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371.
Gaisheng Liu Steven Knobbe Edward C. Reboulet Donald O. Whittemore Falk Händel James J. Butler Jr. 《Ground water》2016,54(3):425-433
Aquifer storage and recovery (ASR) is the artificial recharge and temporary storage of water in an aquifer when water is abundant, and recovery of all or a portion of that water when it is needed. One key limiting factor that still hinders the effectiveness of ASR is the high costs of constructing, maintaining, and operating the artificial recharge systems. Here we investigate a new recharge method for ASR in near‐surface unconsolidated aquifers that uses small‐diameter, low‐cost wells installed with direct‐push (DP) technology. The effectiveness of a DP well for ASR recharge is compared with that of a surface infiltration basin at a field site in north‐central Kansas. The performance of the surface basin was poor at the site due to the presence of a shallow continuous clay layer, identified with DP profiling methods, that constrained the downward movement of infiltrated water and significantly reduced the basin recharge capacity. The DP well penetrated through this clay layer and was able to recharge water by gravity alone at a much higher rate. Most importantly, the costs of the DP well, including both the construction and land costs, were only a small fraction of those for the infiltration basin. This low‐cost approach could significantly expand the applicability of ASR as a water resources management tool to entities with limited fiscal resources, such as many small municipalities and rural communities. The results of this investigation demonstrate the great potential of DP wells as a new recharge option for ASR projects in near‐surface unconsolidated aquifers. 相似文献
372.
Rosemary Knight David O. Walsh James J. Butler Jr. Elliot Grunewald Gaisheng Liu Andrew D. Parsekian Edward C. Reboulet Steve Knobbe Mercer Barrows 《Ground water》2016,54(1):104-114
Nuclear magnetic resonance (NMR) logging provides a new means of estimating the hydraulic conductivity (K) of unconsolidated aquifers. The estimation of K from the measured NMR parameters can be performed using the Schlumberger‐Doll Research (SDR) equation, which is based on the Kozeny–Carman equation and initially developed for obtaining permeability from NMR logging in petroleum reservoirs. The SDR equation includes empirically determined constants. Decades of research for petroleum applications have resulted in standard values for these constants that can provide accurate estimates of permeability in consolidated formations. The question we asked: Can standard values for the constants be defined for hydrogeologic applications that would yield accurate estimates of K in unconsolidated aquifers? Working at 10 locations at three field sites in Kansas and Washington, USA, we acquired NMR and K data using direct‐push methods over a 10‐ to 20‐m depth interval in the shallow subsurface. Analysis of pairs of NMR and K data revealed that we could dramatically improve K estimates by replacing the standard petroleum constants with new constants, optimal for estimating K in the unconsolidated materials at the field sites. Most significant was the finding that there was little change in the SDR constants between sites. This suggests that we can define a new set of constants that can be used to obtain high resolution, cost‐effective estimates of K from NMR logging in unconsolidated aquifers. This significant result has the potential to change dramatically the approach to determining K for hydrogeologic applications. 相似文献
373.
374.
Sung‐Hoon Ji Dae Hyoung Lee In Wook Yeo Kyoung‐Woo Park Yong‐Kwon Koh 《Ground water》2014,52(1):145-155
In this study, the derivative analysis using the derivative of drawdown with respect to log‐time was utilized to determine candidates for hydraulic conductor domains (HCDs). At a 500‐m deep borehole in the study site, the fractured rocks crossing the borehole were first classified in fractured and nonfractured zones by core logging and geophysical loggings, such as acoustic televiewing, density, and flow loggings. After conducting the hydraulic tests such as constant head withdrawal and recovery tests at the fractured zones and the nonfractured zones, the derivative analyses were carried out, of which the results were evaluated to determine the candidates for HCDs. For the nonfractured zones, the diagnostic plot has only a big hump indicating poor connection of the background fractures to the permeable geologic media, while those of the candidates for HCDs show various flow regimes. On the basis of these results, the candidates for HCDs among the fractured zones were determined. From discussion on the results, the combination of the spacing analysis and derivative analysis following a hydraulic test is recommended for determining the candidates for HCDs rather than other geophysical loggings. 相似文献
375.
