Stochastic Subsurface Hydrology From Theory to Applications

Series, Collected Reprint

doi:10.1002/9781118782088.ch12

Cited by 46 publications

(73 citation statements)

References 26 publications

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“…It is clear from Table and equation that in 3‐D, B c ≃1.5. It has been shown (Balberg & Binenbaum, ; Gelhar, ) that the connectivity exponents β , β b , ν , σ , and τ are equal for discrete and continuous systems.…”

Section: Percolation Theorymentioning

confidence: 99%

“…After quantifying the likelihood that flow is controlled by a particular percolation cluster, it is also possible to understand directly the topology of the flow paths through the clusters that dominate solute transport at an arbitrary length scale, linking the subjects of hydraulic conductivity distributions and solute transport. It has long been recognized that the distributions of the hydraulic conductivity must be relevant to solute transport (Dagan, ; Freeze, ; Gelhar & Axness, ; Gelhar, ), but the actual solute transport paths through the regions of spatially variable hydraulic conductivity must control the distribution of the solute arrival times, and it is the connectivity of the paths that is critical to the form of such distributions.…”

Section: Percolation Theorymentioning

confidence: 99%

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Flow, Transport, and Reaction in Porous Media: Percolation Scaling, Critical‐Path Analysis, and Effective Medium Approximation

Hunt

Sahimi

2017

Reviews of Geophysics

141

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We describe the most important developments in the application of three theoretical tools to modeling of the morphology of porous media and flow and transport processes in them. One tool is percolation theory. Although it was over 40 years ago that the possibility of using percolation theory to describe flow and transport processes in porous media was first raised, new models and concepts, as well as new variants of the original percolation model are still being developed for various applications to flow phenomena in porous media. The other two approaches, closely related to percolation theory, are the critical‐path analysis, which is applicable when porous media are highly heterogeneous, and the effective medium approximation—poor man's percolation—that provide a simple and, under certain conditions, quantitatively correct description of transport in porous media in which percolation‐type disorder is relevant. Applications to topics in geosciences include predictions of the hydraulic conductivity and air permeability, solute and gas diffusion that are particularly important in ecohydrological applications and land‐surface interactions, and multiphase flow in porous media, as well as non‐Gaussian solute transport, and flow morphologies associated with imbibition into unsaturated fractures. We describe new applications of percolation theory of solute transport to chemical weathering and soil formation, geomorphology, and elemental cycling through the terrestrial Earth surface. Wherever quantitatively accurate predictions of such quantities are relevant, so are the techniques presented here. Whenever possible, the theoretical predictions are compared with the relevant experimental data. In practically all the cases, the agreement between the theoretical predictions and the data is excellent. Also discussed are possible future directions in the application of such concepts to many other phenomena in geosciences.

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Section: Percolation Theorymentioning

confidence: 99%

Section: Percolation Theorymentioning

confidence: 99%

Flow, Transport, and Reaction in Porous Media: Percolation Scaling, Critical‐Path Analysis, and Effective Medium Approximation

Hunt

Sahimi

2017

Reviews of Geophysics

141

View full text Add to dashboard Cite

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“…The most accurate PTFs to estimate the complete hydraulic conductivity curve described by MvG used the estimated saturated hydraulic conductivity rather than the measured one and an estimated tortuosity parameter, L , rather than the standard value of 0.5 proposed by Mualem (). The reason for the preference for estimated values of hydraulic conductivity over measured ones in general is the inherent scale dependency of this parameter (Gelhar, ; Roth, ). The value for hydraulic conductivity is dependent upon the pore geometry at the scale of interest (Nieman & Rovey, ; Sánchez‐Vila et al, ; Schulze‐Makuch et al, ) and may show atmospheric dependence (Oosterwoud et al, ) seasonal effects (Suwardji & Eberbach, ; Farkas et al, ; Borman & Klaasen, ), and its quantification methods can produce as much variation as the other mentioned factors (Fodor et al, ).…”

