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ARS Home » Pacific West Area » Boise, Idaho » Northwest Watershed Research Center » Research » Publications at this Location » Publication #190134

Title: Application of electromagnetic inductiom sensors for mapping the subsurface in the small watersheds

item Seyfried, Mark
item ABDU, H
item JONES, S
item KNIGHT, R

Submitted to: Trans American Geophysical Union
Publication Type: Abstract Only
Publication Acceptance Date: 9/20/2005
Publication Date: 12/1/2005
Citation: Robinson, D.A., Seyfried, M.S., Urdanoz, V., Abdu, H., Jones, S.B., Chandler, D., Knight, R. 2005. Application of electromagnetic induction sensors for mapping the subsurface in small watersheds. Trans American Geophysical Union.

Interpretive Summary:

Technical Abstract: The development of an integrated approach to characterizing small watersheds is crucial to understanding the complex links and feedback mechanisms within them. High spatial resolution soil texture data is well correlated to soil hydraulic properties. We present preliminary work using electromagnetic induction (EMI) to map subsurface properties in small watersheds. In this work we used both the Geonics EM-38 and the Dualem EMI sensors which were integrated with a GPS receiver and handheld computer to obtain geo-referenced bulk electrical conductivity (ECa) measurements. In the vertical orientation the sensors respond to the ECa of the top meter of soil. The ECa depends on the solution EC, soil water content, clay / rock content and soil depth. Data obtained from EMI in the form of ECa maps, can provide supplementary information for assessing flow pathways and locating monitoring instrumentation without soil-specific calibration. With ECa calibration, soil texture maps can be generated. This work may be more suited to semi-arid climates where seasonal wet and dry periods can be exploited in data analysis. Current work is looking at methods of developing the best survey and calibration methodology to interpret the measured ECa response for hydrological application.