How deep is a well in Georgia?

How deep should a well be? The typical water well in Northeast Georgia is between 200 to 800 feet deep. However, well depth is highly variable from site to site, and cannot be predicted before drilling the well.

What aquifer is under Georgia?

The aquifer system is a southwest-northeast trending belt about 50 miles wide that runs from Columbus to Augusta, Georgia, along the southern boundary of the Piedmont Province . This aquifer is highly productive, second in Georgia only to the Upper Floridan (Pollard and Vorhis, 1980).

How deep are water lines buried in Georgia?

And the deeper the technician must dig to get to your broken or otherwise compromised line, the higher the cost. The nationwide average water service line depth is 4.58 feet, but in Georgia, these lines are buried 3.08 feet deep on average.

What depth is considered a deep water well?

How Deep Should A Well Be For Drinking Water? It is recommended that wells used for drinking water be at least one hundred feet deep to prevent surface contaminants from falling into the well. The typical depth of a well for a private residence ranges anywhere from 100 to 800 feet .

(PDF) Groundwater Conditions in the Brunswick– Glynn County ...Cover photograph. U.S. Highway 17, Sidney Lanier Bridge, from north side of Brunswick River, Brunswick, Glynn County, Georgia

U.S. Department of the InteriorU.S. Geological Survey
Scientific Investigations Report 2011–5087
Prepared in cooperation with the Brunswick–Glynn County JointWater and Sewer Commission
Groundwater Conditions in the Brunswick– Glynn County Area,Georgia, 2009
Cover photograph. U.S. Highway 17, Sidney Lanier Bridge, fromnorth side of Brunswick River, Brunswick, Glynn County, Georgia (byAlan M. Cressler, USGS).
Groundwater Conditions in the Brunswick– Glynn County Area,Georgia, 2009
By Gregory S. Cherry, Michael F. Peck, Jaime A. Painter, andWelby L. Stayton
Prepared in cooperation with the Brunswick–Glynn County JointWater and Sewer Commission
Scientific Investigations Report 2011–5087
U.S. Department of the InteriorU.S. Geological Survey
U.S. Department of the InteriorKEN SALAZAR, Secretary
U.S. Geological SurveyMarcia K. Mcnu*tt, Director
U.S. Geological Survey, Reston, Virginia: 2011
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Although this report is in the public domain, permission must besecured from the individual copyright owners to reproduce anycopyrighted materials contained within this report.
Suggested citation:Cherry, G.S., Peck, M.F., Painter, J.A., andStayton, W.L., 2011, Groundwater conditions in the Brunswick–GlynnCounty area, Georgia, 2009: U.S. Geological Survey ScientificInvestigations Report 2011– 5087, 58 p.
http://www.usgs.govhttp://www.usgs.gov/pubprodhttp://store.usgs.gov
iii
Contents
Georgia Well-Identification System........................................................................................................viiiAcknowledgments......................................................................................................................................viiiAbstract...........................................................................................................................................................1Introduction.....................................................................................................................................................1
Purpose and Scope..............................................................................................................................2Descriptionof Study Area...................................................................................................................2
Methods...........................................................................................................................................................6Hydrogeology..................................................................................................................................................7GroundwaterConditions...............................................................................................................................8
Groundwater Levels.............................................................................................................................8FactorsInfluencing Groundwater Levels................................................................................8
Precipitation........................................................................................................................8GroundwaterWithdrawals..............................................................................................10
Surficial Aquifer System...........................................................................................................11BrunswickAquifer System.......................................................................................................14FloridanAquifer System...........................................................................................................18
Chloride Concentrations....................................................................................................................28UpperFloridan Aquifer..............................................................................................................32Long-TermRecords at Industrial Well Fields........................................................................32
Pinova Well Field...............................................................................................................36Georgia–PacificCellulose Well Field............................................................................42
Real-Time Monitoring of Specific Conductance and Water Levels..................................49Surficial Aquifer System...........................................................................................................53
Summary........................................................................................................................................................54SelectedReferences..................................................................................................................................55Appendix.Regression Statistics..............................................................................................................57
iv
Figures 1–2. Maps showing— 1. Location of study area,Brunswick–Glynn County, Georgia, and major
structural features in coastal Georgia and South Carolina..........................................3 2. Location ofcontinuous groundwater-level monitoring networks for the
Brunswick–Glynn County area, Georgia..........................................................................43. Generalized correlation of geologic and hydrogeologic units inthe Coastal Plain
of Georgia.......................................................................................................................................54. Schematic block diagram showing hydrogeologic units andinfluence of
structural features on their occurrence...................................................................................65–6. Graphs showing— 5. Cumulative departure from normalprecipitation and total daily precipitation
at real-time climatic monitoring site, College of CoastalGeorgia, Georgia, January 2000–December 2009.........................................................................................10
6. Major groundwater pumpage from the Upper Floridan aquifer inthe Brunswick–Glynn County area, Georgia, 1940–2009...................................................11
7. Map showing groundwater-level monitoring network in thesurficial aquifer system, Glynn County, Georgia, and water-levelchange for period of record and 2008–2009. ...12
8. Graphs showing monthly mean water levels and period-of-recordtrend line in wells in the surficial aquifer system, Glynn County,Georgia ..............................................13
9. Map showing groundwater-level monitoring network in theBrunswick aquifer system, Glynn County, Georgia, and water-levelchange for period of record and 2008–2009. ...15
10–12. Graphs showing— 10. Monthly mean water levels andperiod-of-record trend line in wells
in the upper Brunswick aquifer, Glynn County, Georgia.............................................16 11. Monthly meanwater levels and period-of-record trend line in wells
in the lower Brunswick aquifer, Glynn County, Georgia..............................................17 12. Periodicwater-level measurements in wells in the Brunswick aquifersystem,
Jekyll Island, Glynn County, Georgia..............................................................................1713. Map showing groundwater-level monitoring network in the UpperFloridan
aquifer in Glynn County, Georgia, and water-level change forperiod of record and for 2008–2009.......................................................................................................................19
14–15. Graphs showing— 14. Monthly mean water levels andperiod-of-record trend line in wells in the
Upper Floridan aquifer, Glynn County, Georgia.............................................................20 15.Periodic water-level measurements in well 34G029, Upper Floridanaquifer,
Jekyll Island, Glynn County, Georgia..............................................................................2216. Map showing groundwater-level monitoring network in the LowerFloridan aquifer,
Glynn County, Georgia, and water-level change for period ofrecord and 2008–2009 ....23 17. Graphs showing monthly mean waterlevels and period-of-record trend line
in wells in the Lower Floridan aquifer, Glynn County, Georgia............................................24 18–21. Maps showing—18. Potentiometric surface of the Upper Floridan aquifer,Brunswick–Glynn
County, Georgia, August 17–21, 2009.............................................................................2619. Chloride-monitoring network for the Brunswick–Glynn Countyarea, Georgia,
location and enlarged area..............................................................................................2820. Chloride concentration in the Upper Floridan aquifer in theBrunswick area,
Georgia, August 2009........................................................................................................3321. Change in chloride concentration in the Upper Floridan aquiferin the
Brunswick area, Georgia, from 2008 to 2009.................................................................34
v
22–23. Graphs showing chloride concentration in water forselected wells in the— 22. Southern Brunswick–Glynn County area,Georgia, 1968–2009 ..................................35 23.Northern Brunswick–Glynn County area, Georgia, 1968–2009..................................35 24. Maps showing welllocations in the vicinity of the Pinova Inc. facility in
Brunswick, Georgia....................................................................................................................3725–26. Graphs showing— 25. Chloride concentration in selected UpperFloridan aquifer production
wells in the vicinity of the Pinova Inc. well field inBrunswick, Georgia ..................39 26. Chloride concentrationin USGS observation wells 34H344 and 34H334
in the Upper Floridan aquifer in the vicinity of the Pinova Inc.well field in Brunswick, Georgia.......................................................................................................40
27–28. Maps showing— 27. Chloride concentration exceeding theState and Federal secondary drinking-
water standard of 250 milligrams per liter in active UpperFloridan aquifer production wells in the vicinity of the PinovaInc. well field in Brunswick, Georgia, during June 1958, January1964, January 1970, January 1981, April 1990, January 2000, andJuly 2009 ...............................................41
28. Well locations in the vicinity of the Georgia–PacificCellulose LLC facility in Brunswick, Georgia..........................................................................................42
29–30. Graphs showing— 29. Chloride concentration in selectedUpper Floridan aquifer production
wells in the vicinity of the Georgia–Pacific Cellulose LLC wellfield in Brunswick, Georgia...........................................................................................................45
30. Chloride concentration in selected USGS Upper Floridanaquifer observation wells in the vicinity of the Georgia–PacificCellulose LCC well field in Brunswick, Georgia.....................................................................................46
31. Maps showing chloride concentration exceeding the State andFederal secondary drinking-water standard of 250 milligrams perliter in active Upper Floridan aquifer production wells in thevicinity of the Georgia–Pacific Cellulose LCC well field inBrunswick, Georgia, during July 1960, July 1970, July 1980,September 1991, July 2000, and July 2009..........................................................47
32–37. Graphs showing— 32. Correlation between chlorideconcentration and specific conductance
from groundwater samples taken in the Brunswick–Glynn Countyarea, Georgia, July 2008..............................................................................................................50
33. Daily mean groundwater levels and periodic specificconductance in the Upper Floridan aquifer at well 34H514, PerryPark, Brunswick–Glynn County area, Georgia, 2009............................................................................................................51
34. Daily mean water levels in wells 33H324 and 33H325, andspecific conductance in well 33H325 Upper Floridan aquifer,Brunswick–Glynn County area, Georgia, 2009.............................................................................................51
35. Daily mean groundwater levels and periodic specificconductance in the Upper Floridan aquifer at wells 34H504 and34H505, Brunswick–Glynn County area, Georgia, 2009............................................................................................................52
36. Periodic specific conductance in the Upper Floridan aquiferat well 34H134, Brunswick–Glynn County area, Georgia, 2009..............................................................52
37. Chloride concentrations in well 34H438 and in replacementwell 34H515, surficial aquifer system, in the Brunswick–GlynnCounty area, Georgia, 1984–2009 ..................53
vi
Tables 1. Brunswick–Glynn County, Georgia, groundwater-levelmonitoring network, 2009 ...........9 2. Potentiometric andperiodic groundwater-level monitoring networks in the
Upper Floridan aquifer, Brunswick–Glynn County, Georgia................................................27 3. Chlorideconcentrations in water samples collected from wells in theBrunswick–Glynn
County area, Georgia, June 2003–2005, July 2006, July and August2007, July 2008, and August 2009, and change in chlorideconcentration from 2008 to 2009.....................................30
4. Well information in the vicinity of the Pinova Inc. facilityin Brunswick, Georgia ...........38 5. Chloride data available forproduction wells and selected observation wells
in the vicinity of the Pinova Inc. facility in Brunswick,Georgia ..........................................40 6.Construction, location, and contributing aquifer data for wellsnear the
Georgia–Pacific Cellulose LLC facility in Brunswick, Georgia............................................43 7. Chloride dataavailable for production wells at the Georgia–Pacific CelluloseLLC
facility in Brunswick, Georgia...................................................................................................48A–1. Regression statistics.................................................................................................................58
vii
Conversion Factors and Datums
Multiply By To obtain
Length
inch 2.54 centimeter (cm)foot (ft) 0.3048 meter (m)mile (mi)1.609 kilometer (km)
Area
square foot (ft2) 0.09290 square meter (m2)square mile (mi2)2.590 square kilometer (km2)
Volume
gallon (gal) 3.785 liter (L) Million gallons (Mgal) 3,785 cubicmeter (m3)
Flow rate
foot per year (ft/yr) 0.3048 meter per year (m/yr)milliongallons per day (Mgal/d) 0.04381 cubic meter per second (m3/s)
Temperature in degrees Celsius (°C) may be converted to degreesFahrenheit (°F) as follows:
°F = (1.8 × °C) + 32
Temperature in degrees Fahrenheit (°F) may be converted todegrees Celsius (°C) as follows:
°C = (°F – 32) / 1.8
Vertical coordinate information is referenced to the NorthAmerican Vertical Datum of 1988 (NAVD 88).
