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Application of ground-penetrating-radar methods in hydrogeologic studies Application of ground-penetrating-radar methods in hydrogeologic studies

A ground-penetrating-radar system was used to study selected stratified-drift deposits in Connecticut. Ground-penetrating radar is a surface-geophysical method that depends on the emission, transmission, reflection, and reception of an electromagnetic pulse and can produce continuous high-resolution profiles of the subsurface rapidly and efficiently. Traverse locations on land included a...
Authors
Milan Beres, F.P. Haeni

Preliminary delineation of contaminated water-bearing fractures intersected by open-hole bedrock wells Preliminary delineation of contaminated water-bearing fractures intersected by open-hole bedrock wells

Contaminated water‐bearing fractures intersected by open‐hole bedrock wells were preliminarily delineated through a combination of geophysical logging, vertical‐flow measurements, and downhole water sampling as part of remedial site investigations in southeastern New York. The wells investigated range from 100 to 450 feet in depth, have only shallow surface casing, and intersect multiple...
Authors
John Williams, Randall W. Conger

Solving groundwater flow problems by conjugate-gradient methods and the strongly implicit procedure Solving groundwater flow problems by conjugate-gradient methods and the strongly implicit procedure

The performance of the preconditioned conjugate-gradient method with three preconditioners is compared with the strongly implicit procedure (SIP) using a scalar computer. The preconditioners considered are the incomplete Cholesky (ICCG) and the modified incomplete Cholesky (MICCG), which require the same computer storage as SIP as programmed for a problem with a symmetric matrix, and a...
Authors
Mary C. Hill

Brief descriptions of mines, prospects, and mineral occurrences in the Port Moller and Stepovak Bay quadrangles, Alaska peninsula Brief descriptions of mines, prospects, and mineral occurrences in the Port Moller and Stepovak Bay quadrangles, Alaska peninsula

This report contains brief descriptions of known mines, prospects, and mineral occurrences in the Port Moller and Stepovak Bay quadrangles on the Alaska Peninsula. These quadrangles, and the adjoining Simeonof Island quadrangle to the south were the subject of an Alaska Mineral Resource Assessment Program (AMRAP) mapping and mineral resource assessment project. This compilation of...
Authors
Frederic H. Wilson, Willis H. White, Gregory D. DuBois

A guide to commonly used map projections prepared for use in HyperCard, 1988 A guide to commonly used map projections prepared for use in HyperCard, 1988

This guide briefly describes and illustrates the characteristics of 17 map projections commonly used to present thematic data. By means of simple sketches of the basic grid system of longitude and latitude known as the Earth's graticule, the guide shows examples of the following categories of map projections: planes (azimuthal), cones, cylinders, and miscellaneous. The text gives...
Authors
Tau Rho Alpha, Joe F. Vigil, Lauren Buchholz

A comparison of coupled freshwater-saltwater sharp-interface and convective-dispersive models of saltwater intrusion in a layered aquifer system A comparison of coupled freshwater-saltwater sharp-interface and convective-dispersive models of saltwater intrusion in a layered aquifer system

Simulated results of the coupled freshwater-saltwater sharp interface and convective-dispersive numerical models are compared by using steady-state cross-sectional simulations. The results indicate that in some aquifers the calculated sharp interface is located further landward than would be expected.
Authors
Mary C. Hill

Application of seismic-refraction techniques to hydrologic studies Application of seismic-refraction techniques to hydrologic studies

During the past 30 years, seismic-refraction methods have been used extensively in petroleum, mineral, and engineering investigations and to some extent for hydrologic applications. Recent advances in equipment, sound sources, and computer interpretation techniques make seismic refraction a highly effective and economical means of obtaining subsurface data in hydrologic studies. Aquifers...
Authors
F.P. Haeni
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