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Damages caused by urban pluvial floods are believed to increase due to climate change and urbanization as more citizens are impacted in densely populated cities and extreme rainfalls occur more frequently with higher intensities. To prepare cities for these calamities, urban pluvial flood models are created to provide knowledge about how an extreme rainfall event could inundate the studied city. However, due to the scarcity of observation data from these rainfall events, flood models are seldom calibrated which is necessary to ensure their accuracy.  To improve the feasibility of calibrations an emerging data source was tested, crowdsourced images from citizens. Citizens’ observations have become increasingly available due to the increase of mobile phones and the development of social media enabling citizens to document and upload their observations to the public. Researchers could use these observations as an unconventional data source to calibrate models and reduce the knowledge gap regarding urban floods. The aim of this study was to explore and increase our understanding of how citizen’s observations can be used to calibrate an urban pluvial flood model. A case study about the cloudburst event in Malmö was conducted to study this topic. During that event, more than 100 mm of rain fell over a period of 6 hours in the city and caused 60 million euros of damages.  A total of 297 images depicting the flood caused by the cloudburst event were gathered from social media platforms, newspapers archives, and by inquiring citizens. Images were screened and analysed: water levels were estimated in 66 images and were then used to calibrate a 2D flood model. Furthermore, a sensitivity analysis of the calibrated results was conducted by calculating the RMSE for different subsets and compare it with the RMSE for the full dataset of citizens’ observations. This was done to study how different characteristics, such as timestamp and source as well as sample size and location of the images influences the calibration procedure. After the model was calibrated, the importance of spatial variability in the rainfall input was tested by comparing the flood model output between the spatially varied observed rainfall and a Chicago Design Storm rainfall, which lacks spatial variability.  It was concluded that images from citizens can be used to calibrate an urban pluvial flood model, but the procedure is time-consuming. However, it was also evident that images directly inquired from citizens reduced the time needed as their local knowledge could be integrated. The calibration procedure was also sensitive to the quality of the observations, especially when the images were photographed in relation to the rainfall event. Even though the study had limitations it demonstrates new possibilities to calibrate urban pluvial flood models. / Konsekvenserna av översvämningar från skyfall i städer, så kallade pluviala översvämningar, förväntas öka på grund av urbanisering och klimatförändringar. Det är för att fler påverkas av översvämningar i tätbyggda städer samt att skyfall förväntas öka, både i intensitet och frekvens. Med hjälp av skyfallsmodeller kan dock förståelsen för hur extrema regn översvämmar städer öka. Med denna kunskap kan åtgärder för att minimera konsekvenserna implementeras, såsom blågrön infrastruktur. Däremot finns det en brist av observationsdata från pluviala översvämningar och vilket medför att dessa modeller ytterst sällan kalibreras. Kalibrering är viktig för att säkerställa tillförlitliga modeller.  För att öka möjligheten att kalibrera dessa modeller undersöktes hur observationer från medborgare kan implementeras. Dessa observationer är en relativ oprövad metod men har blivit alltmer tillgängliga tack vare allt bättre mobiltelefonkameror och utvecklingen av sociala medier, vilket gör det enkelt för medborgare att dokumentera och ladda upp sina observationer till allmänheten. Syftet med denna studie är därför att öka förståelsen för hur bilder från medborgare kan användas för att möjliggöra kalibreringen av översvämningsmodeller. En fallstudie över ett skyfall i Malmö 2014 används för att utvärdera denna metod. Under detta skyfall regnade det mer än 100 mm vilket orsakade skador för cirka 600 miljoner kronor.  Totalt samlades 297 bilder som föreställde översvämningen som orsakades av skyfallet. Bilderna samlades ifrån sociala media, tidningsbildarkiv och genom att fråga medborgare efter bilder. Vattennivåerna uppskattades i 66 bilder och de användes sedan för att kalibrera en 2D- skyfallsmodell. Utöver kalibreringen genomfördes en känslighetsanalys av de kalibrerade resultaten genom att jämföra medelfelet för olika subgrupper av bilderna mot medelfelet för alla bilder. Detta gjordes för att studera hur olika egenskaper, såsom när bilden togs och deras ursprung samt bildernas urvalsstorlek och placering påverkar kalibreringsprocessen. Efter att modellen kalibrerats testades också betydelsen av spatial variation i nederbörden genom att jämföra de simulerade vattennivåerna mellan den spatialt varierade historiska regnet och ett syntetiskt CDS-regn som saknar variation.  Utifrån det drogs slutsatsen att bilder från medborgare kan användas för att kalibrera en skyfallsmodell, men metoden är tidskrävande. Dock var det tydligt att bilder som direkt efterfrågades från medborgarna minskade arbetsbördan då deras lokalkännedom kunde inkluderas. Kalibreringen var också känslig för observationerna datakvalitet, särskilt när bilderna fotograferades i förhållande till regnet. Även om studien hade begränsningar visar den att det finns stora möjligheter att kalibrera skyfallsmodeller med observationer från medborgare.

