Roseanna Neupauer | University of Colorado, Boulder (original) (raw)

Papers by Roseanna Neupauer

AGU Fall Meeting Abstracts, Dec 1, 2012

Approximately one million pounds of radioactively contaminated lead are currently stored at the I... more Approximately one million pounds of radioactively contaminated lead are currently stored at the Idaho National Engineering Laboratory (INEL) and must be treated according to the Resource Conservation and Recovery Act. This excess lead exists in various forms, including brick, sheet, shot, wool, blankets, steel-jacketed casks, scrap, and miscellaneous solids. Several lead treatment technologies were evaluated based on effectiveness, applicability, feasibility, availability of equipment and materials, health and safety, generation of secondary waste streams, cost, and flexibility. Emphasis is given in this report to those treatment technologies that yield recyclable lead products. Methods that treat lead for storage and disposal were also investigated. Specific treatment technologies for decontaminating the excess lead at the INEL are recommended. The proposed treatment for lead brick, sheet, shot, blankets, and scrap is a series of surface decontamination techniques followed by melt-...

An accurate representation of the permeability anisotropy of a porous medium is needed to success... more An accurate representation of the permeability anisotropy of a porous medium is needed to successfully predict the magnitude and direction of groundwater flow. We use wavelet analysis to identify principal directions of anisotropy in a heterogeneous porous medium. Wavelet analysis involves the integral transform of a permeability field using a kernel function (wavelet) that can be shifted, stretched, and rotated. The magnitude of the resulting wavelet coefficient provides information about the dominant scales (via stretching) and dominant orientations (via rotation) at various spatial positions in the permeability field. We use a fully-anisotropic Morlet wavelet to successfully identify dominant scales and orientations of a 1m x 1m face of Massillon sandstone. In addition, we demonstrate that wavelet analysis can identify localized features that are not identifiable through geostatistical analysis.

<p>In river channels in artic environments, groundwater that discharges to the land... more <p>In river channels in artic environments, groundwater that discharges to the land surface during winter can freeze in the channel, forming large sheet-like masses of layered ice called aufeis.  Water stored in aufeis is released slowly as the aufeis melt during summer, providing a critical course of water to the Arctic river ecosystems late into the summer when other water resources are reduced.  Under warming conditions in the Arctic, the quantity of water stored in aufeis may be reduced and the release of water by melting of the aufeis may end earlier in the summer.  The processes that lead to the formation of aufeis are not well understood; however, an understanding of these processes is necessary to predict how rising air temperature may affect aufeis formation and the availability of water in Arctic river ecosystems.  This work uses numerical simulation to evaluate a conceptual model of subsurface hydrogeothermal conditions that can lead to the formation of aufeis in the Kuparuk aufeis field on the North Slope of Alaska.  At this site, groundwater flows year-round through a talik above the permafrost and beneath the seasonally-frozen active layer just beneath the land surface. Groundwater in this talik discharges to the land surface through unfrozen gaps in the active layer, where it can freeze and form aufeis.  We developed a 2-D heterogeneous vertical profile model to show that subsurface water can discharge to the land surface through subvertical high permeability pathways during winter months while the lower permeability soils near the land surface remain frozen, thus providing a source of water for aufeis formation.  We investigate the effects of the warming conditions on the magnitude and timing of these discharges, which are surrogates for the mass of aufeis and the timing of aufeis formation, respectively.  Aufeis formation and ablation are both sensitive to climatic conditions. The sensitivity analyses presented here form a basis for future investigations of aufeis dynamics across the Arctic.</p>

AGU Fall Meeting Abstracts, Dec 1, 2018

Environmental Modelling & Software, 2015

This study contributes an iterative problem reformulation technique for multi-objective evolution... more This study contributes an iterative problem reformulation technique for multi-objective evolutionary algorithm (MOEA) decision support. Problem formulations consist of objectives, decision variables, and constraints, and directly influence the results generated by the MOEA. Typically, design problems are optimized based on a single problem formulation established a priori. In this paper, we demonstrate an approach to perform iterative optimization using problem formulations updated from analyses of results from prior rounds of optimization, which often reveal design components not initially considered. To demonstrate the approach, we consider a novel groundwater remediation technique, Engineered Injection and Extraction (EIE), which has never been optimized in the literature. Iterative problem reformulation enabled the MOEA to generate EIE solutions with better performance than the heuristically-developed solution used in prior work. We optimize a groundwater remediation strategy using multi-objective optimization.We demonstrate an iterative approach to adapt the problem formulation.We couple visualizations of objective and decision space to analyze solutions.

