Proactive Assessment of Climate Change and Contaminant Spill Impacts on Source Water Quality

Managing the water quality of surface drinking water sources has become an increasingly difficult task for water suppliers due to increased watershed urbanization and climate change. Changes in source water quality may affect public perceptions, treatment effectiveness, and ultimately costs to treat water to drinking standards. Although there are increased threats to current and future drinking water quality, current approaches to managing these threats are typically reactionary. Prior detailed modeling efforts of hypothetical events that may impair raw water quality allow for an understanding of constituent fate and transport, including potential maximum concentrations and travel times to the drinking water intake for constituents which may be of concern. The primary goal of this dissertation was to present proactive frameworks that utilize a hydrodynamic and water quality model to aid in developing scientifically-based management plans prior to an accidental or natural event occurring. The Wachusett Reservoir, a major drinking water supply for metropolitan Boston, Massachusetts, was used as a case study to illustrate proactive modeling efforts to quantify water quality impacts after both short and long-term potential events. This work used a process-based modeling approach to simulate reservoir hydrodynamic and water quality responses to changes in various model inputs (streamflow, constituents, meteorology) and also evaluated current and future management decisions which may mitigate water quality impacts. The approach is demonstrated through a series of proactive modeling studies conducted to evaluate water quality at the drinking water intake in response to contaminant incidences, long-term increasing air temperatures, and extreme precipitation events. For the Wachusett Reservoir, proactive contaminant modeling highlighted the importance of a rapid response by managers to contain a contaminant spill and therefore minimizing the mass of contaminant that is able to enter the water column following an event. In scenarios that simulated long term increasing air temperature increases, model results suggested increases in epilimnion and hypolimnion water temperatures, decreased ice cover, and increased stratification duration by 2112. Extreme precipitation event simulations during the spring and summer resulted in organic matter concentrations that exceeded recorded maximums at the drinking water intake while nutrients for this particular reservoir remained low. The modeling results provide valuable insights into water quality responses to changes in water body inputs and can help inform short and long-term management strategies, prior to water quality degrading events

My Private Lead Service Line Replacement

3 Key Takeaways: A homeowner’s decision to replace their lead service line can be confounded by factors including their understanding of the science, their perceptions of their lead exposure risks, and the cost of the work. First draw and 5-minute flush samples may not capture the peak lead concentration, further confounding a customer’s replacement decision. In my case, lead service line replacement significantly lowered lead concentrations after stagnation based on sequential sampling

Comparison of SELDM Simulated Total-Phosphorus Concentrations with Ecological Impervious-Area Criteria

Ecological studies indicate that impervious cover (IC) greater than approximately 5%–20% may have adverse effects on receiving-stream ecology. It is difficult to separate the effects of runoff quality from other effects of urbanization on receiving streams. This study presents the results of a numerical experiment to assess the effects of increasing IC on water quality using the Stochastic Empirical Loading and Dilution Model (SELDM). Hydrologic and physiographic variables representative of southern New England were used to simulate receiving water quality in a basin with IC ranging from 0.1% to 30%. Simulation results mirror the results of ecological studies; event mean concentrations (EMCs) of total phosphorus (TP) increase proportionally to the logarithms of imperviousness for a given risk percentile. Simulation results indicated that commonly used stormwater treatment methods may be insufficient for mitigating the effects of imperviousness. Therefore, disconnection, rather than treatment, may be needed to protect water quality, and efforts to preserve undeveloped stream basins may be more effective than efforts to remediate conditions in highly developed basins. Results also indicate that commonly used water-quality criteria may be too restrictive for stormwater because TP EMCs frequently exceed these criteria, even in minimally developed basins

A multi-year study of engineering self-efficacy in the US: exploring gender differences in a small engineering program. International Journal of Gender

This study presents the baseline results of an ongoing study at a small liberal arts university in the US and explores the gender differences in engineering selfefficacy, preparedness, and engagement in undergraduate engineering students. Data from the first timepoint of the survey was used to identify factors such as high school grade point average (GPA), math preparedness, high school mentoring, and college extracurricular involvement, and their correlations with engineering selfefficacy, as measured by the Longitudinal Assessment of Engineering Self-Efficacy (LAESE) scale. Investigation of LAESE subscales revealed that students (regardless of gender) who entered college having previously studied calculus reported greater engineering self-efficacy. Results indicate that women enter college with greater math preparation and high school GPA, however, self-efficacy is not any stronger than that of their male peers. However, women had greater coping self-efficacy and math outcome expectations compared to their male peers. These findings suggest a pipeline issue, where only the women with strong preparation self-identify as being capable of earning an engineering degree. The study also provides information about the differential experiences of women in engineering and suggests future factors to explore more deeply, such as mentoring and club involvement

