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David C. Leeth

Publications and source records attributed to David C. Leeth.

12 recordsLinked to original sources
USGS2011

USGS library for S-PLUS for Windows -- Release 4.0

Release 4.0 of the U.S. Geological Survey S-PLUS library supercedes release 2.1. It comprises functions, dialogs, and datasets used in the U.S. Geological Survey for the analysis of water-resources data. This version does not contain ESTREND, which was in version 2.1. See Release 2.1 for information and access to that version. This library requires Release 8.1 or later of S-PLUS for Windows. S-PLUS is a commercial statistical and graphical analysis software package produced by TIBCO corporation(http://www.tibco.com/). The USGS library is not supported by TIBCO or its technical support staff.

Open-File Report↗
USGS2011

Groundwater conditions and studies in Georgia, 2008-2009

The U.S. Geological Survey collects groundwater data and conducts studies to monitor hydrologic conditions, better define groundwater resources, and address problems related to water supply, water use, and water quality. In Georgia, water levels were monitored continuously at 179 wells during 2008 and 181 wells during 2009. Because of missing data or short periods of record (less than 3 years) for several of these wells, a total of 161 wells are discussed in this report. These wells include 17 in the surficial aquifer system, 19 in the Brunswick aquifer and equivalent sediments, 66 in the Upper Floridan aquifer, 16 in the Lower Floridan aquifer and underlying units, 10 in the Claiborne aquifer, 1 in the Gordon aquifer, 11 in the Clayton aquifer, 12 in the Cretaceous aquifer system, 2 in Paleozoic-rock aquifers, and 7 in crystalline-rock aquifers. Data from the well network indicate that water levels generally rose during the 2008-2009 period, with water levels rising in 135 wells and declining in 26. In contrast, water levels declined over the period of record at 100 wells, increased at 56 wells, and remained relatively constant at 5 wells. In addition to continuous water-level data, periodic water-level measurements were collected and used to construct potentiometric-surface maps for the Upper Floridan aquifer in Camden, Charlton, and Ware Counties, Georgia, and adjacent counties in Florida during September 2008 and May 2009; in the Brunswick, Georgia area during July 2008 and July-August 2009; and in the City of Albany-Dougherty County, Georgia area during November 2008 and November 2009. In general, water levels in these areas were higher during 2009 than during 2008; however, the configuration of the potentiometric surfaces in each of the areas showed little change. Groundwater quality in the Floridan aquifer system is monitored in the Albany, Savannah, Brunswick, and Camden County areas of Georgia. In the Albany area, nitrate as nitrogen concentrations in the Upper Floridan aquifer during 2008-2009 generally increased, with concentrations in two wells above the U.S. Environmental Protection Agency (USEPA) 10-milligrams-per-liter (mg/L) drinking-water standard. In the Savannah area, measurement of specific conductance and chloride concentration in water samples from discrete depths in three wells completed in the Upper Floridan aquifer indicate that chloride concentrations in the Upper Floridan aquifer showed little change and remained below the 250 mg/L USEPA secondary drinking-water standard. Chloride concentrations in the Lower Floridan aquifer increased slightly at Tybee Island and Skidaway Island, remaining above the drinking-water standard. In the Brunswick area, maps showing the chloride concentration of water in the Upper Floridan aquifer were constructed using data collected from 28 wells during July 2008 and from 29 wells during July-August 2009, indicate that chloride concentrations remained above the USEPA secondary drinking-water standard in an approximately 2-square-mile area. During 2008-2009, chloride concentrations decreased, with a maximum decrease of 160 mg/L, in a well located in the northern part of the Brunswick area. In the Camden County area, chloride concentration during 2008-2009 was analyzed in water samples collected from eight wells, six of which were completed in the Upper Floridan aquifer and two in the Lower Floridan aquifer. In most of the wells sampled during this period, chloride concentrations did not appreciably change; however, since the closure of the Durango Paper Company in October 2002, chloride concentrations in the Upper Floridan aquifer near the paper mill decreased from a high of 184 mg/L in May 2002 to 41 mg/L in September 2009. Groundwater studies conducted in Georgia during 2008-2009 include the following: * evaluation of groundwater flow, water-quality, and water-level monitoring in the Augusta-Richmond County area; * evaluation of groundwater flow, water-quality, and water

