 2005, through December 31, 2008.

Statistic

Pew Creek at 

Patterson Road 

(02205522)

Apalachee River 

at Fence Road 

(02218565)

Shoal Creek at 

Paper Mill Road 

(02208130)

Streamflow, in cubic feet per second

Minimum 0.650 0.300 0.410

Maximum 161 99.0 247

Mean 8.01 5.78 5.74

Median 4.10 3.35 2.70

Precipitation, in inches

Minimum 0.00 0.000 0.000

Maximum 3.50 4.18 2.97

Mean 0.110 0.110 0.110

Median 0.000 0.000 0.000

Stream temperature, in degrees Celsius

Minimum 2.70 2.60 3.10

Maximum 25.6 25.6 26.3

Mean 15.5 15.2 15.8

Median 15.7 15.1 15.8

Specific conductance, in microsiemens per centimeter at 25 degrees Celsius

Minimum 45.0 44.0 44.0

Maximum 152 196 157

Mean 103 67.9 81.6

Median 107 69.0 82.0

Turbidity, in formazin nephelometric units

Minimum 2.00 2.00 2.00

Maximum 100 182 90.0

Mean 8.05 11.6 9.04

Median 4.20 6.20 6.00
32 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

Figure 16. Mean daily streamflow, precipitation, specific conductance, and water temperature, and median 

daily turbidity at surface-water station 02218565, Apalachee River at Fence Road near Dacula, Georgia, 

2003–2008. (See fig. 3 for location.) Jan Apr July Oct Jan Apr July Oct

Jan

Apr

July

Oct

Jan

Apr

July

Oct

2003 2004 2005 2006

Jan

Apr

July

Oct

Jan

Apr

July

Oct

2007 2008

Figure 16. Mean daily streamflow, precipitation, specific conductance, and water temperature, and median daily 

turbidity at surface-water station 02218565, Apalachee River at Fence Road near Dacula, Georgia, 2003–2008. 

(See fig. 3 for location.)

1

10

100

1,000

0

5

10

15

20

25

30

1

2

3

4

5

6

0

0

50

100

150

200

250

0.1

1

10

100

1,000

STREAMFLOW, IN 

CUBIC FEET PER SECOND

WATER TEMPERATURE,

IN DEGREES CELSIUS

SPECIFIC CONDUCTANCE, 

IN MICROSIEMENS PER 

CENTIMETER AT 

25 DEGREES CELSIUS

TURBIDITY, IN FORMAZIN 

NEPHELOMETRIC UNITS

PRECIPITATION,

 IN INCHES

Blank where 

 data are missing

Trend
Stream-Water Quality 33

Figure 17. Fecal coliform sampling results for surface-water station 02218565, 

Apalachee River at Fence Road near Dacula, Georgia, 2005–2008. 

(See fig. 3 for location.)

FECAL COLIFORM BACTERIA

CONCENTRATION, IN MOST

PROBABLE NUMBER OF COLONIES

 PER 100 MILLILITERS

1 

10 

100 

1,000 

10,000 

100,000 

2005Oct

Jan

Apr

July

Oct

Jan

Apr

July

Oct

Jan

Apr

July

2006 2007 2008

Georgia Environmental Protection Division standard

 for maximum single sample (November–April)

EXPLANATION

Figure 17. Fecal coliform sampling results for surface-water station 02218565, Apalachee River

at Fence Road near Dacula, Georgia, 2005–2008. (See fig. 3 for location.)

Table 6. Georgia Environmental Protection Division fecal 

coliform bacteria standards (modified from Georgia Department 

of Natural Resources, 1994; Gregory and Frick, 2000). 

[All standards and criterion are in most probable number of colonies per 

100 milliliters (MPN col/100 mL); —, no standard or criterion]

Designated 

use

Time of year 

that standards 

apply

30-day 

geometric 

mean1

Maximum 

single 

sample 

Drinking-water 

supply and 

fishing

May–October 200 —

November–

April

1,000 4,000

Recreation Year round 200 —

1

Geometric mean based on at least four samples collected from a

given site over a 30-day period at an interval not less than 24 hours. 

The geometric mean of a series of N terms is the Nth root of their product. 

For example, the geometric mean of 2 and 18 is 6—the square root of 36.
34 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

Redland–Pew Creek 

The Pew Creek site at Patterson Road (02205522; fig. 11;

table 2) serves as a primary monitoring point for drainages 

in the western part of the city. The primary drainages include 

Pew and Redland Creeks, which together drain about 5.5 mi2, 

or 41 percent, of the area covered by the city. Water-quality 

monitoring at the site began in September 2005.

As was the case in the Apalachee River watershed, 

continuous surface-water monitoring data indicate that changes 

in stream-water-quality properties may be related to decreased 

streamflow during the 2006–2008 drought (fig. 18). During 

Figure 18. Mean daily streamflow, precipitation, specific conductance, and water temperature, and median daily 

turbidity at surface-water station 02205522, Pew Creek at Patterson Road near Lawrenceville, Georgia, 2005–2008. 

(See fig. 11 for location.)

WATER TEMPERATURE,

IN DEGREES CELSIUS

TURBIDITY, IN FORMAZIN 

NEPHELOMETRIC UNITS

PRECIPITATION,

 IN INCHES

Figure 18. Mean daily streamflow, precipitation, specific conductance, and water temperature, and median 

daily turbidity at surface-water station 02205522, Pew Creek at Patterson Road near Lawrenceville, Georgia, 

2005–2008. (See fig. 11 for location.) Oct Jan Apr July

Oct

Jan

Apr

July

Oct

Jan

Apr

July

Oct

2005 2006 2007 2008

0 

5 

10 

15 

20 

25 

30 

0 

1 

2 

3 

4 

0 

20 

40 

60 

80 

100 

120 

140 

160 

0 

20 

40 

60 

80 

100 

120 

Blank where 

 data are missing

Trend

0.1 

1 

10 

100 

1,000 

STREAMFLOW, IN 

CUBIC FEET PER SECOND

SPECIFIC CONDUCTANCE, 

IN MICROSIEMENS PER 

CENTIMETER AT 

25 DEGREES CELSIUS
Stream-Water Quality 35

this drought period, values of streamflow and turbidity were 

generally lower than during 2005, whereas stream temperature 

and specific conductance were generally higher. Water 

temperature data show a seasonal fluctuation in response to 

air temperature, with highest values in the summer months.

