Hydraulic Properties Research Articles

The stability of natural and man-made unsaturated slopes influenced by different rainfall patterns.

Many slope failures have been recorded in Malaysia in recent times, particularly during the rainy season. An irregular rainfall is a change in rainfall patterns that is found to affect the slope stability with the infiltration of rainfall. The objective of this research is to investigate variations in the pattern of rainfall and their effect on the stability of natural and man-made unsaturated slopes in two separate site locations. Case A is located near a student's hall in Universiti Kebangsaan Malaysia (UKM), and another is located at the main entrance of UKM. Both cases are simulated with current and projected rainfall. The behaviour of the slopes with applied rainfall is analyzed with generated pore-water pressure, displacement and factor of safety. The first case was conducted by including the rainfall records from January 2011 to January 2021 and future-oriented data in January 2050. The software package used for this case is Plaxis2D. The results indicate that the highest factor of safety captured for 2021 was 1.156, while the lowest factor of safety was 1.11. It is observed that the obtained safety factor decreased with increasing rainfall intensity. Moreover, the displacement obtained was 0.1761m. In Case B, the capillary barrier system was used consisting of two layers of soil with different hydraulic properties as slope cover. A parametric study was performed to investigate the effect of several variables, including the hydraulic conductivity of soil and the rate of infiltration. By using SEEP/W from the GeoStudio, the results obtained show that the pore-water pressure in the initial slope is higher than the slope with the capillary barrier system. In addition, the factor of safety was calculated in SLOPE/W, indicating that the slope with a capillary barrier system has a high factor of safety than the original slope. The capillary barrier system was seen to improve slope stability by reducing the rainwater infiltration. These two cases were investigated in regard to the behaviour of unsaturated slopes within the changing rainfall and the unsaturated soil conditions.

The added value of CoreVESS score and penetration resistance in predicting the soil–water retention curve

Soil hydraulic properties, such as the soil–water retention curve (SWRC), play a crucial role in simulating water transport within the vadose zone. They can be directly measured in the laboratory or field, or indirectly predicted by using Pedotransfer Functions (PTFs). It has been advocated that accounting for soil structure could marginally improve the prediction accuracy of PTFs in its wet range. The aim of this study was to test whether the use of an easy-to-determine soil structure-related variable could effectively increase the prediction accuracy of water retention curve PTFs. Additionally, we explored whether including soil strength, another soil property that is easy and quickly to determine in the field in many replicates, could improve PTF performance. Our investigation involved extensive sampling of 252 soil horizons across 42 cropped fields, each exhibiting within-field variations in soil structural degradation. Soil structure was represented by a soil structural quality score (Sq) taken from a semi-quantitative visual soil assessment (CoreVESS), which was included in the PTFs as predictor variable or as discriminator (Sq) for data grouping in addition to or instead of ‘classical’ predictors such as soil organic carbon content, clay and sand content, bulk density and soil layer. Penetration resistance (PR) was taken as a variable for soil strength. Various regression methods from classical regression to machine learning were evaluated on Train and Test subdatasets. To evaluate the effect of data grouping, the dataset was split in two based on structure and on texture. Both point and parametric PTFs were developed, with the latter predicting the parameters of the Van Genuchten (VG) water retention equation. Overall, the k-nearest neighbors PTFs (KNN-PTFs) achieved the best performance showing the highest R2 and lowest RMSE values. Moreover, the point PTFs showed much better and more stable predictive ability than parametric PTFs. The inclusion of PR as an additional predictor variable slightly improved the prediction performance in the wet range of the SWRC. Interestingly, Sq proved beneficial when substituted for bulk density but not when used in addition to it. Grouping data based on texture and structure improved the prediction accuracy of the PTFs, particularly evident in textural grouping and MLR, but not in KNN.