Historical data collected and stored as National GeodeticVertical Datum of 1929 (NGVD 29).
Horizontal coordinate information is referenced to the NorthAmerican Datum of 1983 (NAD 83).
Altitude, as used in this report, refers to distance above thevertical datum.
Specific conductance is given in microsiemens per centimeter at25 degrees Celsius (µS/cm at 25 °C).
viii
Georgia Well-Identification SystemWells described in this reportare assigned a well identifier according to a system based
on the index of USGS 7.5-minute topographic maps of Georgia.Each map in Georgia has been assigned a two- to three-digit numberand letter designation (for example, 07H) beginning at thesouthwestern corner of the State. Numbers increase sequentiallyeastward, and letters advance alphabetically northward. Quadranglesin the northern part of the State are designated by double letters:AA follows Z, and so forth. The letters “I,” “O,” “II,” and “OO”are not used. Wells inventoried in each quadrangle are numberedconsecutively, beginning with 001. Thus, the fourth wellinventoried in the 34H quadrangle is designated 34H004. In the USGSNWIS database, this information is stored in the “Station Name”field; in NWIS Web, it is labeled “Site Name.”
AcknowledgmentsThe authors appreciate the support and guidanceprovided by Keith Morgan and Billy
Simmons of the Brunswick–Glynn County Joint Water and SewerCommission. Thanks are extended to John Day, of the Jekyll IslandAuthority, for logistical support during the collec-tion ofwater-level measurements. Assistance was provided by Ricky Manningof Pinova Inc., and Kenneth Hase of Georgia–Pacific Cellulose LLCto ensure that the records from chloride sampling at each facilitywere complete. Several USGS employees played an important role inthe collection, processing, and quality assurance of groundwaterdata, including Michael D. Hamrick, O. Gary Holloway, and Alan M.Cressler. Special thanks are extended to David C. Leeth of the USGSfor his assistance with water-level trend analysis and allassociated summary statistics.
Groundwater Conditions in the Brunswick– Glynn County Area,Georgia, 2009
By Gregory S. Cherry, Michael F. Peck, Jaime A. Painter, andWelby L. Stayton
Abstract
The Upper Floridan aquifer is contaminated with salt water in a2-square-mile area of downtown Brunswick, Georgia. The presence ofthis saltwater has limited the development of the groundwatersupply in the Glynn County area. Hydrologic, geologic, andwater-quality data are needed to effectively manage waterresources. Since 1959, the U.S. Geological Survey (USGS) hasconducted a cooperative water program with the City of Brunswickand Glynn County to monitor and assess the effect of groundwaterdevelopment on saltwater intrusion within the Floridan aquifersystem. The potential development of alternative sources of waterin the Brunswick and surficial aquifer systems also is an importantconsideration in coastal areas.
During calendar year 2009, the cooperative water programincluded continuous water-level recording of 13 wells completed inthe Floridan, Brunswick, and surficial aquifer systems; collectingwater levels from 46 wells to map the potentiometric surface of theUpper Floridan aquifer in Glynn County during August 2009; andcollecting and analyzing water samples from 55 wells completed inthe Floridan aquifer system, of which 27 wells were used to mapchloride concentrations in the upper water-bearing zone of theUpper Floridan aquifer in the Brunswick area during August 2009.Periodic water-level measurements also were collected from twowells completed in the Upper Floridan aquifer and four wellscompleted in the Brunswick aquifer system on Jekyll Island.Equipment was installed on one well to enable real-time specificconductance monitoring in the area surrounding the chlorideplume.
During 2008–2009, water levels in 30 of the 32 wells monitoredin the Brunswick–Glynn County area rose at a rate of 0.24 to 7.58feet per year (ft/yr). The largest rise of 7.58 ft/yr was in theUpper Floridan aquifer. These rises corresponded to a period ofabove normal precipitation and decreased pumping. Declines during2008–2009 were recorded in wells completed in the Brunswick aquifersystem (0.37 ft/yr) and Lower Floridan aquifer (0.83 ft/yr).
Chloride data collected by two local industrial ground-waterusers at their well fields since 1958 were compiled and comparedwith data collected by the USGS during the same period. The resultsindicate that chloride concentrations at the two well fields havecontinued to rise despite modifica-tion of production wells toeliminate deep saline zones and decreases in pumpage at bothfacilities. One of the industrial users, Pinova Inc., plugged thelower portions of nine production wells in the mid to late 1960s,which generally decreased chloride concentrations to less than 100milligrams per liter (mg/L) for a period of 10 to 20 years.However, chloride concentrations eventually returned to previouslevels despite decreases in pumpage. During 1990–2009, chlorideconcen trations at the other industrial user’s well field(Georgia–Pacific Cellulose LLC) generally increased despite a 16million gallon per day decrease in pumpage during this period. Datafrom the Georgia–Pacific Cellulose well field and additionalchloride data from USGS observation wells located to the eastindicate continued movement of chloride from the source arealocated southeast of the site toward the well field.
IntroductionIn the Brunswick–Glynn County, Georgia, area (figs.1, 2),
saltwater has been entering the Upper Floridan aquifer for about50 years. As of 2009, within a 2-square-mile (mi²) area in downtownBrunswick, the aquifer yielded water with a chloride concentrationgreater than 2,000 milligrams per liter (mg/L), which exceeds theState and Federal secondary drinking-water standard of 250 mg/L(Georgia Environmental Protection Division, 1997; U.S.Environmental Protection Agency, 2000). Saltwater contamination haslimited further development of the Upper Floridan aquifer in theBrunswick area, prompting interest in the development ofalternative sources of water supply, primarily from the shallowersurficial and Brunswick aquifer systems. Monitoring groundwaterconditions and conducting studies to better define the occurrenceof saltwater contamination and assess alternative water sources isimportant for management of water resources in the Brunswick–GlynnCounty area.
2 Groundwater Conditions in the Brunswick–Glynn County Area,Georgia, 2009
In response to concerns about saltwater intrusion within theUpper Floridan aquifer, a cooperative water program (CWP) betweenthe U.S. Geological Survey (USGS), the City of Brunswick, and GlynnCounty has been in existence since 1959. Since its inception, theCWP has placed emphasis on providing the necessary informationabout the Floridan aquifer system to manage saltwater intrusion andevaluate water-resources data. During 2009, cooperating entitieswere the Brunswick–Glynn County Joint Water and Sewer Commission(JWSC) and the Jekyll Island Authority.
The current study addresses one of the six USGS science strategygoals, “A water census of the United States: Quantifying,forecasting, and securing freshwater for America’s future” (U.S.Geological Survey, 2007). The study also addresses two priorityissues of the USGS 2007 Federal-State Water Cooperative Program:Understanding ecosystems and predicting ecosystem change and therole of environment and wildlife in human health (U.S. GeologicalSurvey, 2007). Finally, this study meets the science plan goal ofthe USGS Georgia Water Science Center to support Federal and Statewater-resources programs through support for increasing thescientific understanding of the occurrence and nature ofgroundwater in the coastal region of Georgia.
Purpose and Scope
This report documents the hydrologic, geologic, andwater-quality data in the Brunswick–Glynn County area during 2009,which are needed to effectively manage water resources in thecoastal area of Georgia. During calendar year 2009, the CWP, whichincludes all of Glynn County (fig. 2), was continued and includedcontinuous water-level and specific conductance monitoring of 13wells completed in the Floridan, Brunswick, and surficial aquifersystems (table 1). Groundwater levels and trends in the surficial,Brunswick, and Floridan aquifer systems are presented for selectedwells throughout Glynn County. Estimated annual water-level change(trend) is reported for the period of record and for 2008–2009.
The potentiometric surface of the Upper Floridan aquifer wasmapped based on water-level measurements in 46 wells during August2009 (table 2). On Jekyll Island, periodic water-level measurementswere collected in six wells com-pleted in the Upper Floridan andBrunswick aquifers during 2009–2010, with additional data during2002–2009 obtained from the Jekyll Island Authority.
