USGS Science⌕ Search

Geology topics

G. K. Speiran

Publications and source records attributed to G. K. Speiran.

11 recordsLinked to original sources
USGS2006

Ground-water flow in the Coastal Plain aquifers of South Carolina

The characteristics of the Coastal Plain aquifers of South Carolina are being studied as a part of the Regional Aquifer System Analysis program of the United States Geological Survey. Potentiometric maps were constructed for the Middendorf aquifer of Cretaceous age and for the Floridan aquifer system and its sand facies equivalent, Tertiary sand aquifer, prior to development. Also constructed was a potentiometric decline map for the period prior to development to November 1982 for the Middendorf aquifer. These maps are used to describe the ground-water flow system. The Coastal Plain aquifers are recharged primarily by precipitation in their outcrop areas. Ground water flows from these areas of recharge, through the aquifers, and discharges to upper Coastal Plain rivers, overlying aquifers as upward leakage, and wells. Ground-water flow in the Floridan aquifer system and the Tertiary sand aquifer prior to development is generally perpendicular to the coast. Predevelopment flow in the Cretaceous aquifers, however, turns northeastward as it approaches the coast, almost paralleling the coast. The change in flow direction is caused by less effective intervening confining units, the aquifers being closer to the land surface, and the rivers at lower altitudes farther upstream in the vicinity of the North Carolina/South Carolina State line. Water-level declines in the Cretaceous aquifers have occurred throughout much of the eastern part of the Coastal Plain of South Carolina due to pumpage in the Myrtle Beach and Florence areas. Large areally extensive water-level declines have also occurred in the Floridan aquifer system in South Carolina due to pumpage in the Savannah, Georgia area.

South Carolina↗
USGS1993

Estimating net drawdown resulting from episodic withdrawals at six well fields in the coastal plain physiographic province of Virginia

The groundwater-flow system of the Virginia Coastal Plain consists of areally extensive and interconnected aquifers. Large, regionally coalescing cones of depression that are caused by large withdrawals of water are found in these aquifers. Local groundwater systems are affected by regional pumping, because of the interactions within the system of aquifers. Accordingly, these local systems are affected by regional groundwater flow and by spatial and temporal differences in withdrawals by various users. A geographic- information system was used to refine a regional groundwater-flow model around selected withdrawal centers. A method was developed in which drawdown maps that were simulated by the regional groundwater-flow model and the principle of superposition could be used to estimate drawdown at local sites. The method was applied to create drawdown maps in the Brightseat/Upper Potomac Aquifer for periods of 3, 6, 9, and 12 months for Chesapeake, Newport News, Norfolk, Portsmouth, Suffolk, and Virginia Beach, Virginia. Withdrawal rates were supplied by the individual localities and remained constant for each simulation period. This provides an efficient method by which the individual local groundwater users can determine the amount of drawdown produced by their wells in a groundwater system that is a water source for multiple users and that is affected by regional-flow systems.

Water-Resources Investigations Report↗
USGS1986

Shallow ground-water resources in the Grand Strand of South Carolina

The shallow aquifers that underlie the Grand Strand of South Carolina average approximately 60 to 400 ft thick and have variable productivity with some wells producing little water and others producing several hundred gal/min. These aquifers are separated from the underlying Black Creek aquifer by a 200 ft to 300 ft thick clay confining unit. The shallow aquifers are recharged by local rainfall and discharge primarily into the Atlantic Ocean, the Intracoastal Waterway, and other surface waters. In the North Myrtle Beach area a vertical difference in potentiometric levels of < 1 ft was observed within the shallow aquifers in 1983. However, the difference in potentiometric levels between the shallow aquifers and the Black Creek aquifer was probably from 25 ft to > 50 ft. The quality of groundwater is also variable. Calcium and bicarbonate are generally the predominant ions in solution as a result of the dissolution of calcite in the aquifer sediments. Concentrations of chloride may be high in the vicinity of the salty surface waters. Concentrations of iron range from 5 to 35,000 micrograms/L, but generally < 2,000 micrograms/L. (Author 's abstract)

