Physical Sciences and Mathematics Commons^™

Evaluating Stormwater Pollutant Removal Mechanisms By Bioretention In The Context Of Climate Change, Amanda Cording

Graduate College Dissertations and Theses

Stormwater runoff is one of the leading causes of water quality impairment in the U.S. Bioretention systems are ecologically engineered to treat stormwater pollution and offer exciting opportunities to provide local climate change resiliency by reducing peak runoff rates, and retaining/detaining storm volumes, yet implementation is outpacing our understanding of the underlying physical, biological, and chemical mechanisms involved in pollutant removal. Further, we do not know how performance will be affected by increases in precipitation, which are projected to occur in the northeastern U.S. as a result of climate change, or if these systems could act as a source or …

Quantifying Soil Greenhouse Gas Emissions And Soil Carbon Storage To Determine Best Management Practices In Agroecosystems, Tyler Goeschel

Graduate College Dissertations and Theses

Intensive agriculture, coupled with an increase in nitrogen fertilizer use, has contributed significantly to the elevation of atmospheric greenhouse gases (GHGs), including carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Rising GHG emissions usually mean a decrease in soil carbon. Currently, soil C is twice that of all standing crop biomass, making it an extremely important player in the C cycle. Fortunately, agricultural management practices have the potential to reduce agricultural GHG emissions whilst increasing soil C. Management practices that impact GHG emissions and soil C include various tillage practices, different N fertilization amounts and treatments (synthetic N, cattle …

High Flow Events As Hot Moments Of Reactive Fe And P Export: Impacts Of Land Cover And Seasonality, Braden Rosenberg

Graduate College Dissertations and Theses

High flow events often comprise the majority of annual discharge and riverine geochemical flux of phosphorus (P) and metals such as iron (Fe) and manganese (Mn) due to glacial melt, snowmelt, and storm-driven sustained high flow. Aquatic ecosystem productivity in receiving water bodies such as Lake Champlain and the Gulf of Alaska (GoA) are impacted by the riverine import of nutrients. The magnitude of these high flow events can be a strong predictor of receiving water body conditions, and in some cases can contribute to eutrophication. We explore the intersection of high flow events and land cover in contrasting catchments …

Long-Term Forest Carbon Storage And Structural Development As Influenced By Land-Use History And Reforestation Approach, Andrea Rose Urbano

Graduate College Dissertations and Theses

Temperate forests are an important carbon sink, yet there is uncertainty regarding land-use history effects on biomass accumulation and carbon storage potential in secondary forests. Understanding long-term biomass dynamics is important for managing forests as carbon sinks and for co-benefits such as watershed protection and biodiversity. However there are many unanswered questions regarding these dynamics in northeastern U.S. forests: How have secondary forests of the U.S. Northeast recovered post nineteenth century agricultural abandonment? How has the region's extensive land-use history influenced long-term structural development and aboveground carbon storage? To answer these questions, we employed a longitudinal study based on twelve …

Impacts Of Transportation Infrastructure On Stormwater And Surface Waters In Chittenden County, Vermont, Usa, Joseph Hollis Bartlett

Graduate College Dissertations and Theses

Transportation infrastructure is a major source of stormwater runoff that can alter hydrology and contribute significant loading of nutrients, sediment, and other pollutants to surface waters. These increased loads can contribute to impairment of streams in developed areas and ultimately to Lake Champlain. In this study we selected six watersheds that represent a range of road types (gravel and paved) and road densities (rural, suburban, and urban) present in Chittenden County, one of the most developed areas in Vermont. The location and density of road networks were characterized and quantified for each watershed using GIS analysis. Monitoring stations in each …

Importance Of Agricultural Systems As Multifunctional Landscapes, Flavio Sutti

Graduate College Dissertations and Theses

Agricultural landscapes provide our society with many benefits. While food production is the primary role of these landscapes, sociocultural and ecological benefits are also provided. However, the full scope of benefits that we obtain from agricultural landscapes are not always taken into account, and with the intensification of agricultural activities, more complex multifunctional landscapes are converted into simpler and less-functional landscapes. I used a heterogeneous agricultural landscape, the Champlain Valley of Vermont, as a case study to examine the interactions between landscape structure and the provision of landscape functions and services.

