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Data from Singha and Gorelick (2005), Saline tracer visualized with electrical resistivity tomography: field scale spatial moment analysis


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Created: Oct 09, 2019 at 12:17 a.m.
Last updated: Oct 15, 2019 at 10:51 p.m.
DOI: 10.4211/hs.d2481d34e4414494a24a0be0f14bd3a1
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Sharing Status: Published
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Abstract

Data from Singha, K. and Gorelick, S.M. (2005). Saline tracer visualized with electrical resistivity tomography: field scale spatial moment analysis. Water Resources Research, 41, W05023, https://doi.org/10.1029/2004WR003460, 17 p.

Cross-well electrical resistivity tomography (ERT) was used to monitor the migration of a saline tracer in a two-well pumping-injection experiment conducted at the Massachusetts Military Reservation in Cape Cod, Massachusetts. After injecting 2200 mg/Lof sodium chloride for 9 hours, ERT data sets were collected from four wells every 6 hours for 20 days. More than 180,000 resistance measurements were collected during the tracer test. Each ERT data set was inverted to produce a sequence of 3-D snapshot maps that track the plume. In addition to the ERT experiment a pumping test and an infiltration test were conducted to estimate horizontal and vertical hydraulic conductivity values. Using modified moment analysis of the electrical conductivity tomograms, the mass, center of mass, and spatial variance of the imaged tracer plume were estimated.Although the tomograms provide valuable insights into field-scale tracer migration behavior and aquifer heterogeneity, standard tomographic inversion and application of Archie’s law to convert electrical conductivities to solute concentration results in underestimation of tracer mass. Such underestimation is attributed to (1) reduced measurement sensitivity to electrical conductivity values with distance from the electrodes and (2) spatial smoothing (regularization) from tomographic inversion. The center of mass estimated from the ERT inversions coincided with that given by migration of the tracer plume using 3-D advective-dispersion simulation. The 3-D plumes seen using ERT exhibit greater apparent dispersion than the simulated plumes and greater temporal spreading than observed in field data of concentration breakthrough at the pumping well.

Subject Keywords

Coverage

Spatial

Coordinate System/Geographic Projection:
WGS 84 EPSG:4326
Coordinate Units:
Decimal degrees
Place/Area Name:
The Massachusetts Military Reservation
North Latitude
41.6839°
East Longitude
-70.4928°
South Latitude
41.6312°
West Longitude
-70.5948°

Temporal

Start Date:
End Date:

Content

Related Resources

This resource is described by Singha, K. and Gorelick, S.M. (2005). Saline tracer visualized with electrical resistivity tomography: field scale spatial moment analysis. Water Resources Research, 41, W05023, https://doi.org/10.1029/2004WR003460, 17 p.

Credits

Funding Agencies

This resource was created using funding from the following sources:
Agency Name Award Title Award Number
National Science Foundation Mapping Aquifer Heterogeneity: Integrated Analysis of Electrical Resistance Tomography, Tracer Tests, and Hydraulic Data EAR-0124262

Contributors

People or Organizations that contributed technically, materially, financially, or provided general support for the creation of the resource's content but are not considered authors.

Name Organization Address Phone Author Identifiers
Steven Gorelick Stanford University

How to Cite

Singha, K. (2019). Data from Singha and Gorelick (2005), Saline tracer visualized with electrical resistivity tomography: field scale spatial moment analysis, HydroShare, https://doi.org/10.4211/hs.d2481d34e4414494a24a0be0f14bd3a1

This resource is shared under the Creative Commons Attribution-NoCommercial CC BY-NC.

http://creativecommons.org/licenses/by-nc/4.0/
CC-BY-NC

Comments

Kamini Singha 4 years, 2 months ago

Note on the data structure of the files inside the ER_data_files folder: all *date*.xls files share the same format. The first column is the measurement # (7200 in total) and cycles from 1-1200 six times because the 3-D array was set up as six 2-D planes, so we could look at images in 2-D. Columns 3,5,7,9 are the electrode numbers used and 10 is the electrical resistance R.

The file alldata.xls in the ER_data_files folder isn't really needed; it is just all of the ER data files put into one data file, if that helps anyone. The strange header at the top (going from 15 to 25.2) is the date: the first data set is from July 15, the last from July 25, and the fractions are just the fraction of the day. This was made for simple plotting in Excel.

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