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Solute movement through homogeneous and heterogeneous soil columns
368A
HYDROGEOLOGY:WATER PRESSURE
permissible limits of drinking water in almost the entire city. A positive correlation of As and Se with other toxic metals such as V, Cr, Fe, B, etc., indicates that all these elements are anthropogenic in origin. Applying multivariate analysis, the source for trace elements in groundwater has been grouped into two major factors: pollution and mobilization factors. (from Authors)
958081 Annual regime characteristics of water level in bedrock wells in Beijing plain (in Chinese) Che Yongtai, Yu Jinzi, Zhang Dawei, Sun Zhenao, Jian Chunlin & Peng Guirong, Seismology & Geology, 16(3), 1994, pp 255-363. In this paper, annual regime characteristics of water level in ten wells in Beijing area are systematically presented, and influences of rainfall and extraction of groundwater on them are analysed. In addition, the reliability of intermediate and long period anomalies of water level in some wells before and after the Datong-Yanggao earthquake is discussed. (English summary)
Chemical and physical changes due to water 958082 Early development of karst systems 2. Turbulent flow A. D. Howard & C. G. Groves, Water Resources Research, 31(1), 1995, pp 91-26. A simulation model developed to explore patterns of fracture enlargement within incipient limestone karst aquifers has been extended to turbulent flow. In contrast to the highly selective passage enlargement that occurs early in cave network development under laminar flow, the transition to turbulent flow results in more general passage enlargement, leading to maze networks when initial fractures are large and hydraulic gradients are high. These results support previously published hypotheses for the development of maze patterns, including formation within structural settings that have created initially large fractures or within flow systems periodically inundated by flooding. (from Authors)
958083
Tilts, strains, and ground-water levels near an early fissure
9.58084 The investigation of dissolution subsidence incorporating microgravity geophysics at Ripon, Yorkshire D. A. Patterson, J. C. Davey, A. H. Cooper & J. K. Ferris, Quarterly Journal of Engineering Geology, 28(1), 1995, pp 83-94. Dissolution subsidence affords some of the most difficult ground conditions with which engineering geologists have to deal. Within the UK, areas underlain by gypsiferous PermoTriassic strata, most notably around Ripon in Yorkshire, are prone to dissolution structures and resultant building failures are well documented. Following a desk study, high-resolution microgravity geophysics was carried out both inside and outside the existing building. This indicated a major negative anomaly of peak amplitude - 74 {~Gal. Subsequent static core probing rotary drilling and trial trenching confirmed the existence of a potentially unstable breccia pipe which could therefore be taken into account in the engineering design. (from Authors)
958085 The potential for metal release by reductive dissolution of weathered mine tallings I. Ribet, C. J. Ptacek, D. W. Blowes & J. L. Jambor, Journal of Contaminant Hydrology, 17(3), 1995, pp 239-273. Remediation programs proposed for decommissioned sulphide tailings may include the addition of a cover layer rich in organic-carbon material such as sewage sludge or eompnsted municipal waste. These covers are designed to consume oxygen and prevent the oxidation of underlying sulphide minerals. The aerobic and anaerobic degradation of such organic-carbon-rich waste can release soluble organic compounds to infiltrating precipitation water. In laboratory experiments, and in natural settings, biotic and abiotic interactions between similar dissolved organic compounds and ferric-bearing secondary minerals have been observed to result in the reductive dissolution of ferric (oxy)hydroxides and the release of ferrous iron to pore waters. To assess the potential for metal release to railings pore water by reductive dissolution reactions, a laboratory study was conducted on weathered tailings collected from the Nickel Rim mine railings impoundment near Sudbury, Ontario, Canada. (from Authors)
Measurement of water pressure and its effects
in the Mimbres Basin, New Mexico W. C. Haneberg & R. L. Friesen, Geological Society of America Bulletin, 107(3), 1995, pp 316-326. Ground-water levels in the Mimbres Basin have fallen by as much as 35 m since the turn of the century, resulting in land subsidence and the appearance of earth fissures throughout the basin. This paper describes near-surface tilt, strain, and water-level changes recorded between January and December 1992 near one Mimbres Basin fissure. Vertical deflection profiles derived from microradian-sensitivity tiltmeter data suggest that an earth fissure in the subsiding Mimbres Basin is located near the inflection point of an evolving surficial fold of infinitesimal amplitude. Calculated curvature profiles further imply that the fissure was within a zone of contraction throughout the study period. Observed fissure-perpendicular tilts and the location of the fissure at an inflection point rather than along an anticlinal crest are consistent with a mode II fracture shearing mode crack or fault rather than a mode I fracture opening mode crack or joint). Tilting parallel to the fissure further suggests a component of mode III (tearing-mode crack) displacement during the study period. (from Authors)
958086
Solute movement through homogeneous and heterogeneous soil columns Renduo Zhang, Kangle Huang & Jiannan Xiang, Advances in Water Resources, 17(5), 1994, pp 317-324. The classical convection-dispersion equation (CDE) and the stochastical convection-dispersion equation (SCDE) were utilized to study solute transport in homogeneous and heterogeneous porous media. Analyses of the experimental data showed that the observed dispersion coefficient increased with the travel distance for both homogeneous and heterogeneous soils. The range of the dispersion coeffidents was from 0.05 to 20 cra2rtain" for the homogeneous soil, and from 3 to 200 ¢m2min "l for the heterogeneous soil. A linear relationship between the dispersion coefficient and travel distance, assumed in the SCDE, described the scaledependent dispersion coefficient reasonably well. (from Authors)