Fault rock properties and conditions produce variance in slip during earthquake rupture propagation at the Nankai Trough

Although drilled samples of fault rocks have yielded information on frictional features of shallow subduction zones, the relationship of rupture propagation to the levels of friction and pore-fluid pressure remains uncertain. To investigate this topic, we performed dynamic rupture simulations along the megasplay fault that slipped during the 1944 Mw 8.0 Tonankai earthquake in the Nankai Trough. We used actual data from friction experiments on rocks from the fault segment and pre-existing pore pressures deduced from geophysical surveys for the shallow portion of 0–10 km depth along the fault. Simulations of low friction (friction coefficient ca. 0.04) produced large slip (about 30 m), whereas simulations using higher friction (friction coefficient ca. 0.2) suppressed the rupture. In simulations with low friction in which the pore-fluid pressure was nearly equal to the lithostatic stress, the slip decreased to about 25 m. However, when the simulations included slip-strengthening at shallow depth and higher friction, the slip still reached roughly 20 m. Such variability in slip during rupture propagation is caused by differences in the friction features and fluid pressure conditions of fault rocks, in which the friction features might be related to the mineral composition. Spatiotemporal heterogeneity in fault-rock type and their physical and hydraulic properties may fundamentally produce the complexity and variability of earthquake rupture propagation along the Nankai plate-subduction boundary.

Electrodeposition of calcareous cement from seawater in marine silica sands

The erosion of marine sediments is a pressing issue for coastal areas worldwide. Established methods to mitigate coastal erosion fail to provide lasting and sustainable solutions to protect marine ecosystems. Here we demonstrate the application of mild electrical stimulations to precipitate calcareous mineral binders from seawater in the pores of marine soils via electrodeposition, an alternative approach to mitigating coastal erosion. Results of electrochemical laboratory experiments unveil that the polymorphs, precipitation sites, intrusion mechanisms, and effects of electrodeposited minerals in marine sands vary as a function of the magnitude and duration of applied voltage, soil relative density, and electrolyte ionic concentration. Surprisingly, in addition to the precipitation of calcium carbonate and magnesium hydroxide, the formation of hydromagnesite is also observed due to electrically driven fluctuations in the local pH\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${pH}$$\\end{document}. These electrodeposits lead to enhanced mechanical and hydraulic properties of the marine sands, indicating that electrodeposition routes could be developed to reinforce marine soils in coastal areas that more closely mimic natural systems.

Application of surface geophysical investigations and pumping test data analysis for better characterization of aquifer hydraulic parameters, Upper Awash Sub-Basin, Central Ethiopia

Study regionUpper Awash River Sub-basin in central Ethiopia Study focusThe research aimed to estimate aquifer parameters and conduct resistivity modeling in the study area. Data were collected from 890 Schlumberger Vertical Electrical Soundings (VES) points strategically distributed across six selected zones. The VES data were analyzed using computer modeling and curve-matching techniques to interpret the resistivity responses of the geological formations. This analysis provided insights into the subsurface characteristics and identified potential aquifer zones. New insights for the regionThe interpreted curves from the VES data and Root Mean Square (RMS%) values ranging from 0.36 % to 1.67 %, indicating a good fit between observed and modeled data. Resistivity modeling and geoelectrical sections were produced along specific lines, visualizing subsurface structures and confirming the resistivity responses of the geological formations. To determine aquifer parameters, the Dar-Zarrouk parameters were calculated from the interpreted curves, yielding crucial information about hydraulic properties such as hydraulic conductivity (K) and transmissivity (T). Hydraulic conductivity values ranged from 1.1 m/day to 21.7 m/day, while transmissivity values ranged from 144.3 m²/day to 2763.3 m²/day. Validation against borehole pumping test data showed strong correlations: R² = 0.9873 for transmissivity and transverse resistance, and R² = 0.9352 for hydraulic conductivity and resistivity. These findings enhance the understanding of the complex volcanic aquifer characteristics in the Upper Awash River Sub-basin, aiding sustainable groundwater management and development in the area.

Modelling the ecohydrological plasticity in soil hydraulic properties of Sphagnum mosses

Modelling the ecohydrological plasticity in soil hydraulic properties of <i>Sphagnum</i> mosses

Unique root hydraulic and mechanical properties support the resilience of grapevines adapted to the Atacama Desert.

