Physical Sciences and Mathematics Commons^™

Tidal Bed Stress Asymmetry And Sediment Transport In Estuaries, Austin Scott Hudson

Dissertations and Theses

Rivers and estuaries provide numerous ecological, economic, and cultural resources. The value of these resources is greatly influenced by sediment transport processes, which can be affected by human activities and climate variability. A key driver of sediment transport in tidal rivers and estuaries is tidal asymmetry of velocity and bed stress, which can manifest from both non-linear tidal interactions and linear interactions among astronomical tidal constituents.

In this study, an analytical framework is developed to examine and describe the dynamics of bed stress asymmetry in semidiurnal, diurnal, and mixed-tide estuaries (Chapter 1). While tidal velocity asymmetry has been previously analyzed, …

Quantifying Channel Change Following Post-Fire Debris Flows In A Steep, Coastal Stream, Big Sur, California, Telemak Olsen

WWU Graduate School Collection

Debris flows commonly occur following wildfire in steep landscapes, introducing large volumes of sediment to downstream fluvial systems. Fire-related sediment supply perturbations impact channel morphology, and importantly, fragile aquatic and riparian ecosystems downstream of disturbance. The Big Creek watershed drains 57 km² of steep chaparral and coast redwood forest along California’s Central Coast. Streams in the Big Creek watershed typically exhibit step-pool/cascade morphology and serve as vital spawning habitat for anadromous Steelhead Trout (Oncorhynchus mykiss). In 2020, 97% of the Big Creek watershed burned in the Dolan Wildfire. In January 2021, an atmospheric river event triggered a series of …

River Response To Sediment Supply: The Sand Bed Case, Christina M. Leonard

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Effective management of in-channel and floodplain habitat requires an ability to forecast river response to changes in water and sediment supply. These changes may result from dam construction/decommissioning, changes in reservoir operations, or changes in grazing or forestry practices. If a change in water and sediment supply causes sediment to be delivered faster than the channel’s capacity to transport it, sediment will accumulate in the reach, leading to changes in channel form and increasing the potential for flooding. A decrease in sediment supply relative to transport capacity can lead to channel incision. The extent and timing of sediment accumulation or …

Factors Controlling Longshore Variations Of Beach Changes Induced By Hurricane Hermine Along Pinellas County Beaches, West-Central Florida, Wenhan Zhai

USF Tampa Graduate Theses and Dissertations

Hurricane Hermine, 2016, impacted the coast of west-central Florida and generated high waves superimposed on elevated wave levels which caused significant beach erosion. A total of 122 profiles, spaced about 300 m apart, were surveyed 2 weeks before and one week after the storm to examine the beach changes along three barrier islands along the coast of west-central Florida. including Sand Key, Treasure Island and Long Key. In order to investigates the longshore variations of beach/nearshore changes induced by storm, several parameters were defined and calculated including beach volume changes, berm height, beach width, foreshore slope, as well as sandbar …

The Morphodynamic Interaction Of River Deltas And Their Marshes, Kelly M. Sanks

Graduate Theses and Dissertations

Globally, many of the largest river deltas contain vast marsh platforms that are currently threatened due to a combination of anthropogenic alterations to rivers and increasing relative sea level rise. Restoration and management plans for river deltas depend on optimizing riverine sediment accumulation in marsh platforms. However, the accumulation of organic material in marsh platforms is often neglected in predictive models and the interaction of ecogeomorphic processes governing marsh accumulation with the physical processes governing river delta growth is poorly understood.

Herein, I investigate this complex relationship through a combination of field and experimental studies. I show that in coastal …

Fine Grained Delta Front Sediment Transport, Sarah Noel

University of New Orleans Theses and Dissertations

Insights into transformative coastal processes are unlocked though understanding sediment transport mechanisms in fine-grained delta front environments. Movement of fine-grained sediments on delta fronts is not wholly explained through advection settling models. While advection settling models generally assume deposition into a still body, numerical modeling of sediment re-entrainment suggests there may be tidal, wave, and/or non-steady hydrograph influences allowing particles to reach greater distances by altering the decelerating velocity field. This research explores both an advection settling model and a mass conservation Rouse profile model to understand the irreducible delta front processes controlling sediment deposition. Using field data collected on …

Sedimentary Processes Influencing Divergent Wetland Evolution In The Hudson River Estuary, Kelly Mckeon