The goal of this paper is to introduce an adjoint approach for calculating stream depletion in a ... more The goal of this paper is to introduce an adjoint approach for calculating stream depletion in a river that is hydraulically connected to an aquifer. This paper presents the coupled forward and adjoint equations of flow in an unconfined aquifer, a confined aquifer, and in a river. Flow in the river is assumed to follow Manning’s equation, and the river is assumed to have a wide, rectangular cross section. With these assumptions, the governing equation of flow in the river is non-linear; thus its adjoint is linear in the adjoint state, but still depends on the state variable of the forward equation, i.e., on the river head. This paper outlines an approach for solving the adjoint equations, which requires some approximations and some modification of a code that solves the forward equations.

World Environmental and Water Resources Congress 2016, 2016

In this paper, two alternatives for a useful description of streamflow time patterns in Ecuadoria... more In this paper, two alternatives for a useful description of streamflow time patterns in Ecuadorian lowlands are proposed. In that region, streamflow rates are influenced by precipitation, which varies seasonally due to annual climate patterns, spatially due to small-scale weather patterns, and temporally over longer periods due to longer-period climate fluctuations. Using wavelet coefficients, different periodicities were identified throughout the series, with a dominant one-year frequency (annual cycle). Nevertheless, other frequencies are noteworthy. For instance, during the period 2005-2012, the frequency of 2 yr suggested a larger difference between the highest peaks during the rainy season (usually from December to April), and the lowest valleys of the dry period (rest of the year), otherwise difficult to perceive using only the raw data. In addition, the filter Baxter-King has been successfully applied for seasonal separation, including extreme years (El Niño events of 1982-1983, and 1997-1998). Hence, the use of wavelets may open opportunities for further research, including gap analysis, and cross-wavelet analysis between river stations belonging to different subbasins, but sharing similar features.

World Environmental and Water Resources Congress 2009, 2009

World Environmental and Water Resources Congress 2010, 2010

This study is to identify the factors that affect middle-aged workers' health promoting behaviors... more This study is to identify the factors that affect middle-aged workers' health promoting behaviors. Methods: 214 middle-aged workers participated in surveys, and the data were collected from August to September 2012 and analyzed by using descriptive statistics, Pearson's correlation coefficient, and multiple regression analysis with PASW 18.0 program. Results: It was found that among the factors, the degree of job stress (t=7.69, p<.001) and depression (t=6.23, p<.001) were significantly high for type D individuals, while non type D showed meaningful degree of self-related health status (t=-3.66, p<.001) and health promoting behaviors (t=-4.71, p<.001). The notable variable that affected the health promoting behaviors of the middle-aged workers was depression for both type D (β=-.357, p = .029) and non type D (β=-.325, p<.001) individuals, and this variable accounted for 24.1% and 18.2% respectively. Conclusion: The study revealed that the middle-aged workers showed high degree of job stress and depression that influenced on their health promoting behaviors. Thus, they are recommended to receive health management programs that offer treatment through consulting considering their individual personalities.

Water Resources Research, 2013

Groundwater pumping may lead to reduction in surface water flows, which can compromise water supp... more Groundwater pumping may lead to reduction in surface water flows, which can compromise water supplies and habitat. In light of these threats, the need to minimize stream depletion, defined as the reduction in the flow rate in streams and rivers caused by groundwater pumping, becomes paramount. We develop adjoint equations to calculate stream depletion due to aquifer pumping. We consider a coupled groundwater and surface water system in which both the river head and river flow rate are impacted by drawdown in the aquifer as a result of pumping. Through an illustrative example, we show that the adjoint method for calculating stream depletion produces accurate results if the model is approximately linear. With only one simulation of the adjoint equations, stream depletion can be calculated for pumping at a well at any location in the model domain, which results in a substantial reduction in computational time as compared to the standard method of calculating stream depletion.

