Physical Sciences and Mathematics Commons^™

Quantifying Thresholds Of Barrier Geomorphic Change In A Cross-Shore Sediment-Partitioning Model, Daniel J. Ciarletta, Jennifer L. Miselis, Justin L. Shawler, Christopher J. Hein

VIMS Articles

Barrier coasts, including barrier islands, beach-ridge plains, and associated landforms, can assume a broad spectrum of morphologies over multi-decadal scales that reflect conditions of sediment availability, accommodation, and relative sea-level rise. However, the quantitative thresholds of these controls on barrier-system behavior remain largely unexplored, even as modern sea-level rise and anthropogenic modification of sediment availability increasingly reshape the world's sandy coastlines. In this study, we conceptualize barrier coasts as sediment-partitioning frameworks, distributing sand delivered from the shoreface to the subaqueous and subaerial components of the coastal system. Using an idealized morphodynamic model, we explore thresholds of behavioral and morphologic change …

Biophysical Controls Of Marsh Soil Shear Strength Along An Estuarine Salinity Gradient, Megan N. Gillen, Tyler C. Messerschmidt, Matthew L. Kirwan

VIMS Articles

Sea-level rise, saltwater intrusion, and wave erosion threaten coastal marshes, but the influence of salinity on marsh erodibility remains poorly understood. We measured the shear strength of marsh soils along a salinity and biodiversity gradient in the York River estuary in Virginia to assess the direct and indirect im-pacts of salinity on potential marsh erodibility. We found that soil shear strength was higher in monospecific salt marshes (5–36 kPa) than in biodiverse freshwater marshes (4–8 kPa), likely driven by differences in below ground biomass. However, we also found that shear strength at the marsh edge was controlled by sediment characteristics, …

How Old Are Marshes On The East Coast, Usa? Complex Patterns In Wetland Age Within And Among Regions, Anna E. Braswell, James B. Heffernan, Matthew L. Kirwan

VIMS Articles

Sea‐level dynamics, sediment availability, and marine energy are critical drivers of coastal wetland formation and persistence, but their roles as continental‐scale drivers remain unknown. We evaluated the timing and spatial variability of wetland formation from new and existing cores collected along the Atlantic and Gulf coasts of the United States. Most basal peat ages occurred after sea‐level rise slowed (after ~4,000 years before present), but predominance of sea‐level rise studies may skew age estimates toward older sites. Near‐coastal sites tended to be younger, indicating creation of wetlands through basin infilling and overwash events. Age distributions differed among regions, with younger …

The Role Of Suspended Sediment In Assessing Coastal Wetland Vulnerability, Daniel J. Coleman

Dissertations, Theses, and Masters Projects

Coastal wetlands sequester carbon, attenuate waves and storm surge, filter out nutrients and pollutants, and act as nursery habitat for important fisheries. The value of these ecosystems is underscored by their vulnerability to climate change, especially sea level rise. To persist under the threat of rising sea level, coastal wetlands must build elevation vertically. Delivery of sediment to the marsh during tidal flooding is a key component in the ecogeomorphic feedbacks that lead to elevation gain. Despite the importance of suspended sediment to assessing coastal wetland vulnerability, many questions remain unanswered. This dissertation addresses the impact of suspended sediment concentration …

Hurricane Sandy Effects On Coastal Marsh Elevation Change, Alice G. Yeates, James B. Grace, Et Al, Scott Lerberg, James C. Lynch, Nichole Maher, J.Patrick Megonigal, W. G. Reay

VIMS Articles

High-magnitude storm events such as Hurricane Sandy are powerful agents of geomorphic change in coastal marshes, potentially altering their surface elevation trajectories. But how do a storm’s impacts vary across a large region spanning a variety of wetland settings and storm exposures and intensities. We determined the short-term impacts of Hurricane Sandy at 223 surface elevation table–marker horizon stations in estuarine marshes located across the northeast region of the United States by comparing post- storm surface elevation change with pre-storm elevation trends. We hypothesized that the storm’s effect on marsh elevation trends would be influenced by position relative to landfall …

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 …

Reconstructing Coastal Sediment Budgets From Beach‐ And Foredune‐Ridge Morphology: A Coupled Field And Modeling Approach, Dj Ciarletta, Jl Shawler, C Tenebruso, Christopher J. Hein, J Lorenzo‐Trueba

