Scholars@Duke
Zbigniew J. Kabala

Zbigniew J. Kabala

Associate Professor of Civil and Environmental Engineering
Civil and Environmental Engineering
zbigniew.kabala@duke.edu
Box 90287, Durham, NC 27708-0287
CIEMAS 2467, Durham, NC 27708

Selected Publications

Water Demand and Conservation in Arid Urban Environments: Numerical Analysis of Evapotranspiration in Arizona

Journal Article Water Switzerland · October 1, 2025 Water management in arid regions, such as Arizona, is critical due to increasing demands from the urban, agricultural, and recreational sectors. In this study, Finite element analysis software COMSOL Multiphysics (COMSOL 6.3) is used to quantify water dema ... Full text Cite

Gaia: Complex systems prediction for time to adapt to climate shocks

Journal Article Vadose Zone Journal · May 1, 2025 Earth's climate has undergone significant fluctuations in the geologic past, while the sun's radiation continues to increase, yet has always returned to conditions highly favorable to life. Thus, the biosphere overall appears able to cancel effects of exte ... Full text Cite

Hydrodynamic Porosity: A New Perspective on Flow through Porous Media, Part I

Journal Article Water Switzerland · August 1, 2024 Pore-scale flow velocity is an essential parameter in determining transport through porous media, but it is often miscalculated. Researchers use a static porosity value to relate volumetric or superficial velocities to pore-scale flow velocities. We know t ... Full text Cite

Hydrodynamic Porosity: A New Perspective on Flow through Porous Media, Part II

Journal Article Water Switzerland · August 1, 2024 In this work, we build upon our previous finding that hydrodynamic porosity is an exponential function of pore-scale flow velocity (or interstitial Reynolds number). We previously discovered this relationship for media with a square cavity geometry&amp ... Full text Cite

Refereeing the Sport of Squash with a Machine Learning System

Journal Article Machine Learning and Knowledge Extraction · March 1, 2024 Squash is a sport where referee decisions are essential to the game. However, these decisions are very subjective in nature. Disputes, both from the players and the audience, regularly occur because the referee made a controversial call. In this study, we ... Full text Cite

Inducing Deep Sweeps and Vortex Ejections on Patterned Membrane Surfaces to Mitigate Surface Fouling.

Journal Article Membranes · January 2024 Patterned membrane surfaces offer a hydrodynamic approach to mitigating concentration polarization and subsequent surface fouling. However, when subjected to steady crossflow conditions, surface patterns promote particle accumulation in the recirculation z ... Full text Cite

Impact of Crustacean Morphology on Metachronal Propulsion: A Numerical Study

Journal Article Fluids · January 1, 2024 Metachrony is defined as coordinated asynchronous movement throughout multiple appendages, such as the cilia of cells and swimmerets of crustaceans. Used by species of crustaceans and microscopic cells to move through fluid, the process of metachronal prop ... Full text Cite

Public Perception of ChatGPT and Transfer Learning for Tweets Sentiment Analysis Using Wolfram Mathematica

Journal Article Data · December 1, 2023 Understanding public opinion on ChatGPT is crucial for recognizing its strengths and areas of concern. By utilizing natural language processing (NLP), this study delves into tweets regarding ChatGPT to determine temporal patterns, content features, and top ... Full text Cite

Predicting and Reconstructing Aerosol–Cloud–Precipitation Interactions with Physics-Informed Neural Networks

Journal Article Atmosphere · December 1, 2023 Interactions between clouds, aerosol, and precipitation are crucial aspects of weather and climate. The simple Koren–Feingold conceptual model is important for providing deeper insight into the complex aerosol–cloud–precipitation system. Recently, artifici ... Full text Cite

Body Morphology and Drag in Swimming: CFD Analysis of the Effects of Differences in Male and Female Body Types

Journal Article Fluids · October 1, 2022 This study analyzes the effect of the morphological characteristics of swimmers on passive drag and determines whether the female or male body type is more efficient for gliding. As a result of puberty, males and females develop different body structures; ... Full text Cite

Comment on “Tu et al., An Analytical Solution of Groundwater Flow in a Confined Aquifer With a Single Well Circulation System, Water Resources Research, First Published: 12 June 2020.”