Fecal coliform sampling began at the Pew Creek site 

in late 2005. During the period November 2005 through 

August 2008, 36 samples were collected and analyzed for fecal 

coliform (fig. 19). In 2007, a sampling strategy was adopted 

for comparison with the State water-quality regulations that 

are based on a geometric mean of four samples taken within 

a 30-day period. Data collected during 2007–2008 were 

combined into seven geometric means of at least four samples 

per mean, all of which met GaEPD water-quality standards 

for fecal coliform. None of the individual samples collected 

during November–April in 2005–2008 exceeded the GaEPD 

criterion of 4,000 MPN col/100 mL. During 2007 and 2008, 

the GaEPD 30-day geometric mean standard of 200 MPN 

col/100 mL for May–October was exceeded twice during 

May–October 2007 and twice during May–August 2008. 

Figure 19. Fecal coliform sampling results for surface-water station 02205522, Pew Creek 

at Patterson Road near Lawrenceville, Georgia, 2005–2008. (See fig. 11 for location.) Figure 19. Fecal coliform sampling results for surface-water station 02205522, Pew Creek 

at Patterson Road near Lawrenceville, Georgia, 2005–2008. (See fig. 11 for location.)

2005Nov

Jan

Apr

July

Oct

Jan

Apr

July

Oct

Jan

Apr

July

2006 2007 2008

Georgia Environmental Protection Division standard

Individual sample (November–April)

30-day geometric mean

May–October

EXPLANATION

1 

10 

100 

1,000 

10,000 

100,000 

Individual sample

FECAL COLIFORM BACTERIA

CONCENTRATION, IN MOST

PROBABLE NUMBER OF COLONIES

 PER 100 MILLILITERS

30-day geometric mean

November–April
36 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

Shoal Creek 

The Shoal Creek site at Paper Mill Road (02208130; 

fig. 20; table 2) serves as a primary monitoring point for 

drainages in the eastern part of the city. Shoal Creek drains 

about 3.6 mi2, or 26 percent, of the area covered by the city. 

According to maps presented by Landers and others (2007), 

urban development in this area is comparable to that of the 

Redland–Pew Creek watershed to the southwest (fig. 1). 

Continuous and periodic water-quality sampling at this site 

began in October 2005, continuous stage and discharge 

monitoring began in October 2006 (fig. 21).

Fecal coliform sampling began at the Shoal Creek site in 

October 2006. A geometric mean sampling strategy was used 

for comparison with State water-quality regulations. During 

October 2006 through August 2008, 36 samples were collected 

and analyzed for fecal coliform (fig. 22). Data collected during 

2006–2008 were combined into nine geometric means of at 

least four samples per mean. None of the individual samples 

collected during November–April in 2006–2008 exceeded 

the GaEPD criterion of 4,000 MPN col/100 mL. During 

2007 and 2008, the GaEPD 30-day geometric mean standard 

of 200 MPN col/100 mL for May–October was exceeded 

twice in May–October 2007 and twice in May–October 2008. 

Figure 20. Surface-water and groundwater monitoring networks, Shoal Creek watershed 

near Lawrenceville, Georgia, 2008.

Creek

Shoal

Rhodes

Jordan

Park

316

20

City limit

City limit

29

120

124

20

124

Airport

Paper Mill Road

Ezzard St

Existing or proposed bedrock

 production well and name—

 Also used for monitoring

Watershed

EXPLANATION

Shoal Creek

Periodic bedrock

Continuous with water quality

Surface-water station and number

Groundwater monitoring well and name

0 0.5 1 MILE

0 0.5 1 KILOMETER

Base modified from U.S. Geological Survey

1:24,000-scale digital raster graphics

N

Figure 20. Surface-water and groundwater monitoring networks, Shoal Creek watershed 

near Lawrenceville, Georgia, 2008.

14FF52

14FF55

14FF16

02208130

GWINNETT

COUNTY

Lawrenceville
Stream-Water Quality 37

Figure 21. Mean daily streamflow, precipitation, specific conductance, and water temperature, and median 

daily turbidity at surface-water station 02208130, Shoal Creek at Paper Mill Road near Lawrenceville, Georgia, 

2005–2008. (See fig. 20 for location.)

WATER TEMPERATURE,

IN DEGREES CELSIUS

TURBIDITY, IN FORMAZIN 

NEPHELOMETRIC UNITS

PRECIPITATION,

 IN INCHES

Figure 21. Mean daily streamflow, precipitation, specific conductance, and water temperature, and median 

daily turbidity at surface-water station 02208130, Shoal Creek at Paper Mill Road near Lawrenceville, Georgia, 

2005–2008. (See fig. 20 for location.) Oct Jan Apr July

Oct

Jan

Apr

July

Oct

Jan

Apr

July

Oct

2005 2006 2007 2008

0

5

10

15

20

25

30

0

0

20

40

60

80

100

120

140

160

180

0.5

1.0

1.5

2.0

2.5

3.0

3.5

1

10

100

Blank where 

 data are missing

Trend

0.1

1

10

100

1,000

STREAMFLOW, IN 

CUBIC FEET PER SECOND

SPECIFIC CONDUCTANCE, 

IN MICROSIEMENS PER 

CENTIMETER AT 

25 DEGREES CELSIUS
38 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

Real-time continuous monitoring of discharge, specific 

conductance, and turbidity during June 1–20, 2007, helped to 

identify a sewage overflow, which began on or about June 7 

and continued through June 12. In general, these streamwater-quality properties show little variation under base-flow 

conditions, with most changes occurring during storm events. 

For example, during base-flow conditions of June 1–6, there 

was little variation in streamflow and specific conductance, 

and only minor variation in turbidity (fig. 23). Conversely, 

during June 15th, there was a large increase in turbidity and 

decrease in specific conductance in response to a storm 

event. Increased specific conductance during June 7–12—

a period of base-flow conditions—indicated a point source 

of contamination into the creek. This finding prompted a site 

inspection where algae growth was observed in the creek. 

Gwinnett County authorities determined that the source of the 

spill was from a clogged sewer line resulting in overflow of a 

nearby manhole (Jonathan B. Evans, U.S. Geological Survey, 

oral commun., June 2007). The sewer line was repaired, and 

water quality returned to normal conditions after June 12.

Figure 22. Fecal coliform sampling results at surface-water station 

02208130, Shoal Creek at Paper Mill Road near Lawrenceville, Georgia, 

2006–2008. (See fig. 20 for location.)

Oct

Jan

Apr

July

Oct

Jan

Apr

July

2006 2007 2008

FECAL COLIFORM BACTERIA

CONCENTRATION, IN MOST

PROBABLE NUMBER OF COLONIES

 PER 100 MILLILITERS

1

10

100

1,000

10,000

EXPLANATION

Individual sample

30-day geometric mean

Georgia Environmental Protection Division standard

Individual sample (November–April)

30-day geometric mean

November–April

May–October

Figure 22. Fecal coliform sampling results at surface-water station 02208130, 

Shoal Creek at Paper Mill Road near Lawrenceville, Georgia, 2006–2008.