In the Floridan aquifer system, water samples were collected andanalyzed for chloride concentration from 55 wells in August 2009(table 3). These data were used to map the configuration of thechloride plume in the Upper Floridan aquifer at the city ofBrunswick. Additional chloride data from 37 production wells wereobtained from two local industries dating back to 1958, whichhelped assess how the configuration of the chloride plume hasdeveloped over time
(tables 4, 5). During 2009, an additional well was equipped withreal-time specific-conductance monitoring capability just north ofthe chloride plume (34H134; table 1).
Description of Study Area
Glynn County is located on the Atlantic Coast about 80 miles(mi) south of Savannah, GA, and about 87 mi north of Jacksonville,Florida (fig. 1). The county covers an area of 422 mi² and includesthe barrier islands of St. Simons, Little St. Simons, and Jekyll(fig. 2). The primary population center is the city of Brunswick,which is located on a peninsula and has an incorporated area thatcovers approximately 50 mi² and a secondary population centeroutside the city limits on the southern part of St. Simons Island.The city of Brunswick serves as the county seat and is bounded onthe east by the offshore islands of St. Simons, Little St. Simons,and Jekyll. Brunswick is bounded on the west and south by tidallyinfluenced estuaries and rivers, including the Brunswick River andthe Little Satilla River. Glynn County is bounded on the north bythe Altamaha River, which empties into the Atlantic Ocean north ofLittle St. Simons Island (fig. 2).
Glynn County is located in the Coastal Plain Physio-graphicProvince (fig. 1), and altitudes range from 0 feet (ft) along thecoast to 40 ft (North American Vertical Datum of 1988; NAVD 88) inthe northwestern part of the county. Outside the urbanized areasnear the city of Brunswick and St. Simons Island, land use in GlynnCounty is a mix of forest, grazed woodland, marsh, and swampland.Glynn County has a mild climate with warm humid summers and mildwinters with an average temperature of 70 degrees Fahrenheit (°F)for the period 1971–2000 (National Oceanic and AtmosphericAdministration, 2002). Mean-annual precipitation for the sameperiod is about 49 inches in the Brunswick area, and rainfalloccurs most often during June, July, and August (Priest, 2004).
Coastal Plain sediments consist of consolidated touncon-solidated layers of sand and clay and semiconsolidated tovery dense layers of limestone and dolomite, which range in agefrom Late Cretaceous to Holocene. In general, these geologic unitshave been divided into aquifers and confining units based upon thewater-bearing characteristics, with the more perme-able layersforming the aquifers and strata of low permeability making up theconfining units (fig. 3). These sedimentary units unconformablyoverlie igneous, metamorphic, and sedimen-tary rocks of Paleozoicto Mesozoic age and reach a maximum thickness of 5,500 ft in CamdenCounty to the south of Glynn County (Wait and Davis, 1986). Thethickness of Coastal Plain sediments varies and is influenced bymajor structural features in the area, such as the SoutheastGeorgia Embayment, which is a shallow east-to-northeast plungingsyncline that allows Coastal Plain sediments to reach a maximumthickness in the Glynn County area (figs. 1, 4). It is postulatedthat subsidence occurred at a moderate rate from the LateCretaceous to late Cenozoic (Miller, 1986).
Introduction 3
Figure 1. Location of study area, Brunswick–Glynn County,Georgia, and major structural features in coastal Georgia and SouthCarolina (modified from Payne and others, 2005).
??
AIKEN
WARE
DIXIE
TAYLOR
BURKE
CLAY
DUVAL
BERKELEY
CLINCH
ALACHUA
COLLETON
PUTNAM
JASPER
BAKER
WAYNE
LAURENS
SUMTER
ORANGEBURG
MADISON
WORTH
RICHLAND
COFFEE
COLUMBIA
NASSAU
BULLOCH
LONG
EMANUEL
CHARLTON CAMDEN
DODGE
SCREVEN
LEXINGTON
TIFT
BRYAN
WILK
ES
LIBERTY
IRWIN
SUWANNEE
WILLIAMSBURG
JONES
APPLING
STJOHNS
BROOKS
BIBB
GLYNN
DOOLY
HAMPTON
CLARENDON
COLQUITT
MIT
CH
ELL
TELFAIR
ECHOLS
LOWNDES
BERRIEN
BARNWELL
WA
SHIN
GTO
N
JASPER
LAFAYETTE
WILCOX
HAMILTON
GREENE
TATTNALL
HANco*ck
CRISP
THOMAS
PIERCE
JEFF
ERSO
N
CHARLESTON
TWIGGS
BRAN
TLEY
TOOM
BS
EDGEFIELD
PUTNAM
JENKINS
DORCHESTER
EFFINGHAM
CHAT
HAM
WILKINSON
MCINTOSH
CALHOUN
JEFFERSON
COOK
BACON
UNION
MORGAN
BAMBERG
WALTON
MONROE
HOUSTON
ALLENDALE
TURNER
ATKINSON
GILCHRIST
MCCORM
ICK
WA
RREN
JOHNSON
OGLETHORPE
WHEELER
RICHMOND
BALDWIN
PULASKI
NEWTON
JEFF DAVIS
COLUMBIA
LINCO
LN
EVANS
LANIER
BEN HILL
CANDLER
BRAD
FORD
MCD
UFFIE GE
ORGE
TOW
N
OCONEE
PEACH
BUTTS
BLECKLEYMACON
GWINNETT
TREUTLEN
CRAWFORD
TAYLO
R
MO
NTG
OM
ERY
TALIAFERRO
GLASco*ck
LEE
ROCK
DALE
SUMTER
HENRY
BEAUFORT
Brunswick
St Marys
Jacksonville
FernandinaBeach
Jesup
Waycross
Savannah
Valdosta
84°
32°
33°
31°
30°
83° 82° 81° 80°
GEORGIA
GEO
RG
IASO
UTH
CA
RO
LINA
FLORIDA
Port Royal Sound
FLORIDA
GEORGIA
Map
are
a
0 50 75 MILES25
0 75 KILOMETERS25 50
Base from U.S. Geological Survey 1:100,000-scale digitaldataStructural features modified from Applied Coastal ResearchLaboratory, 2002; Weems and Edwards, 2001; Kellam and Gorday, 1990;and Paull and Dillon, 1980.
SOUTHCAROLINA
ATLA
NTI
C
OCE
AN
Gulf T
rough
Southeast GeorgiaEmbayment
BeaufortArch
Satilla Line
Study area
Flor
ida–
Hatte
ras
Slop
e
Hilton Head Island
Tybee Island
Skidaway Island
St SimonsIsland
4 Groundwater Conditions in the Brunswick–Glynn County Area,Georgia, 2009
341
17
84
95
33J06535H068
33J062
34J077
34H43634H43734H515
34H334
33J044
33H188
33H20633H20733H208
33H12733H133
34H49534H500
34J08034J08134J082
35H07035H07635H077
34H492
34H514
34H134
34H50434H505
33H32533H324
34H39134H371 34G033 34G060
34G05934G058
34G057
34G048
34G029
WAYNE
BRANTLEY GLYNN
CAMDEN
MCINTOSH
Brunswick
Well in Brunswick–Glynn County monitoring network during2009
Monitoring well in Jekyll Island Authority network
Real-time climatic monitoring site
EXPLANATION
33J062
34J044
ATL
AN
TIC
O
CEA
N
Base modified from U.S. Geological Survey 1:100,000-scaledigital data
Monitoring well in Georgia Geologic Survey network (now known asGeorgia Environmental Protection Division)
College ofCoastalGeorgia
St SimonsIsland
JekyllIsland
LittleSt Simons
Island
34G058
Altamaha
Brunsw
ick R
iver
Intra
coas
tal W
ater
way
Little Satilla River
RiverBrunswickGLYNN COUNTY
GEORGIA
81°20'81°30'81°40'
31°20'
31°10'
6 KILOMETERS
5 6 MILES
5
0 1 2 3 4
0 1 2 3 4
Figure 2. Location of continuous groundwater-level monitoringnetworks for the Brunswick–Glynn County area, Georgia.
Introduction 5
Low
erM
iddl
eUp
per
Post-Miocene
Miocene
Eocene
Oligocene
Paleocene
UpperCretaceous
Undifferentiated
Suwannee Limestone
Ocala Limestone
Avon Park Formation
Oldsmar Formation
Cedar Keys Formation
Undifferentiated
Water-table zone
Uppe
r Flo
ridan
aqu
ifer
FLOR
IDAN
AQU
IFER
SYS
TEM
FLOR
IDAN
AQU
IFER
SYS
TEM
Low
er F
lorid
an a
quife
r
Fernandina permeable
zone
Confining unit
Lower Floridanconfining unit
Lazaretto Creek Formation Upper Floridan confining unit
Lower Coastal Plain3
Geologic unit4Hydrogeologic unit
Barnwell Group
Undifferentiated
Santee Limestone
Upper Coastal Plain1
CongareeFormation
Geologic unit
Snapp FormationEllenton Formation(undifferentiated)
Upper Three Runs
aquifer
Confiningunit
Gordonaquifer
Hydrogeologic unit
Steel Creek Formation
Black Creek Group(undifferentiated)
Confining unit 2
Upper Dublin aquifer
1Modified from Falls and others, 1997. 2In local areas, includesMillers Pond aquifer.
Confiningunit
Upper water-bearing zone
Upper Floridan semi-confining unit
Lower water-bearing zone
Low
erM
iddl
eUp
per
SeriesSavannah Brunswick
3Modified from Randolph and others, 1991; Clarke and Krause,2000.4Modified from Randolph and others, 1991; Weems and Edwards,2001.
UpperBrunswick
aquifer
LowerBrunswick
aquifer
Upper water-bearing zone
Lower water-bearing zone
Tiger Leap Formation
Parachucla FormationMarks Head Formation
Coosawhatchie Formation
Ebenezer Formation
SURF
ICIA
LAQ
UIFE
R SY
STEM
BRUN
SWIC
KAQ
UIFE
R SY
STEMConfining
unit
Confiningunit
Figure 3. Generalized correlation of geologic and hydrogeologicunits in the Coastal Plain of Georgia (modified from Payne andothers, 2005).