Model archive for analysis of the effects of impervious cover on receiving-water quality with the Stochastic Empirical Loading Dilution Model (SELDM): U.S. Geological Survey data release

Impervious runoff-discharge to receiving streams is widely recognized as one of the leading factors contributing to ecological degradation in such streams. Although there are many factors that contribute to ecological degradation with increasing development adverse effects caused by runoff quality is widely recognized as a contributing factor. The objective of this study was to simulate the flows concentrations and loads of impervious-area runoff and stormflows from an undeveloped area over a range of impervious percentages and drainage areas to examine potential relations between these variables and the quantity and quality of downstream flows. Stormwater runoff in a hypothetical stream basin that represents hydrologic and physiographic basin properties in southern New England was simulated using the Stochastic Empirical Loading and Dilution Model (SELDM) to do a numerical experiment designed to explore relations between impervious cover and receiving-water quality. These simulations included a range of impervious cover from 0.1 to 30 percent. These relations were examined to provide planning-level estimates of a population of concentrations and dilution factors as explanatory variables for the changes in stream biota commonly seen as the percentage of impervious areas increase. SELDM is a runoff-quality model developed by the U.S. Geological Survey in cooperation with the Federal Highway Administration to simulate the adverse effects of runoff on receiving waters and provide meaningful information about the potential effectiveness of management measured to reduce water quality risks. This is a model archive for these numerical experiments documenting the input statistics and the simulation results. Model development files include details of simulated hydrology, basin properties, upstream undeveloped area water quality, and developed (impervious area) area runoff quality. Model results include downstream water quality with and without structural best management practices

My Private Lead Service Line

Homeowners’ decisions to replace their lead service lines (LSLs) can be complicated by factors including understanding of the science, perceptions of lead exposure risks, and cost of the work. First-draw and five-minute flush samples may not capture the peak lead concentration, further complicating a customer\u27s replacement decision. In the author\u27s case, sequential sampling indicated that LSL replacement for her home significantly lowered lead concentrations after stagnation

Model archive for analysis of flows, concentrations, and loads of highway and urban runoff and receiving-stream stormwater in southern New England with the Stochastic Empirical Loading and Dilution Model (SELDM)

This data release documents the data and models used to assess flows, concentrations, and loads of highway and urban runoff and of stormwater within receiving streams in southern New England. There are more than 48,000 locations in southern New England where roads cross streams and many more locations where runoff from developed areas may discharge to receiving streams; information about runoff discharges and the quantity and quality of stormflow upstream and downstream of discharge points is needed to inform resource-management decisions. This analysis was done with a version 1.1.1 of the Stochastic Empirical Loading and Dilution Model (SELDM) that was populated with regional statistics for southern New England. SELDM uses basin properties and hydrologic statistics to simulate runoff from a site of interest, which may be a highway site or another developed (urban) area, and concurrent stormflow from an upstream basin to calculate downstream values, which are the sum of contributions from the site of interest and the upstream basin. Because there are few monitoring sites with data relative to the number of potential sites of interest, the probability that data will be available at a site of interest is low. Furthermore, much of the data available at monitored sites is not sufficient to characterize long-term stormwater-quality conditions because most water-quality monitoring sites have less than one year of data. The statistics for highway and upstream basin properties, hydrologic variables, and stormwater quality provided in this data release can be used to represent long-term conditions throughout southern New England. The simulated populations of flows, concentrations, and loads documented in this data release represent long-term conditions at representative sites of interest. This data release also documents results of sensitivity analyses designed to guide the selection of input variables for runoff quality simulations and selected example simulations that illustrate use of simulation results for decision making. The methods and statistics in this study were developed for use with SELDM but may be used with other models. The information provided here can be used for robust decision making by highway practitioners, regulators, and decisionmakers. The project described in this data release was conducted in cooperation with the Federal Highway Administration and the Connecticut, Massachusetts, and Rhode Island Departments of Transportation. The data release contains twenty-one compressed (zip) files, a ReadMe file pertaining to the data release as a whole (ReadMe.txt), and a diagram to illustrate the organization of the zip files and subfolders (ReadMeDiagram.pdf). Please refer to ReadMe files within the zip files and subfolders for more detailed metadata pertaining to the data, statistics, and software provided

Model archive for analysis of flows, concentrations, and loads of highway and urban runoff and receiving-stream stormwater in southern New England with the Stochastic Empirical Loading and Dilution Model (SELDM)

