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Articles 1 - 30 of 3397

Full-Text Articles in Physical Sciences and Mathematics

Validating An Operational Flood Forecast Model Using Citizen Science In Hampton Roads, Va, Usa, Jon Derek Loftis, Molly Mitchell, Daniel Schatt, David Forrest, Harry V. Wang, David Mayfield, William A. Stiles Jul 2019

Validating An Operational Flood Forecast Model Using Citizen Science In Hampton Roads, Va, Usa, Jon Derek Loftis, Molly Mitchell, Daniel Schatt, David Forrest, Harry V. Wang, David Mayfield, William A. Stiles

VIMS Articles

Changes in the eustatic sea level have enhanced the impact of inundation events in the coastal zone, ranging in significance from tropical storm surges to pervasive nuisance flooding events. The increased frequency of these inundation events has stimulated the production of interactive web-map tracking tools to cope with changes in our changing coastal environment. Tidewatch Maps, developed by the Virginia Institute of Marine Science (VIMS), is an effective example of an emerging street-level inundation mapping tool. Leveraging the Semi-implicit Cross-scale Hydro-science Integrated System Model (SCHISM) as the engine, Tidewatch operationally disseminates 36-h inundation forecast maps with a 12-h update frequency ...


A Hydrodynamic Model For Galveston Bay And The Shelf Inthe Northern Gulf Of Mexico, Jiabi Du, Kyeong Park, Jian Shen, Yinglong J. Zhang, Xin Yu, Fei Ye, Zhengui Wang, Nancy N. Rabalais Jul 2019

A Hydrodynamic Model For Galveston Bay And The Shelf Inthe Northern Gulf Of Mexico, Jiabi Du, Kyeong Park, Jian Shen, Yinglong J. Zhang, Xin Yu, Fei Ye, Zhengui Wang, Nancy N. Rabalais

VIMS Articles

A 3-D unstructured-grid hydrodynamic model for the northern Gulf of Mexico was developed, with a hybrid sz vertical grid and high-resolution horizontal grid for the main estuarine systems along the Texas–Louisiana coast. This model, based on the Semi-implicit Cross-scale Hydroscience Integrated System Model (SCHISM), is driven by the observed river discharge, reanalysis atmospheric forcing, and open boundary conditions from global HYCOM output. The model reproduces the temporal and spatial variation of observed water level, salinity, temperature, and current velocity in Galveston Bay and on the shelf. The validated model was applied to examine the remote influence of neighboring ...


Collaborative Science To Enhance Coastal Resilience And Adaptation, C. Reid Nichols, Lynn Wright, Arthur Cosby, Alain Henaff, Jon Derek Loftis, Et Al Jul 2019

Collaborative Science To Enhance Coastal Resilience And Adaptation, C. Reid Nichols, Lynn Wright, Arthur Cosby, Alain Henaff, Jon Derek Loftis, Et Al

VIMS Articles

Impacts from natural and anthropogenic coastal hazards are substantial and increasing significantly with climate change. Coasts and coastal communities are increasingly at risk. In addition to short-term events, long-term changes, including rising sea levels, increasing storm intensity, and consequent severe compound flooding events are degrading coastal ecosystems and threatening coastal dwellers. Consequently, people living near the coast require environmental intelligence in the form of reliable short-term and long-term predictions in order to anticipate, prepare for, adapt to, resist, and recover from hazards. Risk-informed decision making is crucial, but for the resulting information to be actionable, it must be effectively and ...


Toward A Coordinated Global Observing System For Seagrasses And Marine Macroalgae, J. Emmett Duffy, L. Benedetti-Cecchi, Et Al, Robert J. Orth, Et Al Jul 2019

Toward A Coordinated Global Observing System For Seagrasses And Marine Macroalgae, J. Emmett Duffy, L. Benedetti-Cecchi, Et Al, Robert J. Orth, Et Al

VIMS Articles

In coastal waters around the world, the dominant primary producers are benthic macrophytes, including seagrasses and macroalgae, that provide habitat structure and food for diverse and abundant biological communities and drive ecosystem processes. Seagrass meadows and macroalgal forests play key roles for coastal societies, contributing to fishery yields, storm protection, biogeochemical cycling and storage, and important cultural values. These socio-economically valuable services are threatened worldwide by human activities, with substantial areas of seagrass and macroalgal forests lost over the last half-century. Tracking the status and trends in marine macrophyte cover and quality is an emerging priority for ocean and coastal ...