6 Groundwater Conditions in the Brunswick–Glynn County Area,Georgia, 2009
MethodsContinuous water-level measurements were obtained
from 32 wells during 2009. Each well was equipped withelectronic data recorders that recorded water levels at 60-minuteintervals, and the data generally were retrieved bimonthly. Fivewells had real-time satellite telemetry that recorded water levelsat 60-minute intervals. Three of the real-time sites were equippedto monitor water levels and specific conductance and the other twosites recorded water levels only. An additional site monitoredspecific conductance and the real-time satellite telemetry recordeddata at 15-minute intervals because of irregular pumping schedulesat the site, which is an active production well. Real-timesatellite telemetry data are transmitted every 1 to 4 hours (basedon equipment) for display on the USGS Georgia Water Science CenterWeb site at http://waterdata.usgs.gov/ga/nwis/current?type=gw/.
Additional water-level measurements were measured at 46 wellsusing either a pressure transducer or graduated steel tape.Land-surface altitude at each of these well sites, in feet aboveNAVD 88, is either based on land-surface contours taken from a mapor surveyed using leveling or global positioning system equipment.To estimate water-level trends, the Levenberg–Marquardt (LMA)method for minimization
of a weighted least-squares merit function (Janert, 2010) wasused to determine a straight-line fit to both recent (2008–2009)and period-of-record monthly-mean groundwater levels. Estimatedwater levels from these straight-line fits were used to compute anannual rate of change (yearly slope) for the period of record andfor 2008–2009. A more thorough discus-sion of the LMA method ispresented at the end of this report along with associated summarystatistics for each well and for straight-line fits (appendix).
Determination of chloride concentration of USGS samplescollected after 1966 but before 1983 were analyzed using fieldtitration with silver nitrate (Jones and Maslia, 1994). During1983–2006, all USGS samples were analyzed at the USGS laboratory inOcala, FL. Chloride concentrations of groundwater samples analyzedby the USGS laboratory were determined by using ion chromatographyaccording to U.S. Environmental Protection Agency (USEPA) method300.0 (Pfaff, 1999). Since 2006, all samples have been analyzed byTestAmerica Laboratories, Inc., in Savannah, GA, using USEPA method325.1. Water samples collected at the Pinova Inc. andGeorgia–Pacific Cellulose LLC well fields were analyzed at theironsite laboratories using titration with silver nitrate (JulieDickens, Georgia–Pacific Cellulose LLC, written commun., 2010;Ricky Manning, Pinova Inc., written commun., 2010).
Paleo- river
channel
Altamaha River
Savannah River
Gulf Tro
ugh
Brunswick
Savannah
PortRoyalSound
PortRoyalSound
Lower Floridan aquifer
Gordon aquifer
Upper Floridan aquifer
Upper Three Runs aquifer
Brunswickaquifer system
Surficial aquifer system
NNOT TO SCALE Saltw
ater
?
?
??
Confining unit
Fernandina permeable zone
Beau
fort
Arch
Gulf
Trou
gh
South
east
Georgia Em
bayment
SOUTH CAROLINA
GEORGIA
Figure 4. Schematic block diagram showing hydrogeologic unitsand influence of structural features on their occurrence (modifiedfrom Payne and others, 2005).
http://waterdata.usgs.gov/ga/nwis/current?type=gw/http://waterdata.usgs.gov/ga/nwis/current?type=gw/
Hydrogeology 7
HydrogeologyThe primary source of water for all uses in thecoastal
areas of Georgia is the Floridan aquifer system, which consistsof the Upper and Lower Floridan aquifers (Miller, 1986; Krause andRandolph, 1989). Secondary sources of water include the surficialand Brunswick aquifer systems (Clarke, 2003), which consist mostlyof Miocene- to Holocene-age sand separated by confining units ofmuch lower permeability (fig. 3).
The Brunswick aquifer system consists of two water-bearingzones—the upper Brunswick aquifer and the lower Brunswick aquifer(Clarke, 2003; fig. 3). The upper Bruns-wick aquifer consists ofpoorly sorted, fine to coarse, slightly phosphatic and dolomiticquartz sand and dense phosphatic limestone (Clarke and others,1990). The lower Brunswick aquifer consists of poorly sorted, fineto coarse, phosphatic, dolomitic sand (Clarke and others, 1990). Ingeneral, the upper Brunswick aquifer is thinner, and as a result,has smaller transmissivity than the lower Brunswick aquifer.Outside Glynn County, the Brunswick aquifer system thins, or isdiscontinuous, and has a higher percentage of fine-grainedsediments (Clarke, 2003).
The Floridan aquifer system consists of the Upper Floridan andLower Floridan aquifers, which are composed of mostly carbonaterocks that vary in age from predominantly Paleocene to Oligocenethat locally include Upper Cretaceous rocks (Miller, 1986; Krauseand Randolph, 1989; fig. 3). The Floridan aquifer system extendsfrom coastal areas in southeastern South Carolina, west across thecoastal plain of Georgia and Alabama, and south covering Florida.The Upper Floridan aquifer is overlain by a confining unitconsisting of layers of silty clay and dense phosphatic dolomite ofOligo-cene age that separate the aquifer from the Brunswick aquifersystem (Clarke, 2003).
The Upper Floridan aquifer is highly productive and consists ofEocene- to Oligocene-age limestone and dolomite (Clarke and others,1990). In the Brunswick–Glynn County area, the Upper Floridanaquifer is divided into an upper and lower water-bearing zone (UWBZand LWBZ, respectively) identified by Wait and Gregg (1973). Largevariability in the
range of transmissivity where the Upper Floridan aquifer islargely carbonate may indicate the presence of fractures orsolution openings and related anisotropic distribution of hydraulicproperties (Warner and Aulenbach, 1999; Clarke and others, 2004).Maslia (1987) attributed greater anisotropy between local- andregional-scale tests at Brunswick to preferential flow alongvertical solution channels associated with high-angle reversefaults and fractures. Wait and Gregg (1973) documented a well thattapped both the UWBZ and LWBZ, yet 70 percent of production wasestimated to be contributed from the UWBZ and the remainder fromthe LWBZ, indicating that the UWBZ is more productive than theLWBZ. In the Brunswick area, the UWBZ is separated from the LWBZ byabout 160 ft of soft limestone (Gregg and Zimmerman, 1974).
The Upper Floridan aquifer is underlain by a confining unit ofdense recrystallized limestone and dolomite of middle Eocene agethat hydraulically separates to varying degrees the Upper Floridanaquifer from the Lower Floridan aquifer (fig. 3). Locally in theBrunswick area, the confining unit is breached by fractures orsolution openings, which enhance the exchange of water between theUpper and Lower Floridan aquifers (Krause and Randolph, 1989).These features have allowed saline water from the Fernandinapermeable zone to migrate upward into primarily the UWBZ of theUpper Floridan aquifer, where water-level altitudes are lowerbecause of large-scale pumping by local industry.
The Fernandina permeable zone is a deeply buried, cavernous,highly permeable, saline water-bearing unit that, in the Brunswickarea, is included in the Lower Floridan aquifer, which is otherwisecomposed mainly of dolomitic limestone of early and middle Eoceneage (Krause and Randolph, 1989; fig. 4). The lateral extent of thisunit is uncertain. A deep drilling program conducted for theCoastal Sound Science Initiative (CSSI) identified the unit neardowntown Brunswick, but further north the unit is absent on St.Simons Island and in McIntosh County (Payne and others, 2005). Thisunit is important in the Brunswick area because of a postulatedsystem of vertically connected fractures and upward gradientscaused by pumping in the Upper Floridan aquifer that allow thesaline water to migrate upward (Maslia and Prowell, 1990; fig.3).
8 Groundwater Conditions in the Brunswick–Glynn County Area,Georgia, 2009
Groundwater ConditionsGroundwater levels and chlorideconcentrations in
the Brunswick–Glynn County area have been monitored for severaldecades as part of the CWP. Precipitation and groundwater pumpageare monitored to assess their influence on groundwater conditions.These data are used to guide water-management decisions by Stateand local authorities.
Groundwater Levels
During calendar year 2009, groundwater levels and specificconductance in the Brunswick–Glynn County area were continuouslymonitored in 33 wells; 13 wells were funded through the CWP, and 20wells were funded through a similar program with the GeorgiaDepartment of Natural Resources, Environmental Protection Division(GaEPD; fig. 2; table 1). Of the 33 continuous water-levelrecorders, 13 are completed in the Upper Floridan aquifer, 8 in theLower Floridan aquifer, 7 in the Brunswick aquifer system, and 5 inthe surficial aquifer system.
Real-time water-level monitoring was continued at wellscompleted in the UWBZ and/or LWBZ of the Upper Floridan aquiferthat surround the area of chloride contamination—Southside BaptistChurch (34H504 and 34H505), Perry Park (34H514), andGeorgia–Pacific Cellulose LLC (33H324 and 33H325; fig. 2). Thesesites also provide real-time specific conductance monitoring in theUWBZ and LWBZ of the Upper Floridan aquifer. The Brunswick Villawell (34H134) was instrumented during late 2009 and provides onlyreal-time specific conductance data in the UWBZ and LWBZ of theUpper Floridan aquifer (table 1).
Factors Influencing Groundwater LevelsFluctuations and long-termtrends in groundwater levels
occur as a result of changes in recharge to and discharge froman aquifer. Recharge rates vary in response to precipi-tation,evapotranspiration, and surface-water infiltration into an aquifer(Alley and others, 1999). Discharge occurs as natural flow from anaquifer to streams or springs, as evapotrans piration from shallowwater-table aquifers, as leakage to vertically adjacent aquifers,and as withdrawal (pumpage) from wells. When recharge to an aquiferexceeds discharge, groundwater levels rise; when discharge from anaquifer exceeds recharge, groundwater levels decline. Water levelsgenerally are highest in the winter/early spring when precipitation is greatest, evapotranspiration is lowest, and withdrawalsare minimal; water levels are the lowest during
summer and fall when evapotranspiration and pumpage are greatest(Payne and others, 2005). In the Glynn County area, the surficialand Brunswick aquifer systems show a more pronounced response toclimatic effects than the deeper Upper and Lower Floridan aquifers,which show a less pronounced response because they are deeplyburied and receive recharge from outcrop areas located to thenorthwest. Generally in the lower Coastal Plain, climatic effectsare greatly diminished, and fluctuations are largely because ofgroundwater pumping (Priest, 2004).
