Department of Earth and Environmental Science

The mission of the Department of Earth and Environmental Science is to bring the time perspective of the Earth scientist/historian to bear on contemporary problems of natural-resource conservation and environmental quality.

Search results

Now showing 1 - 10 of 210
  • Publication
    Interactions Between Bed Forms: Topography, Turbulence, and Transport
    (2006-06-01) Jerolmack, Douglas J; Mohrig, David
    Results are presented examining the interaction between two sandy bed forms under low–sediment transport conditions in a small laboratory flume. The initial artificially made bed forms were out of equilibrium with the flow field. Temporal evolution of bed forms was monitored using time-lapse photography in order to characterize bed form adjustment to the imposed flow. Velocity measurements were collected using an acoustic Doppler velocimeter to characterize both mean flow and turbulence associated with different bed form geometries. Sandy bed forms all had identical initial geometries; however, the initial distance between bed form crests was varied between experiments. Overall deformation of the bed varied as a function of initial bed form spacing; however, bed forms evolved unpredictably as periods of relatively slow change were punctuated by periods of rapidly changing geometry. Subtle changes in bed form trough geometry were found to have a strong influence on turbulence and therefore sediment transport. Comparison with field studies suggests that the mechanisms described herein are active in natural systems.
  • Publication
    The application of local and regional transfer functions to the reconstruction of Holocene sea levels, north Norfolk, England
    (2005-02-01) Horton, Benjamin P; Edwards, Robin J
    Foraminiferal assemblages from Thornham and Brancaster marshes (Norfolk, UK) illustrate statistically significant relationship with elevation with respect to the tidal frame. We develop local (data from Thornham and Brancaster marshes) and regional (data from Thornham and Brancaster marshes combined with those from 11 other sites around the UK) predictive foraminifera-based transfer functions to reconstruct former sea levels from a Holocene sediment sequence from Holkham, north Norfolk, UK. The two transfer functions produce similar patterns of tidal elevation change during the Holocene. The vertical error ranges of the local transfer function are smaller than those of the regional transfer function, although the difference (0.09 m) is not significant when compared to other factors affecting the reconstructed elevation. The value of the reconstructed elevations also differ between the two transfer functions (by up to 0.43 m), and this is primarily due to the lack of modern analogues in the local transfer function. We conclude that the reconstructions derived from the regional transfer function are more reliable than those of the local transfer function, since the latter achieves its slight increase in precision at the expense of a significant decrease in predictive power. The regional transfer function is used to construct a relative sea-level curve from fossil assemblages within a sediment core from north Norfolk, UK. These results are consistent with existing sea-level data and geophysical model predictions, and illustrate the utility of the foraminifera-based transfer function approach.
  • Publication
    A Business Analytics Approach to Corporate Sustainability Analysis
    (2014-01-01) Wen, Jeff
    Sustainability has become increasingly important to corporations, as stakeholders have called for increased transparency and as corporations have recognized the benefits of considering corporate sustainability. As a result, there has been a dramatic increase in disclosure both through corporate statements and through annual reports in which companies will describe the environmental activities in which they are involved. These documents and reports are of interest to researchers because they represent a wealth of information that can be studied and analyzed. In the past, the contents of these reports have been studied through manual methods; however, there is a great potential for automatic analysis of these reports. This paper will document the methodology taken to produce an automated analytics software that produces outputs that can further be used in analysis. Specifically, the program is meant to calculate the word frequencies of certain words and phrases that are of interest and it also extracts the sentences in which these words or phrases are contained. In this research, the output of the program is used in 2 applications. One regresses the sustainability word frequencies against a published sustainability score and another application uses a simple form of sentiment analysis to analyze the positive and negative sentiment of the extracted sentences. Human methods are usually used to perform tasks such as sentiment analysis and frequency count. The program created in this research provides a first step toward future computational analysis work. While the program is able to perform the tasks for which it was designed, improvements can be made to produce a more comprehensive and versatile program.