Georgia↗
USGS2009

Ground-Water Conditions and Studies in Georgia, 2006-2007

The U.S. Geological Survey collects ground-water data and conducts studies to monitor hydrologic conditions, better define ground-water resources, and address problems related to water supply, water use, and water quality. Water levels were monitored continuously, in Georgia, in a network of 184 wells during 2006 and 182 wells during 2007. Because of missing data or the short period of record (less than 3 years) for several of these wells, a total of 166 wells from the network are discussed in this report. These wells include 18 in the surficial aquifer system, 21 in the Brunswick aquifer system and equivalent sediments, 67 in the Upper Floridan aquifer, 15 in the Lower Floridan aquifer and underlying units, 10 in the Claiborne aquifer, 1 in the Gordon aquifer, 11 in the Clayton aquifer, 12 in the Cretaceous aquifer system, 2 in Paleozoic-rock aquifers, and 9 in crystalline-rock aquifers. Data from the network indicate that water levels generally declined from 2005 levels, with water levels in 99 wells below normal, 52 wells in the normal range, 12 wells above normal, and 3 wells with insufficient data for comparison of 5-year trends and period of record statistics. In addition to continuous water-level data, periodic synoptic water-level measurements were collected and used to construct potentiometric-surface maps for the Upper Floridan aquifer in Camden, Charlton, and Ware Counties, Georgia, and adjacent counties in Florida during September 2006 and 2007, in the Brunswick area during July 2006 and August 2007, and in the City of Albany-Dougherty County area during October 2006 and October 2007. In general, the configuration of the potentiometric surfaces showed little change during 2006-2007 in each of the areas. Ground-water quality in the Upper Floridan aquifer is monitored in the Albany, Savannah, and Brunswick areas and in Camden County; and water quality in the Lower Floridan aquifer is monitored in the Savannah and Brunswick areas and in Camden County. In the Albany area, nitrate concentrations generally have increased since the end of the drought during 2002. During 2006, water from two wells had nitrate as N concentrations above the U.S. Environmental Protection Agency's (USEPA) 10-milligram-per-liter (mg/L) drinking-water standard. During 2007, only one well had concentrations above the drinking-water standard. In the Savannah area, measurement of fluid conductivity and chloride concentration in water samples from discrete depths in three wells completed in the Upper Floridan aquifer and one well in the Lower Floridan aquifer were used to assess changes in water quality in the Savannah area. At Tybee Island, chloride concentrations in samples from the Lower Floridan aquifer decreased during 2006-2007 but were still above the 250-mg/L USEPA drinking-water standard. At Skidaway Island, water in the Upper Floridan aquifer is fresh, and chloride concentrations did not appreciably change during 2006-2007. However, chloride concentrations in samples collected from the Lower Floridan aquifer during 2006-2007 showed disparate changes; whereby, chloride concentration increased in the shallowest sampled interval (900 feet) and decreased slightly in a deeper sampled interval (1,070 feet). At Fort Pulaski, water samples collected from the Upper Floridan aquifer were fresh and did not appreciably changeduring 2006-2007. In the Brunswick area, maps showing the chloride concentration of water in the Upper Floridan aquifer were constructed by using data collected from 29 wells during July 2006 and from 26 wells during August 2007. Analyses indicate that concentrations remained above the USEPA drinking-water standard in an approximate 2-square-mile area. During 2006-2007, chloride concentrations increased in only three of the wells sampled and ranged from 4.0 to 20 mg/L chloride. In the Camden County area, chloride concentration during 2006-2007 was analyzed in water samples collected from eight wells, six completed i

Georgia↗
USGS2008

Well Inventory and Geophysical Logging of Selected Wells in Troup County, Georgia, 2007-2008

