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Quantification of aquifer properties with surface nuclear magnetic resonance in the Platte River valley, central Nebraska, using a novel inversion method

Scientific Investigations Report 2012-5189

Prepared in cooperation with the Central Platte Natural Resources District and the Nebraska Environmental Trust
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Abstract

Surface nuclear magnetic resonance, a noninvasive geophysical method, measures a signal directly related to the amount of water in the subsurface. This allows for low-cost quantitative estimates of hydraulic parameters. In practice, however, additional factors influence the signal, complicating interpretation. The U.S. Geological Survey, in cooperation with the Central Platte Natural Resources District, evaluated whether hydraulic parameters derived from surface nuclear magnetic resonance data could provide valuable input into groundwater models used for evaluating water-management practices. Two calibration sites in Dawson County, Nebraska, were chosen based on previous detailed hydrogeologic and geophysical investigations. At both sites, surface nuclear magnetic resonance data were collected, and derived parameters were compared with results from four constant-discharge aquifer tests previously conducted at those same sites. Additionally, borehole electromagnetic-induction flowmeter data were analyzed as a less-expensive surrogate for traditional aquifer tests. Building on recent work, a novel surface nuclear magnetic resonance modeling and inversion method was developed that incorporates electrical conductivity and effects due to magnetic-field inhomogeneities, both of which can have a substantial impact on the data. After comparing surface nuclear magnetic resonance inversions at the two calibration sites, the nuclear magnetic-resonance-derived parameters were compared with previously performed aquifer tests in the Central Platte Natural Resources District. This comparison served as a blind test for the developed method. The nuclear magnetic-resonance-derived aquifer parameters were in agreement with results of aquifer tests where the environmental noise allowed data collection and the aquifer test zones overlapped with the surface nuclear magnetic resonance testing. In some cases, the previously performed aquifer tests were not designed fully to characterize the aquifer, and the surface nuclear magnetic resonance was able to provide missing data. In favorable locations, surface nuclear magnetic resonance is able to provide valuable noninvasive information about aquifer parameters and should be a useful tool for groundwater managers in Nebraska.

Geospatial Extents

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Quantification of aquifer properties with surface nuclear magnetic resonance in the Platte River valley, central Nebraska, using a novel inversion method
Series title:
Scientific Investigations Report
Series number:
2012-5189
Year Published:
2012
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Reston, VA
Contributing office(s):
Crustal Geophysics and Geochemistry Science Center
Description:
viii, 50 p.
Number of Pages:
61
Country:
United States
State:
Nebraska
County:
Buffalo;Dawson;Hall;Merrick
Other Geospatial:
Central Platte Natural Resources District
Datum:
North American Datum of 1983
Projection:
Lambert Conformal Conic projection
Scale:
100000