Journal Article Water Resources Research · April 1, 2021 Although renewed interest in flow around groundwater circulation wells is a positive development, the multiple and unacknowledged republication of previously published results is not. This is what has happened in a recent paper published in Water Resources ... Full text Cite

Erratum: Acceleration of groundwater remediation by rapidly pulsed pumping: Laboratory column tests (Journal of Environmental Engineering (United States) DOI: 10.1061/(ASCE)EE.1943-7870.0001479)

Journal Article Journal of Environmental Engineering United States · March 1, 2019 This paper was originally published online on October 25, 2018, with an incorrect byline. The correct byline is provided herein. The paper has been republished with the correction. ... Full text Cite

Acceleration of groundwater remediation by deep sweeps and vortex ejections induced by rapidly pulsed pumping

Journal Article Water Resources Research · May 1, 2016 One key limiting factor to groundwater remediation is contaminant sequestered in pores whose contents do not mix well with the bulk flow. Mixing between well-connected (pores whose volume is flushed as water flows through the aquifer) and poorly connected ... Full text Cite

Vadose zone transport of nitrate in the sierra pelona groundwater basin, Agua Dulce, California

Journal Article Proceedings of World Environmental and Water Resources Congress 2009 World Environmental and Water Resources Congress 2009 Great Rivers · October 26, 2009 Using data from previous studies about nitrate contamination in Agua Dulce, CA and the numerical modeling program HYDRUS-1D, nitrate transport in the vadose zone associated with septic system discharges was evaluated. Thirty-six modeling scenarios were ass ... Full text Cite

Quantifying saline groundwater flow into a freshwater lake using the Ra isotope quartet: A case study from the Sea of Galilee (Lake Kinneret), Israel

Journal Article Limnology and Oceanography · January 1, 2009 We investigated the Ra isotope quartet in order to quantify the discharge of saline groundwater into a freshwater lake. The activities of 226Ra, 228Ra, 223Ra, and 224Ra were measured in the Sea of Galilee, Israel ... Full text Cite

Transient flowmeter test: Simi-analytic crossflow model

Journal Article Advances in Water Resources · January 1, 2002 The transient flowmeter test (TFMT) provides more information about the well-aquifer system than the traditional quasi-steady-state flowmeter test (QFMT). The TFMT duration may be much shorter than that of a QFMT, which is desirable at highly contaminated ... Full text Cite

Sensitivity analysis of a no-crossflow model for the transient flowmeter test

Journal Article Stochastic Environmental Research and Risk Assessment · January 1, 2002 Logarithmic sensitivities and plausible relative errors are studied in a simple no-crossflow model of a transient flowmeter test (TFMT). This model is identical to the model of a constant-rate pumping test conducted on a fully penetrating well with wellbor ... Full text Cite

Limitations and potential of commercially available rhodamine WT as a groundwater tracer

Journal Article Water Resources Research · June 9, 2001 We conducted chemical characterization, batch, column, and modeling studies to elucidate the sorption and transport of rhodamine WT (RWT) in the subsurface. The sand-pack material from the Lizzie field site near Greenville, North Carolina, served as our po ... Full text Cite

Sensitiviby analysis of a pumping test on a well with wellbore storage and skin

Journal Article Advances in Water Resources · May 1, 2001 This paper reviews the basic concepts of sensitivity analysis and points out their limitations. A case is then made for logarithmic sensitivity. The magnitude of logarithmic sensitivity alone does not determine the accuracy of an aquifer parameter estimate ... Full text Cite

Rhodamine WT as a reactive tracer: Laboratory study and field consequences

Journal Article IAHS AISH Publication · January 1, 2000 We separated the two isomers of Rhodamine WT (RWT) from a commercially available tracer grade solution and found that their fluorescence emission spectra are distinct. In addition, with RWT and the sand used to fill the sand packs around the monitoring wel ... Cite

Recovering the release history of a groundwater contaminant using a non-linear least-squares method

Journal Article Hydrological Processes · 2000 A non-linear least-squares (NLS) method is used without regularization to recover the release history of a groundwater contaminant plume from its current measured spatial distribution. The flow system is assumed to be one-dimensional, with the plume origin ... Full text Link to item Cite

The dipole-flow test with a tracer: A new single-borehole tracer test for aquifer characterization

