Presentation Type

Poster Presentation

Category

STEM (science, technology, engineering, mathematics)

Abstract/Artist Statement

In this study, we seek to reduce parameter uncertainty in groundwater modeling systems, particularly in reactive transport models, by developing a new technique to quantify field-scale hydrodynamic dispersion using anthropogenic environmental tracer concentrations and numerical groundwater modeling. We generate a series of synthetic aquifer fields using known heterogeneous aquifer parameters to model spatial variability using known atmospheric tracer datasets to determine if a single, unique value of dispersion can be applied field-wide. The atmospheric data is comprised of publicly available Chlorofluorocarbons (CFC11, CFC12, CFC113) and Sulfur-hexafluoride (SF6) concentration atmospheric data. A 2D heterogeneous synthetic truth aquifer developed using synthetic Gaussian simulations is compared with 2D homogeneous synthetic aquifers with varying hydrodynamic dispersion values. Breakthrough curves of tracer concentrations, and ratios thereof, through our synthetic aquifers over time are fit to curves produced through our heterogeneous truth model to assess whether a single field-scale dispersivity value can be adequately identified. The same methodology is applied to 3D simulations to assess the ability to estimate reasonable field-scale hydrodynamic dispersion coefficients in a 3D flow field. To evaluate the accuracy of our method, we compare the observed tracer-derived dispersivity values to dispersivity values calculated from theoretical estimates. This new method of utilizing multiple environmental tracers over a limited time series could be an easy, inexpensive, and effective solution in quantifying field-scale hydrodynamic dispersion and reduce parameter uncertainty in groundwater/contamination transport models.

Mentor Name

W. Payton Gardner

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Using multiple environmental tracers to quantify field-scale hydrodynamic dispersion and reduce parameter uncertainty in reactive transport models.

In this study, we seek to reduce parameter uncertainty in groundwater modeling systems, particularly in reactive transport models, by developing a new technique to quantify field-scale hydrodynamic dispersion using anthropogenic environmental tracer concentrations and numerical groundwater modeling. We generate a series of synthetic aquifer fields using known heterogeneous aquifer parameters to model spatial variability using known atmospheric tracer datasets to determine if a single, unique value of dispersion can be applied field-wide. The atmospheric data is comprised of publicly available Chlorofluorocarbons (CFC11, CFC12, CFC113) and Sulfur-hexafluoride (SF6) concentration atmospheric data. A 2D heterogeneous synthetic truth aquifer developed using synthetic Gaussian simulations is compared with 2D homogeneous synthetic aquifers with varying hydrodynamic dispersion values. Breakthrough curves of tracer concentrations, and ratios thereof, through our synthetic aquifers over time are fit to curves produced through our heterogeneous truth model to assess whether a single field-scale dispersivity value can be adequately identified. The same methodology is applied to 3D simulations to assess the ability to estimate reasonable field-scale hydrodynamic dispersion coefficients in a 3D flow field. To evaluate the accuracy of our method, we compare the observed tracer-derived dispersivity values to dispersivity values calculated from theoretical estimates. This new method of utilizing multiple environmental tracers over a limited time series could be an easy, inexpensive, and effective solution in quantifying field-scale hydrodynamic dispersion and reduce parameter uncertainty in groundwater/contamination transport models.