Masters Theses

Consistent shoreline development and urbanization have historically resulted in the loss of wetlands. However, some construction activities have inadvertently resulted in the emergence of new tidal wetlands, with prominent examples of such anthropogenic wetlands found within the Hudson River Estuary. Here, we utilize two of these human-induced tidal wetlands to explore the sedimentary and hydrologic conditions driving wetland development from a restoration perspective. Tivoli North Bay is an emergent freshwater tidal marsh, while Tivoli South Bay is an intertidal mudflat with vegetation restricted to the seasonal growth of aquatic vegetation during summer months. Using a combination of sediment traps, cores, …

Hydrodynamics, Sediment Transport, And Water Quality Of Two Contrasting Dredge Pits On The Louisiana Shelf, Robert Bales

LSU Master's Theses

Sediment is needed for coastal restoration in Louisiana and is often excavated offshore from both mud-capped and sandy dredge pits. The mined sand from mud-capped pits, like Sandy Point which is west of modern Mississippi Delta of Louisiana, was originally from a paleo river channel and later covered by mud from modern coastal processes. Sandy pits, like Caminada pit in eastern Ship Shoal on Louisiana shelf, generally experience higher energy conditions. To better understand the post-dredging effects on hydrodynamics, sediment transport, and water quality, two tripods were deployed at Caminada and Sandy Point pits in summer 2018 and 2019, respectively, …

Visualizing Effects Of Changing Base Level On Tributary Resources In Lake Powell Reservoir, Madeline Friend

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Lake Powell reservoir is the second-largest reservoir in the United States. As climate change reduces watershed runoff in the Colorado River Basin, questions arise about the management and even existence of Lake Powell. If lake levels continue to drop, what will the emerging canyon look like and what value will we assign it? Lake Powell traps all incoming fine sediment from the Colorado River, the San Juan River, and many smaller tributaries. What is the fate of this sediment under falling reservoir levels and how will it influence other resources? To support a robust public discourse, we provide an immersive …

Field Measurements Of Bed-Load Transport Distances Using Painted Sediment Tracers In An Urban Stream In The Missouri Ozarks, Kristen E. Breckenridge

MSU Graduate Theses

Predictions of bed-load mobility and transport in stream channels are useful for restoration and management purposes. This study uses native gravel tracers to determine transport distances for bed-load in an urban stream in the Ozark Highlands. The objectives of this project are to: (i) determine downstream transport distances of painted tracers of different sizes over a range of flow conditions; (ii) evaluate the influence of channel morphology and thalweg location on transport; and (iii) compare field results to those predicted by mobility equations. The study site is located on South Creek, which drains Springfield, Missouri. The study reach is 132 …

Hydrodynamics And Sediment Dynamics In A Receiving Basin For Sediment Diversion: A Case Study In Barataria Bay, Louisiana, Usa, Guandong Li

LSU Master's Theses

Barataria Bay is a receiving basin of Mid-Barataria Sediment Diversion in Louisiana, USA. In this region the data of sediment transport and hydrodynamics are scarce but important for the design and planning of sediment diversion to be implemented in near future. Four-months bottom boundary layer observation was conducted to study winter and spring hydrodynamics and sediment dynamics in the bay. Hourly waves, tides, currents and bottom suspended sediment concentration were measured using multiple optical and acoustic sensors attached to two tripod platforms. High-temporal resolution data indicated that during winter, salinity at northern bay was mainly controlled by northerly wind during …

Wave Runup And Morphologic Change On A Mixed-Sediment Beach In The Salish Sea, Wa, Avery Maverick

WWU Graduate School Collection

A primary threat to coastal regions is extreme water levels from tides, storm surges, and waves which drive coastal evolution. Predicting wave runup, the vertical extent of wave uprush on a beach above still water level, and the morphologic responses to storms within the Salish Sea is complex because of the high variability of shoreline exposure to waves and wind, morphology, coastal landforms, and tide range across the region. As part of a USGS study, this project was designed to assess how wave energy offshore drives runup, validate existing runup models (van der Meer, 2002; Stockdon et al., 2006; Didier …

Development And Application Of A Catchment Scale Sediment Routing Model, Jordan T. Gilbert