Cortical lacunae caused by drought, especially observed in hybrids originating from Vitis rupestris, disrupt the connection between roots and soil. Yet, the physiological processes behind lacuna formation during drought and its consistency across Vitis species remain unclear. Here, we used a root pressure probe to investigate fine root hydraulic and mechanical properties, in the arid-adapted R-65 and drought-susceptible 101-14Mgt cultivars. We then performed P-V curves, root sap osmolality, and electrolyte leakage (EL) and used fluorescent light microscopy techniques. Only 101-14Mgt showed lacunae formation during drought due to its stiffer cortical tissue, unlike R-65. Lacunae resulted in a notable decline in root hydraulic conductivity during severe drought, with increased EL and root sap osmolality, indicating potential cellular damage. R-65 displayed different and xerophyte-like characteristics featuring a higher turgor loss point and decreased root capacitance, essential for maintaining root structural integrity in arid conditions. Our findings highlight lacuna formation is impacted by root tissue elasticity possibly linked to specific Vitis species favoring deeper rooting. In arid-adapted grapevines, hydraulic regulators such as reduced turgor loss point, and root capacitance could contribute to enhanced drought tolerance.

Characterizing coastal aquifer heterogeneity from a single piezometer head chronicle

We propose a new method for identifying the hydraulic properties of coastal aquifers based on their response to continental and marine influences observed from isolated piezometers displaying both tidal and seasonal fluctuations. From a single piezometer, a first approximation of hydraulic conductivity and porosity can be derived analytically from the mean hydraulic head and its tidal fluctuations. If this approximation also allows a correct simulation of seasonal head variations, the aquifer can be modelled as homogeneous. Otherwise, the seasonal head variations provide constraints on the heterogeneity of hydraulic properties. This new method is applied to a coastal aquifer in Normandy, formed by a relatively flat, kilometer-wide coastal strip of Quaternary sands followed by a foothill of higher Brioverian shales. Hydraulic head variations monitored daily for 8 years in a piezometer located in the Quaternary sand formation enable us to constrain their hydraulic conductivity (5–20 m.d−1) and porosity (7–10 %) within restricted ranges. They also suggest the existence of a significantly more porous formation (15–30 %) upstream of the observation piezometer, which could consist of more porous sands or fractured shales. In the case of limited surface–subsurface interactions, the identification method relies on a step-by-step combination of analytical solutions and simplified 1D numerical models. When more important surface–subsurface interactions are involved, a spatialized 2D model is used, that allows the analysis of seepage areas. Based on this case study, we gradually introduce 1D and 2D approaches, and discuss their applicability. We finally illustrate one major application of this approach by analyzing the interest of aquifer properties investigation on groundwater-induced flooding vulnerability.

Analysis of the unsaturated hydraulic properties of rocks using multiple laboratory methods

Analysis of the unsaturated hydraulic properties of rocks using multiple laboratory methods

Integrated Effects of Soil Moisture on Wheat Hydraulic Properties and Stomatal Regulation.