The U.S. Geological Survey (USGS) - in cooperation with the Troup County Board of Commissioners - conducted a well inventory to provide information to help evaluate ground-water resources for Troup County, Georgia. In addition, borehole geophysical logs were collected in selected wells to provide a better understanding of the subsurface geologic and water-bearing characteristics in specific areas of interest. This investigation provides information to help guide future ground-water development and water-management decisions for Troup County while enhancing understanding of the hydrogeology of fractured rocks in the Piedmont physiographic province. This report presents well data compiled from USGS files and from site visits to wells during November and December 2007. Data were entered into the USGS National Water Information System (NWIS) and made available on the Web at http://waterdata.usgs.gov/ga/nwis/inventory. Previous studies of ground-water resources have been conducted in the vicinity, but did not include Troup County. The ground-water resources of Heard and Coweta Counties, located north and northeast, respectively, of Troup County were part of a larger study by Cressler and others (1983) that encompassed the Greater Atlanta Region. That study evaluated the quantity and quality of ground water in the Atlanta region and described the methods that could be used for locating high-yielding wells in the Piedmont Province. The geology underlying the Atlanta area is similar to that underlying Troup County. Clarke and Peck (1990) conducted a similar investigation that included Meriwether and Coweta Counties, located to the east and northeast of Troup County.

Georgia↗
USGS2007

Ground-Water Conditions and Studies in Georgia, 2004-2005

The U.S. Geological Survey (USGS) collects ground-water data and conducts studies to monitor hydrologic conditions, better define ground-water resources, and address problems related to water supply, water use, and water quality. During 2004-2005, ground-water levels were monitored continuously in a network of 183 wells completed in major aquifers throughout the State. Because of missing data or the short period of record for a number of these wells (less than 3 years), a total of 171 wells from the network are discussed in this report. These wells include 19 in the surficial aquifer system, 20 in the Brunswick aquifer system and equivalent sediments, 69 in the Upper Floridan aquifer, 17 in the Lower Floridan aquifer and underlying units, 10 in the Claiborne aquifer, 1 in the Gordon aquifer, 10 in the Clayton aquifer, 12 in the Cretaceous aquifer system, 2 in Paleozoic-rock aquifers, and 11 in crystalline-rock aquifers. Data from the network indicate that generally water levels rose after the end of a drought (fall 2002), with water levels in 152 of the wells in the normal or above-normal range by 2005. An exception to this pattern of water-level recovery is in the Cretaceous aquifer system where water levels in 7 of the 12 wells monitored were below normal during 2005. In addition to continuous water-level data, periodic synoptic water-level measurements were collected and used to construct potentiometric-surface maps for the Upper Floridan aquifer in the Camden County-Charlton County area during September 2004 and May 2005, in the Brunswick area during June 2004 and June 2005, and in the City of Albany-Dougherty County area during October 2004 and during October 2005. In general, the configuration of the potentiometric surfaces showed little change during 2004-2005 in each of the areas. Ground-water quality in the Upper Floridan aquifer is monitored in the Albany, Savannah, and Brunswick areas, and in Camden County; and the Lower Floridan aquifer, monitored in the Savannah and Brunswick areas and in Camden County. In the Albany area, nitrate concentrations generally increased since the end of the drought during 2002. Concentrations increased in water collected from 13 of the 16 wells sampled during 2004-2005 and by November 2005, water from 2 wells had nitrate as N concentrations that were above the U.S. Environmental Protection Agency's (USEPA) 10-milligram-per-liter (mg/L) drinking-water standard. In the Savannah area, measurement of fluid conductivity and chloride concentration in water samples from discrete depths in three wells completed in the Upper Floridan aquifer and one well in the Lower Floridan aquifer were used to assess changes in water quality in the Savannah area. At Tybee Island, chloride concentrations in samples from the Lower Floridan aquifer increased during 2004-2005 and were above the 250-mg/L USEPA drinking-water standard. At Skidaway Island, water in the Upper Floridan aquifer is fresh, and chloride concentrations did not appreciably change during 2004-2005. However, chloride concentrations in samples collected from the Lower Floridan aquifer during 2004-2005 showed disparate changes; whereby, chloride concentration increased in the deepest sampled interval (1,070 feet) and decreased in a shallower sampled interval (900 feet). At Fort Pulaski, water samples collected from the Upper Floridan aquifer are fresh and did not appreciably change during 2004-2005. In the Brunswick area, maps showing the chloride concentration of water in the Upper Floridan aquifer were constructed using data collected from 41 wells during June 2004 and from 39 wells during June 2005. Analyses indicate that concentrations remained above the USEPA drinking-water standard in an approximate 2-square-mile area. During 2004-2005, chloride concentrations increased in samples from 18 wells and decreased in samples from 11 wells. In the Camden County area, chloride concentrations during 2004-2005 were analyzed in water