Mechanisms Involving Sensory Pathway Steps Inform Impacts Of Global Climate Change On Ecological Processes, Emily B. Rivest, Brittany Jellison, Gabriel Ng, Et Al Jul 2019

Mechanisms Involving Sensory Pathway Steps Inform Impacts Of Global Climate Change On Ecological Processes, Emily B. Rivest, Brittany Jellison, Gabriel Ng, Et Al

VIMS Articles

Human-caused environmental change will have significant non-lethal and indirect impacts on organisms due to altered sensory pathways, with consequences for ecological interactions. While a growing body of work addresses how global ocean change can impair the way organisms obtain and use information to direct their behavior, these efforts have typically focused on one step of the pathway (e.g., reception of a cue/signal), one sensory modality (e.g., visual), or one environmental factor (e.g., temperature). An integrated view of how aspects of environmental change will impact multiple sensory pathways and related ecological processes is needed to better anticipate ...


Assessment Of Spray Polyurethane Foam Worker Exposure To Organophosphate Flame Retardants Through Measures In Air, Hand Wipes, And Urine, Cf Estill, J Slone, Et Al, Mj La Guardia, Et Al Jul 2019

Assessment Of Spray Polyurethane Foam Worker Exposure To Organophosphate Flame Retardants Through Measures In Air, Hand Wipes, And Urine, Cf Estill, J Slone, Et Al, Mj La Guardia, Et Al

VIMS Articles

Tris(1-chloro-2-propyl) phosphate (TCPP, also referenced as TCIPP), a flame retardant used in spray polyurethane foam insulation, increases cell toxicity and affects fetal development. Spray polyurethane foam workers have the potential to be exposed to TCPP during application. In this study, we determined exposure to TCPP and concentrations of the urinary biomarker bis(1-chloro-2-propyl) phosphate (BCPP) among 29 spray polyurethane foam workers over 2 work days. Work was conducted at residential or commercial facilities using both open-cell (low density) and closed-cell (high density) foam. Study participants provided two personal air samples (Day 1 and Day 2), two hand wipe samples ...


Treading Water: Tools To Help Us Coastal Communities Plan For Sea Level Rise Impacts, E A. Smith, W Sweet, M Mitchell, R Domingues, C P. Weaver, M Baringer, G Goni, J Haines, J D. Loftis, J Boon, D Malmquist Jun 2019

Treading Water: Tools To Help Us Coastal Communities Plan For Sea Level Rise Impacts, E A. Smith, W Sweet, M Mitchell, R Domingues, C P. Weaver, M Baringer, G Goni, J Haines, J D. Loftis, J Boon, D Malmquist

VIMS Articles

As communities grapple with rising seas and more frequent flooding events, they need improved projections of future rising and flooding over multiple time horizons, to assist in a multitude of planning efforts. There are currently a few different tools available that communities can use to plan, including the Sea Level Report Card and products generated by a United States. Federal interagency task force on sea level rise. These tools are a start, but it is recognized that they are not necessarily enough at present to provide communities with the type of information needed to support decisions that range from seasonal ...


Advocating For Science: Amici Curiae Brief Of Wetland And Water Scientists In Support Of The Clean Water Rule, Rc Gardner, E Okuno, Et Al, Je Perry, Et Al Jun 2019

Advocating For Science: Amici Curiae Brief Of Wetland And Water Scientists In Support Of The Clean Water Rule, Rc Gardner, E Okuno, Et Al, Je Perry, Et Al

VIMS Articles

The Trump administration has proposed replacing the Clean Water Rule, a 2015 regulation that defined the statutory term Bwaters of the United States^ to clarify the geographic jurisdiction of the Clean Water Act. Since its promulgation, the Clean Water Rule has been subjected to numerous judicial challenges. We submitted an amici curiae brief to the United States Court of Appeals for the Sixth Circuit, explaining why the Clean Water Rule, and its definition of Bwaters of the United States,^ is scientifically sound. The definition of Bwaters of the United States^ is a legal determination informed by science. The best available ...