Graduate Student Theses, Dissertations, & Professional Papers

Sediment regimes, i.e., the processes that recruit, transport and store sediment, create the physical habitats that underpin river-floodplain ecosystems. Natural and human-induced disturbances that alter sediment regimes can have cascading effects on river and floodplain morphology, ecosystems, and a river’s ability to provide ecosystem services, yet prediction of the response of sediment dynamics to disturbance is challenging. We developed the Sediment Routing and Floodplain Exchange (SeRFE) model, which is a network-based, spatially explicit framework for modeling sediment recruitment to and subsequent transport through drainage networks. SeRFE additionally tracks the spatially and temporally variable balance between sediment supply and transport capacity. …

A Numerical Investigation Of Sediment Dynamics In The Northern Gulf Of Mexico In Connection With Hurricanes, Fluid Mud, Climate Change, And Biogeochemical Cycling, Zhengchen Zang

LSU Doctoral Dissertations

Sediment transport and deposition in marginal seas is jointly controlled by many factors including hydrodynamics, fluvial inputs, and the characteristics of sediment particles. This dissertation study employs the coupled ocean-atmosphere-wave-and-sediment transport modeling system (COAWST) to investigate the mechanism of sediment transport in the northern Gulf of Mexico (nGoM) on different temporal scales, as well as its interaction with biogeochemical processes.

First of all, a three-way coupled (atmosphere-wave-ocean) hurricane model reproduced the hydro- and sediment dynamics during hurricane Gustav (2008). Intensive alongshore and offshore currents were simulated on the eastern/western sectors of hurricane track, respectively. High suspended sediment concentration (SSC) was …

Tracking Sediment Bypassing, Geomorphological Analysis, And Regional Sediment Management At Tidal Inlets, Tanya M. Beck

USF Tampa Graduate Theses and Dissertations

Tidal inlets on sandy shorelines separate barrier islands and serve as a conduit for transport of sand and water between embayments and oceans, seas, or other tidally influenced waterbodies. Tides and waves induce currents along the coastline that transport sediment across-shore and alongshore. Coastal managers must optimize barrier-inlet system stability while conserving limited sediment resources, and often base management decisions and engineering design upon geomorphic and numerical models that predict the morphological behavior of tidal inlets on short-to-medium timescales (years to decades). The overall goal of this study was threefold. First, to provide science-based practical guidance for regional sediment management …

River Hydrology, Morphology, And Dynamics In An Intensively Managed, Transient Landscape, Sara Ann Kelly

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Rivers create beautiful patterns and provide drinking water to millions. However an alarming number of rivers in the US and globally are threatened by excess sediment and nutrients. Agricultural rivers draining erodible soils are particularly vulnerable. Rivers of southern Minnesota provide a unique opportunity to study water and sediment dynamics in a naturally vulnerable system. Sediment reduction strategies are needed to ensure biological integrity and adequate water quality. Here, I address the questions: 1) have climate, land use practices, or both affected streamflows in Midwest agricultural rivers?, 2) which streamflows set the rate of river bluff erosion?, and 3) how …

Sediment Transport And Channel Morphology Of A Natural And A Leveed Alluvial River, Bo Wang

LSU Master's Theses

Alluvial rivers are shaped by interactions of flow and sediment transport. Their lower reaches to the world’s oceans are highly dynamic, often presenting engineering and management challenges. This thesis research aimed to investigate channel dynamics and sediment transport in a natural river and a highly engineered river in South Louisiana, in order to gain much-needed science information for helping develop sustainable practices in river engineering, sediment management, and coastal restoration and protection. Especially, the thesis research examined (1) riverbed deformation from bank to bank in the final 500-km reach of the Mississippi River, (2) bed material transport at the Mississippi-Atchafalaya …

Comparison Of Beach Changes Induced By Two Hurricanes Along The Coast Of West-Central Florida, Ruoshu Zhao

USF Tampa Graduate Theses and Dissertations

The beach profiles pre-and post-the Hurricane Hermine (2016) and Irma (2017) along the Sand Key barrier island were collected to quantify longshore variations in storm induced beach changes as well as to compare the beach changes caused by hydrodynamic conditions of the two different hurricanes.

Cross-shore beach profile are examined in 4 sections including dune field, dry beach, sand bar and whole beach to calculate beach change. The volume change for each section and shoreline contour change before and post the hurricane was computed. Hydrodynamic conditions were obtained from adjacent NOAA’s tide and wave gauges.

