USGS ScienceSearch

Geology topics

R. W. Coble

Publications and source records attributed to R. W. Coble.

11 recordsLinked to original sources

Hydrogeology and simulation of ground-water flow at U.S. Marine Corps Air Station, Cherry Point, North Carolina, 1987-90

Geophysical and lithologic well-log data from 30 wells and chloride data, and water-level data from oil-test wells, supply wells, and observation wells were evaluated to define the hydrogeologic framework at the U.S. Marine Corps Air Station, Cherry Point, North Carolina. Elements of the hydrogeologic framework important to this study include six aquifers and their respective confining units. In descending order, these aquifers are the surficial, Yorktown, Pungo River, upper and lower Castle Hayne, and Beaufort. The upper and lower Castle Hayne and Beaufort aquifers and related confining units are relatively continuous throughout the study area. The surficial, Yorktown, Pungo River, and upper and lower Castle Hayne aquifers contain freshwater. The upper and lower Castle Hayne aquifers serve as the Air Station?s principal supply of freshwater. However, the lower Castle Hayne aquifer contains brackish water near its base and there is potential for upward movement of this water to supply wells completed in this aquifer. The potential for brackish-water encroachment is greatest if wells are screened too deep in the lower Castle Hayne aquifer or if pumping rates are too high. Lateral movement of brackish water into aquifers incised by estuarine streams is also possible if ground-water flow gradients toward these bodies are reversed by pumping. The potential for the reversed movement of water from the surficial aquifer downward to the water-supply aquifer is greatest in areas where clay confining units are missing. These missing clay units could indicate the presence of a paleochannel of the Neuse River. A quasi three-dimensional finite-difference ground-water flow model was constructed and calibrated to simulate conditions at and in the vicinity of the Air Station for the period of 1987-90. Comparisons of 94 observed and computed heads were made, and the average difference between them is -0.2 feet with a root mean square error of 5.7 feet. An analysis was made to evaluate the sensitivity of the model to the absence of the Yorktown and Pungo River confining units in a 1-square-mile area in the southern part of the Air Station. This analysis resulted in a maximum simulated head increase of 2 feet in one 0.11-square-mile model cell in the Pungo River aquifer.

North Carolina

Hydrogeologic framework of the North Carolina Coastal Plain aquifer system

The hydrogeologic framework of the North Carolina Coastal Plain aquifer system consists of ten aquifers separated by nine confining units. From top to bottom the aquifers are: the surficial aquifer, Yorktown aquifer, Pungo River aquifer, Castle Hayne aquifer, Beaufort aquifer, Peedee aquifer, Black Creek aquifer, upper Cape Fear aquifer, lower Cape Fear aquifer, and the Lower Cretaceous aquifer. The uppermost aquifer (the surficial aquifer in most places) is a water-table aquifer and the bottom of the system is underlain by crystalline bedrock. The sedimentary deposits forming the aquifers are of Holocene to Cretaceous age and are composed mostly of sand with lesser amounts of gravel and limestone. Confining units between aquifers are composed primarily of clay and silt. The thickness of the aquifers ranges from zero along the Fall Line to more than 10,000 feet at Cape Hatteras. Prominent structural features are the increasing easterly homoclinal dip of the sediments and the Cape Fear arch, the axis of which trends in a southeast direction. The stratigraphic continuity is determined from correlations of 161 geophysical logs along with data from drillers' and geologists' logs. Aquifers were defined by means of these logs plus water-level and water-quality data and evidence of the continuity of pumping effects. Eighteen hydrogeologic sections depict the correlation of these aquifers throughout the Coastal Plain.

North Carolina

Hydrologic environments and water-quality characteristics at four landfills in Mecklenburg County, North Carolina, 1980-86

A water-quality study was conducted during 1980-86 at four landfills in Mecklenburg County, North Carolina. Each landfill has a three-layered hydrogeologic system typical of the Piedmont, consisting of (1) the regolith; (2) a transition zone; and (3) unweathered, fractured crystalline bedrock. As much as 7.6 inches per year of rainfall enters the ground-water system and has the potential to generate leachate within landfill cells. Ground water and leachate discharge to tributaries within the landfill sites or to streams adjacent to them. Water-quality samples were collected from 53 monitoring wells and 20 surface-water sites. Samples were analyzed for selected physical and biological characteristics, major inorganic ions, nutrients, trace elements, and organic compounds. Selected indicators of water quality, including specific conductance; hardness; and concentrations of chloride, manganese, dissolved solids, total organic carbon, and specific organic compounds were analyzed to determine the effects of each landfill on ground- and surface-water quality. Increases in concentrations of inorganic constituents above background levels were detected in ground water downgradient of the landfills. The increases were generally greatest in samples from wells in close proximity to the older landfill cells. In general, the increases in concentrations in downgradient wells were greater for calcium, magnesium, and chloride than for other major ions. Manganese exhibited the largest relative increase in concentration between upgradient and downgradient wells of any constituent, and manganese concentration data were effective in defining areas with extensive anaerobic biological activity. Differences between upgradient and downgradient concentrations of total organic carbon and specific organic compounds generally were not as apparent. The most frequently identified organic contaminants were the herbicides 2,4-D and 2,4,5-T. Chlorofluoromethanes were identified in three of four ground-water samples analyzed for volatile organic compounds. Landfills affected the water quality of several smaller streams but did not noticeably affect larger ones. Apparent effects on water quality were greatest at the oldest landfill, located on Statesville Road, where waste is in cells that are partly below the water table.