Shoreline Dynamics Along A Developed River Mouth Barrier Island: Multi-Decadal Cycles Of Erosion And Event-Driven Mitigation, Christopher J. Hein, Andrrew R. Fallon, Peter Rosen, Et Al May 2019

Shoreline Dynamics Along A Developed River Mouth Barrier Island: Multi-Decadal Cycles Of Erosion And Event-Driven Mitigation, Christopher J. Hein, Andrrew R. Fallon, Peter Rosen, Et Al

VIMS Articles

Human modifications in response to erosion have altered the natural transport of sediment to and across the coastal zone, thereby potentially exacerbating the impacts of future erosive events. Using a combination of historical shoreline-change mapping, sediment sampling, three-dimensional beach surveys, and hydrodynamic modeling of nearshore and inlet processes, this study explored the feedbacks between periodic coastal erosion patterns and associated mitigation responses, focusing on the open-ocean and inner-inlet beaches of Plum Island and the Merrimack River Inlet, Massachusetts, United States. Installation of river-mouth jetties in the early 20th century stabilized the inlet, allowing residential development in northern Plum Island, but ...


Citizen-Science For The Future: Advisory Case Studies From Around The Globe, C Simoniello, J Jencks, Fm Lauro, Jd Loftis, K Deja, Dr Forrest, Et At May 2019

Citizen-Science For The Future: Advisory Case Studies From Around The Globe, C Simoniello, J Jencks, Fm Lauro, Jd Loftis, K Deja, Dr Forrest, Et At

VIMS Articles

The democratization of ocean observation has the potential to add millions of observations every day. Though not a solution for all ocean monitoring needs, citizen scientists offer compelling examples showcasing their ability to augment and enhance traditional research and monitoring. Information they are providing is increasing the spatial and temporal frequency and duration of sampling, reducing time and labor costs for academic and government monitoring programs, providing hands-on STEM learning related to real-world issues and increasing public awareness and support for the scientific process. Examples provided here demonstrate the wide range of people who are already dramatically reducing gaps in ...


Median Energy Imaging Of Supernova Remnants With Chandra X-Ray Observatory, Anne Blackwell May 2019

Median Energy Imaging Of Supernova Remnants With Chandra X-Ray Observatory, Anne Blackwell

Undergraduate Honors Theses

Supernova remnants (SNRs) play an important role in shaping the energy density, chemical enrichment, and interstellar medium (ISM) of galaxies, and in our understanding of stellar evolution. Due to the high plasma temperatures of SNRs, they primarily emit X-rays. Using data collected with the Chandra observatory, we study a novel statistical imaging analysis technique to probe the underlying structure and physical properties of DEM L71, a SNR in the Large Magellanic Cloud. We used the statistical properties of the photons within an image pixel, such as the median energy, to make images of the energetics across the SNR. We have ...


Minimal Principal Series Representations Of Sl(3,R), Jacopo Gliozzi May 2019

Minimal Principal Series Representations Of Sl(3,R), Jacopo Gliozzi

Undergraduate Honors Theses

We discuss the properties of principal series representations of SL(3,R) induced from a minimal parabolic subgroup. We present the general theory of induced representations in the language of fiber bundles, and outline the construction of principal series from structure theory of semisimple Lie groups. For SL(3,R), we show the explicit realization a novel picture of principal series based on the nonstandard picture introduced by Kobayashi, Orsted, and Pevzner for symplectic groups. We conclude by studying the K-types of SL(3,R) through Frobenius reciprocity, and evaluate prospects in developing simple intertwiners between principal series representations.


Pion Identification Through Machine Learning For The Moller Experiment At The Thomas Jefferson National Accelerator Facility, Anne-Katherine Burns May 2019

Pion Identification Through Machine Learning For The Moller Experiment At The Thomas Jefferson National Accelerator Facility, Anne-Katherine Burns

Undergraduate Honors Theses

This report describes the implementation of a deep neural network for particle identification on the MOLLER experiment. The MOLLER experiment, currently in its early stages of design at the Thomas Jefferson National Accelerator Facility (JLab), will attempt to measure the parity-violating asymmetry present in the elastic electron-electron scattering, to a precision of 0.7 ppb. While the Standard Model precisely predicts this asymmetry, if the value measured by the MOLLER experiment were to differ significantly from the predicted value, then the experiment could provide laboratory-based evidence of physics beyhond the Standard Model (BSM) and point researchers in the right direction ...