South Carolina↗
USGS1985

Selected hydrologic data from a wastewater spray disposal site on Hilton Head Island, South Carolina

This study presents data collected during a study of the effects on the water table aquifer from wastewater application at rates of up to 5 inches per week on a wastewater spray disposal site on Hilton Head Island, South Carolina. The study was conducted from April 1982 through December 1983. The disposal site covers approximately 14 acres. Water level and water quality data from organic, inorganic, and nutrient analyses from the water table aquifer to a depth of 30 ft and similar water quality data from the wastewater treatment plant are included. (USGS)

South Carolina↗
USGS1985

Effects of high-rate wastewater spray disposal on the water-table aquifer, Hilton Head Island, South Carolina

A study by the U.S. Geological Survey from April 1982 through December 1983 evaluated the effects of high-rate disposal of treated wastewater on the water table aquifer, Hilton Head Island, South Carolina. Flooding of topographically low areas resulted from the application of 10.8 inches of wastewater in 10 days in January 1983. The water table remained 2-1/2 to 5-1/2 feet below land surface when wastewater was applied at rates of 5 inches per week in August and December 1983. (USGS)

Water-Resources Investigations Report↗
USGS1985

Potential impacts of discharging tertiary-treated wastewater into Port Royal Sound, South Carolina

An assessment of physical characteristics of Port Royal Sound was combined with the results of a dye tracer study and with data collected from a previous environmental study to describe the impact on the water quality from discharging tertiary treated wastewater into the sound. Calculated velocities for the time of maximum velocity in the tidal cycle ranged from 2.32 ft/sec near the bottom to 4.65 ft/sec near the surface of the sound in a cross section in the vicinity of a proposed wastewater outfall. Vertical velocity distributions calculated for the time of maximum velocity were similar at all stations at which velocities were measured except the station in shallow water near the shore. A recent bathymetric chart of the vicinity of the proposed outfall indicates that a bar extends farther along the northern shore of Hilton Head Island than indicated on earlier nautical charts of Port Royal Sound. Continued extension of this bar could alter the impact on water quality from discharge of treated wastewater into the sound. Further study may be needed to monitor changes in the bar if the outfall is located between the bar and Hilton Head Island. Conservative calculations based on the results of the dye tracer study indicate that the discharge of 10.9 million gallons/day of wastewater having concentrations of biochemical oxygen demand and suspended solids of 15 mg/L will result in a maximum cumulative increase in concentrations of biochemical oxygen demand of < 0.01 mg/L and no increase in concentrations of suspended solids at high slack tide in the part of Port Royal Sound most affected by the proposed wastewater discharge. (Author 's abstract)

South Carolina↗
USGS1983

Impact of discharges from point and nonpoint sources on water quality of the upper Reedy River near Greenville, South Carolina

Impacts of discharge from nonpoint sources in the urban area of Greenville, South Carolina and from the point source, the Mauldin Road Wastewater Treatment Plant, on water quality of the Reedy River were studied from October 1979 through September 1980. Streamflow and water-quality data were collected before and during two storms. The pH and concentrations of organic nitrogen, ammonium, nitrate plus nitrate, ultimate carbonaceous biochemical oxygen demand, dissolved oxygen, and orthophosphate were determined. Streamflow and concentrations of dissolved oxygen were measured continuously at three stations from May through September 1980. Discharge from the point source resulted in average daily concentrations of dissolved oxygen less than 5 milligrams per liter in the Reedy River on 34 days during low streamflow in the summer of 1980. During periods of high streamflow that resulted from the two storms. Dissolved oxygen remained at about 5 milligrams per liter in the Reedy River because increased dilution of loads of oxygen-demanding materials reduced the impacts of these loads on the quality of the Reedy River. (USGS)

South Carolina↗