The development of water-saving management relies on understanding the physiological response of crops to soil drought. The coordinated regulation of hydraulics and stomatal conductance in plant water relations has steadily received attention. However, research focusing on grain crops, such as winter wheat, remains limited. In this study, three soil water supply treatments, including high (H), moderate (M), and low (L) soil water contents, were conducted with potted winter wheat. Leaf water potential (Ψleaf), leaf hydraulic conductance (Kleaf), and stomatal conductance (gs), as well as leaf biochemical parameters and stomatal traits were measured. Results showed that, compared to H, predawn leaf water potential (ΨPD) significantly reduced by 48.10% and 47.91%, midday leaf water potential (ΨMD) reduced by 40.71% and 43.20%, Kleaf reduced by 64.80% and 65.61%, and gs reduced by 21.20% and 43.41%, respectively, under M and L conditions. Although gs showed a significant difference between M and L, Ψleaf and Kleaf did not show significant differences between these treatments. The maximum carboxylation rate (Vcmax) and maximum electron transfer rate (Jmax) under L significantly decreased by 23.11% and 28.10%, stomatal density (SD) and stomatal pore area index (SPI) under L on the abaxial side increased by 59.80% and 52.30%, respectively, compared to H. The leaf water potential at 50% hydraulic conduction loss (P50) under L was not significantly reduced. The gs was positively correlated with ΨMD and Kleaf, but it was negatively correlated with abscisic acid (ABA) and SD. A threshold relationship between gs and Kleaf was observed, with rapid and linear reduction in gs occurring only when Kleaf fell below 8.70 mmol m-2 s-1 MPa-1. Our findings demonstrate that wheat leaves adapt stomatal regulation strategies from anisohydric to isohydric in response to reduced soil water content. These results enrich the theory of trade-offs between the carbon assimilation and hydraulic safety in crops and also provide a theoretical basis for water management practices based on stomatal regulation strategies under varying soil water conditions.

Characterizing water level responses to barometric pressure fluctuations from seconds to days

A regression deconvolution method using distributed lags for the efficient calculation of barometric/loading response functions in the presence of Earth tides and background trends was applied to water pressure measurements collected every second. This method was able to simultaneously deconvolve multiple stresses that can be used for both signal decomposition (removal of noise and isolation of signals) and the determination of impulse response functions that can be interpreted for hydraulic properties and subsurface characterization. We also demonstrate how the static barometric efficiency is a deficient parameter when applied to wells having delayed responses and needs to be applied with care. The distributed lag method combined with high frequency monitoring has implications for improved site characterization, determining the continuity of subsurface features, parameter estimation, understanding the degree of confinement, and signal decomposition. The methods for this paper can be found in the R hydrorecipes package.

Numerical study on benchmark analysis of NACIE-UP facility with uniform and non-uniform power distribution

The NACIE-UP (NAtural Circulation Experiment-Upgrade) facility is located at the ENEA Brasimone Research Centre (Italy) and is designed to investigate the thermal–hydraulic properties of Lead-Bismuth Eutectic (LBE) within a wire-spaced assembly under uniform and non-uniform power distribution conditions. This benchmark exercise proposed by ENEA is based on previous experiment results, intending for development and validation of CFD/TH system code, stand-alone CFD simulation, etc. In this study, the thermal–hydraulic characteristics of Fuel Pin Simulator (FPS) are analyzed, which contains inlet bend and outlet section. ANSYS Fluent solver is applied with the COUPLE algorithm of RANS SSTk-ω model. Cheng&Tak correlation and computational conditions are implanted into Fluent in the form of UDFs. Moreover, calculations were performed for ADP10, ADP06 and ADP07. The results show that the RMSEs of ADP10SS1 and ADP10SS2 are 2.52 K and 3.69 K, 7.05 K and 8.48 K for ADP06SS1 and ADP06SS2, respectively, which indicate that the adopted models have good prediction ability for the temperature of the experimental conditions. Meanwhile, the heat transfer characteristics of different sub-channels and sections are investigated and compared with the correlations of Ushakov, Mikityuk, Kazimi and Carelli. The experimental and simulation values of the uniformly heated ADP10 are in good agreement with the correlations, while there is a large deviation for the non-uniformly heated ADP06. Therefore, it is necessary to develop new correlations for the heat transfer characteristics of LBE in wire-wrapped bundle. Above all, this study provides quantitative and qualitative analysis for verification and validation of CFD/TH system code and stand-alone CFD simulation.

Measurements of Soil Water Potential and Conductivity based on a Simple Evaporation Experiment using a Hydraulic Property Analyzer.