Both hurricanes generated high offshore …

Hydrodynamic Controls On The Morphodynamic Evolution Of Subaqueous Landforms, Timothy L. Nelson

University of New Orleans Theses and Dissertations

The southern Chandeleur Islands are an ideal setting to study shoal evolution given their history of submergence and re-emergence. Here, numerical models shed light on the attendant processes contributing to shoal recovery/reemergence following a destructive storm event. Simulations of a synthetic winter storm along a cross-shore profile using Xbeach shows that convergence of wave-induced sediment transport associated with repeated passage of cold-fronts initiates aggradation, but does not lead to reemergence. A Delft3d model of the entire island chain shows that as these landforms aggrade alongshore processes driven by incident wave refraction on the shoal platform, backbarrier circulation and resulting transport …

Investigation Of Sediment Ridges Using Bathymetry And Backscatter Near Clearwater, Florida, Lewis Stewart

USF Tampa Graduate Theses and Dissertations

Changes in sediment morphology on the West Florida Shelf is investigated over a 14-year time period using multibeam bathymetry and backscatter in water depths between 10 m and 20 m, off the coast of Indian Rocks Beach, Pinellas County, Florida. Bathymetric surveys collected in 2002 (Kongsberg EM 3000 at 300 kHz) and 2016 (Reson 7125 at 400 kHz) were processed using CARIS Hips and Sips to create bathymetric maps and backscatter images. These data were then interpreted and compared in order to test hypotheses and answer questions related to sediment migration and sediment volume change.

The following questions prompted this …

Assessing Morphodynamics Of The Lower Mississippi River From 1985 To 2015 With Remote Sensing And Gis Techniques, Bo Wang

LSU Doctoral Dissertations

The Lower Mississippi River is one of the most highly engineered rivers in the world. The river is now completely regulated by a combination of levees, artificial cutoffs, bank revetments, and dike fields; however, the river engineering has also complicated the geomorphological response to the sediment brought in the river. This dissertation research examined morphodynamics of the middle portion of the Lower Mississippi River from Vicksburg, Mississippi (river kilometer: 737) to Red River Landing, Louisiana (river kilometer: 486) to elucidate river engineering effects on sediment transport, storage, and distribution. The Old River Control Structure (ORCS) diverts approximately 25% of the …

Geomorphic Characteristics And Sediment Transport In Natural And Channelized Reaches Of Big Barren Creek, Southeast Missouri, Matthew S. Thies

MSU Graduate Theses

Channelization, levee construction, and gravel mining are land management practices that are used for flood control. However, they often alter the balance between sediment supply and available sediment transporting power in streams, causing channel instability. Streams can respond to instability through channel incision and sediment aggradation which can degrade riparian habitat, increase flood risks, and cause property damage. These problems have been observed along segments of Big Barren Creek, which drains 190 km² of the Missouri Ozarks in Mark Twain National Forest. Field assessment and modeling methods were used to evaluate the spatial distribution of channel instability along the upper …

Channel Bar Morphology, Distribution, And Mining-Related Geochemistry In The Big River, St. Francois County, Missouri: Implications For Geomorphic Recovery, Lindsay Marie Olson

MSU Graduate Theses

Tailings releases associated with large-scale historical Pb mining in St. Francois County, Missouri resulted in system-wide contamination of Pb and excess sediment in the Big River. Previous studies have addressed basin and segment scale variability of the contaminants; however, little is known about reach and bar scale variability. This study addresses how mining sediment inputs influence bar form and geochemistry across a range of scales. Bar sediment samples were collected at 21 reaches and analyzed for particle size and geochemistry, while air photo analysis was used to evaluate channel morphology, bar type, and area. Bar area is initially low in …

Sedimentation And Erosion Patterns Within Anabranching Channels In A Lowland River Restoration Project, Ivan Medel

Cal Poly Humboldt theses and projects

Phase 2A of the Salt River Ecosystem Restoration Project (SRERP) was implemented to increase transport efficiency of water and sediment through a low gradient river reach to alleviate flooding on adjacent properties. The SRERP utilizes a unique anabranching channel design that concentrates base flows within a single deep, narrow channel overflowing onto an alternating series of higher elevation active benches at flood stages. This paper investigated the performance of the project’s hydraulic conveyance and general utility of anabranching channels as a restoration alternative by assessing the distribution and magnitude of deposition and erosion response patterns.

