Transport and speciation of uranium in groundwater-surface water systems impacted by legacy milling operations

Byrne, Patrick; Fuller, Christopher C.; Naftz, David L.; Runkel, Robert L.; Lehto, Niklas J.; Dam, William L.

doi:10.1016/j.scitotenv.2020.143314

Cited by 24 publications

(3 citation statements)

References 50 publications

(74 reference statements)

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“…The Riverton Processing Site (Riverton site) is located approximately 3 km southwest of Riverton, Wyoming (USA) on the Wind River Indian Reservation (Figure 2). This US Department of Energy (DOE) Office of Legacy Management site hosts a former uranium and vanadium ore processing mill that contaminated the shallow alluvial aquifer with tailings wastes during the mid 20th century and has since received extensive site characterization and scientific inquiry (e.g., Byrne et al., 2020; Dam et al., 2015; DOE, 1998a; White et al., 1984).…”

Section: Methods: Riverton Wy Field Sitementioning

confidence: 99%

Utilizing Environmental Tracers to Reduce Groundwater Flow and Transport Model Parameter Uncertainties

Thiros

Gardner

Kuhlman

2021

Water Resources Research

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Process-based numerical models that assess and predict groundwater flow and transport are an invaluable tool for water resource management (Anderson et al., 2015), contaminated site remediation (Steefel et al., 2015), and climate change assessment (Li et al., 2017;Kollet & Maxwell, 2008). Accurate parameterizations of aquifer properties and structural characteristics that control groundwater flow and transport are fundamental components of the modeling process. Yet, natural groundwater systems are typically characterized by property heterogeneity that cannot be fully constrained using direct field measurements nor accurately extrapolated from previously studied sites. As a result, subsurface parameters used in numerical models are commonly estimated through calibration against measurements of hydraulic heads from wells and boundary fluxes (Hill & Tiedeman, 2007;Schilling et al., 2019). In the majority of cases, calibration to hydraulic data alone cannot fully constrain model parameter distributions and the resulting equifinality leads to large uncertainty in estimated aquifer properties and subsequent forecasts of interest (Anderson et al., 2015;Doherty, 2003). Joint calibration to the fluid velocity and solute transport information provided by environmental tracers has the ability to ameliorate many of the limitations and non-uniqueness in calibration to hydraulic data alone, leading to uncertainty reductions in key model parameters (Portniaguine & Solomon, 1998;Reilly et al., 1994;Sanford, 2011;Schilling et al., 2017). Despite the wide use of environmental tracer information within groundwater studies, methodologies and guidelines that optimally assimilate the information they provide into process-based numerical models are not well established (e.g., Suckow, 2014).Environmental tracers are non-applied chemical species with a broad range of input histories and/or decay/ production rates that can provide valuable solute transport information over large spatiotemporal ranges Abstract Non-uniqueness in groundwater model calibration is a primary source of uncertainty in groundwater flow and transport predictions. In this study, we investigate the ability of environmental tracer information to constrain groundwater model parameters. We utilize a pilot point calibration procedure conditioned to subsets of observed data including: liquid pressures, tritium ( 3 H), chlorofluorocarbon-12 (CFC-12), and sulfur hexafluoride (SF 6 ) concentrations; and groundwater apparent ages inferred from these environmental tracers, to quantify uncertainties in the heterogeneous permeability fields and infiltration rates of a steady-state 2-D synthetic aquifer and a transient 3-D model of a field site located near Riverton, Wyoming (USA). To identify the relative data worth of each observation data type, the post-calibration uncertainties of the optimal parameters for a given observation subset are compared to that from the full observation data set. Our results suggest that the calibration-constrained permeability field uncertainties a...

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Section: Methods: Riverton Wy Field Sitementioning

confidence: 99%

Utilizing Environmental Tracers to Reduce Groundwater Flow and Transport Model Parameter Uncertainties

Thiros

Gardner

Kuhlman

2021

Water Resources Research

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“…First, a field validation was performed by conducting point dilution tests in a well‐characterized floodplain aquifer in Riverton, Wyoming. The alluvial aquifer at the site consists of 4–6 m of sand and gravel underlain by shale bedrock (Byrne et al., 2021; Dam et al., 2015; White et al., 1984), with depth to the water table ranging seasonally from 0.5 to 2.5 m below the ground surface. Groundwater velocity within this unit was previously estimated with a calibrated groundwater flow model (U.S. Department of Energy, 1998), through multi‐decadal contaminant plume monitoring (White et al., 1984) and using natural gradient tracer tests (Paradis et al., 2022).…”

