The decision model used by Bugai and others (1996) to evaluate the necessity of proposed protective measures for the Pripyat Town well field located near the Chernobyl Nuclear Power Plant is re-evaluated. The principal features of this re-evaluation are: a) a more comprehensive but computer-intensive simulation model is adopted in deriving estimates of the 90 Sr concentration at a well head, b) a greater number of parameters are treated as stochastic variables rather than as deterministic variables assigned conservative upper or lower bounds, and c) data unavailable to Bugai and others (1996) are used to update estimates of several of the model parameters. When judged against the updated model, Bugai and others (1996) overestimated the cumulative probability of well field contamination during the 70-yr planning horizon by a factor of about 20±5. Elements that were precluded from consideration in the Bugai model that can lead to higher 90 Sr concentration at a well head (such as well interference effects and the duration of source loading at the water table) are outweighed by the relaxation of conservative approximations related to the regional hydraulic gradient, the ground-water recharge rate, the hydraulic conductivity estimates, and the updating of the estimated layer thicknesses. The Bugai model is not conservative with respect to well field contamination during the early years of the planning horizon, but the revised estimates of the probability of well field failure do not have a significant effect in the decision model. Model comparisons show that there can be an advantage in carrying out early sensitivity studies using a detailed model to guide the design of a simpler model that, because of its computational advantage, would be used in estimating the probability of well field contamination.

222 Rn activities were determined for the karst aquifer underlying Walkersville, Maryland, in an area of ground-water discharge from a single geological unit during the summer and fall seasons. Radon-222 equilibrium activities in karst ground waters can be employed in mass-balance models to estimate microfissure, macrofissure, and conduit aperture dimensions. This approach defines 222 Rn generation and loss in karst aquifers as a function of fissure apertures and the 238 U content of the rock. High 222 Rn activities occur in tight fissures and low 222 Rn activities occur in conduits. In the vadose zone, 222 Rn activities are low as a result of degassing, especially if flow is turbulent and activities are decoupled from the phreatic zone. In the phreatic zone, if recharge to fissures causes a reduction of residence time below that required for equilibrium (≈26 days), 222 Rn activities fall. At springs and in the vadose zone, after a rainfall event, 222 Rn activities increase as waters with long residence and with high 222 Rn activities are expelled from fissure and fracture storage. Field data and selected literature values were used to test the model. Models used to predict median microfissure apertures for this karst aquifer yield aperture estimates ranging from 2.8 μ m to 9.2 μ m. Median macrofissure apertures ranged from 5.53 cm to 5.88 cm. Median conduit apertures ranged from 1.16 m to 1.24 m. Comparison of the models results with published data on karst aquifers and observations at the field site suggest that the predicted apertures are reasonable.

Research Article| January 01, 1998 Roadside Geology of Hawaii Frank L. Peterson Frank L. Peterson Department of Geology and Geophysics, University of Hawaii, Honolulu, HI 96892 Search for other works by this author on: GSW Google Scholar Environmental & Engineering Geoscience (1998) IV (1): 140–141. https://doi.org/10.2113/gseegeosci.IV.1.140 Article history first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Frank L. Peterson; Roadside Geology of Hawaii. Environmental & Engineering Geoscience 1998;; IV (1): 140–141. doi: https://doi.org/10.2113/gseegeosci.IV.1.140 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyEnvironmental & Engineering Geoscience Search Advanced Search This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Ground-penetrating radar (GPR) was used to explore alluvial-fan complexes on the piedmont slopes of higher mountains in the Blue Ridge province of North Carolina. On young fans with relatively unweathered surfaces, GPR penetration reached 16 m with 100 MHz antennae and 25 m with 25 MHz antennae. Penetration appears to be deepest near fan apexes. As the fans are composed mainly of bouldery debris flow deposits, the internal structures revealed by GPR profiles are few. The typical profile has a chaotic appearance and is composed of numerous discontinuous reflectors with varying dips and diffraction hyperbolas produced by boulders. On old abandoned fans that have been subjected to intense weathering, boulders in the deposits have decomposed and structures subparallel to the surface are more likely to be seen. Continuous reflectors that may indicate contacts between depositional units, buried soils, or groundwater tables, however, are rare in both kinds of fans. Generally radar velocity and penetration are greatest on young fans, less on old fans, and least on saprolite.