(See fig. 20 for location.)
Stream-Water Quality 39

Figure 23. Streamflow, specific conductance, and turbidity at surface-water station 02208130, Shoal Creek at 

Paper Mill Road near Lawrenceville, Georgia, June 1–20, 2007. (See fig. 20 for location.)

STREAMFLOW, IN 

CUBIC FEET PER SECOND

SPECIFIC CONDUCTANCE, 

IN MICROSIEMENS PER 

CENTIMETER AT 

25 DEGREES CELSIUS

TURBIDITY, IN FORMAZIN 

NEPHELOMETRIC UNITS

Figure 23. Streamflow, specific conductance, and turbidity at surface-water station 02208130, Shoal Creek at 

Paper Mill Road near Lawrenceville, Georgia, June 1–20, 2007. (See fig. 20 for location.)

0

50

100

150

200

1

10

100

1,000

0.1

1

10

100

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

JUNE 2007

Sewage spill

Precipitation

response

Precipitation

response

Precipitation

response

Blank where 

 data are missing
40 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

Groundwater Studies

Groundwater studies were completed during 2003 to 

2008 in support of the city’s continued development and 

management of groundwater resources. These ongoing studies 

provide additional data to help support water-management 

decisions and to continue increasing the understanding of 

hydrologic processes.

Well-Field Expansion in the Upper Alcovy 

River Watershed

In 2001, the City of Lawrenceville drilled its first test 

well in the upper Alcovy River watershed. This test well 

was later converted into production well 14FF59, which is 

capable of producing 350 gal/min (Williams and others, 2004). 

Because of the success of this well, the City of Lawrenceville 

drilled three additional test wells in an attempt to fully develop 

the available groundwater resources in that area. Wells 14FF62 

and 14FF63 were drilled in May 2003, and well 14FF64 was 

drilled in July 2003 (table 1). In addition to the three test 

wells, a new bedrock-monitoring well (14FF65) was drilled 

in July 2003. The locations of the test wells in relation to the 

geology are shown in figure 24, and borehole geophysical logs 

are included in Appendix 1.

The results of the test drilling indicated that well 14FF62

is capable of yielding 85 gal/min whereas the other two test 

wells had well yields below 10 gal/min. The two low-yielding 

test wells, in addition to the new monitoring well, were

incorporated into the existing groundwater monitoring network.

Hydrogeologic Investigation of Ezzard Street 

Well, Shoal Creek Watershed

Well 14FF55 is a new production well located approximately 25 ft south of Shoal Creek and 3,500 ft south of the 

existing production well (14FF16) at Rhodes Jordan Park 

in Lawrenceville (table 1, fig. 20). The rocks penetrated by 

this well include a biotite gneiss unit and an amphibolite unit 

(fig. 25; Williams and others, 2004). Borehole geophysical 

logs and flowmeter surveys conducted by the USGS indicated 

several water-bearing zones, including the following:

• 14–17 ft: 15 gal/min (cavernous zone mostly 

along foliation);

• 100.5–101.5 ft: 5 gal/min (foliation parting);

• 181–182 ft: 20 gal/min (major opening along 

foliation/layering);

• 251–252 ft: 110 gal/min (major opening along 

foliation/layering); and

• 416–417 ft: 100 gal/min (major opening along 

foliation/layering).

Hydrogeologic investigations conducted by the USGS 

at this well involved investigation of water-bearing zones 

connected with surface water and containing elevated 

radionuclide levels.

Surface-Water Interconnection

In February 2005, during the well permitting phase, the 

GaEPD conducted a microscopic particulate analysis (MPA) 

test on well 14FF55 and determined that this well was under 

the influence of surface water. An ambient flowmeter survey of 

the well conducted by the USGS in 2001 (Williams and others, 

2004) identified a shallow fracture about 1 to 2 ft deeper 

than the base of the casing (63 ft), which was losing about 

10 gal/min and was the likely pathway for interconnection 

with surface water. To eliminate the surface-water influence, 

the fracture at 64–65 ft and another fracture at about 100 ft 

were sealed off by installing a 6-inch PVC liner and K-packer 

into the well to a depth of 120 ft in March 2005 (fig. 26).

Following liner installation, flowmeter measurements 

were collected above and below the liner under ambient 

conditions on March 15, 2005, to check for any potential 

leakage behind the newly installed liner. The flowmeter 

measurements indicated less than 0.02 gal/min of upward flow 

(near the detection limit of 0.01 gal/min of the flowmeter) near 

the base of the casing. This result provided a good indication 

that the liner-packer assembly had effectively sealed off the 

shallow fractures.

In addition to the geophysical logs, water-level 

measurements taken by city personnel also gave an indication 

of an effective seal and hydraulic separation of shallow waterbearing zones from the deeper zones (Robert Paul, City of 

Lawrenceville Water Department, written commun., 2005). 

The water level before the liner installation was 1.8 ft 

below land surface (March 14, 2005), and the water level 

after the liner installation was 2.4 ft above land surface 

(March 15, 2005).

The water-level change from below land surface to above 

land surface indicates that shallower, lower head fractures are 

effectively being sealed and that the liner-packer assembly has 

had a measurable effect on the hydraulic condition in the well. 

The second MPA test conducted by the GaEPD on March 28, 

2005, indicated the well was no longer under the influence of 

surface water and that the corrective measure was successful.
Groundwater Studies 41

Figure 24. Geologic map of the upper Alcovy River watershed showing 

locations of test wells drilled in May and July 2003 near Lawrenceville, 

Georgia (modified from Williams and others, 2005).

1,000

1,000

1,000

1,000

1,000

14FF62

14FF63

14FF64

14FF59

gg

a

bg

bs

qs

Granite gneiss 14FF64

Biotite gneiss

Button schist

Amphibolite

Quartzite/schist

Lithologic unit Well and site name

EXPLANATION

Gwinnett County Airport

Figure 24. Geologic map of the upper Alcovy River watershed showing 

locations of test wells drilled in May and July 2003 near Lawrenceville, 

Georgia (modified from Williams and others, 2005).