Section: Methodsmentioning

confidence: 99%

WellSTIC: A Cost‐Effective Sensor for Performing Point Dilution Tests to Measure Groundwater Velocity in Shallow Aquifers

Perzan

Chapin

2023

Water Resources Research

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Estimates of groundwater velocity are integral to any research or remediation project involving groundwater. In particular, understanding lateral groundwater flow in hillslope and mountainous systems constitutes a grand challenge in modern hydrology (Blöschl et al., 2019;Fan et al., 2019;Markovich et al., 2019). Addressing this challenge will require novel techniques to cost-effectively measure groundwater flow at remote field sites, but most modern groundwater velocity methods are expensive, labor-intensive and require vehicle access to a site.Traditional methods of measuring groundwater velocity fall into three categories: Darcy-based methods, interwell tracer tests and in-well techniques. Darcy-based methods measure groundwater velocity using Darcy's law and estimates of the specific discharge and effective porosity of an aquifer. These techniques are simple, but they require knowledge of the aquifer's hydraulic conductivity, which can vary over 13 orders of magnitude in natural media (Freeze & Cherry, 1979). Even geologically homogeneous aquifers can exhibit 10-100X variations in hydraulic conductivity over centimeter scales (Mackay et al., 1986;Sudicky, 1986). Though Darcy methods are simple, errors in hydraulic conductivity estimates can range multiple orders of magnitude, which result in large errors in groundwater velocity.In the second category of methods-inter-well tracer tests-a tracer is injected into an upgradient well while downgradient wells are monitored for tracer arrival. Of the various groundwater velocity techniques, natural

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“…Despite tailings remediation in 1989 and a risk assessment that predicted natural flushing of the groundwater contaminants would occur within 100 years, elevated uranium concentrations persist within the shallow alluvial aquifer (Dam et al, 2015; DOE, 1998). A significant amount of groundwater flow and solute transport research has been performed and is on‐going at the Riverton site to better understand the uranium plume dynamics (e.g., Byrne et al, 2020; DOE, 2015).…”

Section: Methodsmentioning

confidence: 99%

Quantifying subsurface parameter and transport uncertainty using surrogate modelling and environmental tracers

Thiros

Gardner

Maneta

et al. 2022

Hydrological Processes

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We combine physics‐based groundwater reactive transport modelling with machine‐learning techniques to quantify hydrogeological model and solute transport predictive uncertainties. We train an artificial neural network (ANN) on a dataset of groundwater hydraulic heads and 3H concentrations generated using a high‐fidelity groundwater reactive transport model. Using the trained ANN as a surrogate model to reproduce the input–output response of the high‐fidelity reactive transport model, we quantify the posterior distributions of hydrogeological parameters and hydraulic forcing conditions using Markov chain Monte Carlo calibration against field observations of groundwater hydraulic heads and 3H concentrations. We demonstrate the methodology with a model application that predicts Chlorofluorocarbon‐12 (CFC‐12) solute transport at a contaminated field site in Wyoming, United States. Our results show that including 3H observations in the calibration dataset reduced the uncertainty in the estimated permeability field and infiltration rates, compared to calibration against hydraulic heads alone. However, predictive uncertainty quantification shows that CFC‐12 transport predictions conditioned to the parameter posterior distributions cannot reproduce the field measurements. We found that calibrating the model to hydraulic head and 3H observations results in groundwater mean ages that are too large to explain the observed CFC‐12 concentrations. The coupling of the physics‐based reactive transport model with the machine‐learning surrogate model allows us to efficiently quantify model parameter and predictive uncertainties, which is typically computationally intractable using reactive transport models alone.

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Transport and speciation of uranium in groundwater-surface water systems impacted by legacy milling operations

Cited by 24 publications

References 50 publications

Utilizing Environmental Tracers to Reduce Groundwater Flow and Transport Model Parameter Uncertainties

Utilizing Environmental Tracers to Reduce Groundwater Flow and Transport Model Parameter Uncertainties

WellSTIC: A Cost‐Effective Sensor for Performing Point Dilution Tests to Measure Groundwater Velocity in Shallow Aquifers

Quantifying subsurface parameter and transport uncertainty using surrogate modelling and environmental tracers

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