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H.E. Gill

Publications and source records attributed to H.E. Gill.

6 recordsLinked to original sources
USGS2006

Tracing the continuity of pleistocene aquifers in northern New Jersey by seismic methods

Seismic refraction measurements were used to draw a new bedrock contour map in Morris County, New Jersey , where the major ground‐water supplies are found in Quaternary sand and gravel deposits filling pre‐ Pleistocene channels. Aquifer performance tests aided in tracing the continuity of the Quaternary aquifers in these channels. In one case, the lack of continuity between two wells substantiated the seismic prediction that two separate channels were involved. The success of the seismic exploration emphasizes the value of using such methods , so that test drilling can be devoted to exploring the more favorable areas for production wells.

New Jersey↗
USGS1987

Hydrogeology, chemical quality, and availability of ground water in the Upper Floridan aquifer, Albany area, Georgia

Large withdrawals of groundwater in the 1500 sq mi Albany area of southwestern Georgia have lowered water levels in deep aquifers as much as 140 ft. This study was conducted to evaluate the development potential of the shallow Upper Floridan aquifer as an alternate source of groundwater, especially for public supply. The Upper Floridan stores and transmits large quantities of water, mainly in a zone of high permeability in the lower part of the aquifer. The transmissivity of the aquifer ranges from < 10,000 sq ft/day northwest of Albany, to as much as 150 ,000 sq ft/day south and southeast of Albany. Twenty-eight years of agricultural and industrial pumping has not produced a long-term decline of the water level in the Upper Floridan; the aquifer system remains at equilibrium. The Upper Floridan yields hard, calcium bicarbonate-type water but concentrations do not exceed State drinking water standards. In most of the study area , contaminants applied to or spilled on the land surface eventually can be expected to percolate through the overburden and reach the aquifer. Thus, it is important that wells be sited away from areas that have been used for the storage and disposal of potential contaminants and, probably to a lesser extent, the application of agricultural chemicals. In the area of greatest development potential east of the Flint River, wells may penetrate major groundwater conduits. By limiting drawdown during well development and during production, the likelihood of causing sinkholes to form can be minimized. Closed depressions, or sinks, throughout the Dougherty Plain probably are unsuitable as well sites, because (1) they are subject to flooding, (2) they collect water from upgradient areas and could concentrate potential contaminants, (3) water probably percolates through their bottoms and could transport contaminants into the aquifer, and (4) the depressions may overlie limestone cavities filled with sand or clay that could interfere with well yield, development, and production. (Author 's abstract)

Georgia↗
USGS1976

Geology and ground-water resources of Camden County, New Jersey

The major fresh water aquifers in Camden County, N. J., are in the unconsolidated sediments of Cretaceous and Tertiary age. The major aquifers are the sand and gravel units in the Potomac Group and the Raritan and Magothy Formations, the Cohansey Sand, the Wenonah Formation-Mount Laurel Sand, and the Englishtown Formation. The average ground-water use for Camden County was 68 million gallons per day for 1966. All of the major artesian aquifers have had potentiometric head declines due to ground-water withdrawals. The largest water-level decline occurred in the aquifer system in the Potomac Group and the Raritan and Magothy Formations. At Haddon Heights the potentiometric head declined over 110 feet from 1900 to 1968. In the aquifer in the Wenonah Formation-Mount Laurel Sand the potentiometric head declined 43 feet in about 60 years. The quality of ground water is generally good. In the southeastern portion of the county chloride concentrations in excess of 250 mg/liter occur in the Potomac-Raritan-Magothy aquifer system. The high chloride water has remained in the aquifer system from the time of deposition or has re-entered the system from the ocean after the changes in sea level. The greatest potential of future ground-water development is from the Cohansey Sand which is under water table conditions. It also may have the greatest possibility of local ground-water contamination. (Woodard-USGS)

Water-Resources Investigations Report↗
USGS1969

A ground-water reconnaissance of the Republic of Ghana, with a description of geohydrologic provinces

This report gives a general summary of the availability and use of ground water and describes the occurrence of ground water in five major geohydrologic provinces lying in the eight administrative regions of Ghana. The identification and delineation of the geohydrologic provinces are based on their distinctive characteristics with respect to the occurrence and availability of ground water. The Precambrian province occupies the southern, western, and northern parts of Ghana and is underlain largely by intrusive crystalline and metasedimentary rocks. The Voltaian province includes that part of the Voltaian sedimentary basin in central Ghana and is underlain chiefly by consolidated sandstone, mudstone, and shale. Narrow discontinuous bands of consolidated Devonian and Jurassic sedimentary rocks near the coast constitute the Coastal Block Fault province. The Coastal Plain province includes semiconsolidated to unconsolidated sediments of Cretaceous to Holocene age that underlie coastal plain areas in southwestern and southeastern Ghana. The Alluvial province includes the Quaternary alluvial deposits in the principal river valleys and on the delta of the Volta River. Because of the widespread distribution of crystalline and consolidated sedimentary rocks of low permeability in the Precambrian, Voltaian, and Coastal Block Fault provinces, it is difficult to develop large or event adequate groundwater supplies in much of Ghana. On the other hand, small (1 to 50 gallons per minute) supplies of water of usable quality are available from carefully sited boreholes in most parts of the country. Also, moderate (50 to 200 gpm) supplies of water are currently (1964) obtained from small-diameter screened boreholes tapping sand and limestone aquifers in the Coastal Plain province in southwestern and southeastern Ghana, but larger supplies could be obtained through properly constructed boreholes. In the Alluvial province, unconsolidated deposits in the larger stream valleys that are now largely undeveloped offer desirable locations for shallow vertical or horizontal wells, which can induce infiltration from streams and yield moderate to large water supplies. The principal factors that limit development of ground-water supplies in Ghana are (1) prevailing low permeability and water-yielding potential of the crystalline and consolidated sedimentary rocks that underlie most of the country, (2) highly mineralized ground water which appears to be widely distributed in the northern part of the Voltaian province, and (3) potential problems of salt-water encroachment in the Coastal Plain province in the Western Region and in the Keta area. On the other hand, weathering has increased porosity and has thus substantially increased the water-yielding potential of the crystalline and consolidated sedimentary rocks in much of central and northern Ghana. Also, with proper construction and development, much larger yields than those now (1964) prevalent could be obtained from boreholes tapping sand and limestone aquifers in the Coastal Plain province.

Water Supply Paper↗