Spatial information about invasive species abundance is critical for estimating impact and understanding risk to ecosystems and economies. Unfortunately, at landscape and regional scales, most distribution datasets provide limited information about abundance. However, national and regional invasive plant occurrence datasets are increasingly available and spatially extensive. We aim to test whether the frequency of these point occurrences can be used as a proxy for abundance of invasive plants. We compiled both occurrence and abundance data for nine regionally important invasive plants in the northeast US using a combination of herbarium records, surveys of expert knowledge, and various invasive species spatial databases. We integrated all available abundance information based on infested area, percent cover, or qualitative descriptions into abundance rankings ranging from 0 (absent) to 4 (highly abundant). Within equal area grid cells of 800 m, we counted numbers of occurrence points and used an ordinal regression to test whether higher numbers of occurrence points were positively correlated with abundance rankings. We compiled a total 49,341 occurrence points in 18,533 cells, of which 12,183 points (25%) within 4,278 cells (32%) had associated abundance information. In six of nine study species we found slight but significant positive overall relationships between abundance rank and occurrence frequency at high abundance ranks. However, at low abundance rankings the relationship tended to be negative and the magnitude of the overall difference in occurrence frequency was too small to be relevant to management. My results suggest that currently available occurrence datasets are unlikely to serve as effective proxies for abundance, and models derived from invasive plant occurrence datasets should not be interpreted as indicative of plant abundance and associated impact. Increased efforts to collect and report invasive species abundance information, and/or higher densities of occurrence points in heavily infested areas are strongly needed for regional scale assessments of potential abundance and associated impact.

As waterborne disease originating in potable water plumbing systems (such as Legionnaires' Disease and Nontuberculous Mycobacterial (NTM) infections) continue to increase, it is important to better understand the cause(s), responsible parties and interventions to prevent disease. This dissertation begins with a literature review characterizing the propensity of building (premise) plumbing to enhance or diminish opportunistic pathogen growth, including Legionella. It then holistically examines the problem at the field, bench and pilot scale by first discovering problems with lead and Legionella in Flint, MI, during an event popularly referred to as the Flint Water Crisis in 2014-2016. Four years were then spent simulating critical factors hypothesized to have triggered the Legionella outbreak in residences and in a large hospital in Flint. In parallel with that work, pilot scale rigs were operated for several years, to examine the important role of water heater system design and operation on energy efficiency, hot water delivery, and Legionella. The first chapter literature review is entitled "Critical Review of the Propensity of Premise Plumbing Pipe Materials to Enhance or Diminish the Growth of Legionella and Other Opportunistic Pathogens." It examines the complex environments found in premise systems, focusing primarily on the role of pipe materials. The effects of metallic (copper, iron) and plastic pipe materials on opportunistic pathogens and Legionella include their effect on nutrient availability, disinfectant levels, and the composition of the broader microbiome. Design, configuration, and operation are also examined in terms of their potential for influencing opportunistic pathogens. This chapter demonstrates that pipe materials have the potential to stimulate or inhibit pathogen growth, dependent on circumstance and water chemistry. This chapter will be submitted to the journal Pathogens. The field study in this work first predicted, discovered and then exposed problems with lead and Legionella in Flint, Michigan. A citizen science project that sampled Flint water in August 2015, demonstrated a city-wide problem with water lead exceeding the EPA limit of 15 µg/L after corrosion control was interrupted. Follow-up sampling events between August 2015 and August 2017 demonstrated that the switch back to the original water source and addition of enhanced corrosion control in October 2015, dramatically reduced lead, copper and iron levels flowing into consumer homes. Entitled "Evaluating Water Lead Levels During the Flint Water Crisis," this work was published in Environmental Science and Technology in 2018. After our Virginia Tech team's work helped expose a Legionnaires' disease outbreak that killed twelve people and sickened nearly one hundred individuals, the started to explore possible links between corrosion control, plumbing materials and disinfection that could help explain the trajectory of disease in Flint and elsewhere. Three separate experiments were performed using bench-scale simulated glass water heaters. Two of the studies attempted to simulate what occurred in Flint homes before, during and after the water crisis in relation to factors that either encouraged or discouraged Legionella growth, while the third examined the more benign Blacksburg tap water and a broader range of influential plumbing conditions. The first study entitled "Copper Pipe, Lack of Corrosion Control, and Uncontrolled pH Influenced the Trajectory of the Flint Legionnaires' Disease Outbreak," determined that the very low pH levels in summer 2015 and interruption of phosphate corrosion control, could cause explosive growth of Legionella in PEX