Geomorphology Commons^™

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 …

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 …

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.

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 …

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

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 …

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.

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.

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.

An Investigation Of Sand Transport Phenomena In The Rappahannock River Estuary, Virginia, Charles Joseph Natale

Dissertations, Theses, and Masters Projects

Quantitative evidence supplied by bottom sediment textural analysis, Fourier grain-shape analysis and Q-mode factor analysis indicate that river-borne sand-sized sediment originating in the upper reaches of the Rappahannock is actively transported downstream and ultimately delivered to the estuarine sediment regime. Current velocity observations in the upper estuary as well as suspended sediment concentrations measured at stream gaging stations, indicate that short-term extreme hydrological events such as periodic river flooding provide a plausible transport mechanism to move river-borne sands into the estuarine sediment regime.Events of this nature can disrupt average partly-mixed estuarine circulation patterns by displacing the salt-wedge to a more …

Historical Evolution Of Coastal Sand Dunes On Currituck Spit, Virginia/North Carolina, Harold F. Hennigar

Dissertations, Theses, and Masters Projects

No abstract provided.

Late Pleistocene Stratigraphy And Morphology Of The Lower Northern Neck, Virginia, Kathleen M. Farrell

Dissertations, Theses, and Masters Projects

No abstract provided.

The Interaction Of Eolian Sand Transport, Vegetation, And Dune Geomorphology: Currituck Spit, Virginia-North Carolina, Andrew L. Gutman

Dissertations, Theses, and Masters Projects

No abstract provided.

Forecasting Beach Erosion Along The Oceanic Coastlines Of The Northeast And Mid-Atlantic States, William S. Richardson

Dissertations, Theses, and Masters Projects

No abstract provided.

Geomorphic Processes Of A Drowned River Valley, Lower York River Estuary, Virginia, Michael Joseph Carron

Dissertations, Theses, and Masters Projects

No abstract provided.

Geomorphic Interpretation Of Vegetation On Fisherman Island, Virginia, Mark Eliot Boule

Dissertations, Theses, and Masters Projects

No abstract provided.

Beach Sands Of The Southern Delmarva Peninsula, Patterns And Causes, Carey Ingram

Dissertations, Theses, and Masters Projects

No abstract provided.

Quantitative Analysis Of Beach Sand Movement, Virginia Beach, Virginia, John D. Boon

Dissertations, Theses, and Masters Projects

The present study describes a new approach to quantitative sediment tracing with dyed (fluorescent) particles, which can be used to obtain estimates of grain velocity, estimates of mobile layer thickness, and estimates of the rate of longshore sand transport.A simplified stochastic-process model was employed Involving the use of statistical procedures to analyze tracer displacement data on a time-stratified basis. The procedures provide meaningful estimates of the direction and magnitude of the movement of beach sand through set Intervals of time.

Results of a single tracer experiment are reported from a beach located near Virginia Beach, Virginia. The tracer particle-displacement data …