Environmental Science & Technology
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Item Effects of Detritus on the Mosquito Culex pipiens: Phragmites and Schedonorus (Festuca) Invasion Affect Population Performance(MDPI, 2019-10-25) Leisnham, Paul T.; Scott, Brandon; Baldwin, Andrew H.; LaDeau, Shannon L.Species interactions that influence the performance of the exotic mosquito Culex pipiens can have important effects on the transmission risk of West Nile virus (WNV). Invasive plants that alter the vegetation communities of ephemeral ground pools may facilitate or resist the spread of C. pipiens (L.) by altering allochthonous inputs of detritus in those pools. To test this hypothesis, we combined field surveys of roadside stormwater ditches with a laboratory microcosm experiment to examine relationships between C. pipiens performance and water quality in systems containing detritus from invasive Phragmites australis (Cav.) Trin. Ex Steud., introduced Schedonorus arundinaceus (Schreb.) Dumort., or native Juncus effusus L. or Typha latifolia L. In ditches, C. pipiens abundance was unrelated to detritus species but female C. pipiens were significantly larger from ditches with S. arundinaceus and smaller with J. effusus. Larger and smaller C. pipiens were also produced in microcosms provisioned with S. arundinaceus and J. effusus, respectively, yet the per capita rate of population of change did not vary. Larger females from habitats with S. arundinaceus were likely caused by faster decay rates of S. arundinaceus and resultant increases in microbial food, but lower survival as a result of fouling and higher tannin-lignin concentrations resulted in little changes to overall population performance. Larger female mosquitoes have been shown to have greater potential for transmitting arboviruses. Our findings suggest that changed community-level interactions from plant invasions in urban ephemeral ground pools can affect the fitness of C. pipiens and possibly increase WNV risk.Item Rethinking Stormwater: Analysis Using the Hydrosocial Cycle(MDPI, 2020-04-30) Wilfong, Matthew; Pavao-Zuckerman, MitchellWater management and governance continues to rely on the scientific and engineering principles of the hydrologic cycle for decision-making on policies and infrastructure choices. This over-reliance on hydrologic-based, technocratic, command-and-control management and governance tends to discount and overlook the political, social, cultural, and economic factors that shape water-society relationships. This paper utilizes an alternative framework, the hydrosocial cycle, to analyze how water and society shape each other over time. In this paper, the hydrosocial framework is applied to stormwater management in the United States. Two hydrosocial case studies centered on rain and stormwater are investigated to highlight how stormwater management can benefit from a hydrosocial approach. The insights and implications from these case studies are then applied to stormwater management by formulating key questions that arise under the hydrosocial framework. These key questions are significant to progressing stormwater management to more sustainable, resilient, and equitable outcomes for environmental and public safety and health. This paper frames a conversation for incorporating the hydrosocial framework into stormwater management and demonstrates the need for an interdisciplinary approach to water management and governance issues.Item Decentralizing Stormwater Management: Shifting Infrastructure and Evolving Hydrosocial Relationships(2022) Wilfong, Matthew Tyler; Pavao-Zuckerman, Mitchell; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Stormwater management has historically remained in the technocratic realm of engineers and scientists disconnecting society from stormwater to protect public and environmental health. Despite incremental improvements, state and local governments are beginning to change their management practices and techniques in response to climatic changes, increased urbanization, and intensifying regulatory pressures. Scholars and practitioners have argued that this paradigm shift in stormwater management is required to continue to protect public and environmental health and reach regulatory goals. Despite the need for this paradigm shift, there continues to be slow progress towards decentralization. Thisshift is characterized by two key developments: the increased implementation of decentralized green infrastructure and increased involvement of individuals in managing stormwater. Broadly, this dissertation sets out to investigate two key aspects of this paradigm shift: (1) the hydrologic performance of these decentralized practices and (2) the social, political, cultural, and economic dynamics that are currently underpinning this paradigm shift. This dissertation begins with a chapter investigating the hydrologic performance ofdecentralized, green infrastructure treatment trains in Clarksburg, MD. Using stormwater monitoring methodology, we analyze how effectively treatment trains can hydrologically manage stormwater and the effects of precipitation dynamics on the ability of these treatment trains to manage stormwater. This research suggests that these treatment trains are generally highly effective at managing stormwater volumes across a host of storm events with an average of 93% of discharge abated throughout the monitoring period. We also demonstrate that precipitation intensity was the most influential precipitation dynamic on the performance of each treatment train suggesting that designing these treatment trains with the potential higher prevalence of higher intensity storm events due to climate change. To begin the social science portions of the dissertation research, we utilize an alternative framework, the hydrosocial cycle, to analyze how stormwater and society have and continue to shape each other over time. Building upon this work, we investigate the political, social, and cultural dynamics influencing and arising within this paradigm shift occurring within stormwater management. Through semi-structured interviews and Q-methodology within two urban watersheds in Maryland and Washington DC, we assess changes in the hydrosocial relationships between stakeholders and stormwater. Using these insights, we discuss the potential for alignment and cooperation among these diverging hydrosocial relationships and continuing the shift towards decentralizing stormwater management. Arising from this holistic and critical analysis, we seek to provide actionable recommendations focused on how, where, and who manages stormwater to reach more sustainable, resilient, and equitable outcomes. Additionally, we aim to demonstrate the effectiveness of theseframeworks and methodologies to better attend to political and power dynamics involved in water