VIMS Articles

Preserved beach and foredune ridges may serve as proxies for coastal change, reflecting alterations in sea level, wave energy, or past sediment fluxes. In particular, time‐varying shoreface sediment budgets have been inferred from the relative size of foredune ridges through application of radiocarbon and optically stimulated luminescence dating to these systems over the last decades. However, geochronological control requires extensive field investigation and analysis. Purely field‐based studies might also overlook relationships between the mechanics of sediment delivery to the shoreface and foredune ridges, missing insights about sensitivity to changes in sediment budget. We therefore propose a simple geomorphic model of …

Relationships Among Fine Sediment Settling And Suspension, Bed Erodibility, And Particle Type In The York River Estuary, Virginia, Kelsey A. Fall

Dissertations, Theses, and Masters Projects

In order to understand the processes controlling the temporal variability in settling velocity (Ws) and bed erodibility (ε), in the middle reaches of the York River estuary, VA, the relationships between the hydrodynamics and particle types were investigated with a near-­‐bed Acoustic Doppler Velocimeter (ADV) and the York River 3-­‐D Hydrodynamic Cohesive Bed Model.

ADV observations of the flow characteristics that occurred over a strong temporal transition period indicated that Ws and ε were characterized by two distinct regimes with contrasting sediment and water column characteristics: (i) a physically-­‐dominated regime (Regime 1) which was a period dominated by flocculated muds …

Observations Of Storm Morphodynamics Using Coastal Lidar And Radar Imaging System (Claris): Importance Of Wave Refraction And Dissipation Over Complex Surf-Zone Morphology At A Shoreline Erosional Hotspot, Katherine L. Brodie

Dissertations, Theses, and Masters Projects

Elevated water levels and large waves during storms cause beach erosion, overwash, and coastal flooding, particularly along barrier island coastlines. While predictions of storm tracks have greatly improved over the last decade, predictions of maximum water levels and variations in the extent of damage along a coastline need improvement. In particular, physics based models still cannot explain why some regions along a relatively straight coastline may experience significant erosion and overwash during a storm, while nearby locations remain seemingly unchanged. Correct predictions of both the timing of erosion and variations in the magnitude of erosion along the coast will be …

Spatial And Temporal Patterns In Erosional And Depositional Processes: Physical And Biological Controls In The York River, Chesapeake Bay, Virginia, Cielomar Rodríguez-Calderon

Dissertations, Theses, and Masters Projects

No abstract provided.

Modeling Shoreline Change And Resulting Wetland Response Due To Erosion And Sea-Level Rise: A Case Study In Dorchester County, Maryland, Mirtha Karinna Nunez

Dissertations, Theses, and Masters Projects

The present study was focused on developing a shoreline change forecast and wetland response model for Dorchester County, MD, to evaluate the vulnerability of wetlands to shoreline erosion and inundation due to relative sea level rise. The model considers the following forces involved in wetland stability and sustainability: inundation (as a function of topography and sea-level rise), shoreline erosion, vertical accretion and horizontal migration. To predict the long-term risk to nearshore wetlands and the potential habitat zone for wetlands in the next 50 years, shoreline change due to inundation and erosion/accretion was assessed within the frameworks of two-dimensional and three-dimensional …

Quantifying The Overwash Component Of Barrier Island Morphodynamics: Onslow Beach, Nc, Amy C. Foxgrover

Dissertations, Theses, and Masters Projects

A quantification of the role that barrier island overwash plays in the evolution of Onslow Beach, a barrier island located on Marine Corps Base Camp Lejeune, North Carolina, is presented. Ground-penetrating radar (GPR) and sediment vibracores provide an estimate of the relevant-sand prism above a silty/peat contact underlying the island. The average thickness from the surface, as determined from lidar, to this geologically-defined base, is less than 1 m and equates a total volume of approximately 1.8 ± 1.1 × 106 m3 over the 4.8 km stretch of Onslow Beach from 1 km north of the New River Inlet to …

Recent Sedimentation Patterns And Facies Distribution On The Waipaoa River Shelf, N.Z, Lila Eve Rose

Dissertations, Theses, and Masters Projects

No abstract provided.