Georgia↗
USGS2005

Summary of hydraulic properties of the Floridan Aquifer system in coastal Georgia and adjacent parts of South Carolina and Florida

Hydraulic-property data for the Floridan aquifer system and equivalent clastic sediments in a 67-county area of coastal Georgia and adjacent parts of South Carolina and Florida were evaluated to provide data necessary for development of ground-water flow and solute-transport models. Data include transmissivity at 324 wells, storage coefficient at 115 wells, and vertical hydraulic conductivity of 72 core samples from 27 sites. Hydraulic properties of the Upper Floridan aquifer vary greatly in the study area due to the heterogeneity (and locally to anisotropy) of the aquifer and to variations in the degree of confinement provided by confining units. Prominent structural features in the areathe Southeast Georgia Embayment, the Beaufort Arch, and the Gulf Troughinfluence the thickness and hydraulic properties of the sediments comprising the Floridan aquifer system. Transmissivity of the Upper Floridan aquifer and equivalent updip units was compiled for 239 wells and ranges from 530 feet squared per day (ft2/d) at Beaufort County, South Carolina, to 600,000 ft2/d in Coffee County, Georgia. In carbonate rock settings of the lower Coastal Plain, transmissivity of the Upper Floridan aquifer generally is greater than 20,000 ft2/d, with values exceeding 100,000 ft2/d in the southeastern and southwestern parts of the study area (generally coinciding with the area of greatest aquifer thickness). Transmissivity of the Upper Floridan aquifer generally is less than 10,000 ft2/d in and near the upper Coastal Plain, where the aquifer is thin and consists largely of clastic sediments, and in the vicinity of the Gulf Trough, where the aquifer consists of low permeability rocks and sediments. Large variability in the range of transmissivity in Camden and Glynn Counties, Georgia, and Nassau County, Florida, demonstrates the anisotropic distribution of hydraulic properties that may result from fractures or solution openings in the carbonate rocks. Storage coefficient of the Upper Floridan aquifer was compiled for 106 wells and ranges from about 0.00004 at Beaufort County, South Carolina, to 0.04 in Baker County, Florida. Transmissivity of the Lower Floridan aquifer and equivalent updip clastic units was compiled for 53 wells and ranges from about 170 ft2/d in Barnwell County, South Carolina, to about 43,000 ft2/d in Camden County, Georgia. Transmissivity of the Lower Floridan aquifer is greatest where the aquifer is thickest in southeastern Georgia and northeastern Floridawhere estimates are greater than 10,000 ft2/d; at one well in southeastern Georgia transmissivity was estimated to be as high as 200,000 ft2/d. Storage-coefficient data for the Lower Floridan aquifer are limited to three estimates in Barnwell and Allendale Counties, South Carolina, and to estimates determined from six multi-aquifer tests in Duval County, Florida. In the South Carolina tests, storage coefficient ranges from 0.0003 to 0.0004; this range is indicative of a confined aquifer. The storage coefficient for the combined Upper and Lower Floridan wells in Duval County, Florida, ranges from 0.00002 to 0.02. Vertical hydraulic conductivity was compiled from core samples collected at 27 sites. For the Upper Floridan confining unit, values from 39 core samples at 17 sites range from 0.0002 to 3 feet per day (ft/d). For the Lower Floridan confining unit, values from 10 core samples at 9 sites range from about 0.000004 to 0.16 ft/d. Vertical hydraulic conductivity of the Upper Floridan aquifer was compiled from 16 core samples at five sites, mostly in the Brunswick, Georgia, area and values range from 0.00134 to 160.4 ft/d. Vertical hydraulic conductivity for the semiconfining unit separating the upper and lower water-bearing zones of the Upper Floridan at Brunswick, Georgia, compiled from 6 core samples at three sites ranges from 0.000008 to 0.000134 ft/d. The vertical hydraulic conductivity of the Lower Floridan aquifer in a core sample from a well at Brunswick, G