HYDROGEOLOGY:WATER PRESSURE
permissible limits of drinking water in almost the entire city. A positive correlation of As and Se with other toxic metals such as V, Cr, Fe, B, etc., indicates that all these elements are anthropogenic in origin. Applying multivariate analysis, the source for trace elements in groundwater has been grouped into two major factors: pollution and mobilization factors. (from Authors)
958081 Annual regime characteristics of water level in bedrock wells in Beijing plain (in Chinese) Che Yongtai, Yu Jinzi, Zhang Dawei, Sun Zhenao, Jian Chunlin & Peng Guirong, Seismology & Geology, 16(3), 1994, pp 255-363. In this paper, annual regime characteristics of water level in ten wells in Beijing area are systematically presented, and influences of rainfall and extraction of groundwater on them are analysed. In addition, the reliability of intermediate and long period anomalies of water level in some wells before and after the Datong-Yanggao earthquake is discussed. (English summary)
Chemical and physical changes due to water 958082 Early development of karst systems 2. Turbulent flow A. D. Howard & C. G. Groves, Water Resources Research, 31(1), 1995, pp 91-26. A simulation model developed to explore patterns of fracture enlargement within incipient limestone karst aquifers has been extended to turbulent flow. In contrast to the highly selective passage enlargement that occurs early in cave network development under laminar flow, the transition to turbulent flow results in more general passage enlargement, leading to maze networks when initial fractures are large and hydraulic gradients are high. These results support previously published hypotheses for the development of maze patterns, including formation within structural settings that have created initially large fractures or within flow systems periodically inundated by flooding. (from Authors)
958083
Tilts, strains, and ground-water levels near an early fissure
9.58084 The investigation of dissolution subsidence incorporating microgravity geophysics at Ripon, Yorkshire D. A. Patterson, J. C. Davey, A. H. Cooper & J. K. Ferris, Quarterly Journal of Engineering Geology, 28(1), 1995, pp 83-94. Dissolution subsidence affords some of the most difficult ground conditions with which engineering geologists have to deal. Within the UK, areas underlain by gypsiferous PermoTriassic strata, most notably around Ripon in Yorkshire, are prone to dissolution structures and resultant building failures are well documented. Following a desk study, high-resolution microgravity geophysics was carried out both inside and outside the existing building. This indicated a major negative anomaly of peak amplitude - 74 {~Gal. Subsequent static core probing rotary drilling and trial trenching confirmed the existence of a potentially unstable breccia pipe which could therefore be taken into account in the engineering design. (from Authors)
958085 The potential for metal release by reductive dissolution of weathered mine tallings I. Ribet, C. J. Ptacek, D. W. Blowes & J. L. Jambor, Journal of Contaminant Hydrology, 17(3), 1995, pp 239-273. Remediation programs proposed for decommissioned sulphide tailings may include the addition of a cover layer rich in organic-carbon material such as sewage sludge or eompnsted municipal waste. These covers are designed to consume oxygen and prevent the oxidation of underlying sulphide minerals. The aerobic and anaerobic degradation of such organic-carbon-rich waste can release soluble organic compounds to infiltrating precipitation water. In laboratory experiments, and in natural settings, biotic and abiotic interactions between similar dissolved organic compounds and ferric-bearing secondary minerals have been observed to result in the reductive dissolution of ferric (oxy)hydroxides and the release of ferrous iron to pore waters. To assess the potential for metal release to railings pore water by reductive dissolution reactions, a laboratory study was conducted on weathered tailings collected from the Nickel Rim mine railings impoundment near Sudbury, Ontario, Canada. (from Authors)
Measurement of water pressure and its effects
in the Mimbres Basin, New Mexico W. C. Haneberg & R. L. Friesen, Geological Society of America Bulletin, 107(3), 1995, pp 316-326. Ground-water levels in the Mimbres Basin have fallen by as much as 35 m since the turn of the century, resulting in land subsidence and the appearance of earth fissures throughout the basin. This paper describes near-surface tilt, strain, and water-level changes recorded between January and December 1992 near one Mimbres Basin fissure. Vertical deflection profiles derived from microradian-sensitivity tiltmeter data suggest that an earth fissure in the subsiding Mimbres Basin is located near the inflection point of an evolving surficial fold of infinitesimal amplitude. Calculated curvature profiles further imply that the fissure was within a zone of contraction throughout the study period. Observed fissure-perpendicular tilts and the location of the fissure at an inflection point rather than along an anticlinal crest are consistent with a mode II fracture shearing mode crack or fault rather than a mode I fracture opening mode crack or joint). Tilting parallel to the fissure further suggests a component of mode III (tearing-mode crack) displacement during the study period. (from Authors)
958086
Solute movement through homogeneous and heterogeneous soil columns Renduo Zhang, Kangle Huang & Jiannan Xiang, Advances in Water Resources, 17(5), 1994, pp 317-324. The classical convection-dispersion equation (CDE) and the stochastical convection-dispersion equation (SCDE) were utilized to study solute transport in homogeneous and heterogeneous porous media. Analyses of the experimental data showed that the observed dispersion coefficient increased with the travel distance for both homogeneous and heterogeneous soils. The range of the dispersion coeffidents was from 0.05 to 20 cra2rtain" for the homogeneous soil, and from 3 to 200 ¢m2min "l for the heterogeneous soil. A linear relationship between the dispersion coefficient and travel distance, assumed in the SCDE, described the scaledependent dispersion coefficient reasonably well. (from Authors)