This data release documents the data and models used to assess flows, concentrations, and loads of highway and urban runoff and of stormwater within receiving streams in southern New England. There are more than 48,000 locations in southern New England where roads cross streams and many more locations where runoff from developed areas may discharge to receiving streams; information about runoff discharges and the quantity and quality of stormflow upstream and downstream of discharge points is needed to inform resource-management decisions. This analysis was done with a version 1.1.1 of the Stochastic Empirical Loading and Dilution Model (SELDM) that was populated with regional statistics for southern New England. SELDM uses basin properties and hydrologic statistics to simulate runoff from a site of interest, which may be a highway site or another developed (urban) area, and concurrent stormflow from an upstream basin to calculate downstream values, which are the sum of contributions from the site of interest and the upstream basin. Because there are few monitoring sites with data relative to the number of potential sites of interest, the probability that data will be available at a site of interest is low. Furthermore, much of the data available at monitored sites is not sufficient to characterize long-term stormwater-quality conditions because most water-quality monitoring sites have less than one year of data. The statistics for highway and upstream basin properties, hydrologic variables, and stormwater quality provided in this data release can be used to represent long-term conditions throughout southern New England. The simulated populations of flows, concentrations, and loads documented in this data release represent long-term conditions at representative sites of interest. This data release also documents results of sensitivity analyses designed to guide the selection of input variables for runoff quality simulations and selected example simulations that illustrate use of simulation results for decision making. The methods and statistics in this study were developed for use with SELDM but may be used with other models. The information provided here can be used for robust decision making by highway practitioners, regulators, and decisionmakers. The project described in this data release was conducted in cooperation with the Federal Highway Administration and the Connecticut, Massachusetts, and Rhode Island Departments of Transportation. The data release contains twenty-one compressed (zip) files, a ReadMe file pertaining to the data release as a whole (ReadMe.txt), and a diagram to illustrate the organization of the zip files and subfolders (ReadMeDiagram.pdf). Please refer to ReadMe files within the zip files and subfolders for more detailed metadata pertaining to the data, statistics, and software provided

A multi-year study of engineering self-efficacy in the US: exploring gender differences in a small engineering program. International Journal of Gender

This study presents the baseline results of an ongoing study at a small liberal arts university in the US and explores the gender differences in engineering selfefficacy, preparedness, and engagement in undergraduate engineering students. Data from the first timepoint of the survey was used to identify factors such as high school grade point average (GPA), math preparedness, high school mentoring, and college extracurricular involvement, and their correlations with engineering selfefficacy, as measured by the Longitudinal Assessment of Engineering Self-Efficacy (LAESE) scale. Investigation of LAESE subscales revealed that students (regardless of gender) who entered college having previously studied calculus reported greater engineering self-efficacy. Results indicate that women enter college with greater math preparation and high school GPA, however, self-efficacy is not any stronger than that of their male peers. However, women had greater coping self-efficacy and math outcome expectations compared to their male peers. These findings suggest a pipeline issue, where only the women with strong preparation self-identify as being capable of earning an engineering degree. The study also provides information about the differential experiences of women in engineering and suggests future factors to explore more deeply, such as mentoring and club involvement

Understanding the Impacts of COVID-19 on Feelings of Stress and Anxiety in Women Engineering Students

For over two decades, the percentage of women earning bachelor degrees in engineering has remained stagnant at 20%, despite continued growth in the overall number of undergraduate engineering degrees awarded in the US. Understanding how to increase both recruitment and retention is critical to improving the representation of women in engineering. Beyond the interest in drawing more women to engineering majors, the literature cites many reasons for why women choose to leave engineering programs. For example, feelings of worry, discouragement, and anxiety are shown to inhibit learning and academic progress, in ways that disproportionality affect women, and can lead to exiting an engineering program. In the fall of 2018, we piloted a study to better understand differences between women, men, and non-binary engineering students at our liberal arts university in the northeastern US. The survey is administered twice each academic year to explore self-efficacy, belongingness, preparedness, and engagement, both longitudinally and cross-sectionally. In March 2020, our university quickly pivoted to remote learning in response to the outbreak of COVID-19 and in the fall of 2020 our campus re-opened for hybrid learning. The abrupt changes in higher education, brought on by the current public health crisis, affect students\u27 learning and mental health, in ways that will likely be long lasting. To measure the impacts of the pandemic on engineering students, twenty Likert-type screener questions were added to the survey, which was re-administered in June 2020 and again in September 2020. This paper shares findings from the two most recent survey points, with emphasis on the results from the COVID screener questions. Women reported significantly higher levels of stress on ten out of the twenty COVID screener questions, as compared to the men, spanning topics related to home life, physical health, mental health and academics. Fewer significant changes were observed over time in men than women. This study aims to provide insights on how to better recruit, retain and support women in undergraduate engineering programs through measuring differences in feelings of stress and anxiety between genders and across time