Hydrographs from the network of monitoring wells show long-term(period of record) and recent (2008–2009) water-level changes, withmonthly mean water levels presented together with maps in thefollowing sections of this report. Water-level trends are reportedin feet per year of change and were computed by generating astraight-line fit to both the recent and period of recordmonthly-mean groundwater levels using the LMA (Moré, 1978) forminimization of a weighted least-squares merit function (Janert,2010). Using estimated water levels from these straight-line fits,an annual rate of change (yearly slope) was calculated for theperiod of record and for 2008–2009 (Peck and others, 2011). Thesedata are organized and presented for each aquifer. Water-leveltrends for 2008–2009 are presented on maps either by an upwardarrow for a positive rate of change of 0.01 foot per year (ft/yr)or greater, or a downward arrow for a negative rate of change of0.01 ft/yr or greater. A circle represents a water-level change ofless than ± 0.01 ft/yr. Additional well information can be obtainedfrom the USGS National Water Information System (NWIS) athttp://waterdata.usgs.gov/ga/nwis/gw/.
PrecipitationPrecipitation in the Brunswick–Glynn Countyarea
influences groundwater levels in the shallow surficial aquifersystem and, to a lesser degree, in the Brunswick aquifer system. Inaddition, changes in precipitation affect quantities of groundwaterwithdrawn from deeper aquifers and, therefore, have an indirecteffect on groundwater levels in the Upper Floridan aquifer. Themean-annual rainfall of 49 inches is not evenly distributedthroughout the year, and maximum rainfall generally occurs duringthe summer months of June, July, and August (Priest, 2004). Thesemaximum rainfall amounts are often associated with tropical systemsduring the hurricane season that produce heavy rainfall along thecoast. A real-time climatic site was established as part of theCSSI at the College of Coastal Georgia campus at Brunswick tomonitor precipitation in the Brunswick–Glynn County area (seelocation, fig. 2). Real-time monitoring data for this site areaccessible on the Web at http://www.georgiaweather.net accessed onMay 29, 2010).
http://waterdata.usgs.gov/ga/nwis/gw/www.georgiaweather.net
Groundwater Conditions 9
Table 1. Brunswick–Glynn County, Georgia, groundwater-level monitoring network, 2009.
Well number Aquifer SubunitYear
monitoring began
34H515a
34H43734J07733H12733H13334H134b
34H33434H37134H514c
33H18833J04434H39134H436
SurficialUpper BrunswickUpper BrunswickUpper FloridanUpperFloridanUpper FloridanUpper FloridanUpper FloridanUpperFloridanLower FloridanLower FloridanLower FloridanLowerFloridan
Deeper (confined) zoneNoneNoneLower water-bearing zoneUpperwater-bearing zoneUpper and lower water-bearing zonesLowerwater-bearing zoneUpper water-bearing zoneUpper water-bearingzoneFernandina permeable zoneUndifferentiatedBrackish waterzoneBrackish water zone
2005198319981962196420091962196720071978197919701983
Additional wells (funded by Georgia Environmental Protection Division)
33H20834H492
34J082
35H076
33J06534J08133J06234J08035H07733H20733H324c
33H325c
34G03334H504c
34H505c
35H07033H20634H49534H50035H068
SurficialSurficial
Surficial
Surficial
Upper BrunswickUpper BrunswickLower BrunswickLowerBrunswickLower BrunswickUpper FloridanUpper FloridanUpperFloridanUpper FloridanUpper FloridanUpper FloridanUpperFloridanLower FloridanLower FloridanLower FloridanLowerFloridan
Deeper (confined) zoneWater-table zone
None
Deeper (confined) zone
NoneNoneNoneNoneNoneUpper water-bearing zoneUpper water-bearingzoneLower water-bearing zoneNoneUpper water-bearing zoneLowerwater-bearing zoneUpper water-bearing zoneBrackish waterzoneFernandina permeable zoneFresh water-bearing zoneFreshwater-bearing zone
19831999
2002
2007
2001200220012002200519832007200720042007200720071983200120012007
a Replaces 34H438b Real-time station—specific conductance onlycReal-time station
10 Groundwater Conditions in the Brunswick–Glynn County Area,Georgia, 2009
Precipitation data and cumulative departure from normal during2000–2009 are shown in figure 5. The cumulative departure fromnormal precipitation for the period of record can be used toevaluate trends in precipitation, which typically relate torecharge of shallow aquifers. Cumulative departure describes thelong-term surplus or deficit of precipitation during a designatedperiod and is derived by adding succes-sive values of departuresfrom normal precipitation. In this report, normal precipitation fora given day is defined as the average of total daily precipitationduring the period of record (2000–2009). A downward trend in slopeindicates a period of below-normal precipitation, whereas an upwardtrend indicates above-normal precipitation.
Cumulative departure data indicate a period of below-normalprecipitation from January 2000 to June 2004. Between June 2004 andOctober 2005, precipitation was mostly above normal with one shortperiod of below-normal precipitation between November 2004 andFebruary 2005. Rainfall was mostly below normal from November 2005to March 2009 and
mostly above normal from March to October 2009 (fig. 5A). Themaximum amount of rainfall recorded in a 24-hour period was 6.05inches on October 5, 2005 (fig. 5B). During a 6-day period (October2–7, 2005), rainfall associated with Tropical Storm Tammy totalednearly 18 inches in the area, and the cumulative departure wentfrom just over 4 inches to more than 21 inches (fig. 5A).
Groundwater WithdrawalsThe locations of groundwater pumpingcenters and
amounts of water withdrawn from these centers may substantiallyaffect groundwater levels in the Brunswick–Glynn County area.Changes in pumping rates and the addition of new pumping centersmay alter the configuration of poten-tiometric surfaces, reversegroundwater flow directions, and increase seasonal and long-termfluctuations in the aquifers. During 2009, about 48 million gallonsper day (Mgal/d) were withdrawn from the Upper Floridan aquifer inGlynn County, of which 7.97 Mgal/d was for public supply and 39.7Mgal/d
Figure 5. (A) Cumulative departure from normal precipitation and(B) total daily precipitation at real-time climatic monitoringsite, College of Coastal Georgia, Georgia, January 2000–December2009 (see figure 2 for location).
–30
2000 2001
Cum
ulat
ive
depa
rture
from
nor
mal
pre
cipi
tatio
n, in
inch
esPr
ecip
itatio
n, in
inch
es
2002 2003 2004 2005 2006 2007 2008 2009
–20
–10
10
20
30
1
2
3
4
5
6
7
A
B
Groundwater Conditions 11
was for industry (Julia Fanning, U.S. Geological Survey, writtencommun., May 2010).
Pumpage from the Upper Floridan aquifer in Glynn County during2009 was slightly higher than in 2008, and was appreciably lowerthan in 1980. Pumpage decreased from 95.4 Mgal/d during 1980 to47.7 Mgal/d during 2009. This decrease reflects increased waterconservation by local industry and reduced usage by golf courses inGlynn County, which have shifted withdrawals to wells completed inthe Brunswick aquifer system. During 2009, an estimated 2.03 Mgal/dwas withdrawn from the Brunswick aquifer system for irrigation andmunicipal needs in Glynn County (Julia Fanning, U.S. GeologicalSurvey, written commun., May 2010). The reduction in pumpage during1980–2009 had a pronounced effect on groundwater levels in thearea.
Historically, groundwater pumpage in Glynn County peaked in theearly 1980s with the majority of groundwater withdrawals used forindustrial purposes (fig. 6). In calendar year 1980,Georgia–Pacific Cellulose LLC (formerly Bruns-wick Pulp & PaperCompany) and Pinova Inc. (formerly Hercules Inc.), withdrew 58.8and 19.5 Mgal/d, respectively, and groundwater withdrawal forpublic supply averaged 9.8 Mgal/d (L.E. Jones, U.S. GeologicalSurvey, written commun., March 2007). By 2009, withdrawals at theGeorgia–Pacific Cellulose facility decreased to 32.6 Mgal/d andwithdrawals at the Pinova facility decreased to 5.9 Mgal/d.
Water use for public supply has steadily increased due to therise in population within Glynn County. Population was 21,920during 1940, 54,980 in 1980, and 76,820 during
2009 (U.S. Census Bureau, accessed August 11, 2010, athttp://www.census.gov/popest/counties/CO-EST2009-01.html). As aresult, groundwater pumpage for public supply nearly doubled from4.4 Mgal/d during 1940, to 8.0 Mgal/d during 2009, with a peakusage of 11.3 Mgal/d during 1990 (fig. 6). Despite the populationincrease during 1980–2009, pumpage for public supply during 2009 isless than during 1980 because of greater accountability in thewater distribution systems, water conservation measures, anddecreased losses due to system leakage (Keith Morgan,Brunswick–Glynn County Joint Water and Sewer Commission, oralcommun., 2009). During 2009, withdrawal for public supply for GlynnCounty, was 8.1 Mgal/d compared to 9.8 Mgal/d during 1980.
Surficial Aquifer SystemDuring 2009, water levels were monitoredin five wells
completed in the surficial aquifer system in the Brunswick–GlynnCounty area (fig. 7; table 1). Water-level hydrographs for thesewells illustrate monthly mean water levels for the period of record(fig. 8). Seasonal variations are evident on the hydrographs, withperiodic upward or downward trends that indicate a surplus ordeficit in rainfall. Water levels during the period of record inthree of the wells show an upward trend with rates of change from0.03 to 0.15 ft/yr and downward trends in two wells at rates of0.08 and 0.19 ft/yr (fig. 7). During 2008–2009, water levels in allfive wells rose at rates of 0.24 to 1.05 ft/yr, corresponding to aperiod of above-normal precipitation during most of 2009 (fig.5).
