Theses and Dissertations from UMD
Permanent URI for this communityhttp://hdl.handle.net/1903/2
New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM
More information is available at Theses and Dissertations at University of Maryland Libraries.
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Item Applying Green Complete Streets on Georgia Avenue NW: Redesigning an Urban Right-of-Way for Sustainable Mobility and Urban Water Quality(2023) Mejias, Aliya; Ellis, Christopher D.; Plant Science and Landscape Architecture (PSLA); Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The public right-of-way (ROW) makes up nearly one-third of all the public space in cities. With the majority global population expected to reside in cities by 2050, climate change posing a significant threat to urban residents and infrastructure, impervious urban surface impacts on water quality, and knowing traffic fatalities in the US reached a 16-year high, cities must reconsider how this public good can serve people and the environment over to car-centric mobility. Using a segment of Georgia Avenue NW in Washington, DC, this thesis removes automobiles from the ROW to demonstrate how Green Complete Streets, which prioritizes sustainable transportation and urban water quality, can support urban livability on a corridor scale.Item NUTRIENT MOVEMENT IN A VEGETATED COMPOST BLANKET AMENDING A VEGETATED FILTER STRIP ON A HIGHWAY SLOPE(2022) Forgione, Erica Rose; Davis, Allen P; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Excess stormwater runoff caused by rapid urbanization and exacerbated by climate change generates many challenges for public safety and the environment. Large runoff volumes contribute to flooding and pollutants in stormwater runoff pose risks to human and environmental health, including toxicity to the aquatic environment caused by heavy metals and nutrient pollution leading to eutrophication, the cause of harmful algal blooms. An effort is being made to improve the efficiency of existing highway stormwater control systems which have limited performance in terms of volume reduction and pollutant removal. To address this issue, amendment of highway Vegetated Filter Strips (VFS) with a Vegetated Compost Blanket (VCB), a layer of seeded compost placed on an established slope, has been proposed. Compost has high water holding capacity and organic matter content which can immobilize contaminants of concern. However, the high nutrient content of compost poses a threat to net beneficial performance since excess nutrient leaching occurs after application. This research has posed the question: Can a VCB be used as a stormwater control measure (SCM) while avoiding excessive nutrient leaching?The VCB/VFS system was assessed through lab-scale, greenhouse-scale, and field-scale experiments. Hydrologic performance was evaluated in field and greenhouse experiments through evaluation of dynamic flow modification, event volume storage, and cumulative volume retention. Water quality performance was assessed through analysis of Total Suspended Solids (TSS), Nitrate + Nitrite (NOx), Total Kjeldahl Nitrogen (TKN), Total Nitrogen (TN), Total Phosphorus (TP), filtered and total Copper, and total Zinc concentrations. Nitrogen (N) and phosphorus (P) in compost are naturally transformed from organic to inorganic, soluble forms through the microbially-mediated process of mineralization. Nutrient removal occurs through adsorption as compost leachate passes through the VFS soil layer. To further investigate nutrient movement, small scale laboratory experiments were completed to determine the N and P compost mineralization rates and theoretical soil adsorption capacities. Nutrient data from greenhouse and field experiments were empirically evaluated using the lab-obtained mineralization data. Nutrient release was simulated and compared to experimental field data using a new open-source software, OpenHydroQual, which combines hydraulic and water quality modeling. VCBs were found to have a significant impact on both flow and volume reduction, though at the highest flowrates, VCBs were unable to significantly reduce flow and instead acted as conveyance. A useful design estimate for representative storage capacity using the saturated moisture content and wilting point of both the VCB and VFS was determined. Significant TSS removal was observed in both the field and greenhouse studies and particulate metals were largely removed; however dissolved copper leaching was observed in the field experiment, as has been observed previously for some compost in stormwater systems. Highly elevated concentrations of nutrients (as high as 100 mg/L TN and 12 mg/L TP) were observed in the effluent of both field and greenhouse experiments, resulting in net nutrient leaching and concentrations above recommended EPA freshwater limits even after 1-2 years. Additionally, mass loading rates at the field site (as high as 41 kg/ac/yr for TN and 14 kg/ac/yr for TP) were 1-2 magnitudes higher than observed influent mass loading rates (~3.8 kg/ha/yr for TN and ~0.47 kg/ha/yr for TP). Through laboratory mineralization studies, N and P mineralization rates were found to differ between compost batches, with initial nutrient content and age/leaching of compost being important factors. Adsorption experiments indicated increasing P adsorption from compost leachate with increasing soil Al+Fe content. Comparisons to greenhouse and field data showed differences in N speciation, likely due to differences in moisture content and temperature causing differing amounts of nitrification and volatilization. OpenHydroQual modeling showed modest results, with varying levels of accuracy for storm hydrograph simulation and mass release. VCBs are not currently recommended for use due to the risk of nutrient and metals pollution, especially in nutrient and metals sensitive watersheds. However, several impactful factors were identified that may reduce nutrient leaching, including compost composition, compost age/leaching, and VFS soil type.Item GREEN INFRASTRUCTURE IN INTEGRATED URBAN WATER MANAGEMENT: MODELING AND SOCIAL-ECOLOGICAL SYSTEM APPROACHES(2020) Mosleh, Leila; Pavao-Zuckerman, Mitchell Adam; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Urbanization, climate change, increasing water demand, deteriorating water quality, and insufficiencies in system resilience have encouraged city planners to consider integrated urban water management (IUWM) as a solution. One of the main benefits of IUWM is looking into stormwater as a resource to decrease the need for potable water and put less burden on wastewater treatment systems and the environment. Green infrastructure (GI) is an essential part of stormwater management that is designed to mimic the natural hydrological cycle and allows for infiltration, capture and reuse, and treatment of stormwater. This dissertation is designed to inform urban water decision-makers with a special focus on GI via assessment and management frameworks and stakeholder engagement. In my first study, I provided a comparative study of IUWM models aimed at assisting users to select the most appropriate model according to