The University of Nebraska-Lincoln Conservation and Survey Division (CSD) School of Natural Resources has established a new applied geophysics research program in Scottsbluff that is prepared to investigate environmental and agricultural issues in the Scottsbluff area and elsewhere in Nebraska.
Many pieces of geophysical research equipment have been acquired by CSD Geoscientist Dr. Mohamed Khalil Aboushanab since he joined the faculty at the UNL Panhandle Research, Extension and Education Center at Scottsbluff in September 2021.
A key piece of equipment is a new, state-of-the-art resistivity meter that can capture resistivity images of the earth’s subsurface up to 300 feet in depth. These images can help discover and investigate groundwater aquifers, mineral resources, subsurface geological structures, archaeological remains, and many other features. Thus the new equipment can be used to study many different environmental and engineering problems.
To conduct a resistivity survey, a string of non-destructive probes is set up on the ground surface. The probes can measure a slice of subsurface up to 1,300 feet long. An electric current is injected through them, and the electrical resistivity below the surface is measured with a resistivity meter.
After this data is collected, mathematically-based software is used to produce two-dimension and three-dimension images of the subsurface.
Potential applications for the new resistivity meter include studies of groundwater-surface water interactions; nitrate contamination in aquifers; soil salinization; soil piping; rodent burrows; claypans; sinkholes; differential settlement; landslides and other mass movements; drainage pipe problems; irrigation-canal collapses; leak detection at animal-waste storage ponds and treatment lagoons; and tree-root biomass detection.
In addition to the new resistivity meter, Dr. Khalil Aboushanab has acquired frequency-domain electromagnetic equipment, which can measure earth resistivity to depths of up to 200 feet without any contact with the ground, and a self-potential system, which can delineate vertical or horizontal water seepage.
CSD is also investigating the purchase of new time-domain electromagnetic (TDEM) equipment that can survey to maximum depths of approximately 1,300 feet.
Together, the new equipment now available in Scottsbluff and Dr. Khalil Aboushanab’s more than 20 years of experience in using resistivity and electromagnetic methods for geophysical exploration represent a major expansion of CSD’s ability to engage in applied research to serve Nebraskans.
Several views of Mohamed Khalil operating the new resistivity meter at the Panhandle Research, Extension and Education Center: TOP: During the resistivity survey, with a laptop computer to collect and analyze data and a battery for the power source. CENTER LEFT: Setting up the resistivity profile, positioning sensors 1.5 meters apart in an array that is 30 meters long. CENTER RIGHT: The laptop computer monitoring resistivity data during data acquisition for quality control. BOTTOM: This graphic generated from resistivity data by the computer software represents the resistivity section for an area 30 meters long and about seven meters in depth. The blue color indicates a shallow clay layer in the soil.