  • Publication
    Sedimentary Bed Evolution as a Mean-Reverting Random Walk: Implications for Tracer Statistics
    (2014-09-16) Martin, Raleigh L; Purohit, Prashant K; Jerolmack, Douglas J
    Sediment tracers are increasingly employed to estimate bed load transport and landscape evolution rates. Tracer trajectories are dominated by periods of immobility (“waiting times”) as they are buried and reexcavated in the stochastically evolving river bed. Here we model bed evolution as a random walk with mean-reverting tendency (Ornstein-Uhlenbeck process) originating from the restoring effect of erosion and deposition. The Ornstein-Uhlenbeck model contains two parameters, a and b, related to the particle feed rate and range of bed elevation fluctuations, respectively. Observations of bed evolution in flume experiments agree with model predictions; in particular, the model reproduces the asymptotic t−1 tail in the tracer waiting time exceedance probability distribution. This waiting time distribution is similar to that inferred for tracers in natural gravel streams and avalanching rice piles, indicating applicability of the Ornstein-Uhlenbeck mean-reverting model to many disordered transport systems with tracer burial and excavation.
  • Publication
    Calculating the Value of Nature & The Cost of Hurricane Harvey: Leveraging Eco-Adaptation Valuation in American Policy & Practice
    (2018-01-01) Seliem, Karema Mohamed
    Ecosystem-based Adaptation (EbA) is a strategy that “uses biodiversity and ecosystem services…to help people adapt to the adverse effects of climate change” by taking “into account the multiple social, economic and cultural co-benefits for local communities” (SCBD, 2009). EbA valuation is a holistic process that calculates the cost, benefits, and impacts of ecosystem services in adaptation strategies. This research provides methods for valuing ecosystem services and a justification of ecosystem-based adaptation (EbA) in order to leverage effective resilience planning decisions. The goal of this research is to a) show that proactive, land-based adaptation is more cost-effective than reactive mitigation in resilience projects (i.e. EbA is more beneficial than grey infrastructure) and b) provide guidelines for understanding the EbA valuation process and recommendations for communicating EbA to stakeholders. The costly impacts of Hurricane Harvey on Texas are explored to highlight problems that can be addressed by EbA principles to potentially alleviate flooding from future storm surge. EbA valuation trends in policy, practice, and messaging are assessed to provide communication guidelines as methods for influencing resilience policy. This study culminates in visual aids and recommendations based on specific stakeholder values with the aim of generating EbA buyin from American planners, policymakers, and the public. The goal is to influence decisionmakers into utilizing the example of Texas and this study’s recommendations to potentially leverage EbA policy and mainstream EbA valuation in American resilience practice. The overall objective is to alleviate the increasing cost burden of storm surge impacts.
  • Publication
    Impulse Framework for Unsteady Flows Reveals Superdiffusive Bed Load Transport
    (2013-04-16) Phillips, Colin B; Martin, Raleigh L; Jerolmack, Douglas J
    Sediment transport is an intrinsically stochastic process, and measurement of bed load in the environment is further complicated by the unsteady nature of river flooding. Here we present a methodology for analyzing sediment tracer data with unsteady forcing. We define a dimensionless impulse by integrating the cumulative excess shear velocity for the duration of measurement, normalized by grain size. We analyze the dispersion of a plume of cobble tracers in a very flashy stream over two years. The mean and variance of transport distance collapse onto well-defined linear and power-law relations, respectively, when plotted against cumulative dimensionless impulse. Data suggest that the asymptotic limit of bed load tracer dispersion is superdiffusive, in line with a broad class of geophysical flows exhibiting strong directional asymmetry (advection), thin-tailed step lengths and heavy-tailed waiting times. The impulse framework justifies the use of quasi-steady flow approximations for long-term river evolution modeling.