any specific needs. Our results showed that most of IUWM models included stormwater management and GI selection, but do not consider ecosystem services evaluation and the supply and demand from GI. Following these deficiencies of the available models, in my second study, I looked into the stakeholders’ knowledge, perception, and practice of GI with respect to ecosystem services supply and demand. The results showed the study of supply and demand, as well as ecosystem disservices, can help the selection of effective forms of GI to address the priority of stakeholders and environmental issues. Selection of the right type of GI is important for the sustainability of GI in providing ecosystem services, but so is monitoring and evaluation of GI. Thus, my third study focused on developing a generalized social-ecological framework for assessing urban stormwater GI resilience. The results of this study showed that assessing resilience requires linking indicators to critical functionality of GI, as well as a social-ecological approach that goes beyond design and technical specifications. This study can help prioritize resources to address goals related to building resilience. In my last study, I aimed to refine and co-produce a specific social-ecological framework for stormwater GI resilience with stakeholders that links to perceived barriers and challenges of implementing GI. Stakeholders co-created indicators considering current GI challenges and linked them with resilience management dimensions. This framework could inform the management of adverse events and improve resilience by decision-makers and multi-stakeholders in various sectors related to GI planning, design, and implementation.Item EVALUATING THE BENEFITS, SUSTAINABILITY, AND RESILIENCE OF GREEN INFRASTRUCTURE ON A SUSTAINABLE RESIDENTIAL HOME(2018) Thompson, Rhea Ava; Tilley, David; Marine-Estuarine-Environmental Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)With global populations becoming increasingly urbanized, green infrastructure (GI) is progressively being recognized as a sustainable approach to mitigating urban environmental problems. Unlike traditional ‘hard’ engineering approaches that historically viewed problems in isolation and solutions in singular terms, implementation of GI promises some deferment from the effects of urbanization by providing a multitude of benefits such as reduced stormwater runoff and flooding, decreased heat waves, and enlivened local environments and ecological habitats. These benefits are important considering many cities are projected to be more vulnerable to the effects of urbanization with climate change, especially as the vast amount of the global population lives in coastal urban environments. However, the diversity of GI benefits has not been fully characterized, and they are increasingly applied in residential settings. Furthermore, current research has not fully explored the beneficial role of GI in achieving sustainable and resilient communities. Using an Integrated Water: Energy Monitoring System measuring meteorological, water, and energy fluxes over two years (July 2014-June 2016) on a sustainable home in Rockville, Maryland, U.S., the following objectives were explored: (1) Examined how a sloped modular extensive green roof, constructed wetland and bioretention designed in-series affected site hydrology. Furthermore, we studied the effect of season, antecedent substrate water content, storm characteristics (size, intensity, frequency), and vegetation development (green roof only) on hydrological performance. (2) Characterized the seasonal thermal performance of the green roof (to the building and surrounding environment) relative to the cool roof. Evaluated how green roof thermal performance related to evapotranspiration, solar reflectance (albedo) and thermal conductance (U-value). Additionally, the effect of substrate water content, vegetation development, and microclimate on evapotranspiration, albedo and U-values was assessed. (3) Green roof evapotranspiration was measured and compared to values predicted with the FAO-56 Penman-Monteith model. Furthermore, the effects of substrate water content, vegetation characteristics and microclimate on evapotranspiration rates was also evaluated. (4) Finally, using emergy theory, GI sustainability and resilience relative to a gray wastewater system and natural forest was explored.Item Stormwater Green Infrastructure Climate Resilience In Chesapeake Bay Urban Watersheds(2017) Giese, Emma; Pavao-Zuckerman, Mitchell A; Environmental Science and Technology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Stormwater green infrastructure (GI) practices (e.g. bioretention, green roofs) are implemented to reduce stormwater runoff and pollution in urban watersheds. However, current implementation and design is based on historic and current climate. As a result, current implementation may not be sufficient to meet runoff and water quality goals under future climate conditions. This study conducted 1) a review of previous assessments of stormwater GI climate resilience, and 2) a SWAT modeling study of two case study watersheds (one with stormwater GI and one with traditional stormwater management) in Clarksburg, Maryland. Results from both the literature review and modeling study indicate the stormwater GI can help adapt urban watersheds to climate change. Results from the modeling study indicate that stormwater GI is resilient to changes in climate, but that there may be seasonal increases in fall and winter runoff.Item Designing for Interpretive Signage: Best Practices for Increasing Attraction Power(2013) Carter, Emilie Carroll; Ellis, Christopher D; Plant Science and Landscape Architecture (PSLA); Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Interpretive signage, murals, and art installations are an important element of passive outdoor education for those who do not have formal education or knowledge about how landscapes work. The inclusion of passive education in projects has become increasingly necessary as new types of green infrastructures such as rain gardens, bioswales, and floating wetlands, are introduced to the landscape. Landscape architects can contribute to educational efforts by including interpretive signage on a site. While this practice is being implemented among many sites around the United States, it is unclear how effective these installations are in educating the public - specifically adults. This thesis project takes an in-depth look at the effectiveness of interpretive signage located around low-impact design elements and proposes a set of best practices for designing sites with interpretive signage. To support the best practices, data is being collected at two sites with methods that include surveying site occupants, field observation of occupant interactions with signage, and interviews with project designers. Initial data analysis from the pilot study shows that interpretive signage does positively affect people's views on environmentally sensitive design, but a variety of factors such as signage location and visibility of installation can affect the percentage of people who read signage.