Lloyd S. Isaacson Edward D. Burton Richard T. Bush David R.G. Mitchell Scott G. Johnston Bennett C.T. Macdonald Leigh A. Sullivan Ian White 《Applied Geochemistry》2009
Discharge of Fe(II)-rich groundwaters into surface-waters results in the accumulation of Fe(III)-minerals in salinized sand-bed waterways of the Hunter Valley, Australia. The objective of this study was to characterise the mineralogy, micromorphology and pore-water geochemistry of these Fe(III) accumulations. Pore-waters had a circumneutral pH (6.2–7.2), were sub-oxic to oxic (Eh 59–453 mV), and had dissolved Fe(II) concentrations up to 81.6 mg L−1. X-ray diffraction (XRD) on natural and acid-ammonium-oxalate (AAO) extracted samples indicated a dominance of 2-line ferrihydrite in most samples, with lesser amounts of goethite, lepidocrocite, quartz, and alumino-silicate clays. The majority of Fe in the samples was bound in the AAO extractable fraction (FeOx) relative to the Na-dithionite extractable fraction (FeDi), with generally high FeOx:FeDi ratios (0.52–0.92). The presence of nano-crystalline 2-line ferrihydrite (Fe5HO3·4H2O) with lesser amounts of goethite (α-FeOOH) was confirmed by scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX), and transmission electron microscopy (TEM) coupled with selected area electron diffraction (SAED). In addition, it was found that lepidocrocite (γ-FeOOH), which occurred as nanoparticles as little as ∼5 lattice spacings thick perpendicular to the (0 2 0) lattice plane, was also present in the studied Fe(III) deposits. Overall, the results highlight the complex variability in the crystallinity and particle-size of Fe(III)-minerals which form via oxidation of Fe(II)-rich groundwaters in sand-bed streams. This variability may be attributed to: (1) divergent precipitation conditions influencing the Fe(II) oxidation rate and the associated supply and hydrolysis of the Fe(III) ion, (2) the effect of interfering compounds, and (3) the influence of bacteria, especially Leptothrix ochracea. 相似文献
376.
Migmatites from Cone Peak, California, USA and the Satnur-Sangam road, Southern Karnataka, India contain coarser grained orthopyroxene-bearing leucosomes with subordinate biotite in finer grained hornblende-biotite-pyroxene-bearing hosts. At both localities the leucosomes are enriched in quartz and feldspar and have a higher ratio of pyroxene to hornblende + biotite compared to the host rocks. Biotite grains in leucosomes along the Satnur-Sangam road are concentrated at the margins of orthopyroxene grains and have lower abundances of Ti, Fe, and Cl and a higher abundance of F than biotite grains from the host rock. Fluorapatite grains in all rocks from both localities contain monazite inclusions similar to those produced experimentally by metasomatically induced dissolution and reprecipitation. Some fluorapatite grains at both localities are partially rimmed by allanite. The only compositional differences found between fluorapatite grains in the leucosomes and host rocks were higher concentrations of Cl in grains in leucosomes from Cone Peak. The mineralogies of the rocks suggest that the leucosomes formed by dehydration melting reactions that consumed feldspar, quartz, hornblende, and biotite and produced orthopyroxene. Allanite rims at the margins of fluorapatite grains may have formed by the later retrogression of monazite rims formed by incongruent dissolution of fluorapatite in the melt. Biotite grains at the margins of orthopyroxene crystals in the leucosomes from the Satnur-Sangam road apparently formed by retrogression of orthopyroxene upon the solidification of the anatectic melt. A similar high-grade retrogression did not affect orthopyroxene crystals at Cone Peak, indicating that H2O was removed from the crystallizing leucosomes probably in a low H2O activity fluid. Compositional differences between the paleosome and neosomes at Cone Peak are best explained by metasomatic interaction with concentrated brines while elevated Cl concentrations in fluorapatites in the leucosome suggest interaction with a Cl-bearing fluid. Brines may have been responsible for an exchange of elements between the host rock along the Satnur-Sangam road and zones of melt generation now marked by leucosomes, but fluid flow appears to have been less vigorous than at Cone Peak. 相似文献
377.