The measurement of soil hydraulic properties is critical in understanding the physical components of soil health as well as integrated knowledge of soil systems under various management practices. Collecting reliable data is imperative for informing decisions that affect agriculture and the environment. The simple evaporation experiment described here uses instrumentation in a laboratory setting to analyze soil samples collected in the field. The soil water tension of the sample is measured by the instrument, and tension data is modeled by software to return soil hydraulic properties. This method can be utilized to measure soil water retention and hydraulic conductivity and give insight into differences in treatments or environmental dynamics over time. Initial establishment requires a user, but data acquisition is automated with the instrument. Soil hydraulic properties are not easily measured with traditional experiments, and this protocol offers a simple and optimal alternative. Interpretation of results and options for extending the data range are discussed.

Using index and physically-based models to evaluate the intrinsic groundwater vulnerability to non-point source pollutants in an agricultural area in Sardinia (Italy)

This research aims at studying the intrinsic vulnerability of groundwater to diffuse environmental pollutants in the Muravera coastal agricultural area of Sardinia, Italy. The area faces contamination risks arising from agricultural practices, especially the use of fertilizers, pesticides, and various chemicals that can seep into the groundwater. The study examined the interplay among hydrological elements, including soil characteristics, groundwater depth, climate conditions, land use, and aquifer properties. To do that, the outcomes of FLOWS 1D physically-based agrohydrological model were analyzed in parallel with those of the overlay-and-index model SINTACS, in a sort of reciprocal benchmarking. By using FLOWS, water movement and solute transport in the unsaturated zone were simulated by, respectively, solving the Richard Equation (RE) and the Advection-Dispersion equation (ADE). As such, this model allowed to account for the role of soil hydraulic and hydro-dispersive properties variability in determining the travel times of a conservative solute through the soil profile to the groundwater. For FLOWS simulations, a complete dataset was used as input, including soil horizons, soil physical and hydraulic properties of 36 soil profiles, average annual depth to groundwater table at each soil profile (ranging from 1 to 50 meters), and climatic temporal series data on rainfall and evapotranspiration. Detailed analyses of travel times for the movement of 25, 50, 75, and 100% of the solute mass to reach groundwater were conducted, revealing that the depth to groundwater predominantly influences vulnerability. This result was coherent with SINTACS vulnerability map due to the large impact of the depth to groundwater on SINTACS analysis.

Optimization of Irrigation Programming for Different Water Allocation Strategies at Network Level: Method and Application

AbstractOptimum irrigation programming at network level is important not only for maximum yield and benefit from the system but also for sustainable use of constrained resources. The subject of this investigation is to devise a method which enables optimum water allocation in irrigation networks, to apply it to a real system, and to analyze the results. In the first step, the irrigation district was divided into the most suitable water allocation zones considering the hydraulic properties of the canals. Next, alternative system rotation periods were defined in accordance with the properties of the research area, the hydraulic infrastructure of the irrigation network and the crop pattern. In this process, the model was run for five different water allocation strategies. The model was applied to the command area of Sarıkız Irrigation Association in the Ahmetli Regulator Right Bank Irrigation System in the Gediz Basin. Therefore, irrigation programs were prepared for the crop pattern, which receives water from 45 tertiary canals of the Y9 secondary. The irrigation time allocated to each tertiary canal and the amount of irrigation water were evaluated, together with the water shortage levels which occurred in these tertiary canals. The results indicated that the model defined the optimum system rotation period, the borders and the sizes of the most suitable water allocation zones, and the most suitable irrigation programs under the prevailing conditions. The proposed model can provide an insight for decision makers as a decision support tool.

Short high-accuracy tritium data time series for assessing groundwater mean transit times in the vadose and saturated zones of the Luxembourg Sandstone aquifer