0 1,000 2,000 FEET

0 250 500 METERS

Base from U.S. Geological Survey

1:24,000-scale digital data; Lawrenceville

Land surface contour interval is 20 feet

33°59'00"

33°59'30"

33°58'30"

Alcovy

River

Cedars Creek

Cedars

Road

83°57'30" 83°57'00" 83°56'30"

gg

gg

a

a

bg

bs

qs

qs

qs

316

Lawrenceville

Map

area

Upper Alcovy

River watershed
42 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

Elevated Levels of Radionuclides

As described in the previous section, although modification of well 14FF55 effectively eliminated the connection 

to surface water, it also had an unexpected effect on water 

quality. Prior to retrofitting the well with a casing liner in 

March 2005, water samples collected from this well had 

gross-alpha particle activity radiation generally less than 

11 picocuries per liter (pCi/L; table 7). Following well 

modification, the levels increased to 173 pCi/L, indicating a 

large contribution from deeper water-bearing zones containing 

high gross-alpha levels. 

The source of the elevated radiation in well 14FF55 is 

unknown, but may be associated with a pegmatitic zone in 

the biotite gneiss unit (upper interval). Natural gamma logs 

show elevated levels in parts of the upper interval (fig. 25)

that may indicate the location of radioactive zones. Additional 

geophysical, flowmeter, and geochemical investigations 

would be required to identify the specific zone(s) contributing 

radioactive water to the well. Laboratory tests indicated 

the radioactivity associated with the sample collected on 

August 5, 2005 resulted from the presence of uranium with 

an activity of 179 pCi/L. 

In February 2006, the well was sampled following a 

10–14-day period of continuous pumping at a rate of 138 to 

150 gal/min. That sample contained 64 pCi/L of gross-alpha 

particle activity and 58 pCi/L of uranium. The large reduction 

in radioactivity was attributed to the continuous pumping 

of the well prior to collecting the sample. Concentrations 

in samples collected later that month ranged from 56.6 to 

70.6 pCi/L of gross-alpha particle activity and from 58 to 

68.2 pCi/L of uranium (table 7). One of these samples was 

submitted for analysis of uranium mass for the purpose 

of converting picocuries per liter to micrograms per liter, 

which was needed for comparison to the U.S. Environmental 

Protection Agency maximum contaminant level (MCL) of 

30 micrograms per liter (μg/L) (U.S. Environmental Protection 

Agency, 2009). That sample had a uranium activity of 

68.2 pCi/L with a computed concentration of 61.1 μg/L, which 

is almost double the MCL. 

To investigate the source of the elevated radionuclides, 

several packer tests were conducted by the USGS between 

May and August 2005 to isolate and sample the upper and 

lower parts of well 14FF55 (fig. 26). The first test was 

conducted on May 10, 2005, which isolated the upper portion 

of the borehole for sampling. During this test,

• The top of the packer was set at 310–314 ft with 

an inline submersible pump positioned just above 

the packer.

• The packer was inflated to approximately 200 pounds 

per square inch (psi) and held at that pressure for the 

1.5-hour test duration.

• While inflated, the well was pumped at a rate of 

27 gal/min; the water level in the upper part of the 

borehole was monitored until it stabilized at about 

25 ft below land surface (fig. 27).

• A water sample was collected, and the packer assembly 

was removed from the borehole.

Table 7. Summary of radiological testing results for water samples collected from Well 14FF55.

[Lab: GaEPD—Georgia Environmental Protection Division, RadSafe—Radiation Safety Engineering, Chandler, Arizona; MCL, U.S. Environmental Protection 

Agency Maximum Contaminant Level (http://www.epa.gov/safewater/contaminants/index.html#listmcl, accessed August 19, 2009); —, no data; <, less than]

Lab Date

 tested

Picocuries per liter

Gross alpha Radium 226 Radium 228 Total uranium

Value Error MCL Value Error MCL Value Error MCL Value Error

GaEPD 8/28/2001 10 — 15 0.7 — 5 — — 5 — —

GaEPD 7/14/2004 5 — 15 2 — 5 3 — 5 — —

GaEPD 8/5/2005 173 8 15 <1 — 5 <1 — 5 179 20

GaEPD 2/2/2006 64 5 15 1 1 5 <1 — 5 58 4

RadSafe1 2/2/2006 70.6 5.6 15 2 0.2 5 <0.4 0.4 5 63.8 2.1

RadSafe2 2/20/2006 56.6 4.7 15 1.8 0.2 5 <0.4 0.4 5 68.2 2

GaEPD 3/17/2006 62 5 15 2 1 5 1 1 5 70 3

RadSafe 7/26/2007 83.1 6.4 15 2.4 0.3 5 0.4 0.5 5 87.2 2.5

1 Samples taken on February 2, 2006, were after 10–14 days of continuous pumping at a rate of 138–150 gallons per minute.

2 Sample taken on February 20, 2006, also included analysis for isotopic uranium (uranium sass). The result was 61.1 ± 3.4 micrograms per liter.
Groundwater Studies 43

Figure 26. K-packer system used to modify well 14FF55 

to eliminate the influence of surface water, March 2005. 

(Photo by Robert Paul, City of Lawrenceville.)

Figure 25. Upper and lower packer intervals in relation to water-bearing zones 

in well 14FF55 near Lawrenceville, Georgia, 2005. (See fig. 20 for well location.)

Figure 27. Hydrograph showing water level in the 

upper portion of well 14FF55 near Lawrenceville, Georgia, 

during the packer test, May 10, 2005. (See fig. 20 for 

well location.)

K-packer

Figure 26. K-packer system used to modify well 14FF55 

to eliminate the influence of surface water, March 2005. 

(Photo by O. Gary Holloway, U.S. Geological Survey.)

WATER LEVEL BELOW LAND SURFACE, IN FEET

Figure 27. Hydrograph showing water level in the upper 

portion of well 14FF55 near Lawrenceville, Georgia, during the 

packer test, May 10, 2005. (See fig. 20 for well location.)

12:00 13:12 14:24 15:36 16:48

0

5

10

15

20

25

30

MAY 10, 2005

Figure 25. Upper and lower packer intervals in relation to water-bearing zones 

in well 14FF55 near Lawrenceville, Georgia, 2005. (See fig. 20 for well location.)

Biotite gneiss

Amphibolite

Gallons per minute

Potential production zone

Lithologic unit

Water-bearing zone

EXPLANATION

Land

surface

Feet

250

Major

lithologic

units

Waterbearing

zones

Packer 

intervals

tested

100 

200 

300 

400 

Total

well depth

450 feet 

Total air-lift yield for

6-inch hole = 250 gal/min 

PPZ 

PPZ 

PPZ 

PPZ 

PPZ 

PPZ 

15 gal/min

5 gal/min

20 gal/min

gal/min

110 gal/min

100 gal/min

Upper interval Lower interval Cased out

2000 4000

Natural gamma, in 

American Petroleum

Institute Units

Lateral

resistivity,

in ohm-meters

0 500 0
44 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

The results of the upper-zone packer test yielded a grossalpha concentration of 1,054 pCi/L , which is more than an 

order of magnitude greater than the previous “whole-well” 

samples collected earlier that year (table 8). Although 

this result appeared to indicate that the radioactivity was 

originating from the upper portion of the borehole, a second 

packer test was planned to determine the concentrations and 

yield in the lower portion of the borehole. This information 

could help determine whether the lower part of the well could 

produce an adequate yield for production purposes. If the 

lower part of the borehole could yield an adequate amount 

of good-quality water, then the well could be modified by 

extending the liner pipe to a greater depth to isolate the poorer 

quality water.

