Predicting DNAPL mass discharge from pool-dominated source zones

Christ, John A.; Ramsburg, C. Andrew; Pennell, Kurt D.; Abriola, Linda M.

doi:10.1016/j.jconhyd.2010.02.005

Cited by 72 publications

(106 citation statements)

References 52 publications

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“…This makes the task of predicting the source-zone metric more challenging and also provides more data diversity to our learning algorithms. Some of the data used here has been reported [1] for characterizing subsurface contaminant source-zones.…”

Section: Experimental Analysismentioning

confidence: 99%

“…A key component in the design of a remediation strategy for these sites is the characterization of the source zone architecture, that is the existing distribution of DNAPL in the subsurface. Recent work in [1] suggests that a detailed map of the subsurface may not be required to predict the performance of a remediation strategy. Rather, metrics characterizing the distribution of contaminant may suffice.…”

Section: Introductionmentioning

confidence: 99%

“…Rather, metrics characterizing the distribution of contaminant may suffice. Specifically, in [1], the authors demonstrated that the ratio of the volume in the source zone occupied by ganglia (DNAPL saturation below a specified threshold) to that of pools (saturation exceeding the threshold) could be used within a model of subsurface flow and transport to predict remediation performance. In that work however, the authors did not consider how this ganglia-to-pool ratio (GTP) could be determined from data available in the field.…”

Section: Introductionmentioning

confidence: 99%

“…Motivated by [1], in this work we explore the use of machine learning methods for determining metrics defining the source zone architecture. We are interested in predicting percentage-mass of DNAPL in pools (ρ p ) which defines the volume of DNAPL residing in pools at a given time relative to the initial spill volume.…”

Section: Introductionmentioning

confidence: 99%

“…We are interested in predicting percentage-mass of DNAPL in pools (ρ p ) which defines the volume of DNAPL residing in pools at a given time relative to the initial spill volume. This metric is to be determined based upon observations of contaminant concentration observed in a transect oriented orthogonal to the nominal direction of groundwater flow as well as a set of training data comprised of field-scale numerical simulations of realistic DNAPL source zone distributions and their evolving plumes under a variety of release and site heterogeneity conditions [1].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

A discriminative-generative approach to the characterization of subsurface contaminant source zones

Ahmed

Mendoza‐Sanchez²,

Khardon

et al. 2012

2012 IEEE International Geoscience and Remote Sensing Symposium

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Large-scale contamination of ground water due to improper disposal of hazardous chemicals poses a global threat to drinking water supplies. Effective restoration and remediation of such sites relies upon a knowledge of the contaminant's distribution within the subsurface. Obtaining a detailed map of the existing distribution is usually not feasible; rather partial knowledge in terms of certain metrics that characterize the distribution has recently been shown to be sufficient for planning and monitoring remediation strategies. In this work we explore the prediction of a representative metric based upon down-gradient concentration profiles using a classification framework where each class represents a particular sub-range of the metric. Initial experiments show that our proposed model can be used effectively for predicting the metric.

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Section: Experimental Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A discriminative-generative approach to the characterization of subsurface contaminant source zones

Ahmed

Mendoza‐Sanchez²,

Khardon

et al. 2012

2012 IEEE International Geoscience and Remote Sensing Symposium

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Comparison of upscaled models for multistage mass discharge from DNAPL source zones

Kokkinaki

Werth

Sleep

2014

Water Resources Research

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Analytical upscaled models that can describe the depletion of dense nonaqueous phase liquids (DNAPLs) and the associated mass discharge are a practical alternative to computationally demanding and data-intensive multiphase numerical simulators. A major shortcoming of most existing upscaled models is that they cannot reproduce the nonmonotonic, multistage effluent concentrations often observed in experiments and numerical simulations. Upscaled models that can produce multistage concentrations either require calibration, which increases the cost of applying them in the field, or use dual-domain conceptual models that may not apply for spatially complex source zones. In this study, a new upscaled model is presented that can describe the nonmonotonic, multistage average concentrations emanating from complex DNAPL source zones. This is achieved by explicitly considering the temporal evolution of three source zone parameters, namely source zone projected area, the average of local-scale DNAPL saturations, and the average of local-scale aqueous relative permeability, without using empirical parameters. The model is evaluated for two real and twelve hypothetical centimeter-scale complex source zones. The proposed model captures the temporal variations in concentrations better than an empirical model and a dual-domain ganglia-to-pool ratio model. The results provide evidence that effluent concentrations downgradient of DNAPL source zones are controlled by the evolution of the aforementioned macroscopic parameters. This knowledge can be useful for the interpretation of field observations of effluent concentrations downstream of DNAPL source zones, and for the development of predictive upscaled models. Advances in DNAPL characterization techniques are needed to quantify these macroscopic parameters that can be used to guide DNAPL remediation efforts.

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Predicting DNAPL mass discharge and contaminated site longevity probabilities: Conceptual model and high‐resolution stochastic simulation

Koch

Nowak

2015

Water Resources Research

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Improper storage and disposal of nonaqueous-phase liquids (NAPLs) has resulted in widespread contamination of the subsurface, threatening the quality of groundwater as a freshwater resource. The high frequency of contaminated sites and the difficulties of remediation efforts demand rational decisions based on a sound risk assessment. Due to sparse data and natural heterogeneities, this risk assessment needs to be supported by appropriate predictive models with quantified uncertainty. This study proposes a physically and stochastically coherent model concept to simulate and predict crucial impact metrics for DNAPL contaminated sites, such as contaminant mass discharge and DNAPL source longevity. To this end, aquifer parameters and the contaminant source architecture are conceptualized as random space functions. The governing processes are simulated in a three-dimensional, highly resolved, stochastic, and coupled model that can predict probability density functions of mass discharge and source depletion times. While it is not possible to determine whether the presented model framework is sufficiently complex or not, we can investigate whether and to which degree the desired model predictions are sensitive to simplifications often found in the literature. By testing four commonly made simplifications, we identified aquifer heterogeneity, groundwater flow irregularity, uncertain and physically based contaminant source zones, and their mutual interlinkages as indispensable components of a sound model framework.

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Predicting DNAPL mass discharge from pool-dominated source zones

Cited by 72 publications

References 52 publications

A discriminative-generative approach to the characterization of subsurface contaminant source zones

A discriminative-generative approach to the characterization of subsurface contaminant source zones

Comparison of upscaled models for multistage mass discharge from DNAPL source zones

Predicting DNAPL mass discharge and contaminated site longevity probabilities: Conceptual model and high‐resolution stochastic simulation

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