Geomorphology Commons^™

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 …

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 …

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 …

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. …

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 …

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 …

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 …

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 …

Stream Bank Erosion Trends And Sediment Contributions In A Southwestern Missouri River, Ezekiel Allen Kuehn

MSU Graduate Theses

Bank erosion can be a significant source of in-stream sediment that negatively affects water quality and aquatic habitat. However, assessments of the role that eroding banks play in suspended and bed sediment supply are rarely available to managers. The purpose of this study was to quantify bank erosion rates for a 7 km conservation easement the James River in southwest Missouri to evaluate the annual contributions of bank sediment to the channel. The objectives were to: (1) monitor an eroding 260 m bank to better understand short-term, reach scale bank erosion rates; (2) determine historical rates of bank erosion for …