Exclusive Neutral Pion Production And Compton Scattering At Gluex, Zach Baldwin May 2019

Exclusive Neutral Pion Production And Compton Scattering At Gluex, Zach Baldwin

Undergraduate Honors Theses

By using data collected from Thomas Jefferson National Accelerator (JLab), I will be observing two specific reactions from the collision of linearly polarized photons with protons in a liquid hydrogen target. In this work, studies of the neutral pion reaction will be presented along with an exploratory study of the Compton scattering process. These reactions were studied by utilizing the fine-grained calorimetry of the GlueX experiment in order to aid in the understanding of meson production mechanisms in high-energy photoproduction. The separation of neutral pions and Compton events is challenging due to potential merging of the neutral pion decay photons ...


Characterizing Flame-Resistant Polymers Using Single-Sided Nmr, Anna Tsutsui May 2019

Characterizing Flame-Resistant Polymers Using Single-Sided Nmr, Anna Tsutsui

Undergraduate Honors Theses

Many commonly used polymers are inherently flammable. Manufacturers have been able to make polymers more flame-resistant by incorporating additives in polymer matrices. Current testing methods of these materials are destructive. As a result, there is a lack of data that can characterize the long-term effects of thermal exposure on these materials. This study presents single-sided NMR as an alternative technique to characterize the physical properties of these materials before and after thermal exposure. From single-sided NMR, this study finds that it is possible to characterize the molecular behavior of flame-resistant polymers and that additives cause no significant physical change to ...


Optimizing Silver Nanoparticles For Pigment Identification In Art, Carolyn Farling May 2019

Optimizing Silver Nanoparticles For Pigment Identification In Art, Carolyn Farling

Undergraduate Honors Theses

Surface-enhanced Raman spectroscopy (SERS) is a powerful tool for the identification of organic colorants within art samples. The SERS substrate that is widely used, a colloidal suspension of silver nanoparticles (AgNPs), does not always provide reproducible spectral results even when the same procedure is followed within the same laboratory conditions. An investigation to find a metric that can classify each new batch of AgNPs as optimal or suboptimal for application onto a precious art sample are discussed. Next, a quality assurance protocol for SERS-based identification of organic pigments in art is presented. Lastly, pretreatment extraction techniques for sample intervention prior ...


Chiral Transport In Anisotropic Materials, Jacopo Gliozzi May 2019

Chiral Transport In Anisotropic Materials, Jacopo Gliozzi

Undergraduate Honors Theses

Chiral materials are a class of systems in which the momentum of quasiparticles is coupled to a pseudospin degree of freedom, thus affecting their transport properties. In particular, such materials can exhibit Klein tunneling, in which chiral particles tunnel through a potential barrier with probability one due to a suppression of backscattering. In chiral materials with an anisotropic band structure, this tunneling depends nontrivially on the interplay between chirality and the direction of dispersion.

We discuss the consequences of transport in a minimal chiral anisotropic model, highlighting the role of the pseudospin in scattering through a Klein barrier. We implement ...


Exploring Stochastic Quantum Mechanics And Emergent Gravity, John Mitchell May 2019

Exploring Stochastic Quantum Mechanics And Emergent Gravity, John Mitchell

Undergraduate Honors Theses

It has been proposed that gravity is not a fundamental force, but rather a force that emerges at long distances as a result of quantum phenomena. Recent work has attempted to combine the ideas of stochastic quantization and the quantum field theories in which gravity emerges at these distances. In this project, we extend previous work done on this subject and describe a model for stochastic quantization compatible with general relativity. Numerical simulations of these relativistic stochastic systems were created to test for certain quantum mechanical properties expected to arise from this description, and it was shown that classical equations ...


Construction Of An Auger Microscope, Charles Soulen May 2019

Construction Of An Auger Microscope, Charles Soulen

Undergraduate Honors Theses

This thesis describes the design, adaptations and characterizations necessary to partially turn an Auger Electron Spectroscopy Instrument (AES) into an Auger Electron Microscope (AEM). The completed AEM will be able to scan and characterize materials over an area, unlike the AES which only took data from a single point. However, due to time constraints, this thesis only partially describes the creation of an AEM. We were able to show proof-of-concept, though, we were unable to run AEM on a material. We have also increased the theoretical accuracy of the instrument by replacing decades-old electronics with modern alternatives. Again, due to ...


