Regions with vulnerabilities in their food-energy-water nexus may also have economic vulnerabilities. Actions to reduce environmental vulnerabilities may conflict with community concerns about jobs and economic vitality. To account for these potentially competing concerns, this study builds a nexus simulation model that incorporates water, energy, food, and detailed economic data. The model can be

The Generalized Integral Transform Technique (GITT) is employed in combination with a single domain reformulation strategy and a coupled eigenvalue problem expansion base to construct analytical or hybrid numerical-analytical solutions for flow and transport in fractured porous media. The problem formulation and provided formal solutions encompass both continuum (multi-porosity/multi-permeability)

The modelling and simulation of the unsaturated flow or the flow of two immiscible fluid phases in a porous medium is challenging as this flow takes place through the pores of the medium, which form a highly complex domain. Next to the complexity of the domain, a major challenge is to account for the interface separating the fluids, or the unsaturated fluid from the inert filling part, as the location

In different in-situ diffusion experiments carried out in fractured crystalline rocks, sorbing radionuclides have shown a behaviour that strongly differs from what is predicted by homogeneous-based models. Their breakthrough curves are in fact often characterised by a fast first-arrival and these radionuclides can penetrate surprisingly long distances deep into the matrix. The heterogeneous structure

Carbon dioxide sequestration in deep saline aquifers requires accurate and precise methods to monitor carbon capture and storage and detect leakage risks. The assessment of the CO2 plume location during injection and storage depends on the accuracy of the spatial distribution model of petrophysical properties, such as porosity and permeability. This work focuses on stochastic methods for petrophysical

In this work, a grain-scale modelling technique is introduced for the simulation of unsaturated flow in deforming and swelling granular materials. To do so, a pore-scale model for unsaturated flow is coupled to the discrete element method (DEM). It is assumed that initially a dry packing of particles is quickly invaded by a liquid and becomes fully saturated. Particles start absorbing the liquid and

An accurate estimation of terrestrial water storage (TWS) is crucial for water resource management and drought monitoring. However, the uncertainties in model physics, surface parameters and meteorological data often limit the accuracy of land surface hydrological models in estimating TWS. In this study, a multi-model-based framework was developed to predict TWS in China by 2050 using a Bayesian model

The traveling wave responses in an unsaturated medium induced by a solid force and fluid mass sources are derived in 3D Green's functions using the Dirac Delta function decompositions. The wave behaviors are described in pore fluid pressures and solid frame displacement along with fluctuations of capillary pressure in response to time variant fluid injections and solid force loadings. These solutions

In recent years significant breakthroughs in exploring big data, recognition of complex patterns, and predicting intricate variables have been made. One efficient way of analyzing big data, recognizing complex patterns, and extracting trends is through machine-learning (ML) algorithms. The field of porous media, and more generally geoscience, have also witnessed much progress, and recent progress in

Current computing capabilities, in combination with available theoretical frameworks, allow for the petrophysical evaluation of porous rocks from simple images. This procedure represents a less expensive alternative and it complements, generally expensive, laboratory measurements. A porosity, permeability and Forchheimer tensors estimation is reported here through a numerical solution of associated

This work investigates upscaling of capillary pressure curves for modeling gravity segregation under the influence of capillary heterogeneity. We consider two flowing phases driven by gravity and capillary forces and seek the saturation spatial and temporal variation until equilibrium is reached. Existing upscaling methods, found in the literature, are applied to a number of cases. Resulting saturation

The understanding of nonlinear flow in rough-walled rock fractures is critical for underground engineering and geological sciences. The macroscopic behavior and microfluidic field of flow in rough-walled artificial fracture models was investigated through microscopic visualization of hydraulic experiment. The results indicate that there are three states of flow regime in fracture, namely linear, weak

In the present work, a suite of numerical experiments with linear stability analysis are conducted to study density-driven flow with chemical dissolution of two reactive fluids in synthetic porous media. Linear stability analysis at the Darcy scale is first performed to predict the interfacial phenomena and instability at the initial time. Pore-scale simulations using the lattice Boltzmann method (LBM)

Precipitation (P), plant water use, and evaporation from the soil surface control the travel time of streamflow (Q) and evapotranspiration (ET) in a complex way. However, the impact of soil moisture and energy availability on the travel time distribution (TTD) of evaporated and transpired waters are yet less understood. In this study, we investigate how the seasonal variability of P and ET in terms