During the second packer test conducted in August 2005,

• The top of packer was set at 310–314 ft with an inline 

submersible pump positioned just below the packer.

• The packer was inflated to about 200 psi and held at 

that pressure for the duration of the 2-hour test.

• While inflated, the lower (314–450 ft) portion of the 

borehole was pumped at a rate of 37.5 gal/min; no 

water levels were obtained from the pumped zone 

because it was isolated beneath the packer assembly 

and there was no pass-through access for installation 

of a transducer.

• The water level in the borehole above the packer 

(120–310 ft) slowly declined 1.5 ft during the test, 

apparently in response to pumping. This finding 

indicated that although the packer was not leaking, 

the upper and lower zones were hydraulically 

connected through fractures intersecting both zones. 

• A water sample was collected after 2 hours of 

pumping, and the packer assembly was removed 

from the borehole.

The results of the lower-zone packer test yielded a grossalpha concentration of 448 pCi/L, which was approximately 

half the value for the upper zone, but still an order of 

magnitude greater than the previous whole-well samples 

collected earlier that year (table 8). The disparity between 

the whole-well samples and the packer interval samples was 

thought to be related to the shorter period of time the well was 

pumped, the lower pumping rate, or a combination of these 

two factors. The lower pumping rate could cause water to be 

derived from a smaller network of fractures, whereas a larger 

pumping rate could cause water to be derived from a larger 

network of fractures.

 Because high gross-alpha activity was detected in the 

water samples collected through the packer assembly, it was 

determined that a longer-term test should be run to obtain 

more representative samples from the packer intervals. The 

lower interval was selected for testing because the results 

from this zone had about half of the gross-alpha activity as 

the upper interval.

The third and final packer test was designed with the 

following considerations:

• Prior to installing the packer assembly, the well 

should be pumped using the existing production 

pump for 1 to 2 weeks to stabilize radionuclide 

concentrations surrounding the well, and a water 

sample should be collected at the end of the period 

to establish pre-packer conditions.

• The packer installation should be similar to that of 

the previous test to isolate the lower portion of the 

borehole from 314 to 450 ft.

• Following packer inflation and pump startup, samples 

should be collected at various time intervals during 

continuous pumping for analysis of gross-alpha 

particle activity. The packer should be kept fully 

inflated throughout the duration of the test.

Table 8. Summary of radiological testing for water samples collected from discrete packer intervals in well 14FF55.

 [Analysis by Radiation Safety Engineering, Chandler, AZ; gal/min, gallon per minute]

Date tested Zone tested Gross alpha, in 

picocuries per liter Notes

5/10/2007 Upper (120 –310 ft) 1,054±67.0 Sample taken after the packer interval was 

pumped at 27 gal/min for 2 hours

5/30/2009 Lower (314–450 ft) 448±29.0 Sample taken after the packer interval was 

pumped at 31 gal/min for 2.5 hours

8/6/2007 Lower (314–450 ft) 41.0±4.0 Sample taken after the packer interval was 

pumped at 60 gal/min for 5 days

8/11/2007 Lower (314–450 ft) 40.0±4.0 Sample taken after the packer interval was 

pumped at 60 gal/min for 10 days

8/20/2007 Lower (314–450 ft) 41.0±4.0 Sample taken after the packer interval was 

pumped at 60 gal/min for 19 days
Groundwater Studies 45

On July, 30, 2007, after removing the production pump 

from well 14FF55, the packer assembly was set to a depth of 

310–314 ft and inflated. Beneath the packer, a submersible 

pump capable of pumping 60 to 80 gal/min was installed, 

which is twice as large as the pump used for previous packer 

tests. At startup, a constant rate of 75 gal/min was initially 

established, but was shut off only 3 hours into the test because 

of a loss of pressure in the packer assembly. On August 1, 

2007, the packers were re-inflated, and the pump was restarted 

at a rate of 60 gal/min. That rate was maintained for the next 

19 days during which time water samples were collected from 

the lower zone on August 6, 11, and 20. Following pump 

shutdown, the upper and lower zones were monitored in a 

“shut-in” condition for an additional 2 weeks to monitor the 

recovery response in the two zones. The results of the packer 

test are shown in figure 28, listed in tables 8 and 9, and are 

briefly described here. Prior to pumping, water levels in the 

two zones were identical at 2.09 ft; after 1 day of pumping 

the water level in the upper zone declined to 19.22 ft, and 

the water level in the lower zone declined to 23.84 ft. Water 

levels in the upper and lower zones declined slightly during 

the remainder of the pumping period, and by the 19th day, 

were 22.96 and 29.42, respectively (table 9). Total drawdown 

during the test period was 20.87 ft in the upper zone and 

27.33 ft in the lower zone. The hydraulic responses observed 

during the packer test indicate that the upper and lower zones 

are hydraulically connected to some degree as evidenced 

by drawdown response in both zones. Gross-alpha particle 

activity in water samples collected from the lower zone at 

5, 10, and 19 days ranged from 40–41 pCi/L (table 8), 

indicating the radioactivity in water had reached equilibrium 

with stabilization of the pumping water levels.

Results of the packer tests indicate that sealing off the 

upper poor water-quality zone would result in a slight decrease 

in well yield and an improvement in groundwater quality. 

Pumping the lower zone at 60 gal/min resulted in a specific 

capacity of 2.44 gallons per minute per foot [(gal/min)/ft], 

which is slightly less than the value of 2.6 (gal/min)/ft reported 

for a 36-hour test of the combined upper and lower intervals 

(Williams and others, 2004). Because a modified well sealing 

off the upper interval could be installed at a deeper depth, the 

slight loss in yield might be offset by the greater available 

drawdown in the well. Water sampling results indicate that 

well modification may help reduce the overall level of 

radionuclides by as much as 50 percent, although it is possible 

that pumping from the lower zone may eventually induce 

enough leakage between the zones to produce an increase the 

overall concentration of radionuclides.

Figure 28. Hydrograph showing water level responses to 

pumping the lower zone of well 14FF55 near Lawrenceville, 

Georgia, during packer tests, August 2007. (See fig. 20 for 

well location.)