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Research Article| January 01, 1997 Groundwater and Soil Contamination Database Ronald L. Parker Ronald L. Parker Department of Geology and Geophysics, Texas A&M University, College Station, TX 77843 Search for other works by this author on: GSW Google Scholar Author and Article Information Ronald L. Parker Department of Geology and Geophysics, Texas A&M University, College Station, TX 77843 Publisher: Association of Environmental & Engineering Geologists First Online: 09 Mar 2017 Online ISSN: 1558-9161 Print ISSN: 1078-7275 © 1997 Association of Engineering Geologists Environmental & Engineering Geoscience (1997) III (4): 604–606. https://doi.org/10.2113/gseegeosci.III.4.604 Article history First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Ronald L. Parker; Groundwater and Soil Contamination Database. Environmental & Engineering Geoscience 1997;; III (4): 604–606. doi: https://doi.org/10.2113/gseegeosci.III.4.604 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyEnvironmental & Engineering Geoscience Search Advanced Search This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Research Article| January 01, 1997 Exercises in Active Tectonics An Introduction to Earthquakes and Tectonic Geomorphology Deborah J. Green Deborah J. Green Tilford & Green, Environmental & Engineering Geology, P.O. Box 1119, Hilltop Lakes, TX 77871 Search for other works by this author on: GSW Google Scholar Author and Article Information Deborah J. Green Tilford & Green, Environmental & Engineering Geology, P.O. Box 1119, Hilltop Lakes, TX 77871 Publisher: Association of Environmental & Engineering Geologists First Online: 09 Mar 2017 Online Issn: 1558-9161 Print Issn: 1078-7275 © 1997 Association of Engineering Geologists Environmental & Engineering Geoscience (1997) III (3): 462–463. https://doi.org/10.2113/gseegeosci.III.3.462 Article history First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Deborah J. Green; Exercises in Active Tectonics An Introduction to Earthquakes and Tectonic Geomorphology. Environmental & Engineering Geoscience 1997;; III (3): 462–463. doi: https://doi.org/10.2113/gseegeosci.III.3.462 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyEnvironmental & Engineering Geoscience Search Advanced Search This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

The Supersonic Naval Ordnance Research Track (SNORT) located in Indian Wells Valley, California, is being used as a 6.55 km-long tiltmeter and geodetic alignment array. Our scientific usage is a direct result of the track profile and alignment requirements of the rocket powered test sleds used on the track. Data from six surveys during 1952 through 1986 have shown reversible elevation changes of 135 mm and cyclic horizontal changes of 30 mm between subsequent surveys. We attribute the changes to tectonic stress buildup and release associated with earthquakes of about magnitude M = 5, in 1961 and 1982, and to pulsations within a shallow magma body that underlies the SNORT area. Track deformations that occurred between 1984 and 1986 suggest that stress is again building along the nearby and highly active Little Lake fault, which has had three earthquakes of about magnitude 5 since 1938, with recurrence intervals of 21 years. These deformations may be precursors to a moderate-size earthquake that could occur within the next decade, or so.

Research Article| January 01, 1997 Geotechnical Engineering OLIVIER P. MUFF, PE, CG OLIVIER P. MUFF, PE, CG Gerber-Jacques Whitford, 174 South Freeport Road, Freeport, ME 04032-6115 Search for other works by this author on: GSW Google Scholar Environmental and Engineering Geoscience (1997) III (1): 156–157. https://doi.org/10.2113/gseegeosci.III.1.156 Article history first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation OLIVIER P. MUFF; Geotechnical Engineering. Environmental and Engineering Geoscience 1997;; III (1): 156–157. doi: https://doi.org/10.2113/gseegeosci.III.1.156 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu nav search search input Search input auto suggest search filter All ContentBy SocietyEnvironmental and Engineering Geoscience Search Advanced Search This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not currently have access to this article.

Engineering geology has played an essential role in the projects of the California State Department of Water Resources (DWR). Numerous pioneering techniques by DWR geologists include a) the first active element analog/digital model of a groundwater basin, b) cost estimates for tunneling, c) test plots evaluating shallow land subsidence (hydro-compaction), d) a mobile rock mechanics laboratory, e) field and laboratory evaluations of specific yield, and f) determination of coastal aquifers subject to sea-water intrusion. Eventual results of these techniques include a) digital ground-water basin models with increasing complexity, b) and c) choice of the lowest cost route and geotechnical methods to bring water to southern California, d) rock properties available to engineers for preliminary design, e) values of storage capacity for 250 ground-water basins, and f) construction of fresh-water injection barriers to preserve ground-water basins. Geologists obtained and interpreted for their engineer colleagues the essential geologic information utilizing advanced geophysical and drilling techniques for both the California Water Plan and the State Water Project. The former is a master plan for utilization of all the water resources of the state. The latter, now essentially complete, included planning, design, and construction of 14 dams, 21 pumping plants, an underground power plant, 11 power recovery stations, 6 tunnels, and 561 mi of aqueduct, bringing water to the San Francisco Bay area and from the central and northern parts of the State to the heavily populated south. A geothermal test well completed by DWR in the Imperial Valley encountered fluid of insufficiently high temperature for economic development. DWR geologists have been active in the initial organization and the development of the Association of Engineering Geologists, and have also been active in the Geological Society of America, particularly in the Engineering Geology and Hydrogeology Divisions.