Combining Models of Root-Zone Hydrology and Geoelectrical Measurements: Recent Advances and Future Prospects

Abstract

Recent advances in measuring and modeling root water uptake along with refined electrical petrophysical models may help fill the existing gap in hydrological root model parametrization. In this paper, we discuss the choices to be made to combine root-zone hydrology and geoelectrical data with the aim of characterizing the active root zone. For each model and observation type we discuss sources of uncertainty and how they are commonly addressed in a stochastic inversion framework. We point out different degrees of integration in the existing hydrogeophysical approaches to parametrize models of root-zone hydrology. This paper aims at giving emphasis to stochastic approaches, in particular to Data Assimilation (DA) schemes, that are generally identified as the best way to combine geoelectrical data with Root Water Uptake (RWU) models. In addition, the study points out a more suitable objective function taken from the optimal transport theory that better captures complex geometry of root systems. Another pathway for improvement of geoelectrical data integration into RWU models using DA relies on the use of stem based methods as a leverage to introduce more extensive root knowledge into RWU macroscopic hydrological models.

Time-Lapse Electrical Resistivity Tomography (TL-ERT) for Landslide Monitoring: Recent Advances and Future Directions

“…In order to make the landslide monitoring effective by applying the TL-ERT method, an appropriate and correct geological model must be adopted. As reported by other authors, the petrophysical models used to transform resistivity values in hydrological parameters are site-specific [81,85], and cannot be used to define resistivity thresholds applicable for the activation of landslides in any geological environment. The main evolution of the petrophysical relationships reported in the literature has regarded the change of the number of phases to be considered in the model [86].…”

“…Except for a few studies [80,85], all the acquisitions were carried out along 2D longitudinal profiles. This still represents a limitation of the method, as the investigated object has a 3D structure.…”

Physical Soil Parameter and Resistivity Profile in the Vadose Zone: Preliminary Result of Groundwater Recharge Study

“…Tree roots also known as rhizosphere are part of the vadose zone, which has continuously been studied as a multi-disciplinary approach in hydro(geo)logy, ecohydrology, and soil-plant science due to its complexity and reclaimed status as the critical part that poses potential threats to the saturated or water table beneath [4,5,6]. Invasive methods such as Induced Polarization, Electrical Tomography, and Ground Penetrating Radar have been used to characterize spatial tree root zone distribution and also compare it with the soil's physical properties, notably soil water content, permeability, and total porosity [7,8,9], hence the evaporation and or percolation processes can be approached by simulating numerically the soil properties profile [10,11,12].…”

Identifying soil-plant interactions in a mixed-age orange orchard using electrical resistivity imaging

“…Moreover, Michot et al (2003) calculated 2-D SWC sections from ER-based surveys using field-scale calibration relationships obtained between the ER of each soil horizon and its SWC. In general, petro-physical relationships are site-specific and need to be calibrated before serving as translation between ER and SWC (Mary et al 2021). In addition, petro-physical relationships at the root zone level suffer from biases due to the influence of the root system on the measured ER (Cimpoiaşu et al 2020).…”

“…In particular, time-lapse ERI (or electrical resistivity tomography, ERT) approaches show strong potential for monitoring SWC changes (Michot et al 2003;Calamita et al 2012;Vanella et al 2021), RWU (Beff et al 2013;Vanella et al 2018Vanella et al , 2019) and root zone system processes (Cassiani et al 2015) in the unsaturated zone. Recently, Mary et al (2021) stated that time lapse ERI or ERT measurements are the most informative tools to derive SWC movement and variation due to RWU.…”