Sediment Transport And Erodibility In The York River Estuary: A Model Study, Jeffrey Paul Rinehimer

Dissertations, Theses, and Masters Projects

A cohesive sediment bed model was implemented in the Community Sediment Transport Modeling System (CSTMS) to examine processes influencing sediment erodibility and suspended sediment concentrations. Estimates of eroded mass from the sediment bed model were calibrated and verified with erosion chamber measurements from the York River, Virginia, a tidally-dominated environment. A constant erosion rate parameter combined with depth-varying critical shear stress was sufficient to model erosion observations of depth-limited sediment cores. Sensitivity of total eroded mass to seasonal variations in erodibility and changes in consolidation time scale was evaluated during spring-neap variations in bottom stresses. Differences were greatest during spring …

Factors Controlling Tidal Flat Morphology In South San Francisco Bay Between The 1890s And 2005, Joshua Alexander Bearman

Dissertations, Theses, and Masters Projects

There is currently a project underway to restore many of the man-made salt ponds along the shores of South San Francisco Bay (SSFB) back to tidal marsh, potentially reestablishing these areas as sinks for SSFB sediments. While there have been recent studies examining the evolution of newly restored marsh areas in SSFB, there have been no recent projects focusing on the expected response of valuable tidal flat environments adjacent to the restored marshes. To help fill this void, this project seeks to characterize SSFB tidal flat morphodynamics, both spatially and temporally, through examination of historic morphologic variability and change along …

Variability In Geologic Framework And Shoreline Change: Assateague And Wallops Islands, Eastern Shore Of Virginia, Geoffrey L. Wikel

Dissertations, Theses, and Masters Projects

No abstract provided.

The Impact Of Drainage Ditches On Salt Marsh Flow Patterns, Sedimentation And Morphology: Rowley River, Massachusetts, Lynsey E. Lemay

Dissertations, Theses, and Masters Projects

Salt marshes along many tidal systems in New England have been ditched since colonial times. These ditches have been thought to help control mosquito populations and increase salt marsh hay production by improving water drainage from the marsh. Although these ditches are prominent geomorphic features, little quantitative work has focused on how these man-made ditches may alter marsh hydrology and geomorphology. This study attempts to quantify the ways in which ditches alter sediment and water transport pathways and how that affects the overall morphology and surface geology. This study also addresses treatment affects on sedimentation from fertilization and fish removal …

Physical Processes Behind Delta Propagation And Flood Layer Dynamics, Po River, Italy, Aaron J. Bever

Dissertations, Theses, and Masters Projects

Rivers discharge around 20 billion tonnes of sediment to the coastal ocean each year (Milliman and Syvitski, 1992). Many supply dominated rivers possess large subareal and subaqueous deltas, whose growth depends on the physical processes controlling sediment deposition or removal. There has yet to be a complete understanding of how short term processes such as settling from buoyant plumes, wave/current resuspension, and transport by currents and gravity flows, interact to produce the depositional products that develop over varying timescales. The Po River in Northern Italy forms a substantial delta in the Adriatic Sea. It has five distributary mouths, and is …

Little Creek Naval Amphibious Base Chesapeake Bay Shoreline, C. Scott Hardaway Jr., Donna A. Milligan, George R. Thomas, Linda M. Meneghini

Reports

Little Creek Naval Amphibious Base (NAB) is located in Virginia Beach, Virginia. It’s shoreline along the southern Chesapeake Bay extends from Little Creek Inlet eastward approximately 1.5 miles to the NAB’s eastern boundary. In 1997, a study and report entitled “LITTLE CREEK NAVAL AMPHIBIOUS BASE, CHESAPEAKE BAY SHORELINE, SHORELINE MANAGEMENT PLAN and OFFICER’S BEACH SHORE PROTECTION EVALUATION” was produced by VIMS’s Shoreline Studies Program (Hardaway et al., 1997). The purpose of that report was to assess the rates and patterns of beach change along the Chesapeake Bay shoreline at Little Creek NAB in order to develop a shoreline management plan, …

Linking Framework Geology And Nearshore Morphology: Correlation Of Paleo-Channels With Shore-Oblique Sandbars And Gravel Outcrops, A. Grace Browder

Dissertations, Theses, and Masters Projects

No abstract provided.

Shore-Oblique Bars, Nearshore Gravel Outcrops, And Their Correlation To Shoreline Change, Courtney A. Schupp

Dissertations, Theses, and Masters Projects

No abstract provided.

Tangier Island, Virginia Shoreline Management Plan For The West Coast Of The Uppards, C. Scott Hardaway Jr.

