The induced polarization model developed recently by Revil and Florsch to understand the complex conductivity of fully saturated granular materials has been extended partial saturation conditions.It is an improvement over previous models like Vinegar Waxman model, which do not account explicitly for effect frequency.The can be considered as a limiting case in limit where distribution relaxation times very broad.The applied unconsolidated sands partially with oil water.Laboratory experiments...

ABSTRACT The interdependence between geoelectrical signatures at underground petroleum plumes and the structures of subsurface microbial communities was investigated. For sediments contaminated with light non-aqueous-phase liquids, anomalous high conductivity values have been observed. Vertical changes in properties were concomitant significant community as determined by construction evaluation 16S rRNA gene libraries. DNA sequencing clones from four libraries different depths a field site...

Induced polarization (more precisely the magnitude and phase of impedance subsurface) is measured using a network electrodes located at ground surface or in boreholes. This method yields important information related to distribution permeability contaminants shallow subsurface. We propose new time-lapse 3-D modelling inversion algorithm image evolution complex conductivity over time. discretize subsurface hexahedron cells. Each cell assigned resistivity value. Using finite-element approach,...

Groundwater flow advects heat, and thus, the deviation of subsurface temperatures from an expected conduction-dominated regime can be analysed to estimate vertical water fluxes. A number analytical approaches have been proposed for using heat as a groundwater tracer, these typically assumed homogeneous medium. However, heterogeneous thermal properties are ubiquitous in environments, both at scale geologic strata finer scales streambeds. Herein, we apply solution Shan Bodvarsson (2004),...

We investigated the bulk electrical conductivity and microbial population distribution in sediments at a site contaminated with light nonaqueous‐phase liquid (LNAPL). The was measured using in‐situ vertical resistivity probes; most probable number method used to characterize spatial of aerobic heterotrophic oil‐degrading populations. purpose this study assess if high observed aged LNAPL‐impacted sites may be related degradation LNAPL. results show higher coincident zones, contrast...

A new version of the computer program 1DTempPro extends original code to include capabilities for (1) automated parameter estimation, (2) layer heterogeneity, and (3) time-varying specific discharge. The serves as an interface U.S. Geological Survey model VS2DH supports analysis vertical one-dimensional temperature profiles under saturated flow conditions assess groundwater/surface-water exchange estimate hydraulic conductivity cases where head is known.

Abstract Zones of strong groundwater upwelling to streams enhance thermal stability and moderate extremes, which is particularly important aquatic ecosystems in a warming climate. Passive tracer methods used quantify vertical rates rely on downward conduction surface temperature signals. However, high flux (>−1.5 m d −1 ) restrict propagation diurnal signals, therefore the applicability several passive methods. Active streambed heating from within high‐resolution fiber‐optic sensors...

We present and demonstrate a recursive-estimation framework to infer groundwater/surface-water exchange based on temperature time series collected at different vertical depths below the sediment/water interface. formulate heat-transport problem as state-space model (SSM), in which spatial derivatives convection/conduction equation are approximated using finite differences. The SSM is calibrated estimate time-varying specific discharge Extended Kalman Filter (EKF) Rauch-Tung-Striebel Smoother...

A newly proposed geoelectrical model for hydrocarbon contaminated sites predicts high conductivities coincident with the zone as opposed to traditionally accepted low conductivity. The attributes mineral weathering resulting from byproducts of microbial redox processes. To evaluate this conductive model, in situ vertical conductivity measurements were acquired a light non‐aqueous phase liquid (LNAPL) site. results showed contamination and within smear influenced by seasonal water table...

Bulk electrical conductivity of sediments during microbial mineralization diesel was investigated in a mesoscale laboratory experiment consisting biotic contaminated and uncontaminated columns. Population numbers oil degrading microorganisms increased with clear pattern depth zonation within the column not observed column. Microbial community structure determined from ribosomal DNA intergenic spacer analysis showed highly specialized The temporal increases bulk conductivity, dissolved...

