37 Innovations in Research of Groundwater-Surface Water Interactions over Multiple Spatio-Temporal Scales

This session will focus on fluxes of water and solutes between groundwater and surface water, which play a crucial role in freshwater supplies for humans and ecosystems.

Sunday, 19 October 2025
1:30 PM - 5:30 PM
HBGCC, 209

An empirical equation for predicting soil bulk electrical conductivity from soil suction and physical properties

Paper number: 37-3
Program: Technical Sessions
Time: 1:56 PM – 2:11 PM

Authors

Abstract

Soil bulk electrical conductivity (σ), an important parameter in soil science and related disciplines, serves as a valuable proxy for investigating the spatial and temporal variabilities of soil properties, including salinity, clay content, and volumetric water content (θ). As both soil water suction (h) and σ strongly depend on θ, it is appealing to relate h to the more readily measurable σ. However, a general equation directly linking these two parameters has yet to be developed. In this study, we develop a new empirical equation between σ and h by combining the van Genuchten water retention model and Archie’s second law. We test this σ(h) relationship against laboratory measurements of three distinct soils and validate it using independent datasets from the literature. A two-electrode resistivity system was developed to measure σ continuously as samples underwent various suction levels using a hanging column or pressure plate extractors. The model parameters are derived from the physical properties of the soil samples. The results show that σ values predicted by the model closely match measured values, with dependable error metrics. This σ(h) relationship could help in spatial monitoring of h dynamics at the field scale using geophysical survey methods.

[This work was supported by the U.S. Department of Agriculture under Non-Assistance Cooperative Agreement 58-6060-6-009. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the U. S. Department of Agriculture.]

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-413530

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