Abstract. Among the manifold of environmental tracers at hand, tritium is the only one that can give information on groundwater age within the timescale of 100 years for the entire flow system, i.e., unsaturated and saturated. However, while in the Southern Hemisphere, a single water sample is sufficient for tritium-based young groundwater dating, several tritium measurements spanning multiple years are still needed in the Northern Hemisphere to disentangle the natural cosmogenic tritium input from that caused by the atmospheric thermonuclear weapons tests mainly carried out in the early 1960s. Although it is advised to focus tritium dating on sites where long chronicles of tritium data are available, in this study we tested the potential for short high-accuracy tritium data series (∼4 years) to date groundwater from 35 springs draining the Luxembourg Sandstone aquifer (central western Europe). We determined groundwater mean transit times using the lumped-parameter model approach in a Monte Carlo uncertainty estimation framework to provide uncertainty ranges inherent to the low number of tritium data at hand and their related analytical errors. Our results show that unambiguous groundwater mean transit time assessments cannot be determined solely based on such recent short tritium time series, given that several ranges of mean transit times appeared theoretically possible. Nonetheless we succeeded in discriminating groundwater mean transit times in the vadose and saturated zones of the aquifer through a stepwise decision process guided with several supplementary data. The mean transit time required for water to cross the vadose zone was estimated to be between 0.5±0.5 and 8.1±1.2 years depending on the spring, while for water to flow through the saturated zone, it varied from 5.7±2.4 to 18.9±4.6 years (median ± half of the 5–95 percentile range). Our findings are consistent with both the tritium measurements of individual springs and the hydrogeological context of the study area. We specifically corroborated the dating results using the known hydrogeological properties of the Luxembourg Sandstone aquifer, the hydrochemistry of the studied springs, and their discharge dynamics. When translated into water velocities (which average ∼12 and ∼170 m yr−1 for the vadose and the saturated zones, respectively), the tritium dating results mirrored the horizontal–vertical anisotropy of the aquifer's hydraulic properties caused by the bedded character of the Luxembourg Sandstone. In addition to improving our understanding of water transit times in the Luxembourg Sandstone aquifer, this study demonstrates how it is currently possible to use short tritium time series to date young groundwater bodies at new sites in central Europe.

Development of a new hydraulic electric index for rock typing in carbonate reservoirs

Rock typing techniques have relied on either electrical or hydraulic properties. The study introduces a novel approach for reservoir rock typing, the hydraulic-electric index (HEI), which combines the strengths of traditional electrical and hydraulic rock typing methods to characterize carbonate reservoirs more accurately. By normalizing the ratio of permeability and formation resistivity factor (K/FRF) with respect to porosity, the HEI method is applied to two datasets of carbonate core samples: dataset 1 consists of 112 carbonate core samples from the Tensleep formation in the Bighorn basin of Wyoming and Montana, and dataset 2 includes 81 carbonate core samples from the Asmari formation in the south-west of Iran. Statistical analysis confirms the effectiveness of the HEI in predicting permeability, with high determination coefficients for both datasets (resulting in determination coefficients (R2) of 0.965 and 0.904 for dataset 1 and dataset 2, respectively). The results classify the rock samples into distinct rock types, nine rock types for dataset 1 and four rock types for dataset 2, and demonstrate the HEI ability to capture the relationship between hydraulic conductivity and electrical resistivity in carbonate reservoir rocks. Applying the HEI method to the validation dataset yielded highly accurate permeability predictions, with average of determination coefficients of 0.883 and 0.859 for dataset 1 and dataset 2, respectively. Validation of the HEI method further confirms (20% of the dataset was set aside for validation, while the remaining 80% was used for the rock typing approach (5 folds)) its accuracy in predicting permeability, highlighting its robust predictive capacity for estimating permeability in carbonate reservoirs.

The role of light intensity in water transport and homeostasis across different vapor pressure deficit conditions