Geologic boundaries juxtaposing fine- against coarse-grained rock, have a profound impact on multiphase flow, giving rise to a spectrum of non-linear flow behaviours, ranging from capillary filtration, capillary holdup and the formation of transient ’vapour locks’, to spontaneous imbibition. Although these discontinuities tend to be small-scale features, their impact is felt on the large scale where

A tracer breakthrough curve (BTC) for each sampling station is the ultimate goal of every quantitative hydrologic tracing study, and dataset size can critically affect the BTC. Groundwater-tracing data obtained using in situ automatic sampling or detection devices may result in very high-density data sets. Data-dense tracer BTCs obtained using in situ devices and stored in dataloggers can result in

This study investigates the effect of heterogeneity on CO2–brine two-phase flow behavior and capillary trapping at the field scale. A model based on macroscopic invasion percolation is developed to simulate CO2 migration and trapping in strongly heterogeneous systems with bimodal permeability distributions. Stochastic simulations are performed on heterogeneous permeability fields generated by considering

The discrete fracture model (DFM) has been widely used to describe the flow problems in fractured media. In low-permeability media with conductive fractures embedded in, there is large capillary pressure contrast between fracture and matrix. It may cause very sharp changes of physical quantities near the matrix-fracture interface, which makes it difficult to calculate the matrix-fracture transfer flux

The dispersion coefficient is the most crucial parameter that governs the model prediction of pollutant mixing in rivers. However, the spatial variability of dispersion coefficient associated with velocity structures has not yet been thoroughly investigated. In this study, two types of spatially varying dispersion tensors were considered using both the vertical velocity profiles (DF) and the depth-averaged

The effective conductivity of heterogeneous aquifers Kefu relates the mean flux to the mean head gradient in mean uniform (natural gradient) flow. While Kefu depends on the hydraulic conductivity K statistical moments (KG, the geometric mean and σY2, the logconductivity variance for a given structure model) it is not a local property for strongly nonuniform well flow. In hydraulic tomography, flow

This paper presents analytical solutions for pumping from a poroelastic, confined aquifer where the combined effects of a finite-thickness skin zone and the wellbore storage are fully incorporated. The pumping-induced axisymmetric stress, plane strain deformation, and pore pressure are derived in the Laplace transform domain. Time-domain solutions are obtained using the Stehfest inversion algorithm

Wettability is a pore-scale property that has an important impact on capillarity, residual trapping, and hysteresis in porous media systems. In many applications, the wettability of the rock surface is assumed to be constant in time and uniform in space. However, many fluids are capable of altering the wettability of rock surfaces permanently and dynamically in time. Experiments have shown wettability

Tremendous efforts have been made for obtaining surface soil moisture (SM) at high spatial resolutions from microwave-based products via spatial downscaling. In recent years, machine learning has been one of the most advanced techniques in SM spatial downscaling. The performance of a machine learning technique in SM spatial downscaling varies with the algorithm and the underlying surface; however,

The feasibility of probabilistic Bayesian inversion strongly depends on the dimensionality and complexity of the statistical prior model. Most geostatistical inversion approaches assume multi-Gaussian fields, and some assume (non-Gaussian) categorical fields, e.g., via multiple-point geostatistics. We combine these two into one hierarchical joint problem, which accounts for two (and possibly more)

Channel meanders in rivers induce complex three-dimensional (3D) flow characteristics such as secondary flows and flow recirculation. Helical secondary flows promote transverse dispersion, and flow recirculation zones trap tracers. As a result, these meander-driven flows may cause anomalous transport manifested by unusually elevated levels of tracer concentration at early and late times of breakthrough

Floods result in substantial damage throughout the world every year. An accurate predictions of floods can significantly alleviate the loss of lives and properties. However, due to the complexity during flood formation, the accuracy of traditional flood forecasting models suffer from the performance degradation with the increasing of required prediction period. According to the mutual information(MI)

In this paper, a computational framework based on the material point method (MPM) is developed to study the coupled seepage-erosion-deformation process within unsaturated soils. Based on the mixture theory, the unsaturated erodible soil is conceptualized as a three-phase multi-species porous medium, which is represented as a set of Lagrangian material points in a three-phase multi-species single point