Water Resources Research, 2000

Computers & Geosciences, 2001

Journal of Hydrologic Engineering, 2022

AGU Fall Meeting Abstracts, Dec 1, 2012

Approximately one million pounds of radioactively contaminated lead are currently stored at the I... more Approximately one million pounds of radioactively contaminated lead are currently stored at the Idaho National Engineering Laboratory (INEL) and must be treated according to the Resource Conservation and Recovery Act. This excess lead exists in various forms, including brick, sheet, shot, wool, blankets, steel-jacketed casks, scrap, and miscellaneous solids. Several lead treatment technologies were evaluated based on effectiveness, applicability, feasibility, availability of equipment and materials, health and safety, generation of secondary waste streams, cost, and flexibility. Emphasis is given in this report to those treatment technologies that yield recyclable lead products. Methods that treat lead for storage and disposal were also investigated. Specific treatment technologies for decontaminating the excess lead at the INEL are recommended. The proposed treatment for lead brick, sheet, shot, blankets, and scrap is a series of surface decontamination techniques followed by melt-...

An accurate representation of the permeability anisotropy of a porous medium is needed to success... more An accurate representation of the permeability anisotropy of a porous medium is needed to successfully predict the magnitude and direction of groundwater flow. We use wavelet analysis to identify principal directions of anisotropy in a heterogeneous porous medium. Wavelet analysis involves the integral transform of a permeability field using a kernel function (wavelet) that can be shifted, stretched, and rotated. The magnitude of the resulting wavelet coefficient provides information about the dominant scales (via stretching) and dominant orientations (via rotation) at various spatial positions in the permeability field. We use a fully-anisotropic Morlet wavelet to successfully identify dominant scales and orientations of a 1m x 1m face of Massillon sandstone. In addition, we demonstrate that wavelet analysis can identify localized features that are not identifiable through geostatistical analysis.

&lt;p&gt;In river channels in artic environments, groundwater that discharges to the land... more &lt;p&gt;In river channels in artic environments, groundwater that discharges to the land surface during winter can freeze in the channel, forming large sheet-like masses of layered ice called aufeis.&amp;#160; Water stored in aufeis is released slowly as the aufeis melt during summer, providing a critical course of water to the Arctic river ecosystems late into the summer when other water resources are reduced.&amp;#160; Under warming conditions in the Arctic, the quantity of water stored in aufeis may be reduced and the release of water by melting of the aufeis may end earlier in the summer.&amp;#160; The processes that lead to the formation of aufeis are not well understood; however, an understanding of these processes is necessary to predict how rising air temperature may affect aufeis formation and the availability of water in Arctic river ecosystems.&amp;#160; This work uses numerical simulation to evaluate a conceptual model of subsurface hydrogeothermal conditions that can lead to the formation of aufeis in the Kuparuk aufeis field on the North Slope of Alaska.&amp;#160; At this site, groundwater flows year-round through a talik above the permafrost and beneath the seasonally-frozen active layer just beneath the land surface. Groundwater in this talik discharges to the land surface through unfrozen gaps in the active layer, where it can freeze and form aufeis.&amp;#160; We developed a 2-D heterogeneous vertical profile model to show that subsurface water can discharge to the land surface through subvertical high permeability pathways during winter months while the lower permeability soils near the land surface remain frozen, thus providing a source of water for aufeis formation.&amp;#160; We investigate the effects of the warming conditions on the magnitude and timing of these discharges, which are surrogates for the mass of aufeis and the timing of aufeis formation, respectively.&amp;#160; Aufeis formation and ablation are both sensitive to climatic conditions. The sensitivity analyses presented here form a basis for future investigations of aufeis dynamics across the Arctic.&lt;/p&gt;

AGU Fall Meeting Abstracts, Dec 1, 2018

Environmental Modelling & Software, 2015

This study contributes an iterative problem reformulation technique for multi-objective evolution... more This study contributes an iterative problem reformulation technique for multi-objective evolutionary algorithm (MOEA) decision support. Problem formulations consist of objectives, decision variables, and constraints, and directly influence the results generated by the MOEA. Typically, design problems are optimized based on a single problem formulation established a priori. In this paper, we demonstrate an approach to perform iterative optimization using problem formulations updated from analyses of results from prior rounds of optimization, which often reveal design components not initially considered. To demonstrate the approach, we consider a novel groundwater remediation technique, Engineered Injection and Extraction (EIE), which has never been optimized in the literature. Iterative problem reformulation enabled the MOEA to generate EIE solutions with better performance than the heuristically-developed solution used in prior work. We optimize a groundwater remediation strategy using multi-objective optimization.We demonstrate an iterative approach to adapt the problem formulation.We couple visualizations of objective and decision space to analyze solutions.