North Carolina

Regional study of the Castle Hayne Aquifer of eastern North Carolina

The Castle Hayne aquifer is an eastward sloping and thickening wedge of limestone and sandstone, located in a 12,500 sq mi area in the eastern part of North Carolina. The Castle Hayne aquifer is the major source of freshwater for much of coastal North Carolina where the aquifers underlying the Castle Hayne contain saltwater. A regional study of the Castle Hayne aquifer was conducted to provide definitive information on the declines in water levels and of saltwater intrusion in the area. A series of geohydrologic maps produced from the study, show the altitude of the top of the aquifer, location of saltwater in the aquifer, aquifer thickness, aquifer transmissivity, and confining-unit thickness. The history of groundwater pumpage can be compared with historical water levels in the aquifer. These geohydrologic, pumpage, and water level data can be used to develop estimates of aquifer and confining-unit hydraulic coefficients and to develop a groundwater flow model for the Castle Hayne aquifer. The model will increase the understanding of the groundwater flow system and also can be used to assess various groundwater development scenarios for the entire Castle Hayne aquifer.

North Carolina

A technique for estimating heights reached by the 100-year flood on unregulated, nontidal streams in North Carolina

A method for estimating the heights reached by floods having a recurrence interval of 100 years is defined for nontidal streams with unregulated flows in North Carolina. The flood heights are the vertical distance between stream stage at median discharge (50 percent duration) and the 100-year flood stage and are defined for streams draining areas between 1 and 10,000 square miles for each of the three physiographic areas in the State. An illustrated example of how the method can be used in conjunction with topographic maps to estimate flood heights and delineate inundated areas by interpolation is given.

North Carolina

The water resources of southeast Iowa

Water is vital in the lives of the people and the economy of any area. In order to utilize this natural resource in the most efficient and beneficial manner, a basic knowledge and understanding of its sources and the occurrence and potential of each source must be gained. To provide this knowledge, the Water Resources Division of the U.S. Geological Survey in cooperation with the Iowa Geological Survey compiled this atlas describing the water resources available for development in an 11-county area in southeast Iowa. The report contains information on the availability, quality, and utilization of water from all known sources and the future demands upon the water resources in southeast Iowa. The information is presented to aid water users and other persons searching for and evaluating sources of water in a particular place, and planners and water managers who must consider water resources on a regional basis.

Iowa

Hydrologic effects of the earthquake of March 27, 1964, outside Alaska, with sections on Hydroseismograms from the Nunn-Bush Shoe Co. well, Wisconsin, and Alaska earthquake effects on ground water in Iowa: Chapter C in The Alaska earthquakes, March 27, 1964: effects on hydrologic regimen

The Alaska earthquake of March 27, 1964, had widespread hydrologic effects throughout practically all of the United States. More than 1,450 water-level recorders, scattered throughout all the 50 States except Connecticut, Delaware, and Rhode Island, registered the earthquake. Half of the water-level records were obtained from ground-water observation wells and half at surface-water gaging stations. The earthquake is also known to have registered on water-level recorders on wells in Canada, England, Denmark, Belgium, Egypt, Israel, Libya, Philippine Islands, South-West Africa, South Africa, and Northern Territory of Australia. The Alaska earthquake is the first for which widespread surface-water effects are known. The effects were recorded at stations on flowing streams, rivers, reservoirs, lakes, and ponds. The 755 surface-water stations recording effects are spread through 38 States, but are most numerous in the south-central and southeastern States, especially in Florida and Louisiana. Most of the fluctuations recorded can be referred to more precisely as seismic seiches; however, a few stations recorded the quake as a minor change in stage. The largest recorded seiche outside Alaska was 1.83 feet on a reservoir in Michigan. The next largest was 1.45 feet on Lake Ouachita in Arkansas. The largest fluctuation in a well was 23 feet registered by a pressure recorder near Belle Fourche, S. Dak. Fluctuations of more than 10 feet were reported from wells in Alabama, Florida, Georgia, Illinois, Missouri, and Pennsylvania. A 3.40-foot fluctuation was recorded in a well in Puerto Rico. The Alaska earthquake was registered by about seven times as many water-level recorders as recorded the Hebgen Lake, Mont., earthquake of August 19, 1959.

Professional Paper

The Alaska earthquake, March 27, 1964: effects on hydrologic regimen

This is the fourth in a series of six reports that the U.S. Geological Survey published on the results of a comprehensive geologic study that began, as a reconnaissance survey, within 24 hours after the March 27, 1964, Magnitude 9.2 Great Alaska Earthquake and extended, as detailed investigations, through several field seasons. The 1964 Great Alaska earthquake was the largest earthquake in the U.S. since 1700. Professional Paper 544, in 5 parts, describes the effects on hydrologic regimen.

Alaska

The water story in Central Iowa

"The general welfare of the people of the state of Iowa requires that the water resources of the state be put to beneficial use to the fullest extent of which they are capable." This can be achieved only by a knowledge and understanding of the water resources - their use, their source, their quality, their availability, and the demands place upon them. To provide such knowledge and understanding, the United States Geological Survey in cooperation with the Iowa Geological Survey produced this report on the utilization and availability of water in central Iowa. This report contains information on the past, present, and future statues of central Iowa;s water; information that can be used by the regional developer, the resource planner and manager, and other informed persons whose opinions and sound judgements are required in making decisions toward efficient development, management, use, and conservation of water. It gives an over-all view of the area's water resources and is aimed at guiding the people of central Iowa to the best available sources of water.

Iowa