Reports

Utilizing geo-rectified aerial photography from 1938, 1960, 1987, and 2001, shoreline change rates were determined along the Uppards. Shoreline change rates vary but are all erosional except for areas around the north end where sand bars come and go. In the area of concern between baseline stations 4000 and 4600, the rates of erosion have increased with time. Using the rate calculated from the 1938 to 2001 shorelines for station 4000, 16 ft/yr, the 400 ft marsh isthmus width between the shoreline and Toms Gut would breach in about 25 years. This would essentially break the Uppards in two and …

Environmental Survey Of Potential Sand Resource Sites, Offshore Delaware And Maryland : Final Report, Virginia Institute Of Marine Science

Reports

• Technical summary / Carl H. Hobbs
• Non-technical summary / Carl H. Hobbs
• Part. 1. Benthic mapping and resource evaluation of potential sand mining areas, offshore Mayland and Delaware, 1998-1999 / G.R. Cutter and R.J. Diaz
• Part. 2. Transitory species (vertebrate nekton) / John A. Musick
• Part. 3. Literature survey of reproductive finfish and ichthyoplankton present in proposed sand mining locations within the Middle Atlantic Bight / John Olney, Donna Marie Bilkovic
• Part. 4. Potential modifications to waves due to dredging and other oceanographic considerations / Jerome P.-Y. Maa, Sung C. Kim
• Part. 5. Maryland-Delaware shoreline : long-term trends and short-term …

The Geomorphology And Shallow Structure Of The Northeastern New Jersey Continental Slope, Nicole D. Scott

Dissertations, Theses, and Masters Projects

No abstract provided.

An Investigation Of The Late Quaternary Morphology Of Mobjack Bay, Va And Application Of A Facies Model, Donna Angela Milligan

Dissertations, Theses, and Masters Projects

No abstract provided.

Investigation Of Isolated Sand Shoals On The Inner Shelf Of Southern Virginia : Final Report, Suzette M. Kimball, James K. Dame, Carl H. Hobbs Iii

Reports

Offshore of Sandbridge Beach, Virginia, the surface of the inner continental shelf is a generally featureless, gently sloping plain, broken by several isolated sand shoals. The westernmost shoal, commonly called the Sandbridge Shoal, is located approximately 5.5 km from the shoreline in 1 O - 12 m of water. An analogous feature is located approximately 15 km northeast of the Sandbridge Shoal at depths greater than 15 m. During a pretiminary study conducted in 1987, 534 km of trackline were surveyed with acoustic subbottom and side-scan sonar systems. Geophysical data were recorded for an additional 318 km of trackline between …

Acoustic Geology Of A Portion Of Virginia's Innermost Continental Shelf, Carl H. Hobbs Iii

VIMS Books and Book Chapters

Side-scan sonography of the innermost continental shelf between Cape Henry and the Virginia-North Carolina border depicts a relatively typical inner shelf bottom generally characterized by medium density, meso-scale roughness. Subbottom acoustic protiles depict the stratigraphy as a Tertiary age basement separated from Quatenary-age deposits by a regional, angular(?) unconformity. Holocene-age sediments form a discontinuous layer above another unconformity. The area's topography appears to be a function of the presence of the modern sediments.

Geological History Of A Holocene Drainage System: Hack Creek, Virginia, Robert A. Gammisch

Dissertations, Theses, and Masters Projects

No abstract provided.

Evaluation Of Sediment Sources And Sinks: A Sediment Budget For The Rappahannock River Estuary, Craig G. Lukin

Dissertations, Theses, and Masters Projects

No abstract provided.

Metal Inventory And Fate Of Suspended Sediment In Chesapeake Bay, Maynard M. Nichols, Galen Thompson, Bruce Nelson

Reports

This report aims to provide new information that meets selected objectives of the EPA-States Taxies Plan of Action: i.e. (1) to determine the state of the Bay with respect to the distribution and concentration of selected metals in suspended material and fluid mud; (2) to establish the temooral variations of sediment and metal loading: (3) to identify potential zones of metal accumulation and trace their transport routes, and (4) to provide recommendations for monitoring contaminated sediment.

Field observations provide longitudinal coverage of the Bay with transects into Baltimore Harbor and Hampton Roads. They include contrasting conditions of seasonal high-low river …