Florida, Georgia, South Carolina↗
USGS2005

Effects of decreased ground-water withdrawal on ground-water levels and chloride concentrations in Camden County, Georgia, and ground-water levels in Nassau County, Florida, from September 2001 to May 2003

During October 2002, the Durango Paper Company formerly Gillman Paper Company) in St. Marys, Georgia, shut down paper-mill operations; the shutdown resulted in decreased ground-water withdrawal in Camden County by 35.6 million gallons per day. The decrease in withdrawal resulted in water-level rise in wells completed in the Floridan aquifer system and the overlying surficial and Brunswick aquifer systems; many wells in the St. Marys area flowed for the first time since the mill began operations during 1941. Pumping at the mill resulted in the development of a cone of depression that coalesced with a larger adjacent cone of depression at Fernandina Beach, Florida. Since closure of the mill, the cone at St. Marys is no longer present, although the cone still exists at Fernandina Beach, Florida. Historical water-level data from the production wells at the mill indicate that the pumping water level ranged from 68 to 235 feet (ft) below North American Vertical Datum of 1988 (NAVD 88) and averaged about 114 ft when the mill was operating. Since the shutdown, it is estimated that water levels at the mill have risen about 140 ft and are now at about 30 ft above NAVD 88. The water-level rise in wells in outlying areas in Camden County was less pronounced and ranged from about 5 to 10 ft above NAVD 88. Because of the regional upward water-level trend in the Upper Floridan aquifer that started during 19992000 in most of the coastal area, combined with a steeper upward trend beginning during October 2002, it was not possible to determine if the 510 ft rise in water levels in wells away from St. Marys was due to the mill closure. In addition to water-level rise of 2226 ft in the Floridan aquifer system, water-level rises in the overlying surficial and Brunswick aquifer systems at St. Marys after the shutdown indicate upward leakage of water. Water levels had stabilized in the confined surficial and Upper and Lower Floridan aquifers by AprilMay 2003; however, the water level in the upper Brunswick aquifer was still rising as of May 2003. Chloride concentrations in the Upper Floridan aquifer in Camden County do not exceed the State and Federal drinking-water standard of 250 milligrams per liter (mg/L). With the exception of three wells located at St. Marys, all of the wells sampled during this study (from September 2002 to May 2003) had chloride concentrations ranging from 30 to 50 mg/L, which are considered within background levels for the Upper Floridan aquifer in this area. The three wellstwo at the Durango Paper Company and the other an old unused City of St. Marys wellhad chloride concentrations that ranged from 74 to 175 mg/L, which are above the background level, but were still below the 250-mg/L drinking-water standard. The source has not been determined for the elevated chloride concentration in these wells; the chloride concentration in one of the wells has decreased slightly since the paper-mill shutdown. Chloride concentrations throughout Camden County showed little change after the paper-mill shutdown.