plumbing held at warm temperature, without disinfectant and with constant mixing. Under the same conditions copper pipe had antimicrobial properties that markedly reduced Legionella in our experiments. This work has been submitted for review to Environmental Science and Technology. The second companion study conducted at a higher pH, without mixing and with trace chlorine, found 2.5 log10 lower levels of Legionella compared to the worst-case conditions in the aforementioned study, demonstrating the importance of mixing and traces of chlorine. Higher levels of disinfectant and the presence of copper pipe also enhanced control of Legionella. This manuscript is titled "Interactive Effects of Copper Pipe, Stagnation, Corrosion Control, and Disinfectant Residual Influenced Reduction of Legionella pneumophila during Simulations of the Flint Water Crisis," and it has been published in Pathogens. The third simulated glass water heater study examined the disinfection of opportunistic pathogens in the presence of six different premise plumbing materials or conditions in Blacksburg tap water. Generally speaking, all of the premise plumbing materials reduced disinfection of opportunistic pathogens compared to a control condition with glass surfaces. Chlorine decay was catalyzed by iron pipe, warmer temperature and the presence of organic matter, increasing the persistence of Legionella. Magnesium anodes in particular, encouraged much higher Legionella growth compared to all other materials. This work titled "Chlorine and Chloramine Disinfection of Legionella spp., L. pneumophila, and Acanthamoeba Under Warm Water Premise Plumbing Conditions," has been submitted to Microorganisms. Results of a six-year pilot study titled "Elucidating the Role of Water Heater System Configuration in Energy Efficiency, Consumer Comfort and Legionella Proliferation," examined different types of residential-sized water heater systems with plastic pipes including: a standard tank system with water stagnant between uses, a recirculating tank system with flowing water between uses, and an on-demand system which only heated water and had flow during use. Considering the volume of water in each tank between 38 and 47 ° C as a measure of Legionella growth risk, with a heater setpoint at 48 °C (118 °F) the recirculating system had 90% of its volume at risk daily compared to only 24% of the standard system volume. The on-demand system used a minimum of 10% less energy than the standard tank, and 50% less energy than the recirculating tank, and had one tenth of the volume at risk of growing Legionella than either tank system. In fact, it was only by contriving a system to keep distal lines artificially warmed to above room temperature, that Legionella growth could occur in the on-demand system, whereas it rose to 107 L. pneumophila MPN per liter in a normally operating recirculating system. On the other hand, the on-demand heaters were repeatedly subject to mechanical malfunction during the study, and had difficulty delivering water at the desired temperature and flow rates versus traditional tank systems. This manuscript will be submitted to Water Research. / Doctor of Philosophy / Recent water crises in Flint, Michigan and Legionnaires' Disease outbreaks in Flint, New York City, and Quincy, Illinois have demonstrated the need to better understand the cause(s), responsible parties, and interventions required to prevent waterborne diseases. As waterborne disease originating in building plumbing systems (premise plumbing), such as Legionnaires' Disease and Nontuberculous Mycobacterial infections, continue to increase each year, the burden on healthcare systems and impact on public health also grows. In this dissertation, a literature review, a field study of water in Flint, small-scale laboratory studies, and residential-sized water heater systems were examined to study interactions between water chemistry, premise plumbing, and disease-causing opportunistic pathogens (OPs) with a focus on Legionella, the OP which causes Legionnaires' Disease. The first chapter literature review is entitled "Critical Review of the Propensity of Premise Plumbing Pipe Materials to Enhance or Diminish the Growth of Legionella and Other Opportunistic Pathogens." It examines the complex environments found in premise systems, and the important role of pipe material selection. The effects of metallic (copper, iron) and plastic pipe materials on opportunistic pathogens and Legionella include their impact on nutrient availability, disinfectant levels, and the composition of the broader microbiome. Design, configuration, and operation of plumbing systems are also examined in terms of their potential for influencing growth of opportunistic pathogens. This chapter demonstrates that pipe materials have the potential to stimulate or inhibit pathogen growth, dependent on circumstance and water chemistry. The field study in this work exposed problems with lead and Legionella in Flint, Michigan, during an event known in the popular press as the Flint Water Crisis 2014-2016. In August 2015, a citizen science sampling campaign demonstrated a citywide lead in water problem. After a federal emergency was declared, follow-up sampling events between August 2015 and August 2017 demonstrated that the switch back to the original water source, enhanced disinfection, and corrosion control under federal direction had reduced lead levels to half of the EPA limit. Additionally, the pipe material installed between each home and the water main (service lines) affected levels of lead and copper in water, with the lowest lead concentrations measured in homes with copper service lines. After our teams' work in Flint helped expose a Legionnaires' disease outbreak that killed twelve people and sickened nearly one hundred other individuals, we