In horizontally layered soils of different electrical properties, electrical potential distribution becomes complex and the
obtained resistivity data may be limited in reflecting the actual soil profile. Thus the objective of this study was to identify
the factors that affect resistivity measurement on the cone penetrometer and further investigate the sensitivity of measured
resistivity to different types and concentrations of contaminants at the subsurface level. First, a theoretical resistivity
equation was derived to provide a means of computing the geometric factor. The effective volume of measurement on the cone
penetrometer was investigated and laboratory soil box tests verified the dominance of partially high resistivity regions within
the effective volume of measurement over the apparent resistivity. Such effect was found to lead to possible discrepancies
between the recorded resistivity data and the actual depth of measurement. Measurements on contaminated soil layers indicated
that resistivity cones are efffective in delineating inorganic contaminants in soils of high water contents, and detecting
NAPLs floating above the groundwater table provided that soils adjacent to the plume are not dry of water.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
378.
H. S. Jeon S. Cho Y. S. Kwak J. K. Chung J. U. Park D. K. Lee M. Kuzmicz-Cieslak 《Astrophysics and Space Science》2011,332(2):341-351
The atmospheric mass density of the upper atmosphere from the spherical Starlette satellite’s Precise Orbit Determination
is first derived with Satellite Laser Ranging measurements at 815 to 1115 km during strong solar and geomagnetic activities.
Starlette’s orbit is determined using the improved orbit determination techniques combining optimum parameters with a precise
empirical drag application to a gravity field. MSIS-86 and NRLMSISE-00 atmospheric density models are compared with the Starlette
drag-derived atmospheric density of the upper atmosphere. It is found that the variation in the Starlette’s drag coefficient
above 800 km corresponds well with the level of geomagnetic activity. This represents that the satellite orbit is mainly perturbed
by the Joule heating from geomagnetic activity at the upper atmosphere. This result concludes that MSIS empirical models strongly
underestimate the mass density of the upper atmosphere as compared to the Starlette drag-derived atmospheric density during
the geomagnetic storms. We suggest that the atmospheric density models should be analyzed with higher altitude acceleration
data for a better understanding of long-term solar and geomagnetic effects. 相似文献
379.
A 1 ° × 1 ° global detailed gravimetric geoid has been computed, using a combination of the Goddard Space Flight Center (GSFC) GEM‐8 potential field model and a set of 38,406 1° × 1° mean surface free air anomalies. Numerous short wavelength features are shown in the geoid contour map, e.g., the steep gradients associated with oceanic trenches. Comparison of this geoid with geoceiver derived and astrogeodetic geoid heights in the United States resulted in an r.m.s. difference of about 1.7 m. Comparisons with three GEOS‐3 altimeter derived geoidal profiles revealed that for areas with good surface data coverage, the relative agreement is generally better than 5 m. 相似文献
380.
A stability analysis of reinforced foundation soil is presented in this paper. A method based on the discrete element method (DEM) is suggested for calculating the bearing capacity on strip footings over multilayer soils reinforced with a horizontal layer of geosynthetics. The proposed method can estimate the ultimate bearing capacity and the distribution of tensile force developed in the geosynthetics of the footing system by Winkler springs to account for the compatibility between soil blocks and tensile elements to consider the tensile behavior between soil and geosynthetics. For footings on various multilayer soils with or without reinforcement of geosynthetics, the results of the method were compared to the field test results as well as to those obtained by various methods proposed by other researchers. 相似文献