Florida, Georgia↗
USGS2003

Ground-water conditions and studies in Georgia, 2001

The U.S. Geological Survey (USGS) collects ground-water data and conducts studies to monitor hydrologic conditions, to better define ground-water resources, and address problems related to water supply and water quality. Data collected as part of ground-water studies include geologic, geophysical, hydraulic property, water level, and water quality. A ground-water-level network has been established throughout most of the State of Georgia, and ground-water-quality networks have been established in the cities of Albany, Savannah, and Brunswick and in Camden County, Georgia. Ground-water levels are monitored continuously in a network of wells completed in major aquifers of the State. This network includes 17 wells in the surficial aquifer, 12 wells in the upper and lower Brunswick aquifers, 73 wells in the Upper Floridan aquifer, 10 wells in the Lower Floridan aquifer and underlying units, 12 wells in the Claiborne aquifer, 1 well in the Gordon aquifer, 11 wells in the Clayton aquifer, 11 wells in the Cretaceous aquifer system, 2 wells in Paleozoic-rock aquifers, and 7 wells in crystalline-rock aquifers. In this report, data from these 156 wells were evaluated to determine whether mean-annual ground-water levels were within, below, or above the normal range during 2001, based on summary statistics for the period of record. Information from these summaries indicates that water levels during 2001 were below normal in almost all aquifers monitored, largely reflecting climatic effects from drought and pumping. In addition, water-level hydrographs for selected wells indicate that water levels have declined during the past 5 years (since 1997) in almost all aquifers monitored, with water levels in some wells falling below historical lows. In addition to continuous water-level data, periodic measurements taken in 52 wells in the Camden County-Charlton County area, and 65 wells in the city of Albany-Dougherty County area were used to construct potentiometric-surface maps for the Upper Floridan aquifer. Ground-water quality in the Upper Floridan aquifer is monitored in the cities of Albany, Savannah, and Brunswick and in Camden County; and monitored in the Lower Floridan aquifer in the Savannah and Brunswick areas. In the Albany area since 1998, nitrate concentrations in the Upper Floridan aquifer have increased in 4 of the 11 wells monitored, and in 1 well, concentrations were above the U.S. Environmental Protection Agency's (USEPA) 10 milligrams per liter (mg/L) drinking-water standard. In the Savannah area, chloride concentration in water from four wells in the Upper Floridan aquifer showed no appreciable change during 2001, remaining within the USEPA 250 mg/L drinking-water standard; in seven wells completed in the Lower Floridan aquifer and in underlying zones, the chloride concentration remained above the drinking-water standard, with one well showing an increase over previous years. In the Brunswick area, water samples from 66 wells completed in the Upper or Lower Floridan aquifers were collected during June 2001 and analyzed for chloride. A map showing chloride concentrations in the Upper Floridan aquifer during June 2001 indicates that concentrations remained above USEPA drinking-water standards across a 2-square-mile area. In the north Brunswick area, chloride concentrations in the Upper Floridan aquifer continued to increase, whereas in the south Brunswick area, concentrations continued to decrease. In the Camden County area, chloride concentrations in six wells completed in the Upper Floridan aquifer remained within drinking-water standards. With the exception of one well, concentrations remained the same and were below 40 mg/L. In one well, concentrations showed a sharp decline during 2001, but remained above 130 mg/L. Ongoing studies during 2001 include evaluation of agricultural chemicals in shallow ground water in southwestern Georgia; evaluation of saltwater intrusion and water-level and water-quality m

Georgia↗
USGS2002

Water Resources Data, Georgia, 2002--Volume 2: Continuous ground-water-level data, and periodic surface-water- and ground-water-quality data, Calendar Year 2002

Water resources data for the 2002 water year for Georgia consists of records of stage, discharge, and water quality of streams; and the stage and contents of lakes and reservoirs published in two volumes in a digital format on a CD-ROM. Volume one of this report contains water resources data for Georgia collected during water year 2002, including: discharge records of 154 gaging stations; stage for 165 gaging stations; precipitation for 105 gaging stations; information for 20 lakes and reservoirs; continuous water-quality records for 27 stations; the annual peak stage and annual peak discharge for 72 crest-stage partial-record stations; and miscellaneous streamflow measurements at 50 stations, and miscellaneous water-quality data recorded by the NAWQA program in Georgia. Volume two of this report contains water resources data for Georgia collected during calendar year 2002, including continuous water-level records of 155 ground-water wells and periodic records at 132 water-quality stations. These data represent that part of the National Water Data System collected by the U.S. Geological Survey and cooperating State and Federal agencies in Georgia.

