Geology topics

G. E. Hileman

Publications and source records attributed to G. E. Hileman.

5 recordsLinked to original sources

USGS1996

Hydrogeologic terranes and potential yield of water to wells in the Valley and Ridge Physiographic Province in Maryland, New Jersey, and Pennsylvania

The hydrogeologic framework of the Valley and Ridge Physiographic Province in Maryland, New Jersey, and Pennsylvania was analyzed by the U.S. Geological Survey as part of the Appalachian Valleys— Piedmont Regional Aquifer-System Analysis project. Local differences in lithology, structure, and weathering result in large variation in the water-yielding properties of the rock that underlies the area, Selected rock types, however, can account for a substantial part of this variation because of the unique way in which these rock types deform and weather to produce secondary openings. On the basis of the relations among rock type and water-yielding openings and properties, the regolith and consolidated rock were classified and mapped as five hydrogeologic terranes—alluvium, dolomite. limestone, argillaceous carbonate rock, and siliciclastic rock. Specific-capacity data for homogeneous data sets, which consist of all wells that have the same characteristics in regard to casing diameter, primary use of the water, and topographic setting, revealed significant differences in water-yielding properties among the five hydrogeologic terranes. According to results of Tukey tests at a probability (alpha level) of 0.10, eight out of ten pairs of hydrogeologic terranes had significantly different median specific-capacity values. Estimates of potential yields to public- and industrial-supply wells were calculated from specific-capacity data for most-productive wells—wells with casing diameter of 7 inches or more, used primarily for public or industrial supply, and in a valley—using median drawdowns for each hydrogeologic terrane, Estimated interquartile ranges in potential yields to most-productive wells in the hydrogeologic terranes, in gallons per minute, were 170 to 600 in alluvium; 280 to 1,700 in dolomite, 80 to 520 in limestone; fish to 550 in argillaceous carbonate rock; and 60 to 24s) in siliciclustic rock.

Maryland, New Jersey, Pennsylvania↗

USGS1996

Hydrogeologic terranes and potential yield of water to wells in the Valley and Ridge Physiographic Province in the eastern and southeastern United States

The Valley and Ridge Physiographic Province is underlain by deformed sedimentary rock of Paleozoic age including dolomite, limestone, shale, and sandstone. Regolith (soil, sediment, and weathered rock) covers the Paleozoic rock throughout most of the province. Local differences in lithology, structure, and weathering can result in four orders of magnitude variation in the water-yielding properties of the geologic units that underlie the area. Selected rock types, however, can account for a substantial part of this variation because of the unique way in which these dense, consolidated sedimentary rock types deform and weather to produce secondary openings. On the basis of relations among rock type, water-yielding openings, and water-yielding properties (as indicated by specific capacity), the regolith and consolidated rock were classified and mapped as five hydrogeologic terranes alluvium, dolomite, limestone, argillaceous carbonate rock, and siliciclastic rock. The hydrogeologic terranes are named after the predominant outcrop lithology within them. The western toe of the Blue Ridge Mountains is classified as a subdivision of the dolomite hydrogeologic terrane that may produce yields of water in excess of 1,000 gallons per minute (gal/min) to public and industrial supply wells. Specific-capacity data for homogeneous data sets, which consist of all wells that have the same characteristics in regard to casing diameter, primary use of the water, and topographic setting, revealed significant differences in water-yielding properties among the five hydrogeologic terranes. According to results of Tukey statistical tests at a probability (alpha level) of 0.05, 8 out of 10 pairs of hydrogeologic terranes (for example, alluvium/limestone) had significantly different median specific-capacity values. The median value for public and industrial supply wells in the western toe is three times greater than the value for comparable wells in the dolomite hydrogeologic terrane elsewhere. Estimates of potential yields to public and industrial supply wells were calculated from specific-capacity data for most-productive wells, which have casing diameter of 7 in. or more, discharge water primarily for public or industrial supply, and are in a valley. Median constant drawdowns, calculated from reported drawdowns, were assumed to be between 10 and 90 ft for wells completed in each of the five hydrogeologic terranes, and well-entrance losses were assumed to be negligible. Estimated interquartile ranges in potential yields to 412 mostproductive wells in the five hydrogeologic terranes were 170 to 580 gal/min, alluvium; 210 to 1,400 gal/min, dolomite; 80 to 720 gal/min, limestone; 65 to 850 gal/min, argillaceous carbonate rock; and 70 to 280 gal/min, siliciclastic rock.