Figure 6. Major groundwater pumpage from the Upper Floridanaquifer in the Brunswick–Glynn County area, Georgia, 1940–2009.
10
20
30
40
50
60
70
1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 20002005 2009
Pum
page
, in
mill
ion
gallo
ns p
er d
ay
Geor
gia-
Paci
fic C
ellu
lose
LLC
Pino
va In
c.Pu
blic
sup
ply
http://www.census.gov/popest/counties/CO-EST2009-01.html
12 Groundwater Conditions in the Brunswick–Glynn County Area,Georgia, 2009
Figure 7. Groundwater-level monitoring network in the surficialaquifer system, Glynn County, Georgia, and water-level change forperiod of record and 2008–2009.
33H32533H324
33J06533J062
34G033
34J07733J044
33H188
34H334
34H49534H500
34H514
33H12733H133
34H514
34H39134H371
341
17
84
95
34H515
33H208
34J082
35H076
34H492
WAYNE
BRANTLEY
MCINTOSH
CAMDEN
Brunswick
St SimonsIsland
JekyllIsland
GLYNN
AT
LA
NT
IC
OC
EA
N
BrunswickGLYNN COUNTY
GEORGIA
Base modified from U.S. Geological Survey 1:100,000-scaledigital data
Observation well, site name, and water-level change from 2008 to2009
EXPLANATION
Water-level rise >0.01 foot per year33H208
6 KILOMETERS
5 6 MILES
5
0 1 2 3 4
0 1 2 3 4
81°20'81°30'81°40'
31°20'
31°10'
Site name Year monitoring beganWater-level trend, in feet peryear1
Period of record 2008 to 2009
33H208 1983 0.15 1.0534H492 1999 0.08 0.8834H515 2005 0.030.2434J082 2002 –0.08 0.4035H076 2005 –0.19 0.43
1See appendix for summary statistics.
Groundwater Conditions 13
Figure 8. Monthly mean water levels and period-of-record trendline in wells in the surficial aquifer system, Glynn County,Georgia (note different periods of record and vertical scales; seefigure 7 for well locations).
1
2
3
4
5
6
7
8
9
10
Well 33H208
1
2
3
4
5
6
7
Mon
thly
mea
n w
ater
leve
l bel
ow la
nd s
urfa
ce, i
n fe
etM
onth
ly m
ean
wat
er le
vel
belo
w la
nd s
urfa
ce, i
n fe
et
Well 34H492
1.5
2.0
2.5
3.0
3.5
4.0
4.5
Well 34H515
4.55.0
5.56.0
6.57.0
7.58.0
8.59.0
9.5
20001999 2003 2004 2006 20092001 2002 2005 2007 2008
Well 34J082
17.0
17.5
18.0
18.5
19.0
19.5
Well 35H076
Blankwhere
data aremissing
Trend
0.15 footper year
1982 1985 1988 1991 1994 1997 2000 2003 2006 2009
0.08 foot per year
–0.08 foot per year
14 Groundwater Conditions in the Brunswick–Glynn County Area,Georgia, 2009
Brunswick Aquifer SystemWater levels in the Brunswick aquifersystem are
monitored continuously in four wells completed in the upperBrunswick aquifer and three wells completed in the lower Brunswickaquifer (figs. 9–11; table 1). Water-level fluctua-tions reflectchanges in local pumping, interaquifer-leakage effects, andrecharge. Water-level hydrographs showing monthly mean water levelsfor the period of record indicate periodic upward or downwardtrends that reflect surplus rainfall or deficits in rainfall andchanges in pumping. During the period of record, water levels infour of the wells declined at rates of 0.06 to 0.94 ft/yr, remainedabout the same in two wells, and rose in one well at a rate of 0.16ft/yr (fig. 9). During 2008–2009, water levels in six of the wellsrose at rates of 0.32 to 2.30 ft/yr and declined in one well at arate of 0.37 ft/yr. The water-level rises corresponded to a periodof above-normal precipitation during most of 2009 (fig. 5).
Water levels in the Brunswick aquifer system in north-centralGlynn County are influenced by pumpage at the Golden Islesdevelopment, which began pumping from the Brunswick aquifer systemin 1999, and is one of the earliest users of the Brunswick aquifersystem in coastal Georgia.
During 1999–2009, average annual pumping ranged from 0.26 to0.68 Mgal/d (Vicki Trent, Georgia Environmental ProtectionDivision, written commun., November 15, 2010). Monitoring at well34J077 (fig. 9), located about 0.6 mi from a production welllocated at the Golden Isles development, provides a long-termrecord of the effects of pumping on the Brunswick aquifer system.During 1999–2008, the water level in well 34J077 dropped about 20ft, followed by recovery at a rate of 2.3 ft/yr during 2008–2009(fig. 10). Well 34J080, open to the Lower Brunswick aquifer, isalso influenced by pumping at Golden Isles, and the decline sincethe well began recording water levels in 2002 has been at a rate of0.52 ft/yr (figs. 9, 11).
Periodic water-level measurements also are collected from fivewells completed in the Brunswick aquifer system located on JekyllIsland (fig. 2, 12). Periodic measurements were collected by theUSGS during 2009–2010 and the Jekyll Island Authority during2002–2009 (John Day, Jekyll Island Authority, written commun.,October 13, 2010). Hydrographs showing these periodic measurementsindicate no appreciable water-level trend with water levels aboveland surface throughout the period of record.
Groundwater Conditions 15
341
17
84
95
33J065
34H437
33J062
35H077
34J080
34J077
34J081
WAYNE
BRANTLEY
MCINTOSH
CAMDEN
Brunswick
St SimonsIsland
JekyllIsland
GLYNN
AT
LA
NT
IC
OC
EA
N
Golden IslesDevelopment
production well
BrunswickGLYNN COUNTY
GEORGIA
81°20'81°30'81°40'
31°20'
31°10'
Observation well, site name, and water-level change from 2008 to2009
EXPLANATION
Water-level rise >0.01 foot per year
Water-level decline >0.01 foot per year33J062
33J065Base modified from U.S. Geological Survey 1:100,000-scaledigital data
Site name
Year monitoring began
Water-level trend, in feet per year1
Period of record 2008 to 2009
33J062 2001
16 Groundwater Conditions in the Brunswick–Glynn County Area,Georgia, 2009
–2.5
–2.0
–1.5
–1.0
–0.5
0.5
1.0
1.5
Well 33J065
–6
–4
–2
2
4
6
81982 1985 1988 1991 1994 1997 2000 2003 2006 2009
Well 34H437
5
10
15
20
25
30
35
1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
Well 34J077
11
12
13
14
15
16
17
18
19
Well 34J081
Mon
thly
mea
n w
ater
leve
l bel
ow a
nd a
bove
(–) l
and
surf
ace,
in fe
etM
onth
ly m
ean
wat
er le
vel b
elow
and
abov
e (–
) lan
d su
rface
, in
feet
Blank wheredata aremissing
Trend0.16 foot per year
Groundwater Conditions 17
–20
–18
–16
–14
–12
–10
–8
–6
–4
–2
Well 34G060
–30
–25
–20
–15
–10
–5
Well 34G059
–20
–18
–16
–14
–12
–10
–8
–6
–4
–2
0 2002 2003 2004 2005 2006 2007 2008 2009 20102002 2003 20042005 2006 2007 2008 2009 20102002 2003 2004 2005 2006 2007 20082009 2010
Well 34G048
Wat
er le
vel a
bove
(–) l
and
surfa
ce,
in fe
et
Figure 12. Periodic water-level measurements in wells in theBrunswick aquifer system, Jekyll Island, Glynn County, Georgia(note vertical scales vary; see figure 2 for well locations).
–18
–16
–14
–12
–10
–8
–6
2001 2002 2003 2004 2005 2006 2007 2008 2009
Well 33J062
–10123456789
10
Well 34J080
12 14 16 18 20 22 24 26 28 30 32
Well 35H077
Mon
thly
mea
n w
ater
leve
l bel
ow a
nd a
bove
(–) l
and
surf
ace,
in fe
et
Blankwhere
data aremissing
Trend
18 Groundwater Conditions in the Brunswick–Glynn County Area,Georgia, 2009
Floridan Aquifer SystemWater levels in the Floridan aquifersystem in the
Brunswick–Glynn County area are continuously monitored in 12wells completed in the Upper Floridan aquifer and 8 wells completedin the Lower Floridan aquifer (figs. 13–17; table 1). Water levelsin the Upper and Lower Floridan aquifers are influenced primarilyby changes in pumping.
During the period of record, water levels in 11 of the 12 UpperFloridan aquifer wells had rising trends with rates of changeranging from 0.05 to 4.26 ft/yr (figs. 13, 14). The highest ratesof annual water-level rise were generally in wells where monitoringbegan after 2004 (fig. 13). Well 34G033 had a declining trend of1.49 ft/yr; however, the period of record for this well begins in2004 and misses much of the earlier period in which water levelswere rising in the area because of decreases in pumpage during the1990s (fig. 6). The downward trend in well 34G033 reflects aregional decline during 2004–2008 that was evident in most of thewells in the area. During 2008–2009, water levels in all 12 wellsrose at rates of 0.85 to 7.58 ft/yr (fig. 13).
Periodic water-level measurements are also collected from well34G029 completed in the Upper Floridan aquifer on Jekyll Island(fig. 15). The water-level hydrograph for this well illustratesperiodic measurements collected by the USGS during 2009–2010 andhistorical measurements collected by the Jekyll Island Authorityprior to 2009 (John Day, Jekyll
Island Authority, written commun., October 13, 2010). Waterlevels in the well rose during 2002–2003, declined during2003–2008, rose from 2008 to the end of 2009, and declined throughJune 2010 (fig. 15).