Section: Ptfs In Earth System Sciencesmentioning

confidence: 99%

Pedotransfer Functions in Earth System Science: Challenges and Perspectives

Looy

Bouma

Herbst

et al. 2017

Reviews of Geophysics

411

297

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Soil, through its various functions, plays a vital role in the Earth's ecosystems and provides multiple ecosystem services to humanity. Pedotransfer functions (PTFs) are simple to complex knowledge rules that relate available soil information to soil properties and variables that are needed to parameterize soil processes. In this paper, we review the existing PTFs and document the new generation of PTFs developed in the different disciplines of Earth system science. To meet the methodological challenges for a successful application in Earth system modeling, we emphasize that PTF development has to go hand in hand with suitable extrapolation and upscaling techniques such that the PTFs correctly represent the spatial heterogeneity of soils. PTFs should encompass the variability of the estimated soil property or process, in such a way that the estimation of parameters allows for validation and can also confidently provide for extrapolation and upscaling purposes capturing the spatial variation in soils. Most actively pursued recent developments are related to parameterizations of solute transport, heat exchange, soil respiration, and organic carbon content, root density, and vegetation water uptake. Further challenges are to be addressed in parameterization of soil erosivity and land use change impacts at multiple scales. We argue that a comprehensive set of PTFs can be applied throughout a wide range of disciplines of Earth system science, with emphasis on land surface models. Novel sensing techniques provide a true breakthrough for this, yet further improvements are necessary for methods to deal with uncertainty and to validate applications at global scale.

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“…For instance, Chesapeake Bay restoration scientists seek to understand how the spatial arrangement of riparian buffers impacts the delivery of nutrients from agricultural fields to streams (Baker et al 2006). On the other hand, hydrogeology has a rich history of predicting spatially averaged fluxes from patch area and connectivity using an upscaled, effective permeability, k eff (Gelhar 1986, de Dreuzy et al 2010) that is constructed as a power-law area-weighted average of the permeability k i of the different patch types (Ronayne and Gorelick 2006): However, little consensus about how to quantify functional connectivity for surfacewater applications has emerged.…”

Section: Information Content Of Connectivity-orientation Curvesmentioning

confidence: 99%

Directional connectivity in hydrology and ecology

Larsen

Choi

Nungesser

et al. 2012

Ecological Applications

114

104

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Quantifying hydrologic and ecological connectivity has contributed to understanding transport and dispersal processes and assessing ecosystem degradation or restoration potential. However, there has been little synthesis across disciplines. The growing field of ecohydrology and recent recognition that loss of hydrologic connectivity is leading to a global decline in biodiversity underscore the need for a unified connectivity concept. One outstanding need is a way to quantify directional connectivity that is consistent, robust to variations in sampling, and transferable across scales or environmental settings. Understanding connectivity in a particular direction (e.g., streamwise, along or across gradient, between sources and sinks, along cardinal directions) provides critical information for predicting contaminant transport, planning conservation corridor design, and understanding how landscapes or hydroscapes respond to directional forces like wind or water flow. Here we synthesize progress on quantifying connectivity and develop a new strategy for evaluating directional connectivity that benefits from use of graph theory in ecology and percolation theory in hydrology. The directional connectivity index (DCI) is a graph-theory based, multiscale metric that is generalizable to a range of different structural and functional connectivity applications. It exhibits minimal sensitivity to image rotation or resolution within a given range and responds intuitively to progressive, unidirectional change. Further, it is linearly related to the integral connectivity scale length--a metric common in hydrology that correlates well with actual fluxes--but is less computationally challenging and more readily comparable across different landscapes. Connectivity-orientation curves (i.e., directional connectivity computed over a range of headings) provide a quantitative, information-dense representation of environmental structure that can be used for comparison or detection of subtle differences in the physical-biological feedbacks driving pattern formation. Case-study application of the DCI to the Everglades in south Florida revealed that loss of directional hydrologic connectivity occurs more rapidly and is a more sensitive indicator of declining ecosystem function than other metrics (e.g., habitat area) used previously. Here and elsewhere, directional connectivity can provide insight into landscape drivers and processes, act as an early-warning indicator of environmental degradation, and serve as a planning tool or performance measure for conservation and restoration efforts.

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Stochastic Subsurface Hydrology From Theory to Applications

Cited by 46 publications

References 26 publications

Flow, Transport, and Reaction in Porous Media: Percolation Scaling, Critical‐Path Analysis, and Effective Medium Approximation

Flow, Transport, and Reaction in Porous Media: Percolation Scaling, Critical‐Path Analysis, and Effective Medium Approximation

Pedotransfer Functions in Earth System Science: Challenges and Perspectives

Directional connectivity in hydrology and ecology

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