started to explore possible links between corrosion control, plumbing materials, and disinfection that could affect the trajectory of disease in Flint and elsewhere. Three follow-up studies, using small glass bottles to simulate water heaters, provided more specific comparisons between water conditions in premise plumbing and OP occurrence. Two studies expanded on phosphate corrosion control, chlorine (disinfectant) decay, and pH-related research questions, which arose during the Flint water crisis field study. The first determined that properly treated drinking water and some mixing could inhibit Legionella growth in copper pipes. The second study found that without mixing, copper could be antimicrobial and reduce Legionella growth even if the water chemistry was slightly altered with higher pH. The third simulated water heater study examined the reduction of OPs using a chlorine or chlorine plus ammonia disinfectant to reduce Legionella in the presence of six different plumbing conditions. The reduction of Legionella with chlorine was inhibited when carbon was increased and in the presence of a magnesium anode rod, a necessary water heater component. A six-year study using a residential-sized water heater system holistically examined three different types of water heater systems with plastic pipes: one using a standard water heater tank with water stagnant between uses, one using a water heater tank connected to a recirculating pump to provide constantly flowing water, and one tankless (on-demand) heater which only heated water and provided flow during use. Using temperature as an indicator of risk for Legionella growth, the recirculating system at a temperature setpoint of 48 °C (118 °F) would be at high risk for Legionella growth (water volume at 38-47 °C or 100-117 °F) in 90% of the tank volume each day, whereas the standard system would only be at high risk in 24% of the tank each day. The on-demand system provided the safest alternative for hot water distribution with virtually undetectable levels of Legionella risk when the pipes were kept at room temperature as per normal operation. The on-demand system also used at least 50% less energy than the recirculating system and 10% less energy than the standard system; however, we were not successful in finding a reliable on-demand system that could also provide hot water at the desired temperature and flow rate.

The US Safe Drinking Water Act (SDWA), established in 1974, has improved water quality nationwide through the introduction of maximum contaminant levels, source water protection, and treatment guidelines and requirements. Despite the obvious success many important water quality issues are not covered by regulation. These include the following four topics in this dissertation: 1) Support infrastructure for private well users, 2) Identification and analysis of contaminants in private wells, 3) Leaks or corrosion within building plumbing, and 4) The role of citizen scientists in addressing water quality concerns. Private wells, which provide water for approximately 13% of the population (42.5 million people), are not subject to any federal regulation and well users are responsible for ensuring their own water safety. When water quality issues do arise, state or local organizations can provide critically important support. For instance, in North Carolina (NC) local health departments (LHDs) are required to have private well programs that enforce statewide well construction standards, offer water testing services, and provide well water outreach and assistance. Little is known about the effectiveness of such programs, however, so this work conducted a survey of all NC LHDs to determine their capacity for well water outreach and identify differences among programs around the state. All LHDs reported overseeing the construction of new wells as required by law. However, services provided to existing well users were offered infrequently and/or inconsistently offered. Lack of uniformity was observed in the number of LHD staff and their assigned responsibilities; the costs and availability of well water testing; and the comfort of LHD staff communicating with well owners. While the total number of staff was lower in LHDs in rural counties, the number of outreach activities and services offered was typically not related to the number of well users served. Variations in structure and capacity of well programs at LHDs has created unequal access to services and information for well users in NC. Such gaps in NC, which has among the most stringent state guidelines for well water support, suggests the need to examine conditions in other states nationwide. While direct support to private well users is more common at the state and local levels, the scientific information and resources needed by these officials can be supplemented at the federal level or through academia, especially with respect to emerging contaminants, which many officials may not yet have experience with. For instance, following Hurricane Florence in 2018, dam failures and flooding of coal ash disposal and reuse sites in NC prompted concerns about potential contamination of well water with hexavalent chromium. There is also widespread naturally occurring Cr(VI) in the groundwater however, and methods accessible to state and local officials to identify sources are needed. Literature was reviewed related to source tracking techniques and they were applied to Cr(VI) data we collected from 1,265 private wells across 22 NC counties. Almost two thirds of private wells tested (62.0%) exceeded the Cr(VI) public health goal of 0.07 ppb, with concentrations ranging from <0.02-13.9 ppb (median=0.12 ppb). In the literature review, we identified 33 Cr(VI) groundwater tracking techniques from 51 publications and only 5 techniques were used in more than 