I analyzed sociocultural and production functions indices obtained via …

Erosion Rates In Subtropical, Rapidly Developing Countries: An Isotopic Approach To Measuring Background Rates Of Erosion In Brazil And China, Veronica Sosa-Gonzalez

Graduate College Dissertations and Theses

Erosion, a surface process, can be quantified over long-term (assumed to be the natural erosion rate of the landscape) and contemporary (modern) timeframes. My research used the rare cosmogenic isotope 10Be in sand and cobbles collected from rivers in southeastern Brazil (Santa Catarina and Rio de Janeiro states) and southwestern China (Yunnan province) to quantify long-term, background rates of erosion and sediment supply. These measurements will also increase number of such measurements in tropical and subtropical climates. I assessed the relationship between landscape parameters (topographic and climatic) and background erosion rates in order to understand factors related to erosion.

My …

Influence Of Mission, Audience, And Policy Context On Issue Framing: A Case Study Of Mobilization Against Hydraulic Fracturing In The Marcellus Shale, Rezwana Zafar

Graduate College Dissertations and Theses

The case of mobilization against hydraulic fracturing by interest groups provided an opportunity to examine the influence of three factors (mission, audience, and policy context) on diagnostic, prognostic, and motivational framing. A comparative analysis was conducted of the mobilization activities of five national environmental organizations with a local presence in the Pennsylvania and New York Marcellus Shale regions. The organizations varied with respect to organizational mission, the audiences they were targeting (urban and rural), and the policy context in which they worked (pro and anti-hydraulic fracturing). Data came from eleven semi-structured in-depth interviews with organization personnel, and from the organizations' …

Edge-Of-Field Water And Phosphorus Losses In Surface And Subsurface Agricultural Runoff, Laura B. Klaiber

Graduate College Dissertations and Theses

Quantifying effectiveness of soil management practices on surface and subsurface water quality at the field scale is becoming increasingly important in the Lake Champlain Basin and other agricultural watersheds. During 2012 and 2013, field plots (22.9 x 45.7 m) were established at the Lake Alice Wildlife Area in Chazy, NY to begin a long-term water quality monitoring study. Plots were established in a cool season grass field (1 ha) leased and managed by the William H. Miner Agricultural Research Institute in Chazy, NY. The soil type transitions from an excessively drained outwash soil on the upslope to a very poorly …

Renewable Energy Transition: Dynamic Systems Analysis, Policy Scenarios, And Trade-Offs For The State Of Vermont, Christopher Ernest Clement

Graduate College Dissertations and Theses

There is broad consensus that a transition to renewable energy and a low-carbon economy is crucial for future development and prosperity, yet there are differing perspectives on how such a transition should be achieved. The overarching goal of this dissertation, which is comprised of three interrelated studies, is to analyze and compare energy futures scenarios to achieve a renewable energy transition and low-carbon economy in the State of Vermont. In the first study, an analysis is presented of the role of energy pricing regimes and economic policy in the context of pursuing a renewable energy transition in the State of …

Methods For The Spatial Modeling Of Forest Carbon In The Northern Forest, Alison Adams

Graduate College Dissertations and Theses

The ability to accurately assess forest carbon storage is critical to understanding global carbon cycles and the effects of changes in land cover on ecological processes. However, existing methods for calculating carbon storage do not explicitly account for differences in carbon stored by different species of trees. Those methods that do reflect some of this variability, such as remotely-sensing canopy structure to estimate biomass, can be resource-intensive and difficult to reproduce over past or future time steps in order to assess change. I examined the accuracy of several carbon mapping approaches to understand how specificity of forest type classification (for …

The Role Of Transportation In Expanding The Democratic Ideal Of National Parks, Xiao Xiao