Table 9. Water levels in the upper and lower zones in well 14FF55 during packer test, August 1–19, 2007. 

[Head separation: when positive, water level in lower zone is deeper than in upper zone]

Zone depth 

(feet below land surface)

Water level, in feet below land surface

Start test 1 day 5 days 10 days 19 days

Upper (120 –310) 2.09 19.22 22.59 23.97 22.96

Lower (134 –450) 2.09 23.84 27.11 28.46 29.42

Head separation 0.00 4.62 5.73 5.61 5.55 WATER LEVEL BELOW LAND SURFACE, IN FEET

2007

July 27 Aug 6 Aug 16

Lower packer interval 

 greater than 310 feet

Upper packer interval 

 less than 310 feet

Aug 26 Sept 5 Sept 15

Figure 28. Hydrograph showing water level responses to 

pumping the lower zone of well 14FF55 near Lawrenceville, 

Georgia, during packer tests, August 2007. (See fig. 20 for 

well location.)

5

0

10

15

20

25

30
46 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

Lithology and Water-Bearing Characteristics 

at Lawrenceville–Suwanee No. 2 Test Well, 

Redland–Pew Creek Watershed

Well 13FF34 is a 605-ft-deep test well drilled by the City 

of Lawrenceville in June 2008 to explore additional water 

resources in the Redland–Pew Creek watershed (table 1). 

The well is located near the city boundary on the west side 

of Lawrenceville–Suwanee Road (fig. 11). 

The rocks penetrated by this well include an upper 

and lower amphibolite unit, biotite gneiss and button schist 

unit, and a quartzite/schist unit. Borehole geophysical logs 

and examination of drill cuttings by the USGS indicated 

four water-bearing zones: (1) within the upper amphibolite 

unit, (2) near the contact of the upper amphibolite unit 

and the biotite gneiss and button schist unit, (3) within the 

quartzite/schist unit, and (4) near the basal contact of the 

lower amphibolite unit (fig. 29). The final air-lift yield was 

measured at about 22 gal/min.

Figure 29. Lithology and borehole geophysical log characteristics for test well 13FF34 near 

Lawrenceville, Georgia. (See fig. 11 for well location; gal/min, gallons per minute)

Lithology

Amphibolite

Air lifting approximately 1 to 2 gal/min

Biotite gneiss with button schist

(shearing)

Quartizite/schist

10 gal/min at contact

Air lifting approximately 10 to 12 gal/min

10 gal/min gained in this unit

Air lifting approximately 22 gal/min

5000

Pegmatite/granite

Amphibolite

Schist/quartzite/biotite gneiss

Fracture near contact approximately 2 to 3 gal/min

Biotite schist/schistose-biotite gneiss

Biotite gneiss and button schist

Biotite gneiss

Approximate location of water-bearing zone based on air-lift yield during drilling

100

Land

surface

200

300

400

500

600

Figure 29. Lithology and borehole geophysical log characteristics for test well 13FF34 

near Lawrenceville, Georgia. (See fig. 11 for well location; gal/min, gallons per minute)

Feet

Natural gamma, in 

American Petroleum

Institute Units

Lateral

resistivity,

in ohm-meters

Caliper,

in inches

5 7 0 700 0
Summary 47

Summary

Hydrologic studies conducted as part of the cooperative 

water program between the U.S. Geological Survey and the City 

of Lawrenceville provide important data for the management 

of water resources. Focus areas during 2003–2008 included 

hydrologic and surface-water-quality monitoring and geologic 

studies to better understand groundwater flow and hydrologic 

processes in a crystalline rock setting. Hydrologic monitoring data 

are being used by the City of Lawrenceville to quantify baseline 

hydrologic conditions in anticipation of expanded groundwater 

development. Surface-water-quality data are being used to 

provide an understanding of how stream quality is affected by 

natural factors (such as precipitation) and anthropogenic factors 

(such as impervious area) and to provide information that is 

essential for successful watershed management.

Groundwater-level, streamflow, base flow, and 

precipitation-monitoring networks were established in the 

Lawrenceville area during 2003–2008 to provide the City 

of Lawrenceville a means to estimate the sustainability of 

the hydrologic system under normal or anticipated pumping 

conditions. The network includes each of the two watersheds 

projected for groundwater development—the Redland–Pew 

Creek and the upper Alcovy River watersheds—and the upper 

Apalachee River watershed, which serves as a background 

or control watershed because of its similar geologic and 

hydrologic characteristics to the pumped watersheds. 

The upper Apalachee River watershed covers a 

5.68-square-mile (mi2) area in the northeastern part of the 

study area. Precipitation is the main control on hydrologic 

conditions in the Apalachee River watershed. Increased 

precipitation generally results in increases in both streamflow 

and groundwater levels; decreased precipitation results in 

decreased streamflow and groundwater levels. Precipitation 

was generally greater during 2003–2005 than during 2006–

2008, resulting in a corresponding decrease in streamflow and 

groundwater levels.

The upper Alcovy River watershed covers a 10-mi2 area 

in the north-central part of the study area. The current (2008) 

main production well for the city (14FF16) is located in the 

adjacent Shoal Creek watershed, about 1 mi southwest of 

the watershed boundary. During 2003–2008, precipitation, 

streamflow, and groundwater levels in the upper Alcovy 

River watershed showed a general downward trend. Most 

groundwater-level declines were from 2.4 to 6.9 feet (ft), with 

the greatest decline of 28.5 ft in bedrock well 14FF52 that 

corresponded to periodic pumping from well 14FF55. The 

most extensive streamflow measurement effort was conducted 

in September 2006, when seepage gains were measured at 

five of the nine reaches evaluated, with losses measured at the 

other four reaches. 

The Redland–Pew Creek watershed covers a 7.5-mi2

area in the southwestern part of the study area. Several well 

sites in this area have been identified for development of 

groundwater supplies for the city, including well 13FF18, 

which was brought online in the fall of 2008. During 2003–

2008, precipitation, streamflow, and groundwater levels in the 

Redland–Pew Creek watershed showed a general downward 

trend. Groundwater-level declines were measured in 12 of the 

13 wells monitored, ranging mostly between 2.8 and 6.5 ft, 

with considerably greater declines in bedrock wells 13FF16 

(40.4 ft) and 13FF13 (49.1 ft). The water-level change in 

well 13FF16 represented a temporary decline during a watersampling event in September 2008, whereas the decline in 

well 13FF13 corresponded to the initiation of pumping in 

well 13FF18, located westward along the trend of foliationparallel partings that provide an interconnection between 

the wells. Seepage measurement data collected at 12 reaches 

during 2003–2008 indicate that most stream reaches were 

gaining throughout the period. 