12 papers. All papers used different combinations of techniques. We applied these techniques to our well sampling data, and inconclusive results were reported for 7 techniques, while three techniques suggested potential geogenic sources whereas three techniques indicated anthropogenic Cr(VI) sources. Specifically looking at coal ash, two techniques did not support coal ash as a primary source and three were inconclusive. Overall, these techniques did not agree as to the origins of Cr(VI) in well water. This may be due to the fact that these techniques primarily focused on regional scale identification, rather than household-level occurrence. This study demonstrates the difficulty and complexity in identifying and distinguishing the source(s) responsible for Cr(VI) in well water. In addition to private wells, another gap in the SDWA framework involves corrosion of plumbing within a home or private building. The Lead and Copper Rule (LCR) was the first SDWA legislation to include sampling at the tap in private buildings, although these results are only used to inform control of the corrosivity of the water at the treatment plant. Thus, there is no maximum level of lead or copper enforced at the consumers tap, and protection against excessive private plumbing corrosion is not required. A survey conducted about a decade ago suggested that recent efforts to increase temperatures of hot water systems to better control Legionella bacteria might also be increasing pinhole leaks in copper plumbing. Recently, an overseas large building experienced at least 300 pinhole leaks in a hot water recirculation system that frequently exceeded > 65°C in 2018. The occurrence of leaks along the top of the pipes where thick deposited of metal oxides were not visibly protective, was not consistent with conventional patterns of failure, but seemed to be a manifestation of an unusual type of hot water pitting due to the presence of cathodic iron or manganese oxide suggested in prior literature. A macro-cell apparatus was developed and tested to mechanistically test this novel hot water pitting corrosion mechanism experimentally. Cathodic manganese oxides deposits were shown to drive pitting corrosion on a part of the pipe surface without deposits. Pitting occurred over a wide range of pH and was worst at a high ratio of sulfate to bicarbonate. While iron oxide coatings tested in this work did not behave cathodically, as suggested in prior literature, further research could determine if some iron oxides might behave similarly to the manganese oxide tested in this work. Past failures to follow provisions of the SDWA has undermined trust in water safety nationally. Collaborations between citizens and scientists can sometimes expose problems with water safety. Over the last decade we have helped consumers evaluated their concerns using citizen science collaborative approaches. We documented and summarized several case studies conducted by the U.S. Water Study team at Virginia Tech that had varying degrees of success in exposing problems with water supplies via citizen science collaborations. The case studies start with a discussion of work in Flint, MI (lead and Legionella bacteria) in 2015 and St. Joseph, LA in 2016 (lead and iron). Later cases included: Enterprise, LA (lead and iron), Denmark, SC (lead, iron, and Halosan), Chicago, IL (lead), Moore, OK (arsenic), Santa Barbara, CA (copper), anonymous town in SC (Acanthamoeba), and Harrisonburg, VA (Legionella). Approaches, challenges and outcomes of each case study are reviewed along with lessons learned. Overall, this dissertation explored water quality issues which, for various reasons, fall outside of the existing SDWA regulatory framework. The importance of well water support was emphasized by documenting inequalities between local health departments well services and by critically reviewing literature to find a lack of scientific guidance for source determination for an important emerging contaminant. Development of a novel apparatus for monitoring of chemistry related hot water pitting allows for a better understanding of this mechanism and provides a baseline of guidance for avoiding or mitigating such problems in the future. Finally, the use of citizen science to address past water quality concerns and that considers reasonable expectations for future work was evaluated. / Doctor of Philosophy / In the United States, drinking water is usually collected and treated by a local drinking water treatment plant before being sent out to all customers within a city or community. Since the 1970's, the US Environmental Protection Agency (EPA) has regulated treatment plants to make sure they do not send out water that could be potentially dangerous to the health of those drinking, cooking, or bathing with it. These EPA regulations have helped deliver cleaner and cleaner water across the country, but they do not protect every aspect of drinking water for every person in the US. This dissertation covers four topics that EPA regulations do not cover including: 1) Support systems for people getting their water from private wells, 2) Understanding dangers to safe water in unregulated private wells, 3) Leaks in plumbing within a building, and 4) The role of citizens working closely with scientists to determine if their water is safe. More than 1 in 10 people in the US get their drinking water from private wells, and EPA regulations do not protect the safety of that water. Instead, consumers are on their own to make sure it is safe to drink. When water that could be dangerous is discovered, state or local governments are important sources where residents can get help in treating it. For instance, in North Carolina (NC), local county health departments are required to have programs focused on private wells. The goals of these programs