Graduate College Dissertations and Theses

National parks have famously been called "America's best idea" and preserve the nation's natural and cultural resources for the enjoyment of all. One of the current working priorities of the National Park Service (NPS) is enhancing the relevancy and engagement of the national parks with diverse audiences, especially for underserved groups. To address this priority, transportation is needed to provide access to national parks, but transportation may not be equally accessible to all groups in society. Understanding the effects of transportation on visitation to the national parks by racial/ethnic groups is essential for the NPS to improve the accessibility of …

A Framework For Estimating Nutrient And Sediment Loads That Leverages The Temporal Variability Embedded In Water Monitoring Data, Baxter G. Miatke

Graduate College Dissertations and Theses

Rivers deliver significant macronutrients and sediments to lakes that can vary substantially throughout the year. These nutrient and sediment loadings, exacerbated by winter and spring runoff, impact aquatic ecosystem productivity and drive the formation of harmful algae blooms. The source, extent and magnitude of nutrient and sediment loading can vary drastically due to extreme weather events and hydrologic processes, such as snowmelt or high flow storm events, that dominate during a particular time period, making the temporal component (i.e., time over which the loading is estimated) critical for accurate forecasts. In this work, we developed a data-driven framework that leverages …

Measurement And Modeling Of Stormwater From Small Suburban Watersheds In Vermont, Joel Nipper

Graduate College Dissertations and Theses

Despite decades of U.S. water quality management efforts, over half of assessed waterbody units were threatened or impaired for designated uses in the most recent assessments, with urban runoff being a leading contributor to those impairments. This cumulative research explores several aspects of urban runoff dynamics through a combination of field study and modeling.

Stormwater ponds are ubiquitous in developed landscapes due to their ability to provide multiple forms of treatment for stormwater runoff. However, evolving design goals have reduced the applicability of much of the early work that was done on pond effectiveness. In this study, we instrumented a …

Placing Natural Resource Decisions In Social And Historical Contexts: Sociological Inquiries Into Agency Communications, Management Rationalities, And Community Change, Emilian Geczi

Graduate College Dissertations and Theses

A sociological understanding of natural resource management decisions traces the links between historical change (How does this historical period differ from other periods?), society (What social relations exist at this time and how do they persist or change?), and individuals (What types of conduct and discourse prevail in this society and in this period?). The papers submitted for this dissertation examine the connections between identity, social milieu, and historical change relative to three resource management issues:

(1) The promotion of nature play areas as a novel landscape form. Analysis of agency materials suggests that these spaces are advertised as bucolic …

Invasive Plant Ecology In Vermont: Insights From Spatial Analysis And Interactions Of Garlic Mustard (Alliaria Petiolata) With Native Plants And Invertebrates, Chenin Kathleen Limback

Graduate College Dissertations and Theses

Causes and patterns of invasive plant species establishment and success depend broadly upon their ecology, including habitat suitability and interactions with other plants and animals. Here I examine the traits and distribution of invasive plants in Vermont, using spatial analysis, laboratory and field studies. I used GIS to investigate environmental factors correlated with presence of 19 invasive plant species in Vermont campgrounds. My results support the assumption that human dispersal of invasive plant seed and stock may be more important than natural dispersal of these plant species to new sites. I also investigate in-depth the relationships of invasive herbaceous garlic …

Impacts Of Forest Disturbance On Small Mammal Distribution, Allyson Lenora Degrassi

Graduate College Dissertations and Theses

Natural habitat in the eastern United States has diminished over the past century because of the effects of invasive species. Both plant and animal invaders can alter habitat structure and may decrease survival of native species. The degree to which an invasive species alters ecosystem function depends on the functional characteristics of affected species and the resulting cascading effects. The loss of important native species, such as foundation species, can potentially influence the structure and distribution of animal communities because of the foundation species' unique ecosystem roles. The foundation species concept is relatively new to the terrestrial ecology and the …