Continuous water-quality data were collected at gage 

sites located on Pew Creek and Shoal Creek inside the city 

limits, and at a background site on the Apalachee River 

located outside the city boundary. Continuous surface-watermonitoring data indicate that changes in stream-water-quality 

properties at all three sites may be related to decreased 

streamflow during the 2006–2008 drought. During this 

drought period, values of streamflow and turbidity were 

generally lower than during 2003–2005, whereas water 

temperature and specific conductance were generally higher. 

In comparison to the other two stream sites, water at the 

Apalachee River site had the lowest mean and median values 

for specific conductance and the greatest mean and median 

values for turbidity during October 2005–December 2008. In 

the Shoal Creek watershed, real-time continuous monitoring 

of discharge, specific conductance, and turbidity during 

June 1–20, 2007, helped to identify a sewage overflow, which 

began on or about June 7 and continued through June 12.

In addition to water-quality monitoring, samples were 

collected to determine fecal coliform bacteria concentrations. 

None of the individual samples from the three water-quality 

sites exceeded the Georgia Environmental Protection Division 

(GaEPD) limit of 4,000 MPN col/100 mL for November through 

April. In the Redland–Pew Creek and Shoal Creek watersheds, 

the GaEPD 30-day geometric mean standard of 200 most 

probable number of colonies per 100 milliliters for May–

October was exceeded twice during May–October 2007 and 

twice during May–October 2008.

Selected groundwater studies were completed during 

2003–2008 in support of the city’s continued development 

and management of groundwater resources. These 

included flowmeter surveys and water sampling at well 

14FF55 in the Shoal Creek watershed to evaluate the 

effectiveness of installing a casing liner to eliminate the 

influence of surface water and to identify the source of 

radionuclides, and test drilling and logging of four wells 

drilled in the upper Alcovy River watershed and one 

well in the Redland–Pew Creek watershed to determine 

subsurface geology and locations of water-bearing zones.
48 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

Selected References

Albertson, P.N., 2005, Establishment of a groundwater and 

surface-water monitoring network to assess the potential 

effects of groundwater development in an igneous 

and metamorphic rock aquifer, and preliminary data, 

Lawrenceville, Georgia, 2003–2004, in Hatcher, K.J., ed., 

Proceedings of the 2005 Georgia Water Resources 

Conference, held April 25–27, 2005, at the University 

of Georgia Institute of Ecology, The University of 

Georgia, Athens, Georgia, accessed November 22, 2009, 

at http://ga.water.usgs.gov/pubs/other/gwrc2005/pdf/

GWRC05_Albertson.pdf.

Brunett, J.O., Barber, N.L., Burns, A.W., Fogelman, 

R.P., Gillies, D.C., Lidwin, R.A., and Mack, T.J., 1997, 

A quality-assurance plan for district groundwater activities 

of the U.S. Geological Survey: U.S. Geological Survey 

Open-File Report, 97–11, 19 p., accessed October 6, 2009, 

at http://water.usgs.gov/ogw/pubs/OFR9711/gwqap.pdf.

City-Data.com, 2009, Lawrenceville, Georgia, accessed 

February 4, 2009, at http://www.city-data.com/city/

Lawrenceville-Georgia.html.

Clark, W.Z., and Zisa, A.C., 1976, Physiographic map of 

Georgia: Atlanta, Ga., Georgia Department of Natural 

Resources, Geologic and Water Resources Division, 

1 pl., scale 1:2,000,000.

Garber, M.S., and Koopman, F.C., 1968, Methods of 

measuring water levels in deep wells: U.S. Geological 

Survey Techniques of Water-Resources Investigations, 

book 8, chap. A1, 23 p.

Georgia Humanities Council, 2008, The new Georgia 

encyclopedia, accessed February 4, 2009, at 

http://74.125.47.132/search?q=cache:v5MHoiKuCK8J:

www.georgiaencyclopedia.org/nge/Article.jsp%3Fid%3Dh2233+population+lawrenceville+ga+1980&hl=en&ct

=clnk&cd=6&gl=us.

Gotvald, A.J., and Stamey, T.C., 2005, Surface-water qualityassurance plan for the USGS Georgia Water Science Center: 

U.S. Geological Survey Open-File Report 2005–1246, 

45 p., accessed October 6, 2009, at http://pubs.usgs.gov/

of/2005/1246/.

Gray, J.R., and Glysson, G.D., eds., 2003, Proceedings of 

the Federal Interagency Workshop on Turbidity and Other 

Sediment Surrogates, April 30–May 2, 2002, Reno, Nevada: 

U.S. Geological Survey Circular 1250, 56 p., accessed 

October 6, 2009, at http://pubs.usgs.gov/circ/

2003/circ1250/.

Gregory, M.B., and Frick, E.A., 2000, Fecal-coliform bacteria 

concentrations in streams of the Chattahoochee River 

National Recreation Area, Metropolitan Atlanta, Georgia, 

May–October 1994 and 1995: U.S. Geological Survey 

Water-Resources Investigations Report 00–4139, 8 p., 

accessed October 6, 2009, at http://pubs.usgs.gov/wri/

wri004139/.

Hirsch, R.M., Hamilton, P.A., and Miller, T.L., 2006, U.S. 

Geological Survey perspective on water-quality monitoring 

and assessment: Journal of Environmental Monitoring, v. 8, 

p. 512–518.

Laenen, T.A., 1985, Acoustic velocity meter systems: 

U.S. Geological Survey Techniques of Water-Resources 

Investigations, book 3, chap. A13, 38 p.

Landers, M.N., and Ankcorn, P.D., 2008, Methods to 

evaluate influence of onsite septic wastewater-treatment 

systems on base flow in selected watersheds in Gwinnett 

County, Georgia, October 2007: U.S. Geological Survey 

Scientific Investigations Report 2008–5220, 12 p., accessed 

October 6, 2009, at http://pubs.usgs.gov/sir/2008/5220/.

Landers, M.N., Ankcorn, P.D., and McFadden, K.W., 

2007, Watershed effects on streamflow quantity and 

quality in six watersheds of Gwinnett County, Georgia: 

U.S. Geological Survey Scientific Investigations 

Report 2007–5132, 54 p., accessed October 6, 2009, at 

http://pubs.usgs.gov/sir/2007/5132/.

Metropolitan North Georgia Water Planning District, 2007, 

Standards and methodologies for surface water quality 

monitoring, March 2007, accessed November 22, 2009, 

at http://www.northgeorgiawater.com/files/MNGWPD_

StandardsMethodologies_March2007a.pdf.