are to make sure new wells are built according to legal codes, offer to test well water for residents, and answer questions people have about their well water. No one has ever determined how well how well health departments meet these goals. This work sent a survey to each health department in NC to figure out how much each was doing and identify any differences between counties. All health departments were checking new wells to make sure they were installed according to state law. But all health departments did not provide support or answer questions of people who had older wells. Some of the differences were due to the number of staff working on these problems, costs charged for well water testing, and the confidence with which staff answered well water questions. Well users in different NC counties get a different level of service as a result. The fact that these differences exist in NC, a state believed among the best in supporting private well owners, suggests a need for a similar analysis in other states. Local health departments and state agencies are more likely to work directly with people concerned about their well water. College or federal government researchers can still help support these groups. Extra support is important when contaminants that state or local officials haven't experienced before become concerning. In one example, after Hurricane Florence in NC in 2018, sites where coal power plants had been throwing away their coal ash became flooded, and coal ash was introduced into floodwaters. Coal ash has been known to contain Cr(VI), which can is believed to increase chances of cancer if consumed in drinking water. Cr(VI) also occurs naturally, when it is leached from rocks in groundwater. Figuring out where Cr(VI) found in a private well is from is difficult. To determine methods of figuring out the sources of Cr(VI) we reviewed scientific literature and documented the methods that had been used before to determine Cr(VI) sources. Then, we conducted a sampling campaign across the state, and sampled 1,265 private wells from 22 different NC counties. Cr(VI) was found in many of the wells we tested, and nearly 2/3 had Cr(VI) above the level established by the NC state government as a potential health concern. From previous literature, we reviewed 51 papers and found 33 methods that had been used to determine the source of Cr(VI) in groundwater. Only five of these methods were used by more than 12 papers and while many papers used more than one method, no papers used the same grouping of methods. When we used the methods from the literature to see how the results compared between methods, they did not all agree. Three said that Cr(VI) was coming from natural sources, three indicated it came from industry, and seven made no prediction. Overall, this study shows how difficult it can be to find out the source of Cr(VI) that occurs in private wells. Leaks in copper plumbing inside of a home or building are also not covered at all by EPA laws. The Lead and Copper Rule (LCR), passed in 1991, does include testing the water coming out of peoples' faucets for copper. But those testing results are only used to make changes at the water treatment plant to make the water less corrosive. Over the last 10-20 years, scientists have become worried that pipes may be at risk of forming more leaks, when higher hot water temperatures are used to prevent the growth of dangerous bacteria that can grow in plumbing. In one large building outside the US, at least 300 leaks were found in hot water pipes, costing large amounts of money to fix. In the past, most leaks like this were at the bottom of pipes, under settled particles with iron and manganese oxides in them. In this building though, leaks were at the top of pipes, where there was no deposit, which was very surprising. One reason for this could have been a type of reaction from past studies where iron or manganese coatings cause a reaction which forms leaks in nearby copper pipe. No experiments have ever proven this reaction though. Our study made a lab setup to learn more about this reaction and proved that it is possible and was due to manganese oxide. We found the most corrosion occurred in water with high pH and high levels of sulfate. Iron oxide particles did not cause the reaction in our study, but it is possible that other types of iron oxide could still have a role in making the reaction happen. Past examples of cities or towns not following EPA rules has caused distrust in public drinking water. Citizens and scientists working closely together have sometimes been able to find out about such problems and get them fixed. Over the last 10 years, we have helped people learn more about their water concerns by working with them to take and analyze water tests. We documented a number of those cases which had different levels of success. The first case we talk about is Flint, MI in 2015, then St. Joseph, LA in 2016. Later cases include cities in Louisiana, South Carolina, Illinois, Oklahoma, California, and Virginia, with a number of different water risks. The first two cases caused drastic and quick changes to water safety and drinking water emergencies were declared. But after that the response was less urgent. If scientists want to pursue work with citizens who have concerns, they will need to be ready for keep working on it for a long time, and face disagreement from agencies and government groups who provide the water. Overall, this work tried to help people, who were not being protected by government rules, or who felt that they were being harmed by governments or companies who were breaking the rules. Many of these problems make people worried about their water, or create worries that are not necessary, or cost consumers a lot of money. More work is needed to address this type of problem.