governance and management, more broadlyItem Effects of Detritus on the Mosquito Culex pipiens: Phragmites and Schedonorus (Festuca) Invasion Affect Population Performance(MDPI, 2019-10-25) Leisnham, Paul T.; Scott, Brandon; Baldwin, Andrew H.; LaDeau, Shannon L.Species interactions that influence the performance of the exotic mosquito Culex pipiens can have important effects on the transmission risk of West Nile virus (WNV). Invasive plants that alter the vegetation communities of ephemeral ground pools may facilitate or resist the spread of C. pipiens (L.) by altering allochthonous inputs of detritus in those pools. To test this hypothesis, we combined field surveys of roadside stormwater ditches with a laboratory microcosm experiment to examine relationships between C. pipiens performance and water quality in systems containing detritus from invasive Phragmites australis (Cav.) Trin. Ex Steud., introduced Schedonorus arundinaceus (Schreb.) Dumort., or native Juncus effusus L. or Typha latifolia L. In ditches, C. pipiens abundance was unrelated to detritus species but female C. pipiens were significantly larger from ditches with S. arundinaceus and smaller with J. effusus. Larger and smaller C. pipiens were also produced in microcosms provisioned with S. arundinaceus and J. effusus, respectively, yet the per capita rate of population of change did not vary. Larger females from habitats with S. arundinaceus were likely caused by faster decay rates of S. arundinaceus and resultant increases in microbial food, but lower survival as a result of fouling and higher tannin-lignin concentrations resulted in little changes to overall population performance. Larger female mosquitoes have been shown to have greater potential for transmitting arboviruses. Our findings suggest that changed community-level interactions from plant invasions in urban ephemeral ground pools can affect the fitness of C. pipiens and possibly increase WNV risk.Item The stormwater retention benefits of urban trees and forests(2018) Phillips, Tuana Hilst; Pavao-Zuckerman, Mitchell; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The use of urban tree canopies as strategies to mitigate stormwater runoff is limited in part by a lack of empirically observed data. This thesis quantifies soil infiltration capacity in 21 forest patches in Baltimore, Maryland, and reports results from a meta-analysis on urban tree transpiration. Results show that the degree to which soil infiltration and tree transpiration functions reduce stormwater runoff depends on soil physical properties, tree characteristics, and management drivers. Yet, results conservatively estimate that Baltimore forest patch soils are capable of infiltrating ~68% of rainfall. In addition, urban trees transpire ~1.7 mm of water per day in the growing season or ~0.8 mm of water per day on an annual basis, an amount of water that equals approximately 26% of the annual rainfall in the Baltimore region. Thus, urban trees and forests impact urban hydrology and are an important component of stormwater green infrastructure in built environments.Item KNOWLEDGE, ATTITUDES, AND IMPLEMENTATION OF BMPS AND MOSQUITO MANAGEMENT ACROSS A SOCIOECONOMIC GRADIENT(2017) Maeda, Potential Kanoko; Leisnham, Paul T.; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)To reduce nutrient pollution in our waterways and restore impaired watersheds, residents are needed to voluntarily practice a range of stormwater best management practices (BMPs). The overall goal of my thesis was to better understand barriers to BMP implementation by exploring the links among resident demographics, knowledge, and behaviors, as well as mosquito management, so that appropriate education can be more effectively developed and targeted. Importantly, this study found respondents who defined themselves as Caucasian or other races, and that were in owned houses, had higher mean BMP knowledge than respondents that identified themselves as African American and who are renters, respectively. This study also found that one barrier to BMP implementation, concern of mosquito breeding in BMPs, was not significant. Estimated abundances for all mosquito abundance metrics were significantly higher in combined other types of wet containers compared to wet disconnected downspouts, a commonly found BMP.Item Pedogenesis in Rain Gardens: The Role of Earthworms and Other Organisms in Long-Term Soil Development(2009) Ayers, Emily Mitchell; Kangas, Patrick; Biological Resources Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)As bioretention comes into widespread use, it has become increasingly important to understand the development of bioretention soils over time. The objective of this research is to investigate the development of bioretention soils and the importance of ecological processes in the performance of rain gardens. The research includes descriptive studies of pre-existing rain garden soil profiles, laboratory experiments quantifying the effect of earthworms on infiltration rates, and a simulation model describing the influence of earthworms and soil organic matter on infiltration. Surveys of several different rain gardens of various ages provide the first detailed descriptions of rain garden soil profiles. The study revealed a great deal of biological activity in rain gardens, and evidence of pedogenesis even in very young sites. The uppermost soil layers were found to be enriched with organic matter, plant roots, and soil organisms. The field sites surveyed showed no signs of clogging due to the trapping of suspended solids carried in stormwater runoff. Some evidence was found of higher than expected infiltration rates at the field sites, which may be attributable to the effects of bioturbation by living organisms. The ability of earthworms to mitigate the effects of trapped suspended solids on bioretention soils was assessed in the laboratory. Results show that earthworms are capable of maintaining the infiltration rate of bioretention soils, but that their effects have a high degree of variability. This variability is attributed to soil aggregate instability caused by the oversimplification of the ecosystem. Other organisms play a significant role in stabilizing earthworm burrows and casts, and may be essential ingredients in a self-maintaining bioretention ecosystem. A simulation model of the action of earthworms on soil infiltration rates was developed in order to illustrate the physical processes taking place as a result of earthworm activity. The model was calibrated using data from the field study and microcosm experiment. This research is intended to provide a first glimpse into the biological processes at work in rain garden soils. The research shows that soil organisms are present in rain gardens, and suggests that their impact on bioretention performance may be significant.