Vapor pressure deficit (VPD) directly affects the driving force of plant water movement by altering the water potential gradient between the atmosphere and plants and indirectly influences the resistance to water movement by regulating plant structure. Concurrently, light intensity modulates both the driving force and resistance to water movement by regulating plant morphology and nonstructural carbohydrate synthesis. Despite significant advances in the understanding of the regulatory effects of VPD on water absorption and transport in tomatoes, the effect of light intensity regulation under varying VPDs on water transport and homeostasis remains to be clarified. Here, we investigated the effects of two light intensities (L300; 300 µmol m–2 s–1, L600; 600 µmol m–2 s–1) on plant anatomy, physiological traits, hydraulic properties, and expression of plasma membrane intrinsic proteins (PIPs) and tonoplast intrinsic proteins (TIPs) in tomatoes subjected to long-term high and low VPDs. In addition, we analysed the correlations and path coefficients of these indicators. These results indicate that higher light intensity reduces resistance to water movement by enhancing root morphology, vessel parameters in roots and stems, leaf vein density, stomatal morphology, physiological traits, and expression of SlTIPs and SlPIPs in both roots and leaves. Concurrently, increased light intensity boosts the driving force of water movement by amplifying the water potential difference and transpiration under low VPD. However, under high VPD, elevated light intensities create a larger water potential difference, prompting plants to reduce this excessive force by decreasing transpiration and stomatal conductance, thereby maintaining water homeostasis. These findings suggest that light intensity can effectively regulate water homeostasis by dynamically optimising plant structure, hydraulic properties, and the expression of SlTIPs and SlPIPs across different VPDs, providing a theoretical foundation for practical light intensity management in agriculture.

Physics‐Informed Neural Networks Trained With Time‐Lapse Geo‐Electrical Tomograms to Estimate Water Saturation, Permeability and Petrophysical Relations at Heterogeneous Soils

AbstractDetermining soil hydraulic properties is complex, posing ongoing challenges in managing subsurface and agricultural practices. Electrical resistivity tomography (ERT) is an appealing geophysical method to monitor the subsurface due to its non‐invasive, easy‐to‐apply and cost‐effective nature. However, obtaining geoelectrical tomograms from raw measurements requires the inversion of an ill‐posed problem, which causes smoothing of the actual structure. Furthermore, the spatial resolution is determined from the distances in the electrode placement, thus inherently upscaling the obtained structure. This study explores the applicability of physics‐informed neural networks (PINNs) for upscaling permeability and petrophysical relations and monitoring water dynamics at heterogeneous soils using time‐lapse geoelectrical data. High‐resolution numerical simulations mimicking water infiltration were used as benchmarks. Synthetic ERT surveys with electrode spacing 10 times larger than the numerical model resolution were conducted to provide 2D electrical tomograms. The tomograms were fed to a PINNs system to obtain the permeability, petrophysical relations, and water content maps. An additional PINNs system incorporating water content measurements was trained to examine measurement sensitivity. Results have shown that the PINNs system could produce reliable results regarding the upscaled permeability and petrophysical relations fields. Water dynamics at the subsurface was accurately predicted with an average error of ∼3%. Adding water content measurements to PINNs training improved the system outcomes, mainly at the ERT low sensitivity zones. The PINNs system reduced water saturation errors by more than 30% compared to the common practice of directly translating the geoelectrical tomograms to water saturations using known, homogeneous petrophysical relations.

Theoretical evaluation of high-permeability wellbore skin effect on aquifer response under pumping

Skin zones with distinct hydraulic properties often form around wellbores during drilling operations. Conventional skin-factor models, developed for low-permeability (positive) skin, assume discontinuous hydraulic heads between the wellbore and aquifer. However, these models may be inadequate for high-permeability (negative) skin scenarios resulting from intensive well development. This study derives a new skin-factor approach for negative skin approaches based on the two-zone model approach. We derive a new skin-factor approach that maintains continuous heads between the wellbore and aquifer while allowing for discontinuous fluxes. Using Laplace and finite cos-Fourier transformations, we develop a groundwater flow model for aquifer pumping under a partially penetrating well, incorporating this new approach. An asymptotic expansion method is employed to obtain a large-time solution. The proposed model is also compared to the existing two-zone model. Sensitivity analysis reveals that high-permeability skin significantly affects drawdown, particularly when there is a sudden increase in porosity within the skin zone. This revised approach provides a more accurate framework for modeling various skin effects, offering valuable insights for groundwater management and well hydraulic modeling in both hydrogeology and petroleum engineering applications.