Alabama, Georgia, Maryland, New Jersey, Pennsylvan↗

USGS1993

Geochemistry of and radioactivity in ground water of the Highland Rim and Central Basin aquifer systems, Hickman and Maury counties, Tennessee

A reconnaissance of the geochemistry of and radioactivity in ground water from the Highland Rim and Central Basin aquifer systems in Hickman and Maury Counties, Tennessee, was conducted in 1989. Water in both aquifer systems typically is of the calcium or calcium magnesium bicarbonate type, but concentrations of calcium, magnesium, sodium, potassium, chloride, and sulfate are greater in water of the Central Basin system; differences in the concentrations are statistically significant. Dissolution of calcite, magnesium-calcite, dolomite, and gypsum are the primary geochemical processes controlling ground-water chemistry in both aquifer systems. Saturation-state calculations using the computer code WATEQF indicated that ground water from the Central Basin system is more saturated with respect to calcite, dolomite, and gypsum than water from the Highland Rim system. Geochemical environments within each aquifer system are somewhat different with respect to dissolution of magnesium-bearing minerals. Water samples from the Highland Rim system had a fairly constant calcium to magnesium molar ratio, implying congruent dissolution of magnesium-bearing minerals, whereas water samples from the Central Basin system had highly variable ratios, implying either incongruent dissolution or heterogeneity in soluble constituents of the aquifer matrix. Concentrations of radionuclides in water were low and not greatly different between aquifer systems. Median gross alpha activities were 0.54 picocuries per liter in water from each system; median gross beta activities were 1.1 and 2.3 picocuries per liter in water from the Highland Rim and Central Basin systems, respectively. Radon-222 concentrations were 559 and 422 picocuries per liter, respectively. Concentrations of gross alpha and radium in all samples were substantially less than Tennessee’s maximum permissible levels for community water-supply systems. The data indicated no relations between concentrations of dissolved radionuclides (uranium, radium-226, radium-228, radon-222, gross alpha, and gross beta) and any key indicators of water chemistry, except in water from the Highland Rim system, in which radon-222 was moderately related to pH and weakly related to dissolved magnesium. The only relation among radiochemical constituents indicated by the data was between radium-226 and gross alpha activity; this relation was indicated for water from both aquifer systems.

Tennessee↗

USGS1992

Potential effects of dredging the South Fork Obion River on ground-water levels near Sidonia, Weakley County, Tennessee

The U.S. Army Corps of Engineers has proposed dredging an approximate 7-mile reach of the South Fork Obion River near Sidonia, Tennessee. This dredging will have an effect on ground-water levels in a wetland area near the river. The river cuts into a sandy aquifer that is confined by an overlying clay layer. Ground water in the confined aquifer flows from a ridge on the north side of the study area toward the river. Estimates of aquifer transmissivity range from 3,300 to 18,800 feet squared per day. Assuming a 3-foot decline in stream stage due to dredging, the maximum decline in ground-water levels would be about 2.4 feet at low flow. Ground-water levels in the aquifer would decline by at least 2 feet at a distance of 0.5 mile from the river within 60 days after the change in stream stage, regardless of the assumed transmissivity value. Water-level declines in the upper clay layer probably would be much smaller. The time required for a specified change in ground-water level is dependent on the aquifer properties and distance from the river.

Tennessee↗

USGS1990

Water-quality, well-construction, and ground-water level data for an investigation of radionuclides in ground water, Hickman and Maury counties, Tennessee

Water- quality, well-construction, and ground-water level data were collected for an investigation of radionuclides in ground water in Maury and Hickman Counties, Tennessee. Seventeen wells and 3 springs were sampled in Hickman County, and 20 wells were sampled in Maury County. Data are presented in tables. Maps of each county show the Location of the data-collection sites. Samples from each site were analyzed for radionuclides, common and trace inorganic ions, indicators of redox conditions, selected nutrients, total organic carbon, and selected physical characteristics. Well-construction data were obtained to help determine the source of the water. Where possible, ground-water Level measurements were made for each well sampled. Samples were collected from May 1989 through mid-August 1989.

Tennessee↗