Measuring Magnetic Field Gradients Using Electromagnetically Induced Transparency In Rb Vapor, Ravn Jenkins May 2019

Measuring Magnetic Field Gradients Using Electromagnetically Induced Transparency In Rb Vapor, Ravn Jenkins

Undergraduate Honors Theses

We demonstrate a new method for measuring magnetic gradients in the presence of large constant magnetic fields using electromagnetically induced transparency in rubidium vapor. As the Earth provides a near-constant magnetic field of 25-50 µT, most measurements of small magnetic fields involve subtracting or shielding the Earth's field. Our method can measure small gradients in the presence of large magnetic fields using Electromagnetically Induced Transparency in 87Rb. By comparing the resonances of two laser beams in a dual-rail arrangement propagating through rubidium vapor in a spatially changing magnetic field, we are able to measure a constant gradient of ...


A Qubit Algorithm For Simulating The Nonlinear Schroedinger Equation, Connor Simpson May 2019

A Qubit Algorithm For Simulating The Nonlinear Schroedinger Equation, Connor Simpson

Undergraduate Honors Theses

Recent work in mathematical physics and nonlinear optics has shown that Hamiltonians that are non-Hermitian but still symmetric under parity and time reversal can describe eigenstates of a system with real eigenvalues. Other research has also showed that the nonlinear Schrodinger equation can be generalized to describe PT-symmetric systems, which generates novel solutions not described by its Hermitian equivalent. The Hermitian form of the nonlinear Schroedinger equation can also be extended to describe a particular case of the general PT-symmetric NLS, suggesting a connection between the two. I attempted to generate a unitary operator that will be useful for unitary ...


Totally Positive Completable Matrix Patterns And Expansion, David Allen May 2019

Totally Positive Completable Matrix Patterns And Expansion, David Allen

Undergraduate Honors Theses

Though some special cases are now understood, the characterization of TP-completable patterns is far from complete. Here, a new idea is developed: the \underline{expansion} of a pattern. It is used to explain some recent results, such as border patterns. The effects of expansion on certain cases of non-completable and completable patterns is examined, as well as an attempt to characterize $3$-by-$n$ TP-completable patterns. While many TP-completable patterns remain so under expansion, a counterExample shows that this is not always so. In the process, some new results about TP-completability are given.


Twitter Sentiment Analysis On Leicester City's Phenomenal 2015/16 Epl Title Winning Season, Eyosyas Dagnachew May 2019

Twitter Sentiment Analysis On Leicester City's Phenomenal 2015/16 Epl Title Winning Season, Eyosyas Dagnachew

Undergraduate Honors Theses

Microblogging has become one of the most useful tools for sharing everyday life events and news, especially popular sporting events, and for expressing opinions about those events. The English Premier League (EPL), the most popular professional soccer league in the world, is talked about on Twitter every day, and the 2015/16 season, whose title underdogs Leicester City managed to win, was one for the history books to remember. As Twitter posts are short and constantly being generated, they are a great source for providing public sentiment towards events that occurred throughout the 2015/16 EPL season. In this project ...


Spheroidal Carbonaceous Particles In A Virginia Mill Pond Provide A Record Of Local And Regional Coal Combustion, Kayla Cahoon May 2019

Spheroidal Carbonaceous Particles In A Virginia Mill Pond Provide A Record Of Local And Regional Coal Combustion, Kayla Cahoon

Undergraduate Honors Theses

Spheroidal carbonaceous particles (SCP), a constituent of coal fly ash, are a sensitive indicator of local and regional coal combustion archived in lake sediments. Their unique morphology and chemical composition are not replicated by any naturally occurring substance on Earth. SCP accumulation in sediments has also been correlated to accumulation of heavy metals such as Mn, Fe, Ti, and Pb. We reconstructed SCP accumulation in a former mill pond in Williamsburg, VA, Lake Matoaka, and find a bimodal distribution with peaks c. 1790 and c. 1953. We believe that our study is the first to identify SCPs in sediments prior ...


Atomic Force Microscopy Measurements Of Interfacial Forces Between Boron Nitride And Polymers For Development Of An Optimum Nano-Composite, Hall Zhang May 2019

Atomic Force Microscopy Measurements Of Interfacial Forces Between Boron Nitride And Polymers For Development Of An Optimum Nano-Composite, Hall Zhang

Undergraduate Honors Theses

Boron Nitride Nanotubes (BNNT’s) and their use in a BNNT nano-composite have been the focus of an increasing number of studies due to their theorized high thermal conducitivty (3,000 W(m•K-1)) as well as high thermal stability. One of our hopes is to integrate BNNT’s into polymer composites to transfer their strength and thermal conductivity into said composites. However, there is little information on boron nitride interfacial forces with different composite polymer resins. Here, we chose to look at nanoscale interfacial forces by functionalizing an Atomic Force Microscopy (AFM) probe cantilever with a silica bead ...