Private lands encompass over half of the continental United States and serve as critical habitat for the majority of federally threatened and endangered species. Despite the importance of private lands for conservation, they remain understudied by conservation scientists. Conservation research programs that study private lands biodiversity not only help to fill this research gap but may also contribute more broadly to private lands conservation by influencing the conservation behaviors of individuals that participate in the program. However, little is known about how conservation behavior outcomes may differ across varying levels of participation in a program and what factors may influence this conservation behavior change. This thesis focuses specifically on conservation behavior outcomes associated with participation in a conservation research program and participants' perceived impact on conservation behaviors. For my first chapter, I interviewed private landowners that had provided property access to the Smithsonian conservation research program, Virginia Working Landscapes (VWL), between 2010 and 2020. We found that landowners perceived their participation in VWL influenced their conservation behaviors across multiple categories; yet, land stewardship behaviors were more commonly positively influenced than social environmentalism or environmental citizenship behaviors. Landowners also reported that various aspects of the program including program events, on-site interactions with staff and citizen scientists, and landowner reports had the strongest influence on their engagement in conservation behaviors, while other aspects such as program newsletters and annual reports influenced their engagement in conservation behaviors to a lesser degree. For my second chapter, I surveyed citizen scientists and non-citizen scientists that were associated with VWL between 2010 and 2020. VWL citizen scientists had significantly higher perceived impacts of the program on their engagement in conservation behaviors compared to non-citizen scientists. The strongest predictors of respondents' perceptions of VWL's impact on their conservation behaviors include participation as a citizen scientist, program-related normative beliefs, attendance at program events, and reading program newsletters, while characteristics of the participants (i.e. demographics, actual behavioral control, personal norms, environmental attitude) were not predictive of perceptions of impact. Findings from this thesis can inform efforts to influence program participants' conservation behaviors. In particular, program managers may increase conservation outcomes through incorporating citizen science opportunities; fostering direct interactions between landowners, citizen scientists, researchers, and peers; training citizen scientists in effective science communication skills; and tailoring program communications to specific target audiences. / Master of Science / Over half of the mainland United States are under private ownership and these private lands are important habitat for federally threatened and endangered species. Even though private lands are important for conservation, the majority of conservation research studies take place on public lands. Conservation research programs that study species on private lands can contribute to conservation by providing insights into questions that are critical to species' management. These programs can also contribute to conservation by influencing the people who participate in the program to engage in conservation behaviors. However, people can participate in conservation research programs in many different ways and it is unclear how participation in a program influences people's conservation behaviors. This thesis explored the different conservation behaviors associated with participation in a conservation research program and participants' perceived impact on conservation behaviors. For my first chapter, I interviewed private landowners that had provided property access to the Smithsonian conservation research program, Virginia Working Landscapes (VWL), between 2010 and 2020. The landowners we interviewed perceived that their participation in VWL influenced them to engage in conservation behaviors across multiple categories, but land stewardship behaviors (e.g. landscape improvements that benefit wildlife or their habitat) were more commonly influenced than social environmentalism (e.g. behaviors that focus on social engagement) or environmental citizenship behaviors (e.g. supporting environmental causes through voting, donations, or civic engagement). Certain aspects of the program such as program events, on-site interactions with staff and citizen scientists, and landowner reports were the most influential on landowners' engagement in conservation behaviors, while other aspects such as program newsletters and annual reports influenced their engagement in conservation behaviors less often. For my second chapter, I surveyed citizen scientists (i.e. volunteer members of the public who gather or analyze data for scientific research) and non-citizen scientists (i.e. individuals subscribed to VWL's newsletter but had never volunteered as citizen scientists) associated with VWL. VWL citizen scientists were positively influenced by the program to engage in conservation behaviors significantly more than non-citizen scientists. Characteristics of the program including participation as a citizen scientist, program-related normative beliefs (i.e. one's perception of whether other individuals will approve or disapprove of a certain behavior), attendance at program events, and program materials were associated with the program's influence on survey respondents' engagement in conservation behaviors. Characteristics of the participants (i.e. demographics, actual behavioral control, personal norms, environmental attitude) were not found to be significant predictors of impact. Results from this thesis may be helpful to programs aiming to increase their influence on participants' conservation behavior engagement. For example, programs may incorporate citizen science; foster direct interactions between landowners, citizen scientists, researchers, and peers; train citizen scientists in science communication skills, and tailor program communications to specific audiences.

Group signature schemes enable anonymous-yet-accountable communications. Such a capability is extremely useful for modern applications such as smartphone-based crowdsensing and citizen science. A prototype named GROUPSENSE was developed to support anonymous-yet-accountable crowdsensing with SRBE in Android devices. From this prototype, an Android crowdsensing application was implemented to support privacy in citizen science. In this thesis, we will evaluate the usability of our privacy-preserving crowdsensing application for citizen science projects. An in person user study with 22 participants has been performed showing that participants understood the importance of privacy in citizen science and were willing to install privacy-enhancing applications, yet over half of the participants did not understand the privacy guarantee. Based on these results, modifications to the crowdsensing application have been made with the goal of improving the participants' understanding of the privacy guarantee. / Master of Science / A group signature scheme is a security solution that allows any member of a group to create a digital signature without revealing his or her identity. This enables an application user to remain anonymous-yet-accountable during communication. Such a capability is extremely useful when collecting data for scientific research, referred to as citizen science, through a modern smartphone application. A prototype named GROUPSENSE was developed to support anonymous-yet-accountable data collection with SRBE, an advanced group signature scheme, in Android devices. From this prototype, an Android application was implemented to support privacy in citizen science. In this thesis, we will evaluate the usability of our privacy-preserving application developed for citizen science projects. An in person user study with 22 participants has been performed showing that participants understood the importance of privacy in citizen science and were willing to install privacy-enhancing applications, yet over half of the participants did not understand the specified privacy guarantee. Based on these results, modifications to the application have been made with the goal of improving the participants’ understanding of the privacy guarantee.