In the Lower Floridan aquifer, water levels during the period ofrecord rose at rates of 0.09 to 1.22 ft/yr in five wells, declinedin two wells at rates of 0.06 and 0.08 ft/yr, and remained the samein one well (figs. 16, 17). Water levels in each of the wellsshowed a pronounced rise during 2002 that marked the end of aprolonged drought and response to a pumping shutdown by a majorindustrial user in the St. Marys area of Camden County (Peck andothers, 2005; fig. 17). According to Payne and others (2006), thesimulated steady-state water-level change in the Lower Floridanaquifer in the Glynn County area due to this shutdown rangedbetween 2 and 4 ft. During 2008–2009, water levels in seven of thewells rose at rates ranging from 1.41 to 1.98 ft/yr and declined inwell 33H188 at a rate of 0.83 ft/yr.
In addition to continuous recorders, synoptic water-levelmeasurements were collected in 46 wells completed in the UpperFloridan aquifer during August 2009, and a potentio metric-surfacemap was prepared based on the data (fig. 18; table 2). The mapindicates the continued presence of a cone of depression created bylarge industrial withdrawals in the northern and western parts ofthe Brunswick area, with the principal direction of groundwaterflow toward the cone of depression.
Groundwater Conditions 19
341
17
84
95
34H334
33H207
33H12733H133
33H32433H325
35H070
34G033
34H37134H50434H505
34H514
WAYNE
BRANTLEY
MCINTOSH
CAMDEN
Brunswick
St SimonsIsland
JekyllIsland
GLYNN
AT
LA
NT
IC
OC
EA
N
BrunswickGLYNN COUNTY
GEORGIA
Observation well, site name, and water-level change from 2008 to2009
EXPLANATION
Water-level rise >0.01 foot per year34G033
6 KILOMETERS50 1 2 3 4
Base modified from U.S. Geological Survey 1:100,000-scaledigital data
5 6 MILES0 1 2 3 4
81°20'81°30'81°40'
31°20'
31°10'
Site name
Year monitoring began
Water-level trend, in feet per year 1
Period of record 2008 to 2009
33H127 1962 0.05 2.0733H133 1964 0.27 2.4333H207 1983 0.470.8933H324 2007 1.73 2.2433H325 2007 4.26 7.5834G033 2004 –1.491.3834H334 1962 0.17 1.5434H371 1967 0.14 1.2834H504 2007 1.151.3434H505 2007 0.76 1.2834H514 2007 1.29 1.6035H070 2005 0.880.851See appendix for summary statistics.
Figure 13. Groundwater-level monitoring network in the UpperFloridan aquifer in Glynn County, Georgia, and water-level changefor period of record and for 2008–2009.
20 Groundwater Conditions in the Brunswick–Glynn County Area,Georgia, 2009
–15
–10
–5
5
10
15
–5
5
10
15
20
25
–10
–5
5
10
15
20
–12–10
–8–6–4–2
02468
10
1955 19651960 1970 1975 1980 1985 19951990 2000 2005
–12
–10
–8
–6
–4
–2
2
4
6
Mon
thly
mea
n w
ater
leve
l bel
ow a
nd a
bove
(–) l
and
surf
ace,
in fe
et
0.05 foot per year
0.27 foot per year
0.47 foot
per year
0.17 foot per year
0.14 foot per year
Well 33H127 Blankwhere
data aremissing
Trend
Well 33H133
Well 33H207
Well 34H334
Well 34H371
Figure 14. Monthly mean water levels and period-of-record trendline in wells in the Upper Floridan aquifer, Glynn County, Georgia(note different periods of record and vertical scales; see figure13 for well locations).
Groundwater Conditions 21
789
10 11 12 13 14 15 16 17
Well 33H324
30
35
40
45
50
55
60
65
Well 33H325
–24
–22
–20
–18
–16
–14
–12
2004 2005 2006 2007 2008 2009
Well 34G033
–7
–6
–5
–4
–3
–2
–1
Well 34H504
–8
–7
–6
–5
–4
–3
–2
–1
Well 34H505
Mon
thly
mea
n w
ater
leve
l bel
ow a
nd a
bove
(–) l
and
surf
ace,
in fe
et
Figure 14. Monthly mean water levels and period-of-record trendline in wells in the Upper Floridan aquifer, Glynn County, GA (notedifferent periods of record and vertical scales; see figure 13 forwell locations).—Continued
–1.49 feet per year
Figure 14. Monthly mean water levels and period-of-record trendline in wells in the Upper Floridan aquifer, Glynn County, Georgia(note different periods of record and vertical scales; see figure13 for well locations).—Continued
22 Groundwater Conditions in the Brunswick–Glynn County Area,Georgia, 2009
–1
1
2
3
4
5
6
7
8
2007 2008 2009
Well 34H514
9
10
11
12
13
14
15
16
17
Well 35H070
Mon
thly
mea
n w
ater
leve
l bel
ow a
nd a
bove
(–) l
and
surfa
ce, i
n fe
et
Figure 14. Monthly mean water levels and period-of-record trendline in wells in the Upper Floridan aquifer, Glynn County, GA (notedifferent periods of record and vertical scales; see figure 13 forwell locations).—Continued
Figure 14. Monthly mean water levels and period-of-record trendline in wells in the Upper Floridan aquifer, Glynn County, Georgia(note different periods of record and vertical scales; see figure13 for well locations).—Continued
–20
–18
–16
–14
–12
–10
–8
–6
–4
–2
0 Wat
er le
vel a
bove
(–) l
and
surfa
ce, i
n fe
et
2002 2003 2004 2005 2006 2007 2008 2009 2010
Figure 15. Periodic water-level measurements in well 34G029,Upper Floridan aquifer, Jekyll Island, Glynn County, Georgia (seefigure 2 for well location).
Groundwater Conditions 23
341
17
84
95
35H068
35H068
33H206
33J044
34H50034H391
33H188
34H436
34H495
WAYNE
BRANTLEY
MCINTOSH
CAMDEN
Brunswick
St SimonsIsland
JekyllIsland
GLYNN
AT
LA
NT
IC
OC
EA
N
BrunswickGLYNN COUNTY
GEORGIA
Observation well, site name, and water-level change from 2008 to2009
EXPLANATION
Water-level rise >0.01 foot per year
Water-level decline >0.01 foot per year34H188
33J044
Base modified from U.S. Geological Survey 1:100,000-scaledigital data
6 KILOMETERS50 1 2 3 4
5 6 MILES0 1 2 3 4
81°20'81°30'81°40'
31°20'
31°10'
Site name
Year monitoring began
Water-level trend, in feet per year1
Period of record 2008 to 2009
33H188 1978 –0.08 –0.8333H206 1983 0.25 1.5433J044 1979 0.091.9834H391 1975 0.17 1.5734H436 1983 0.18 1.4634H495 2001 1.221.6334H500 2001 –0.06 1.9035H068 2007
24 Groundwater Conditions in the Brunswick–Glynn County Area,Georgia, 2009
–16
–18
–14–12–10–8–6–4–2
20
–14–12–10–8–6–4–2
0246
–6
–8–10
–4–2
02468
10
–12–14–16
–10–8–6–4–2
024
1970 1975 1980 1985 1990 1995 2000 2005
–16–18
–14–12–10–8–6–4–2
02
Mon
thly
mea
n w
ater
leve
l bel
ow a
nd a
bove
(–) l
and
surf
ace,
in fe
et
–0.08 footper year
0.25 footper year
0.09 footper year
0.17 footper year
0.18 footper year
Blankwhere
data aremissing
Trend
Well 33H188
Well 33H206
Well 33J044
Well 34H391
Well 34H436
Figure 17. Monthly mean water levels and period-of-record trendline in wells in the Lower Floridan aquifer, Glynn County, Georgia(note different periods of record and vertical scales; see figure16 for well locations).
Groundwater Conditions 25
–22
–24
–20–18–16–14–12–10
–8–6–4
Well 34H495
–18
–16
–14
–12
–10
–8
–6
–4
2001 2002 2003 2004 2005 2006 2007 2008 2009
Well 34H500
2
3
4
5
6
7
8
9
10
Well 35H068
Mon
thly
mea
n w
ater
leve
l bel
ow a
nd a
bove
(–) l
and
surf
ace,
in fe
et
Figure 17. Monthly mean water levels and period-of-record trendline in wells in the Lower Floridan aquifer, Glynn County, GA (notedifferent periods of record and vertical scales; see figure 16 forwell locations).—Continued
1.22 feet per year
–0.06 foot per year
Figure 17. Monthly mean water levels and period-of-record trendline in wells in the Lower Floridan aquifer, Glynn County, Georgia(note different periods of record and vertical scales; see figure16 for well locations).—Continued
26 Groundwater Conditions in the Brunswick–Glynn County Area,Georgia, 2009
UV25
17
341
17
82
4.3
6.88
14.3
14.6925.08
10.03
12.39
12.2712.23
11.09
12.21
15.91
26.09
30.74
33.02
21.19
28.2822.54
27.96
39.72
ll
ll
ll
ll
ll
ll l l
ll
ll
ll
ll
ll
l
llll
ll
ll
l
lllll
ll
l
l l l ll
l
llllll
ll
l l
10
10
15
20
5
10
5
10
51.9
9.4
4.98
4.28
7.29
4.86 7.064.81
6.82 9.177.12
2.13 4.12
11.34.86
7.629.89
7.82
9.32
–0.88–4.69
–2.59
12.07
13.65
15.04
17.73
21.76
4TH AVE
4TH STRE
ET
NEW
CASTLE ST
303
3299
25
520
17
341
25
95
St S
imon
s
Soun
d
Turtle River
GLYNNCOUNTY
CAMDENCOUNTY
81°20'81°25'81°30'81°35'81°40'
31°15'
31°10'
31°05'
20 15
15
20
25
10
30
5
35
10
25
5
5
0 2 3 41 5 MILES
0 2 3 41 5 KILOMETERS
Base modified from the National Atlas of the United States,2008Roads, 1:100,000 scaleCoastline-Hydrology, 1:1,000,000scale
Potentiometric contour—Shows altitude at which water level wouldhave stood in tightly cased wells, August 2009. Hachures indicatedepression. Contour interval 5 feet. Datum is NAVD 88
9.89 Well and water level—In feet above NAVD 88
General direction of groundwater flow
10
EXPLANATION
CAMDENCOUNTY
Area ofmap above
GLYNNCOUNTY
Figure 18. Potentiometric surface of the Upper Floridan aquifer,Brunswick–Glynn County, Georgia, August 17–21, 2009.