Utilizing Machine Learning Classifiers To Identify Ssh Brute Force Attacks, Dmytro Shmagin May 2019

Utilizing Machine Learning Classifiers To Identify Ssh Brute Force Attacks, Dmytro Shmagin

Undergraduate Honors Theses

SSH brute force attacks are a type of network attack in which an attacker tries to guess the username and password of a user on the Secure Shell protocol. This kind of attack is simple to perform, and the results from a successfully compromised system can lead to a number of destructive outcomes. Because of its simplicity and potential payout, large networks experience many instances of these attacks in their traffic, and current prevention methods rely heavily on per-machine logs that, in aggregate, take up a large amount of space. This paper explores the usage of machine learning algorithms in ...


Spatial Encoding With Single-Sided Nmr, Madeline Brass May 2019

Spatial Encoding With Single-Sided Nmr, Madeline Brass

Undergraduate Honors Theses

Single-sided NMR is an important non-invasive, non-destructive technique used to characterize molecules. Specifically, single-sided NMR has applications in biomedicine, elastomers, solid polymers, moisture in porous media, and cultural heritage. Single-sided magnets can be used to analyze T2 relaxation to gauge the relative motion of molecules in the sample. However, the are few methods to characterize heterogeneous samples with single-sided NMR. Most experiments take one set of data for the entire sample regardless if the sample is heterogeneous or homogeneous. New methods to spatially encode with single-sided NMR were explore and characterized based on their advantages and disadvantages. These methods include ...


Virginia Game Fish Tagging Program Annual Report 2018, Susanna Musick, Lewis Gillingham May 2019

Virginia Game Fish Tagging Program Annual Report 2018, Susanna Musick, Lewis Gillingham

Reports

Through 2018, the Virginia Game Fish Tagging Program (VGFTP) has maintained a 23-year database of records for tagged and recaptured fish. The program is a cooperative project of the Virginia Saltwater Fishing Tournament (VSFT) under the Virginia Marine Resources Commission-(VMRC) and the Virginia Institute of Marine Science (VIMS) of the College of William and Mary (under the VIMS Marine Advisory Program).


Monitoring The Abundance Of American Shad And River Herring In Virginia's Rivers - 2018 Annual Report, Eric J. Hilton, Robert Latour, Patrick E. Mcgrath, Brian Watkins, Ashleigh Magee Apr 2019

Monitoring The Abundance Of American Shad And River Herring In Virginia's Rivers - 2018 Annual Report, Eric J. Hilton, Robert Latour, Patrick E. Mcgrath, Brian Watkins, Ashleigh Magee

Reports

This report describes the results of the twenty-first year of a continuing study to estimate the relative abundance and assess the status of American shad (Alosa sapidissima) stocks in Virginia by monitoring the spawning runs in the James, York and Rappahannock rivers in spring 2018, evaluating hatchery programs, and contributing to coast-wide assessments (ASMFC 2007). We also report on two fishery-independent monitoring programs using anchor gillnets in the Rappahannock River (year 1) and the Chickahominy River (year 4; a major tributary of the James River), to determine relative abundance and stock structure for the adult spawning run of river herring ...


How Effective Are Retention Ponds At Mitigating The Effects Of Urban Runoff?, Joanne C. Ensley Apr 2019

How Effective Are Retention Ponds At Mitigating The Effects Of Urban Runoff?, Joanne C. Ensley

Undergraduate Honors Theses

Retention ponds are commonly used to mitigate the negative effects of the increased volume of surface runoff produced by urbanization. Many studies, however, suggest that these ponds are not actually effective at protecting the downstream channel from the changes in channel morphology and degradation of water quality driven by urbanization. The goal of this study is to evaluate how well a retention pond located in James City County, Virginia protects the downstream channel from changes in sediment transport regime and fluctuations in salinity and water temperature. Discharge, salinity, and water temperature data from adjacent watersheds, one urbanized with a retention ...