Journal Article Journal of Contaminant Hydrology · January 1, 2000 We propose a new aquifer characterization test, the dipole-flow test with a tracer (DFTT), and develop its interpretation methodology. Combining the dipole-flow test (DFT) and a tracer test, the DFTT is a single-borehole, forced-gradient tracer test. The D ... Full text Cite

Discussion of papers

Journal Article Ground Water · January 1, 2000 Full text Cite

Evaluation of flowmeter-head loss effects in the flowmeter test

Journal Article Journal of Hydrology · October 12, 1999 In this study, we develop an axisymmetric groundwater flow model to numerically simulate the hydraulic head loss across the flowmeter during a flowmeter test. Using it, we investigate the influence of flowmeter induced hydraulic head losses and filter pack ... Full text Cite

Flowing partially penetrating well: Solution to a mixed-type boundary value problem

Journal Article Advances in Water Resources · September 15, 1999 A new semi-analytic solution to the mixed-type boundary value problem for a flowing partially penetrating well with infinitesimal skin situated in an anisotropic aquifer is developed. The solution is suited to aquifers having a semi-infinite vertical exten ... Full text Cite

Maximum inclination path for laminar settling of axisymmetric particles in viscous fluids

Journal Article Journal of Environmental Engineering · 1999 Previous researchers' asymptotic results stating that a settling long axisymmetric body can deviate from the vertical by a maximum angle of γmax = 19.5° is generalized, and corresponding relations are found for settling prolate and oblate spheroi ... Full text Link to item Cite

Hydraulics of a partially penetrating well: Solution to a mixed-type boundary value problem via dual integral equations

Journal Article Journal of Hydrology · November 1, 1998 New semi-analytic solutions are obtained for well response to the pumping test and slug test performed on a partially penetrating well. The solutions account not only for the wellbore storage, infinitesimal skin, and aquifer anisotropy, but also for the mi ... Full text Cite

Deconvolution of a nonparametric transfer function for solute transport in soils

Journal Article Journal of Hydrology · June 25, 1998 Solute transport in soils can be described in terms of solute travel time probability density functions (pdfs). In the past, parameterized functional forms for the travel time pdf have been derived based on models of physical transport processes and the pr ... Full text Cite

Technical comment on: 'On the stochastic theory of solute transport by unsteady and steady groundwater flow in heterogeneous aquifers', by M.L. Kavvas and A. Karakas (Journal of Hydrology Vol. 179 (1996) 321-351)

Journal Article Journal of Hydrology · June 5, 1998 In this note, we demonstrate that statements made in a recent paper by Kavvas and Karakas (1996) (J. Hyrol., 179:321-351), concerning the assumptions underlying the stochastic model of solute transport in spatially-heterogeneous aquifers developed by Kabal ... Full text Cite

Spatial and temporal variations in nitrate contamination of a rural aquifer, California

Journal Article Journal of Environmental Quality · 1998 The quality of groundwater in the Sierra Pelona watershed, California is examined as an example of a small rural groundwater basin in a mountainous area of arid climate. Water quality in this region has been seriously impacted by nitrate (NO3) contaminatio ... Cite

Natural and anthropogenic nitrate contamination of groundwater in a rural community, California

Journal Article Environmental Science and Technology · 1998 Contamination of small basins impacts the quality of groundwater resources and the health of residents dependent on local, limited water supplies. Understanding contaminant sources is crucial not only to planning mitigation and cleanup but also to the rura ... Full text Link to item Cite

Limitations in recovering the history of a groundwater contaminant plume

Journal Article Journal of Contaminant Hydrology · January 1, 1998 Groundwater contaminant transport is a dispersive process and consequently there are limits to what may be learned about a contaminant's origins (history) from measurements of its present spatial distribution. The extent of these limitations in a particula ... Full text Cite

Numerical evaluation of the flowmeter test in a layered aquifer with a skin zone

Journal Article Journal of Hydrology · December 31, 1997 In this study, we used a two-dimensional groundwater flow model to numerically evaluate the single flowmeter test in a series of two-layer confined aquifers for a fully penetrating well with a skin zone (i.e. a disturbed zone, filter-pack envelope, etc.). ... Full text Cite