Georgia↗
USGS2000

Estuarine water-quality and sediment data, and surface-water and ground-water-quality data, Naval Submarine Base Kings Bay, Camden County, Georgia, January 1999

In January 1999, the U.S. Geological Survey collected estuarine-water, estuarine-sediment, surface-water, and ground-water quality samples in the vicinity of Naval Submarine Base Kings Bay, Camden County, Georgia. Data from these samples are used by the U.S. Navy to monitor the impact of submarine base activities on local water resources. Estuarine water and sediment data were collected from five sites on the Crooked River, Kings Bay, and Cumberland Sound. Surface-water data were collected from seven streams that discharge from Naval Submarine Base, Kings Bay. Ground-water data were collected from six ground-water monitoring wells completed in the water-table zone of the surficial aquifer at Naval Submarine Base Kings Bay. Samples were analyzed for nutrients, total and dissolved trace metals, total and dissolved organic carbon, oil and grease, total organic halogens, biological and chemical oxygen demand, and total and fecal coliform. Trace metals in ground and surface waters did not exceed U.S. Environmental Protection Agency Drinking Water Standards; and trace metals in surface water also did not exceed U.S. Environmental Protection Agency Surface Water Standards. These trace metals included arsenic, barium, cadmium, chromium, copper, lead, mercury, selenium, silver, tin, and zinc. Barium was detected in relatively high concentrations in ground water (concentrations ranged from 18 to 264 micrograms per liter). Two estuarine water samples exceeded the Georgia Department of Natural Resources, Environmental Protection Division standards for copper (concentrations of 6.2 and 3.0 micrograms per liter).

Georgia↗
USGS1999

Hydrogeology of the surficial aquifer in the vicinity of a former landfill, Naval Submarine Base Kings Bay, Camden County, Georgia

Neogene and Quaternary sediments constitute the surficial aquifer beneath the study area; in descending order from youngest to oldest these include-the Quaternary undifferentiated surficial sand and Satilla Formation; the Pliocene(?) Cypresshead Formation; and the middle Miocene Coosawhatchie Formation. Beneath the surficial aquifer, the upper Brunswick aquifer consists of part of the lower Miocene Marks Head Formation. The surficial aquifer is divided into three water-bearing zones on the basis of lithologic and geophysical properties of sediments, hydraulic-head differences between zones, and differences in ground-water chemistry. The shallowest zone-the water-table zone-consists of medium to fine sand and clayey sand and is present from land surface to a depth of about 77 feet. Below the water-table zone, the confined upper water-bearing zone consists of medium to very coarse sand and is present from a depth of about 110 to 132 feet. Beneath the upper water-bearing zone, the confined lower water-bearing zone consists of coarse sand and very fine gravel and is present from a depth of about 195 to 237 feet. Hydraulic separation is suggested by differences in water chemistry between the water-table zone and upper water-bearing zone. The sodium chloride type water in the water-table zone differs from the calcium bicarbonate type water in the upper water-bearing zone. Hydraulic separation also is indicated by hydraulic head differences of more than 6.5 feet between the water-table zone and the upper water-bearing zone. Continuous and synoptic water-level measurements in the water-table zone, from October 1995 to April 1997, indicate the presence of a water-table high beneath and adjacent to the former landfill-the surface of which varies about 5 feet with time because of recharge and discharge. Water-level data from clustered wells also suggest that restriction of vertical ground-water flow begins to occur at an altitude of about 5 to 10 feet below sea level (35 to 40 feet below land surface) in the water-table zone because of the increasing clay content of the Cypresshead Formation.

Georgia↗