River stage influences on uranium transport in a hydrologically dynamic groundwater‐surface water transition zone

Zachara, John M.; Chen, Xingyuan; Murray, Chris; Hammond, Glenn Edward

doi:10.1002/2015wr018009

Cited by 43 publications

(56 citation statements)

References 63 publications

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“…26, 27 The subsurface desorption kinetics of U(VI) species suggest a nonequilibrium sorption behavior with Fe-oxides, Mn-oxides, and phyllosilicates. 7, 28, 29 Uranium transport can also be attributed to dissolution of mineral phases. For example, U transport from contaminated subsurface Hanford sediments was affected by the dissolution of metatorbernite [Cu(UO 2 ) 2 (PO 4 ) 2 ·8H 2 O], cuprosklodowskite (Cu[(UO 2 )-(SiO 2 OH)] 2 ·6H 2 O), and Na-boltwoodite [NaUO 2 (SiO 3 OH)·1.5H 2 O].…”

Section: Introductionmentioning

confidence: 99%

Reactive Transport of U and V from Abandoned Uranium Mine Wastes

Avasarala¹,

Lichtner

Ali³

et al. 2017

Environ. Sci. Technol.

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The reactive transport of uranium (U) and vanadium(V) from abandoned mine wastes collected from the Blue Gap/Tachee Claim-28 mine site in Arizona was investigated by integrating flow-through column experiments with reactive transport modeling, and electron microscopy. The mine wastes were sequentially reacted in flow-through columns at pH 7.9 (10 mM HCO3−) and pH 3.4 (10 mM CH3COOH) to evaluate the effect of environmentally relevant conditions encountered at Blue Gap/Tachee on the release of U and V. The reaction rate constants (km) for the dissolution of uranyl–vanadate (U–V) minerals predominant at Blue Gap/Tachee were obtained from simulations with the reactive transport software, PFLOTRAN. The estimated reaction rate constants were within 1 order of magnitude for pH 7.9 (km = 4.8 × 10−13 mol cm−2 s−1) and pH 3.4 (km = 3.2 × 10−13 mol cm−2 s−1). However, the estimated equilibrium constants (Keq) for U–V bearing minerals were more than 6 orders of magnitude different for reaction at circumneutral pH (Keq = 10−38.65) compared to acidic pH (Keq = 10−44.81). These results coupled with electron microscopy data suggest that the release of U and V is affected by water pH and the crystalline structure of U–V bearing minerals. The findings from this investigation have important implications for risk exposure assessment, remediation, and resource recovery of U and V in locations where U–V-bearing minerals are abundant.

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Section: Introductionmentioning

confidence: 99%

Reactive Transport of U and V from Abandoned Uranium Mine Wastes

Avasarala¹,

Lichtner

Ali³

et al. 2017

Environ. Sci. Technol.

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“…Although PFLOTRAN is also capable of simulating coupled flow and thermal processes in the subsurface, including explicit representation of liquid-ice phase (Karra et al, 2014) as well as soil nutrient cycles (Hammond and Lichtner, 2010;Zachara et al, 2016;Tang et al, 2016), those processes are not coupled between the two models in this study. A schematic representation of the coupling between CLM4.5 and PFLO-TRAN is shown in Fig.…”

Section: Model Couplingmentioning

confidence: 99%

Coupling a three-dimensional subsurface flow and transport model with a land surface model to simulate stream–aquifer–land interactions (CP v1.0)