<p dir="ltr">New cultivars of compact tomato (<i>Solanum lycopersicum</i>) and pepper (<i>Capsicum annuum</i>) plants are available to consumers, creating niche market opportunities for greenhouse growers who produce vegetable bedding plants for spring sale. However, production guidelines for these crops are limited. We conducted two experiments to evaluate non-chemical means of height control for these plants. In the first experiment, we treated ‘Siam’ tomato and ‘Basket of Fire’ pepper plants with 0, 50, 100, 150, or 200 mg·L^–1 nitrogen (N) during the “production” phase and used a similar or higher N concentration during the “fruiting” phase. Our results show that although height of these plants can be controlled with lower fertilizer concentration, their yield will likely be affected by limiting fertilizer availability. In addition, our findings suggest that these plants can be grown without the addition of fertilizer during production, provided that the substrate has a starter fertilizer charge, and that sufficient fertilizer is applied during the fruiting phase. In the second experiment, we characterized the effects of fertilizer use and substrate volumetric water content (VWC) during production using the same compact plants, and evaluated post-production carryover effects on growth and yield. Plants either received water-soluble fertilizer (100 mg·L^–1 N) once a week, or were irrigated with tap water only, relying on the starter fertilizer charge in the substrate. In addition, plants were irrigated when the substrate VWC reached 0.15, 0.30, 0.45, or 0.60 m³·m^–3. Overall, our results show that substrate VWC had minimal effects on growth and yield, but plants that were not fertilized were shorter, had less biomass, and produced less fruit than those treated with fertilizer. These findings suggest that growth and yield of these compact tomato and pepper plants are affected to a larger extent by fertilizer use than by substrate VWC.</p><p dir="ltr">In effort to better understand consumer preferences for these new compact plants, we used a citizen-science approach in another experiment. Approx. 300 participants from three states in the USA (IN, IA, and TN) compared three compact tomato cultivars (Red Robin, Cocoa, and Micro Tom) started from seed or as transplants. In addition, we compared pre- and post-experiment survey responses to assess potential changes in behaviors, beliefs, and attitudes towards gardening as a result of the experiment. Cocoa was the preferred cultivar, closely followed by Red Robin. Our results indicate participants valued plant appearance, fruit yield, and fruit taste when making these preference choices. Approximately 70% of participants preferred plants started as transplants compared to those from seed, regardless of cultivar. Most participants reported they would be willing to pay between $1.00 to $7.49 more for a transplant of their favorite cultivar compared to tomato plants available at local nurseries. Results for dietary behaviors show that participants increased their consumption frequency of fruit, lettuce salad, vegetables, and food mixed with vegetables at the end of the experiment, but few differences were measured for beliefs and attitudes towards gardening, likely due to previous positive biases towards gardening among project participants. In conclusion, results from our experiments show that growth and yield of compact tomato and pepper plants can be controlled by adjusting fertilizer management practices. In addition, citizen science was shown to be an effective research method to assess plant-performance and consumer-preference data, and to measure potential changes in behavior of project participants.</p>

Unter dem englischen Begriff Citizen Science und seiner deutschen Entsprechung Bürgerwissenschaften werden eine Reihe von Konzepten gefasst, die eine Beteiligung von Laien bei der Generierung wissenschaftlicher Erkenntnisse bezeichnen. Diese Konzepte sind eng verbunden mit der Vorstellung einer Offenen Wissenschaft (Open Science) und ihrem Ziel, 'Wissenschaft einer größeren Zahl von Menschen einfacher zugänglich zu machen' (Wikipedia). Der Vortrag im Rahmen der Konferenz 'Forschungsdesign 4.0. Datengenerierung und Wissenstransfer in interdisziplinärer Perspektive' des Instituts für Sächsische Geschichte und Volkskunde e.V. vom 19. bis 21. April 2018 an der Sächsischen Landesbibliothek - Staats- und Universitätsbibliothek Dresden untersuchte unterschiedliche Definitionsansätze zusammengeführt und skizzierte am Beispiel aktueller Projekte aus Sachsen Probleme und Perspektiven von Citizen Science allgemein.

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