Nowadays, the great power of modern computers allows to develop computational models able to deal with simulations of several coupled phenomena over detailed complex topography. An efficient and properly calibrated computational model represents a useful tool to provide insight into the catchment dynamics at hydrological and geomorphological levels. In addition, it allows to develop detailed risk management

Understanding flow and transport processes in the critical zone relies heavily on characterising the interactions between evaporation and vegetation uptake of soil water; however, the magnitude, sources, and ages of these water fluxes are rarely well-constrained. We adapted the StorAge Selection (SAS) function framework to estimate the residence time of stored water, and transit times of eco-hydrologic

Sensitivity to the boundary conditions (BC’s) when determining macroscopic transport coefficients by numerical upscaling in finite domains is a well known methodological issue, explored here with the purpose of: quantifying the influence of the BC’s in relation with the parameters of the system (porosity, characteristic length scale, conductivity contrast); assessing the level of confidence associated

Understanding fluid flow and transport within clay rock is essential for predicting caprock integrity in underground gas storage or as host rock in deep radioactive waste storage. The connectivity and topology of the nanopore space, which drive the transfer mechanisms of these materials, are still poorly known and direct 3D imaging is particularly challenging. In this work, we investigate and compare

Lattice Boltzmann method (LBM) is widely adopted in simulating flow and reactive transport in porous media due to its easy treatment of boundaries and high computational efficiency. There have been various boundary schemes developed in the LBM due to their vital roles when dealing with fluid-solid interface. In the present work, we aim to review and intercompare all the single-node boundary schemes

The equivalent permeability of layered fractured rocks plays an important role in hydrocarbon recovery, underground energy storage, waste disposal management, groundwater hydrology, and subsurface contaminant transport. Borehole data contain some uncertainties/sampling bias during collection and interpretation. This sampling effect may lead to an inaccurate characterization of the fractured media.

A three-scale model for flow in karst conduit networks in fractured carbonates is rigorously constructed based on a reiterated homogenization procedure. The first upscaling, performed from the high-fidelity flow model, is based on sequential partially and fully topological model reduction procedures considering two discrete networks of solution-enlarged fractures and conduits. The subsequent macroscopization

Characterization of underground porous media parameters at the micro and macro scales is fundamental in geosciences. A thorough comprehension of flow phenomena requires analyses and observations at the micro scale through adoption of micromodels as representative as possible of real geological formations. In this paper we focus on the analysis of 2D binary images of real rock thin sections to characterize

Data assimilation for parameter and state estimation in subsurface transport problems remains a significant challenge because of the sparsity of measurements, the heterogeneity of porous media, and the high computational cost of forward numerical models. We present a multiphysics-informed deep neural network machine learning method for estimating space-dependent hydraulic conductivity, hydraulic head

Accurate modeling of variably saturated flow (VSF) in fractured porous media with the discrete fracture-matrix (DFM) model is a computationally challenging problem. The applicability of DFM model to VSF in real field studies at large space and time scales is often limited, not only because it requires detailed fracture characterization, but also as it involves excessive computational efforts. We develop

Groundwater level (GWL) forecasting is crucial for irrigation scheduling, water supply and land development. Machine learning (ML) (e.g., artificial neural networks) has been increasingly adopted to forecast GWL due to its ability to model nonlinearities between GWL and its drivers (e.g., rainfall). Although ML approaches have been successful at forecasting GWL, they are often inaccurate when GWL exhibits

Derivation of macroscopic models for advection-diffusion processes in the presence of dominant heterogeneous (e.g., surface) reactions using homogenisation theory or volume averaging is often deemed unfeasible (Valdés-Parada et al., 2011; Battiato and Tartakovsky, 2011a) due to the strong coupling between scales that characterise such systems. In this work, we show how the upscaling can be carried

The estimation of drag exerted by vegetation is of great interest because of its importance in assessing the impact of vegetation on the hydrodynamic processes in aquatic environments. In the current research, genetic programming (GP), a machine learning (ML) technique based on natural selection, was adopted to search for a robust relationship between the bulk drag coefficient (Cd) for arrays of rigid