Oberg, K.A., and Mueller, D.S., 2007, Validation of streamflow measurements made with Acoustic Doppler Current 

Profilers: Journal of Hydraulic Engineering, v. 133, 

no. 12, p. 1421–1432.

Rantz, S.E., 1982a, Measurement and computation of streamflow—Volume 1, Measurement of stage and discharge: 

U.S. Geological Survey Water-Supply Paper 2175, accessed 

October 6, 2009, at http://pubs.usgs.gov/wsp/wsp2175/html/

WSP2175_vol1_pdf.html.

Rantz, S.E., 1982b, Measurement and computation of 

streamflow—Volume 2, Computation of discharge: U.S. 

Geological Survey Water-Supply Paper 2175, accessed 

October 6, 2009, at http://pubs.usgs.gov/wsp/wsp2175/

html/wsp2175_vol2.html.

Sauer, V.B., and Meyer, R.W., 1992, Determination of error in 

individual discharge measurements: U.S. Geological Survey 

Open-File Report 92–144, 21 p.
Selected References 49

Taylor, C.J., and Alley, W.M., 2001, Ground-water-level 

monitoring and the importance of long-term water-level 

data: U.S. Geological Survey Circular 1217, 68 p.

U.S. Environmental Protection Agency, 1997, Guidelines 

for preparation of the comprehensive state water-quality 

assessments (305b reports and electronic updates): 

Washington, D.C., U.S. Environmental Protection Agency, 

Office of Water, EPA-841-B-97-002a, variously paginated.

U.S. Environmental Protection Agency, 2009, Drinking water 

contaminants, accessed August 19, 2009, at http://www.epa.

gov/safewater/contaminants/index.html#listmcl.

Wagner, R.J., Mattraw, H.C., Ritz, G.F., and Smith, B.A., 

2000, Guidelines and standard procedures for continuous 

water-quality monitors—Site selection, field operation, 

calibration, record computation, and reporting: U.S. 

Geological Survey Water-Resources Investigations 

Report 00–4252, 53 p., accessed October 6, 2009, at 

http://pubs.usgs.gov/tm/2006/tm1D3/. 

Wilde, F.D., Radke, D.B., Gibs, Jacob, and Iwatsubo, R.T., 

1998, National field manual for the collection of waterquality data—Handbooks for water-resources investigations: 

U.S. Geological Survey Techniques of Water-Resources 

Investigations, book 9, accessed October 6, 2009, at 

http://water.usgs.gov/owq/FieldManual/.

Williams, L.J., Albertson, P.N., Tucker, D.D., and Painter, J.A., 

2004, Methods and hydrogeologic data from test drilling 

and geophysical logging surveys in the Lawrenceville, 

Georgia, area: U.S. Geological Survey Open-File Report 

2004–1366, 38 p., accessed October 6, 2009, at http://pubs.

usgs.gov/of/2004/1366/.

Williams, L.J., Kath, R.L., Crawford, T.J., and Chapman, M.J., 

2005, Influence of geologic setting on ground-water 

availability in the Lawrenceville area, Gwinnett County, 

Georgia: U.S. Geological Survey Scientific Investigations 

Report 2005–5136, 43 p., accessed October 6, 2009, at 

http://pubs.usgs.gov/sir/2005/5136/.

Appendix 1. Borehole Geophysical Logs For Wells 14FF62, 

14FF63, 14FF64, and 14FF65, Lawrenceville Area, Georgia
52 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

Figure 1–1. Figure 1–1. Borehole geophysical logs for well 14FF62, Lawrenceville area, Georgia. Borehole geophysical logs for well 14FF62, Lawrenceville area, Georgia.

Feet

Caliper,

in inches

0 5000

0 100

5 10 0 1000 60 90

Gamma, in APIU

(American Petroleum

Institute Units)

Fluid resistivity,

in ohm-meters

Fluid temperature,

in degrees Fahrenheit

Land

surface

50

100

150

200

250

300

350

400

450

500

550

600

0 5000

Resistivity,

in ohm-meters

64-inch 

normal

Lateral

16-inch 

normal

Single-point

resistance

in ohms
Appendix 1 53

Figure 1–2. Figure 1–2. Borehole geophysical logs for well 14FF63, Lawrenceville area, Georgia. Borehole geophysical logs for well 14FF63, Lawrenceville area, Georgia.

Feet

Caliper,

in inches

0 5000

0 100

5 10 0 1000 60 90

Gamma, in APIU

(American Petroleum

Institute Units)

Fluid temperature,

in degrees Fahrenheit

Land

surface

50

100

150

200

250

300

350

400

450

500

550

600

0 5000

64-inch 

normal

Lateral

16-inch 

normal

Fluid resistivity,

in ohm-meters

Resistivity,

in ohm-meters

Single-point

resistance

in ohms
54 Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008

Figure 1–3. Figure 1–3. Borehole geophysical logs for well 14FF64, Lawrenceville area, Georgia. Borehole geophysical logs for well 14FF64, Lawrenceville area, Georgia.

Feet

Caliper,

in inches

0 5000

0 100

5 10 0 1000 60 90

Gamma, in APIU

(American Petroleum

Institute Units)

Fluid temperature,

in degrees Fahrenheit

Land

surface

50

100

150

200

250

300

350

400

450

500

550

600

64-inch 

normal

Lateral

16-inch 

normal

0 5000

Fluid resistivity,

in ohm-meters

Resistivity,

in ohm-meters

Single-point

resistance

in ohms
Appendix 1 55

Figure 1–4. Borehole geophysical logs for well 14FF65, Lawrenceville area, Georgia. Figure 1–4. Borehole geophysical logs for well 14FF65, Lawrenceville area, Georgia.

50

100

150

200

250

300

350

400

450

Feet

Caliper,

in inches

0 5000

0 100

5 10 0 1000 60 90

Gamma, in APIU

(American Petroleum

Institute Units)

Fluid temperature,

in degrees Fahrenheit

64-inch 

normal

Lateral

16-inch 

normal

0 5000

Fluid resistivity,

in ohm-meters

Resistivity,

in ohm-meters

Land

surface

Single-point

resistance

in ohms
Manuscript approved on February 16, 2010

Editing by Kimberly A. Waltenbaugh

Illustrations and layout by Bonnie J. Turcott

For more information about this publication, contact:

USGS Georgia Water Science Center

3039 Amwiler Road

Atlanta, GA 30360

telephone: 770-903-9100

http://ga.water.usgs.gov/
Clarke and Williams—Hydrologic Conditions, Stream-Water Quality, and Selected Groundwater Studies, Lawrenceville, Georgia, 2003–2008—Scientific Investigations Report 2010–5032