Field geophysical studies have identified anomalously high conductivities in and below the free product zone at many sites with aged contamination by light, non-aqueous phase liquids (LNAPL). Laboratory experiments were conducted to test hypothesis that these can result from products of LNAPL biodegradation. Soil a hydrocarbon-impacted site was washed repeatedly remove soluble constituents, recontaminated diesel fuel (DF), pores filled water simulate saturated smear zone. Nutrients provided...

Disimilatory iron-reducing bacteria play an important role in the reduction of Fe(hydr)oxides and production secondary solid-iron mineral phases that can have magnetic properties. Magnetic susceptibility therefore identifying zones where microbial-mediated iron is occurring. We investigated variations a hydrocarbon-contaminated aquifer methanogenesis are main biogeochemical processes. Our objectives to (1) determine variability susceptibility, (2) hydrobiogeochemical controls on variability,...

Abstract A new computer program, 1DTempPro , is presented for the analysis of vertical one‐dimensional ( 1D ) temperature profiles under saturated flow conditions. a graphical user interface to U.S. Geological Survey code Variably Saturated 2‐Dimensional Heat Transport VS2DH ), which numerically solves and heat‐transport equations. Pre‐ postprocessor features allow calibrate models estimate groundwater/surface‐water exchange also hydraulic conductivity cases where head known.

Conceptual models for the geophysical responses associated with hydrocarbon degradation suggest that long-term evolution of an oil plume will result in a more conductive anomaly than initial contamination. In response to Deepwater Horizon (DH) spill into Gulf Mexico 2010, autonomous resistivity monitoring system was deployed on Grand Terre, Louisiana, attempt monitor natural processes hydrocarbon-impacted beach sediments this island. A 48-electrode surface array 0.5-m spacing installed...

We have previously documented changes in bulk electrical conductivity, self-potential (SP), and ground-penetrating-radar (GPR) reflections a field setting caused by biogeochemical transformations of hydrocarbon-contaminated media. These are associated with hydrocarbon biodegradation. The results surface geophysical surveys acquired 1996, 2003, 2007 document signatures removing mass the contaminated zone. Initial investigations 1996 showed that relative to background, area was characterized...

[1] We investigated magnetic susceptibility (MS) variations in hydrocarbon contaminated sediments. Our objective was to determine if MS can be used as an intrinsic bioremediation indicator due the activity of iron-reducing bacteria. A and uncontaminated core were retrieved from a site with crude oil near Bemidji, Minnesota subsampled for measurements. The revealed enriched zones within smear zone, which is related iron-reduction coupled oxidation compounds vadose coincident zone methane...

We investigated the sensitivity of low‐frequency electrical measurements (0.1–1000 Hz) to (1) microbial cell density, (2) live and dead cells, (3) attachment onto mineral surfaces clean quartz sands iron oxide–coated sands. Three strains Pseudomonas aeruginosa PAO1 (wild type rhlA pilA mutant) with different motility properties were used. Varying concentrations both cells P. wild in sand columns showed no effect on real conductivity component ( σ ′). However, imaginary ″) increased linearly...

Electromagnetic (EM-31), dc resistivity, and ground penetrating radar (GPR) methods were used to investigate part of a former refinery site in Kalamazoo, Michigan, USA. The study area is underlain by about [Formula: see text] heterogeneous glacial drift deposits overlying sandy outwash unit. Three large above storage tanks (ASTs) formerly occupied the removed U.S. Environmental Protection Agency (USEPA) 1997. EM-31 surveys revealed eight remnants buried pipe ranging from more than length....

Time-lapse joint inversion of geophysical data is required to image the evolution oil reservoirs during production and enhanced recovery, [Formula: see text] sequestration, geothermal fields production, monitor contaminant plumes. Joint schemes reduce space-related artifacts in filtering out noise that spatially uncorrelated, time-lapse algorithms time-related uncorrelated over time. There are several approaches possible perform inverse problem. In this work, we investigate structural...