Aggradation was not observed within …

Sediment Transport And Slope Stability In The Northern Gulf Of Mexico, Jeffrey Blake Obelcz

LSU Doctoral Dissertations

Sediment transport and slope stability are fundamental organizing agents of the geological record. These processes have been extensively studied along the northern margin of the Gulf of Mexico basin for both basic and applied purposes, but our knowledge of them is limited by the spatial and temporal sampling capabilities of traditional geologic oceanographic surveying tools such as coring, single-beam echosounders, and sidescan sonar. This dissertation seeks to update the state of knowledge regarding northern Gulf of Mexico sediment transport and slope stability from annual to millennial timescales, primarily using relatively high-resolution acoustic geophysical tools such as swath bathymetric echosounders and …

Sediment Transport And Channel Morphology Dynamics Of Highly Regulated Alluvial Rivers - A Case Study Of The Lowermost Mississippi River., Sanjeev Joshi

LSU Doctoral Dissertations

The Mississippi River delta is facing severe land loss. An urgent need exists to examine sediment transport and channel morphology dynamics along this highly engineered alluvial river that has shaped and will continue to shape its delta. This dissertation research focuses on investigating channel morphology dynamics and sediment transport in the recent three decades along a 327-km reach (from about 492 to 167 km upstream from the river’s outlet in the Gulf of Mexico) of the Lowermost Mississippi River (LmMR). The specific objectives of this research were to: 1) analyze riverbed adjustment, i.e., channel-bed aggradation or channel erosion at seven …

Modern Fair-Weather And Storm Sediment Transport Around Ship Island, Mississippi: Implications For Coastal Habitats And Restoration Efforts, Eve Rettew Eisemann

Master's Theses

The Mississippi – Alabama barrier island chain is experiencing accelerated sea level rise, decreased sediment supply, and frequent hurricane impacts. These three factors drive unprecedented rates of morphology change and ecosystem reduction. All islands in the chain have experienced land loss on the order of hectares per year since records began in the 1840s. In 1969, Hurricane Camille impacted as a Category 5, breaching Ship Island, and significantly reduced viable seagrass habitat. Hurricane Katrina impacted as a Category 3 in 2005, further widening Camille Cut. To better understand the sustainability of these important islands and the ecosystems they support, sediment …

An Assessment Of Long-Term Changes In The Characterisitcs Of Precipitation In The Upper Midwest, Blake Steven Lea

MSU Graduate Theses

As climate change progresses, many forecasts for the upper Midwest predict increases in annual precipitation, but with a shift in seasonal patterns that will leave the summer months drier with less frequent, higher magnitude storm events. Changes in precipitation patterns have the potential to alter the sediment budget and discharge patterns in watersheds. The purpose of this study was to determine the effects changes in frequency, magnitude, duration, and intensity of precipitation might have on streamflow and sediment budgets in the upper Midwest. This analysis was carried out using hourly precipitation data from 1948 to 2013 from 23 sites and …

Particulate Inorganic Carbon Flux And Sediment Transport Dynamics In Karst: Significance To Landscape Evolution And The Carbon Cycle., Randall Lee Paylor

LSU Doctoral Dissertations

Research focused on three areas of karst hydrogeology and sediment transport that have been poorly studied in the past: the role of particulate inorganic carbon transport in calculating carbon sink rates in karst; rapid changes in surface vs. subsurface sediment mixing in karst conduits; and comparison of landscape denudation calculations using dissolved carbonate load vs. total dissolved/sediment load. Carbonate bedrock weathering is a significant component of the atmospheric carbon sink. Particulate inorganic carbon (PIC) in bed and suspended sediment load of karst waters is frequently dismissed as insignificant for calculating denudation and carbon transport/sink rates, but PIC flux has not …

Interactions Among Hydrology, Sediment And Vegetation In Accreting Wax Lake Delta: Physical And Biogeochemical Implications For Coastal Louisiana Restoration, Courtney Erin Elliton

LSU Master's Theses

River discharge pulses, wind, waves, tides, and the presence of dense vegetation are factors that interact and regulate the transport and retention of sediment in coastal regions. In particular, vegetation structural and physiognomic traits promote fine sediment trapping during tidal and river flow, maintaining the balance between soil elevation and relative sea level rise on coastline stability and land building. Mike Island, located within Wax Lake Delta, Louisiana, USA, is part of a deltaic system created by a man-made freshwater diversion (1941) and one of few coastal areas where land is expanding in coastal Louisiana as result of pulsing river …