  • Publication
    Penn Park: A Study of Ecological Health in an Urban Environment
    (2019-01-01) Royer, Sam
    Penn Park (PP) was built in 2011 serving a vital need for the University of Pennsylvania’s athletic programs, faculty, staff, and students. This space has had many different land uses over time from agriculture to railyard use and, more recently, as a parking lot. PP covers 24 acres that include two multipurpose fields, 12 outdoor tennis courts, a softball stadium, six acres of native grass meadow, and over 550 trees. This project created corridors that were previously unavailable for people who live and work in the area. Upon completion of the structural engineering, storm water controls and athletic field designs, an ecological community was created to surround and soften the architectural elements. Assessment of the current ecological conditions of PP revealed overall successful growth of the tree canopy and efficient performance of the hydrologic system. However, invasive plants have taken hold in the native grass meadows and turf grass areas requiring more focused management and a re-evaluation of current management guidelines. Carbon sequestration rates for turf grass and native meadow areas are estimated at over 2 million g of C/m2/year and for trees at over 180 million kg of carbon dioxide. Over 20’ of compacted fill deposited over 200 years of assorted land use inhibited ground water recharge and required designers to capture storm water runoff through a variety of drainage systems while controlling water flow to meet required discharge rates. The irrigation system primarily uses captured rainwater from an underground cistern that can hold over 200,000 gallons of water. This system is estimated to provide between 50-70% of PP irrigation needs. Soil tests showed that PP soils consist of greater than 90% sand and have low nutrient status and cation exchange capacity which could contribute to the abundance and diversity of invasive weeds. This condition has led to management strategies that reduce turf lawn areas and increase native meadow plantings which are more drought tolerant, require less nutrients, and may compete with invasive weeds.
  • Publication
    (2021-01-01) Kwasniewska, Paula
    Approximately twenty-five million individuals in the United States suffer from asthma, a chronic lung disease that makes it difficult to breathe. Environmental factors, such as air quality, contribute to asthma prevalence. Unfortunately, socioeconomic status is also a key risk factor for asthma, where people of color or of low-income have the highest prevalence of asthma. In the City of Philadelphia, policy-driven segregation helped create underserved and underrepresented communities, where this public health issue is highly prevalent. This study examines the relationship between community demographics, socioeconomic status, air quality, and asthma prevalence from an environmental justice perspective in the City of Philadelphia. Geospatial and correlation analyses were used to determine relationships between community demographics, median household income, yearly average concentration of PM 2.5, and asthma prevalence. Parts of North Philadelphia and West Philadelphia have a relatively high number of non-Hispanic Black residents, relatively low annual median household income, relatively high PM2.5 concentration, and relatively high asthma prevalence. Recommendations for improving air quality and public health include reducing PM2.5 sources, planting more vegetation to reduce PM2.5 levels, promotion of equitable health services, reduction of systemic racism, and implementation of policy-driven reform to promote equity leading to social and environmental justice.
  • Publication
    Environmental Psychology and Urban Green Space: Supporting Place-Based Conservation in Philadelphia, PA
    (2014-01-01) Coleman, Alicia
    Green space and stormwater infrastructure are of valued importance within the City of Philadelphia, but little research exists on understanding the unique contribution that green spaces can make in developing environmentally-conscious citizens. Using a multi-disciplinary approach, this project aims to explore theoretical components of environmental psychology and place attachment as related to the socioenvironmental benefits of urban green space. Two methods were used in 2013-2014 at one green space with stormwater management on the University of Pennsylvania campus: behavior mapping and a 200-person place attachment survey. An initial conclusion is that few participants have attachment to the space, but this does not inhibit perceptions of its quality and worth. The extensive use of the space indicates ample opportunity for environmental education on green stormwater infrastructure. Further research should be conducted to see if perceptual attachment leads to attitudinal correlates to environmental stewardship of place-centered conservation techniques, like green stormwater infrastructure.
  • Publication
    A Pre-Glacial, Warm-Temperate Floral Belt in Gondwana (Late Visean, Early Carboniferous)
    (2002-12-01) Iannuzzi, Roberto; Pfefferkorn, Hermann W
    Unusual fossil macrofloras from South America (Peru, Bolivia, Brazil), Africa (Niger), India, and Australia are distinctly different from both the Early and Late Carboniferous floras of Gondwana. These floras can be correlated with each other based on macrofloral and palynologic composition, and dated as Late Visean to earliest Serpukhovian through palynologic data from several floras and isotopic data from Australia. The floras are dominated by pteridosperm foliage and characterized by the occurrence of tree-lycopsids, and represent a warm-temperate, frost-free floral belt in Gondwana that reached from 30 8 to as far as 60 8 South that existed directly before the onset of the major episode of the Carboniferous glaciation. The plants lived during an interval of very warm climate as indicated by the width and extent of the floral belt, conditions that facilitated the migration of plants into this area from other parts of the globe. The term Paraca floral realm is redefined and extended to include all of these Late Visean-earliest Serpukhovian floras throughout Gondwana.