A Preliminary Field Study to Examine the Potential of Hydrogeophysical Methods to Monitor Soil Moisture Dynamics in Quaternary Outwash Materials

Abstract

This thesis examines the capacity of a suite of near-surface geophysical techniques (i.e., ground-penetrating radar (GPR), electromagnetic induction (EMI) and electrical resistivity tomography (ERT)) to monitor soil moisture dynamics over a complete annual cycle at the Arkell Research Station (ARS). The ARS is located at the terminal edge of the Paris moraine within the outwash plain and consists of highly heterogeneous coarse grained deposits. The characterization of the soil moisture conditions at this site would represent an important component in furthering our understanding of the capabilities of geophysical methods in coarse grained materials. Soil water contents can be monitored through measurements of dielectric permittivity from GPR surveys and electrical conductivity from EMI and ERT surveys. The geophysical measurements made during this study qualitatively agree with the soil moisture conditions determined through gravimetric sampling and inferred from weather data. However, the quantitative correlation between the geophysical and gravimetric data was found to be low. Hence, while it is apparent from this work that the responses of these geophysical methods are sensitive to soil moisture conditions in coarse grained soils, more work is required to extract quantitative soil moisture information from geophysical data for these soils.