Performance of the steady-state dipole flow test in layered aquifers

Journal Article Hydrological Processes · October 15, 1997 Steady-state numerical simulations of the dipole flow test in layered aquifers demonstrate that the test produces a good estimate of the equivalent hydraulic conductivity anisotropy ratio for the part of the aquifer spanned by the well chambers. The effect ... Full text Cite

Response of a partially penetrating well in a heterogeneous aquifer: Integrated well-face flux vs. uniform well-face flux boundary conditions

Journal Article Journal of Hydrology · July 1, 1997 A two-dimensional integrated well-face flux (IWFF) model is developed for computing the draw-down at the well-face and around a fully or partially penetrating well with wellbore storage, situated in a layered confined aquifer. In this model, we calculate d ... Full text Cite

Hydraulics of one- and two-dimensional flow fields in aquifers

Journal Article Hydrological Sciences Journal · January 1, 1997 New solutions in the Laplace and time domains are developed that describe the transient response of a leaky aquifer to constant and transient discharge into a fully or partially penetrating sink with storage, A parameter estimation procedure based on the N ... Full text Cite

Well Hydraulics with the Weber-Goldstein Transforms

Journal Article Transport in Porous Media · January 1, 1997 Two new integral transforms, ideally suited for solving boundary value problems in well hydraulics, are derived from one of the Goldstein identities which generalizes a corresponding Weber identity. The two transforms are, therefore, named the Weber-Goldst ... Full text Cite

Soil water depletion by oak trees and the influence of root water uptake on the moisture content spatial statistics

Journal Article Water Resources Research · January 1, 1997 The space-time statistical structure of soil water uptake by oak trees was investigated in a 3.1-m-diameter closed top chamber using a three-dimensional measurement grid of soil moisture and pressure, and measurements of tree transpiration. Using the time ... Full text Cite

Analytical solutions for the coefficient of variation of the volume-averaged solute concentration in heterogeneous aquifers

Journal Article Stochastic Hydrology and Hydraulics · January 1, 1997 Under the assumption that local solute dispersion is negligible, a new general formula (in the form of a convolution integral) is found for the arbitrary k-point ensemble moment of the local concentration of a solute convected in arbitrary m spatial dimens ... Full text Cite

Numerical evaluation of flowmeter test interpretation methodologies

Journal Article Water Resources Research · April 1, 1996 We evaluate systematic errors inherent in two flowmeter test interpretation methodologies. A physically consistent two- dimensional groundwater flow model is used to numerically simulate the single flowmeter test and the double flowmeter test in 25 differe ... Full text Cite

Recovering the History of a Groundwater Contaminant Plume: Method of Quasi‐Reversibility

Journal Article Water Resources Research · January 1, 1995 The method of quasi‐reversibility (QR) (Lattes and Lions, 1969) has been used previously to solve the diffusion equation with reversed time. We develop a quasi‐reversible solution to a convection‐dispersion equation by solving the QR diffusion operator in ... Full text Cite

Statistical moments of reactive solute concentration in a heterogeneous aquifer

Journal Article Water Resources Research · January 1, 1994 Neglecting local solute dispersion, we prove that under realistic conditions the ensemble moments of the local concentration satisfy a mean convection dispersion equation (CDE) for both conservative and instantaneously adsorbing solutes, provided that the ... Full text Cite

Recovering the release history of a groundwater contaminant

Journal Article Water Resources Research · January 1, 1994 Finding the history of a groundwater contaminant plume from measurements of its current spatial distribution is an ill‐posed problem and, consequently, its solution is extremely sensitive to errors in the input data. In this paper, Tikhonov regularization ... Full text Cite

Measuring distributions of hydraulic conductivity and specific storativity by the double flowmeter test

Journal Article Water Resources Research · January 1, 1994 The flowmeter test, when modified, can be applied long before the well response reaches a quasi‐steady state. In many practical applications the traditional flowmeter test provides only an order of magnitude estimate of the hydraulic conductivity distribut ... Full text Cite

A master equation for reactive solute transport in porous media

Journal Article Stochastic Hydrology and Hydraulics · December 1, 1993 The mean value of a density of a "cloud of points" described by a generalized Liouville equation associated with a convection dispersion equation governing adsorbing solute transport yields a joint concentration probability density. The general technique c ... Full text Cite