A new generation of smart stormwater systems promises to reduce the need for new construction by enhancing the performance of the existing infrastructure through real-time control. Smart stormwater systems dynamically adapt their response to individual storms by controlling distributed assets, such as valves, gates, and pumps. This paper introduces a real-time control approach based on Reinforcement

In this paper we focus on a general model to describe compressible and immiscible three-phase flow in porous media. The underlying idea is to replace Darcy’s law by more general momentum balance equations. In particular, we want to account for viscous coupling effects by introducing fluid-fluid interaction terms. In [Qiao, et al. (2018) Adv Water Resour 112: 170–188] a water-oil model based on the

In the present work, a novel DOT ADER numerical solver capable of handling porosity and bottom discontinuities in the framework of the 1D porous Shallow Water Equations (SWEs) is presented. In order to ensure the preservation of the water at rest condition, a new set of well-balanced governing equations based on the isotropic porosity parameter is derived. The effects exerted by the bed slope and porosity

Bars are large sediment deposits alternating with deeper areas that arise from alluvial river bed instability and forcing. The present study aimed at investigating the combined influence of flow and longitudinal width variations on the co-evolution between bar pattern and sediment sorting in a sandy-gravel river reach. To this goal, a fully non-linear 2D numerical model was developed to reproduce the

Pore-scale modeling is a rapidly evolving area of research because modeling multiphase flow directly on 3D pore geometries is of utmost importance in wide variety of research areas, including oil and gas development, hydrology and material sciences. Although there are numerous methods to model flow, only so-called pore-network models are computationally effective enough to perform simulations in large

Investigation of seepage law of fluid flow through a self-affine, rough fracture has attracted broad attention because of its fundamental importance for complex hydrodynamic problems. Although it is natural to assume that permeability value depends on aperture size, it is hard to determine which is the appropriate relationship between them because of the large number of parameters related to the multi-scale

The immiscible fluid displacement pattern, controlled by the balance of viscous and capillary forces has a significant effect on the recovery or storage efficiency in subsurface processes. The phase diagram of displacement patterns has been extensively studied for the two-dimensional (2D) micromodel; however, that of the three-dimensional (3D) porous media has received little attention. This work experimentally

The aim of this work is to evaluate the accuracy of physically based models using the 2D Shallow Water Equations (SWE) for the simulation of rain-induced runoff. A key expectation of these models is to be able to reproduce properly both hydrograph at the outlet of the watershed and the associated velocity field within the spatial domain for a given rain event. However, this ability can be very challenging

Spatial Markov random walk models (SMM) have been demonstrated to accurately predict conservative solute transport across a wide range of hydro-geological systems, with recent advances enabling the SMM to model systems with linear kinetic reactive processes. However, the proposed reactive SMM’s applicability is limited to systems that can be partitioned into a series of identical periodic cells where

We propose a coupled model for suspended and bedload sediment transport in the shallow water framework. The model is deduced under hydrostatic pressure assumptions and will not assume any Boussinesq hypothesis. The numerical resolution is carried out in a segregated way. First the underlying system of conservation laws is solved by using a first order path-conservative Riemann solver. Then, the source

The problem of a spatially discontinuous diffusion coefficient (D(x)) is one that may be encountered in hydrogeologic systems due to natural geological features or as a consequence of numerical discretization of flow properties. To date, mass-transfer particle-tracking (MTPT) methods, a family of Lagrangian methods in which diffusion is jointly simulated by random walk and diffusive mass transfers

Climate change has increased frequency, severity and areal extent of droughts across the world in the last few decades magnifying their adverse impacts. Prediction of droughts is immensely helpful in early warning and preparing the most vulnerable communities to their adverse impacts. For the first time, this study investigated the potential of developing drought prediction models over Pakistan using

This paper is concerned with the estimation of the effective transport characteristics of fluid-saturated porous media via rigorous microstructure-property relations. We are particularly interested in predicting the formation factor F, mean survival time τ, principal NMR (diffusion) relaxation time T1, principal viscous relaxation time Θ1, and fluid permeability k. To do so, we employ rigorous methods

CO2 reinjection in petroleum reservoirs brings advantages in oil production but may cause dissolution in carbonate reservoirs. Two-scale continuum models have been successfully used to simulate acidification. However, the use of realistic porosity and permeability fields in mesh simulations is still a challenge, in such a way that uniform and normal distributions have been used to generate these fields