Groundwater Conditions 27
Table 2. Potentiometric and periodic groundwater-levelmonitoring networks in the Upper Floridan aquifer, Brunswick–GlynnCounty, Georgia.[NAVD 88, North American Vertical Datum of 1988; T,transducer; S, steel tape; negative values for depth to waterrepresent measurements above land surface]
Wellnumber
Latitudea LongitudeaMeasurement
date
Altitudeb
(feet aboveNAVD 88)
Depth towater belowland surfacec
(feet)
Water levelaltitude
(feet aboveNAVD 88)
Method ofwater-level
measurementDegrees, minutes, seconds NAD 83
33G008 31°07'06.8"N 81°31'58.1"W 08-20-2009 6.41 –16.13 22.54T33G024 31°07'12.7"N 81°36'36.1"W 08-19-2009 6.92 –21.36 28.28T33H120 31°10'36"N 81°30'26"W 08-17-2009 10.88 6.60 4.28 S33H12731°10'06.6"N 81°30'16.5"W 08-18-2009 5.14 –1.68 6.82 T33H13031°10'21"N 81°30'31"W 08-18-2009 9.78 7.88 1.90 S33H13331°10'06.82"N 81°30'16.5"W 08-18-2009 5.70 0.89 4.81 S33H14131°10'44"N 81°32'31"W 08-17-2009 11.53 – 0.68 12.21 T33H18031°11'07"N 81°30'00"W 08-20-2009 14 9.02 4.98 S33H193 31°13'45"N81°37'04"W 08-18-2009 8.99 –12.20 21.19 T33H207 31°09'25"N81°31'22"W 08-20-2009 5.97 –3.92 9.89 T33H209 31°09'12"N 81°32'53"W08-18-2009 8.95 –6.96 15.91 T33H211 31°10'27"N 81°31'13"W08-17-2009 11.59 12.47 – 0.88 S33H213 31°10'08"N 81°30'58"W08-17-2009 5.58 8.17 –2.59 S33H324 31°10'22"N 81°30'46"W 08-18-20094 8.69 – 4.69 S34G002 31°07'26.6"N 81°28'53.1"W 08-17-2009 9.04–12.72 21.76 T34G009 31°01'03"N 81°25'40"W 08-19-2009 8.96 –30.7639.72 T34G016 31°06'07"N 81°24'15"W 08-19-2009 8.89 –19.07 27.96T34G017 31°06'58"N 81°25'01"W 08-19-2009 6.04 –20.05 26.09 T34G02031°05'10"N 81°25'16"W 08-19-2009 9.01 –21.73 30.74 T34G04131°03'32"N 81°26'48"W 08-19-2009 9 –24.02 33.02 T34G054 31°06'21"N81°29'31.8"W 08-17-2009 7 –7.69 14.69 T34G056 31°06'13.6"N81°29'29.6"W 08-18-2009 8.96 –16.12 25.08 T34H062 31°10'05"N81°28'27"W 08-20-2009 7.71 –1.46 9.17 T34H095 31°07'35.7"N81°29'19.1"W 08-20-2009 4 –13.73 17.73 T34H112 31°08'42.2"N81°29'40.6"W 08-18-2009 7.57 –4.50 12.07 T34H117 31°08'52.4"N81°29'53.2"W 08-18-2009 5.69 –3.63 9.32 T34H144 31°09'47"N81°26'52"W 08-18-2009 10 5.70 4.30 S34H328 31°13'19"N 81°23'29"W08-20-2009 11.40 – 0.99 12.39 T34H334 31°09'37.6"N 81°28'51.5"W08-20-2009 7.33 –3.97 11.30 T34H355 31°09'24.3"N 81°29'52.6"W08-17-2009 12.97 3.57 9.40 S34H371 31°08'18.1"N 81°29'36.8"W08-18-2009 8.48 – 6.56 15.04 T34H373 31°09'40"N 81°29'33"W08-18-2009 8.28 4.16 4.12 S34H374 31°09'53"N 81°29'59"W 08-18-200916 8.88 7.12 S34H393 31°08'24.6"N 81°29'42.1"W 08-18-2009 5.94–7.71 13.65 T34H400 31°09'36"N 81°29'49"W 08-18-2009 11.49 6.634.86 S34H401 31°09'45"N 81°29'55"W 08-18-2009 12.15 10.02 2.13S34H408 31°08'18.8"N 81°29'41.5"W 08-20-2009 17 4.77 12.23 S34H41031°12'07"N 81°27'50.5"W 08-18-2009 5.51 – 6.76 12.27 T34H42431°10'11"N 81°29'31"W 08-20-2009 14 6.94 7.06 S34H427 31°10'16"N81°29'42"W 08-20-2009 13 8.14 4.86 S34H434 31°09'10.8"N81°29'40.8"W 08-18-2009 9 1.18 7.82 S34H444 31°10'07"N 81°24'58"W08-19-2009 4.63 –9.67 14.30 T34H469 31°10'20"N 81°29'52"W08-18-2009 12.91 5.62 7.29 S34H514 31°09'31"N 81°29'10"W 08-18-200910 2.38 7.62 S35H050 31°12'20"N 81°19'27"W 08-19-2009 7.03 0.156.88 S35H051 31°11'46"N 81°20'13"W 08-19-2009 7.03 – 4.06 11.09T35J004 31°16'40"N 81°20'37"W 08-18-2009 9 –1.03 10.03 T
aAccuracy varies based on method of measurement. Values reportedto tenths of a second represent measurement made by globalpositioning techniques.bAccuracy varies based on method ofmeasurement. Values reported to tenths or hundreths of a footrepresent measurement made by surveying or global
positioning techniques.c Values reported to hundreth of afoot.
28 Groundwater Conditions in the Brunswick–Glynn County Area,Georgia, 2009
Chloride Concentrations
Chloride concentrations have been monitored in the Brunswickarea since the late 1950s when saltwater was first detected inwells completed in the Upper Floridan aquifer in the southernmostpart of Brunswick (Wait, 1965). Saltwater has migrated upward fromdeep saline zones through breaches
in confining units as a result of reduced hydraulic head inwater-bearing zones of the Upper Floridan aquifer. By the 1960s,chloride-contaminated groundwater had migrated northward toward twomajor industrial pumping centers. As of 2009, the USGS collects andanalyzes samples from a network of 81 wells on an annual basis forthe CWP (figs. 19A, B; table 3).
32H001 33H19233H193
33H190
34H01234H507
33G02433G001
33H17733H18833G002
33G00833G028
33G003 34G03634G05434G003
34G005
34G008
34G027
G L Y N N C O U N T Y
Area ofmap in
figure 19B
32H001
N
6 MILES3
Base from U.S. Geological Survey1:250,000-scale digital data
6 KILOMETERS3
Well in chloride-monitoring network andidentifierEXPLANATION
A
Figure 19. Chloride-monitoring network for the Brunswick–GlynnCounty area, Georgia. (A) Location and (B) enlarged area.
Groundwater Conditions 29
N
B
34H134
33H222 33H120 34H449
33H211 33H22133H130
33H15433H227
34H46934H427
33H183 33H13333H127
33H21333H212 34H075
34H45033H113
34H374
34H41334H07834H40234H401
34H373 34H42634H34434H33434H400
34H51433H20733H206
34H35534H354
34H43434H125
34H445
34H43834H515
34H43634H117
34H112
34H44834H446
34H39334H403
34H128
34H391 34H37134H428
34H399 34H398
34H09534G002
34G001
34H363
34H076
34H425
34H552
34H424
34H392
33H214
33H189
Base from U.S. Geological Survey1:100,000 scale digitalorthophotos for Glynn County
Well with chloride concentration data and site name
EXPLANATION0 0.5 KILOMETER0.25
0 0.5 MILE0.25
34G002
Figure 19. Chloride-monitoring network for the Brunswick–GlynnCounty area, GA. (A) Location and (B) enlarged area.—Continued
East River
Oglethorpe Bay
TurtleRiver
Figure 19. Chloride-monitoring network for the Brunswick–GlynnCounty area, Georgia. (A) Location and (B) enlargedarea.—Continued
30 Groundwater Conditions in the Brunswick–Glynn County Area,Georgia, 2009
Table 3. Chloride concentrations in water samples collected fromwells in the Brunswick–Glynn County area, Georgia, June 2003–2005,July 2006, July and August 2007, July 2008, and August 2009, andchange in chloride concentration from 2008 to 2009.
[Well locations shown in fig. 19; aquifer or system:S–Surficial, BAS–Brunswick aquifer system, LBA–lower Brunswickaquifer, UFA–Upper Floridan aquifer, FAS–Floridan aquifer system,LFA–Lower Floridan aquifer; —, no data]
Wellnumber
Aquiferor
system
June 2003
June 2004
June 2005
July 2006
July and August 2007
July 2008
August 2009
Change 2008–2009
Chloride concentration, in milligrams per liter
34H428 S 13.9 12.8 11.3 14.0 13.3 13.5 13.6 0.134H438 S 2,8702,540 — — — — — —34H448 S 20.7 18.3 15.3 19.0 — — — —34H515a S — —5,370 5,130 5,250 5,450 5,850 40033G028 BAS — 14.0 12.4 15.2 14.8 —— —34H446 LBA 285 285 297 290 — — — —33G002 UFA — 70.5 72.8 76.873.4 76.3 — —33G008 UFA — 24.1 23.7 29.8 30.0 32.7 31.2 –1.533G024UFA 18.6 16.8 14.7 18.8 17.7 18.2 17.5 –0.734G002 UFA 37.1 79.177.3 78.0 72.1 79.8 74.7 –5.134G003 UFA 136 150 153 — 150 —

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