Probing soil and aquifer material porosity with nuclear magnetic resonance

Journal Article Water Resources Research · January 1, 1993 Nuclear magnetic resonance relaxation measurements were used to identify different characteristic porosity domains in soil and aquifer materials. The porosity distribution can be inferred from these measurements by a regularization method applicable to any ... Full text Cite

The dipole flow test: A new single‐borehole test for aquifer characterization

Journal Article Water Resources Research · January 1, 1993 A new single‐borehole measurement technique for confined aquifers, the dipole flow test, yields the vertical distributions of the horizontal hydraulic conductivity, the vertical hydraulic conductivity, and the specific storativity when applied to different ... Full text Cite

Well response in a leaky aquifer and computational interpretation of pumping tests

Journal Article Proceedings National Conference on Hydraulic Engineering · January 1, 1993 An analytic solution is derived describing flow in a horizontal confined leaky aquifer of infinite extent around a fully penetrating well of negligible storage capacity. The differences between the new solution and the Hantush and Jacob [1955] solution are ... Cite

Skin effect and its elimination for single-borehole aquifer tests

Journal Article Finite Elements in Water Resources Proceedings of the International Conference · December 1, 1992 We analyze the skin effect for three single-borehole tests, the flowmeter test, the packer-pumping test, and the dipole-flow test. The estimated aquifer hydraulic conductivity and its anisotropy ratio when obtained from tests conducted on wells surrounded ... Cite

Water Transport in an Unsaturated Medium to Roots with Differing Local Geometries

Journal Article Soil Science Society of America Journal · November 1, 1992 Pearl millet [Pennisetum glaucum (L.) R. Br.: syn. P. americanum (L.) Leeke] develops substantially lower predawn leaf water potentials than cowpea [Vigna unguiculata (L.) Walp.] under conditions of soil dehydration, but overall root length densities are g ... Full text Cite

Sensitivity analysis of partial differential equations: A case for functional sensitivity

Journal Article Numerical Methods for Partial Differential Equations · January 1, 1991 Sensitivity analysis allows for analyzing the effects of parameter uncertainty. For functional parameters, the sensitivity of the system is described by the functional derivatives of the output variables with respect to the parameters. Approximation of eac ... Full text Cite

Sensitivity Analysis of Infiltration, Exfiltration, and Drainage in Unsaturated Miller‐Similar Porous Media

Journal Article Water Resources Research · January 1, 1991 The effects of soil heterogeneity on the transport of moisture in the unsaturated zone are studied by means of functional sensitivities, which are more suitable than elementary (or conventional) sensitivities for analyzing continuous systems. The earlier d ... Full text Cite

A stochastic model of reactive solute transport with time‐varying velocity in a heterogeneous aquifer

Journal Article Water Resources Research · January 1, 1991 The cumulant expansion method, used previously by Sposito and Barry (1987) to derive an ensemble average transport equation for a tracer moving in a heterogeneous aquifer, is generalized to the case of a reactive solute that can adsorb linearly and undergo ... Full text Cite

Stochastic differential equations in the theory of solute transport through inhomogeneous porous media

Journal Article Advances in Porous Media Vol 1 · January 1, 1991 Stochastic differential equations for solute transport are constructed from corresponding deterministic transport equations by re-interpreting their physical parameters as random functions of space and time. A partial differential equation for the ensemble ... Cite

Sensitivity analysis of flow in unsaturated heterogeneous porous media: Theory, numerical model, and its verification

Journal Article Water Resources Research · January 1, 1990 Sensitivity analysis is one of the tools available for analyzing the effects of parameter uncertainty and soil heterogeneity on the transport of moisture in the unsaturated similar porous media. Direct differentiation of the discretized Richards equation w ... Full text Cite

Integrated modeling and remote sensing of soil moisture.

Journal Article Hydrologic Applications of Space Technology Proc Workshop Cocoa Beach Fl 1985 · January 1, 1986 We propose that the problem of integrating models and remote sensing be approached using the extended Kalman filter (EKF). The EKF integrates uncertain state dynamics and uncertain measurement models to arrive at an optimal estimate of the system states. T ... Cite

Analysis of Well‐Aquifer Response to a Slug Test

Journal Article Water Resources Research · January 1, 1985 The response of a fully penetrating well to a slug test in a confined aquifer can be described by a single differential equation that is valid for any degree of damping. Although an analytical solution is not available, numerical methods are readily applie ... Full text Cite