The goal of this paper is to introduce an adjoint approach for calculating stream depletion in a ... more The goal of this paper is to introduce an adjoint approach for calculating stream depletion in a river that is hydraulically connected to an aquifer. This paper presents the coupled forward and adjoint equations of flow in an unconfined aquifer, a confined aquifer, and in a river. Flow in the river is assumed to follow Manning’s equation, and the river is assumed to have a wide, rectangular cross section. With these assumptions, the governing equation of flow in the river is non-linear; thus its adjoint is linear in the adjoint state, but still depends on the state variable of the forward equation, i.e., on the river head. This paper outlines an approach for solving the adjoint equations, which requires some approximations and some modification of a code that solves the forward equations.

World Environmental and Water Resources Congress 2016, 2016

In this paper, two alternatives for a useful description of streamflow time patterns in Ecuadoria... more In this paper, two alternatives for a useful description of streamflow time patterns in Ecuadorian lowlands are proposed. In that region, streamflow rates are influenced by precipitation, which varies seasonally due to annual climate patterns, spatially due to small-scale weather patterns, and temporally over longer periods due to longer-period climate fluctuations. Using wavelet coefficients, different periodicities were identified throughout the series, with a dominant one-year frequency (annual cycle). Nevertheless, other frequencies are noteworthy. For instance, during the period 2005-2012, the frequency of 2 yr suggested a larger difference between the highest peaks during the rainy season (usually from December to April), and the lowest valleys of the dry period (rest of the year), otherwise difficult to perceive using only the raw data. In addition, the filter Baxter-King has been successfully applied for seasonal separation, including extreme years (El Niño events of 1982-1983, and 1997-1998). Hence, the use of wavelets may open opportunities for further research, including gap analysis, and cross-wavelet analysis between river stations belonging to different subbasins, but sharing similar features.

World Environmental and Water Resources Congress 2009, 2009

World Environmental and Water Resources Congress 2010, 2010

This study is to identify the factors that affect middle-aged workers' health promoting behaviors... more This study is to identify the factors that affect middle-aged workers' health promoting behaviors. Methods: 214 middle-aged workers participated in surveys, and the data were collected from August to September 2012 and analyzed by using descriptive statistics, Pearson's correlation coefficient, and multiple regression analysis with PASW 18.0 program. Results: It was found that among the factors, the degree of job stress (t=7.69, p<.001) and depression (t=6.23, p<.001) were significantly high for type D individuals, while non type D showed meaningful degree of self-related health status (t=-3.66, p<.001) and health promoting behaviors (t=-4.71, p<.001). The notable variable that affected the health promoting behaviors of the middle-aged workers was depression for both type D (β=-.357, p = .029) and non type D (β=-.325, p<.001) individuals, and this variable accounted for 24.1% and 18.2% respectively. Conclusion: The study revealed that the middle-aged workers showed high degree of job stress and depression that influenced on their health promoting behaviors. Thus, they are recommended to receive health management programs that offer treatment through consulting considering their individual personalities.

Water Resources Research, 2013

Groundwater pumping may lead to reduction in surface water flows, which can compromise water supp... more Groundwater pumping may lead to reduction in surface water flows, which can compromise water supplies and habitat. In light of these threats, the need to minimize stream depletion, defined as the reduction in the flow rate in streams and rivers caused by groundwater pumping, becomes paramount. We develop adjoint equations to calculate stream depletion due to aquifer pumping. We consider a coupled groundwater and surface water system in which both the river head and river flow rate are impacted by drawdown in the aquifer as a result of pumping. Through an illustrative example, we show that the adjoint method for calculating stream depletion produces accurate results if the model is approximately linear. With only one simulation of the adjoint equations, stream depletion can be calculated for pumping at a well at any location in the model domain, which results in a substantial reduction in computational time as compared to the standard method of calculating stream depletion.

Water Resources Research, 2000

Computers & Geosciences, 2001

Journal of Hydrologic Engineering, 2022