et al. 2017

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Abstract. A fully coupled three-dimensional surface and subsurface land model is developed and applied to a site along the Columbia River to simulate three-way interactions among river water, groundwater, and land surface processes. The model features the coupling of the Community Land Model version 4.5 (CLM4.5) and a massively parallel multiphysics reactive transport model (PFLOTRAN). The coupled model, named CP v1.0, is applied to a 400 m × 400 m study domain instrumented with groundwater monitoring wells along the Columbia River shoreline. CP v1.0 simulations are performed at three spatial resolutions (i.e., 2, 10, and 20 m) over a 5-year period to evaluate the impact of hydroclimatic conditions and spatial resolution on simulated variables. Results show that the coupled model is capable of simulating groundwater-river-water interactions driven by river stage variability along managed river reaches, which are of global significance as a result of over 30 000 dams constructed worldwide during the past half-century. Our numerical experiments suggest that the land-surface energy partitioning is strongly modulated by groundwater-river-water interactions through expanding the periodically inundated fraction of the riparian zone, and enhancing moisture availability in the vadose zone via capillary rise in response to the river stage change. Meanwhile, CLM4.5 fails to capture the key hydrologic process (i.e., groundwater-river-water exchange) at the site, and consequently simulates drastically different water and energy budgets. Furthermore, spatial resolution is found to significantly impact the accuracy of estimated the mass exchange rates at the boundaries of the aquifer, and it becomes critical when surface and subsurface become more tightly coupled with groundwater table within 6 to 7 meters below the surface. Inclusion of lateral subsurface flow influenced both the surface energy budget and subsurface transport processes as a result of river-water intrusion into the subsurface in response to an elevated river stage that increased soil moisture for evapotranspiration and suppressed available energy for sensible heat in the warm season. The coupled model developed in this study can be used for improving mechanistic understanding of ecosystem functioning and biogeochemical cycling along river corridors under historical and future hydroclimatic changes. The dataset presented in this study can also serve as a good benchmarking case for testing other integrated models.

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“…The hierarchical sensitivity analysis framework was implemented to evaluate the relative importance of various model inputs that contribute to the overall uncertainty in groundwater flow and transport modeling at the U.S. Department of Energy's Hanford 300 Area Integrated Field Research Challenge (IFRC) site [ Zachara et al ., ]. A persistent uranium groundwater plume exists at this site that discharges to the nearby Columbia River through a hydrologically dynamic groundwater‐surface water interaction zone [ Zachara et al ., ]. The results of comprehensive field characterization measurements, and numerous field experiments and modeling studies performed at the site [ Hammond and Lichtner, ; Zachara et al ., ] provide a strong technical basis for the test case used herein.…”

Section: Application To Dynamic Groundwater Flow and Transport Modelingmentioning

confidence: 99%

A geostatistics‐informed hierarchical sensitivity analysis method for complex groundwater flow and transport modeling

Dai

Song

et al. 2017

Water Resources Research

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Sensitivity analysis is an important tool for development and improvement of mathematical models, especially for complex systems with a high dimension of spatially correlated parameters. Variance‐based global sensitivity analysis has gained popularity because it can quantify the relative contribution of uncertainty from different sources. However, its computational cost increases dramatically with the complexity of the considered model and the dimension of model parameters. In this study, we developed a new sensitivity analysis method that integrates the concept of variance‐based method with a hierarchical uncertainty quantification framework. Different uncertain inputs are grouped and organized into a multilayer framework based on their characteristics and dependency relationships to reduce the dimensionality of the sensitivity analysis. A set of new sensitivity indices are defined for the grouped inputs using the variance decomposition method. Using this methodology, we identified the most important uncertainty source for a dynamic groundwater flow and solute transport model at the Department of Energy (DOE) Hanford site. The results indicate that boundary conditions and permeability field contribute the most uncertainty to the simulated head field and tracer plume, respectively. The relative contribution from each source varied spatially and temporally. By using a geostatistical approach to reduce the number of realizations needed for the sensitivity analysis, the computational cost of implementing the developed method was reduced to a practically manageable level. The developed sensitivity analysis method is generally applicable to a wide range of hydrologic and environmental problems that deal with high‐dimensional spatially distributed input variables.

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River stage influences on uranium transport in a hydrologically dynamic groundwater‐surface water transition zone

Cited by 43 publications

References 63 publications

Reactive Transport of U and V from Abandoned Uranium Mine Wastes

Reactive Transport of U and V from Abandoned Uranium Mine Wastes

Coupling a three-dimensional subsurface flow and transport model with a land surface model to simulate stream–aquifer–land interactions (CP v1.0)

A geostatistics‐informed hierarchical sensitivity analysis method for complex groundwater flow and transport modeling

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