Engineering Commons^™

Numerical Investigation Of Sediment Flushing And Morphological Changes In Tamsui River Estuary Through Monsoons And Typhoons, Tung Chou Hsieh, Yan Ding, Keh Chia Yeh, Ren Kai Jhong

Faculty and Student Publications

The removal of reservoir silt and the restoration of existing reservoir capacities through land excavation and hydraulic sediment flushing have become necessary. Hydraulic sediment flushing discharge changes flow and sediment conditions of the downstream river channel. In the Tamsui River estuary in Taiwan, sediment flushing from the Shihmen reservoir upstream has potential impacts on the morphology of the navigation channels and the adjacent coasts. This study employed a validated coastal and estuarine processes model to investigate: (1) the influence of sediment flushing and tidal levels on morphological changes during flood and flushing‐discharge operations of the reservoir, and (2) the differences …

Force And Torque Model Sensitivity And Coarse Graining For Bedload-Dominated Sediment Transport, Liheng Guan, Jorge Salinas, ‪Nadim Zgheib, S. Balachandar

Mechanical Engineering Faculty Publications and Presentations

We present results from Euler–Lagrange simulations of turbulent flow over an erodible monodisperse bed of particles at a shear Reynolds number of R e τ = 180 . The Galileo number G a and the ratio of Shields to the critical Shields number Θ / θ c r were varied in the range 11.4 to 29.8 and 1.32 to 5.98, respectively. Two drag force models were investigated along with the influence of lift, particle rotation, and tangential collision forces for each model. Both models give similar results as far as mean particle flux and Shields stress are concerned, however we …

The Role Of Bed-Penetrating Kelvin–Helmholtz Vortices On Local And Instantaneous Bedload Sediment Transport, Liheng Guan, J. S. Salinas, ‪Nadim Zgheib, S. Balachandar

Mechanical Engineering Faculty Publications and Presentations

We present results from open-channel, Euler–Lagrange (EL) simulations of turbulent flow over an erodible particle bed at a shear Reynolds number of Reτ=180 . Upon space and time averaging, our simulations correctly reproduce the Wong & Parker (ASCE J. Hydraul. Engng, vol. 132, issue 11, 2006, pp. 1159–1168) bedload transport relation (WP). However, local and instantaneous sediment flux shows orders of magnitude scatter around the WP prediction. Visualization of the vortical structures using swirling strength shows the existence of bed-penetrating Kelvin–Helmholtz (KH) vortex packets, which coupled with particle inertia are primarily responsible for the large scatter. The results also show …

Development Of An Rfid Tracking System For Coarse Sediment Transport In A Flume Setting, Peter Mahoney Jr.

ENGS 88 Honors Thesis (AB Students)

Development of an RFID Tracking System for Coarse Sediment Transport in a Flume Setting

Peter E. Mahoney

Professor Carl Renshaw

Understanding how sediment moves through a fluvial system has important implications for the study of river systems, sediment flux, and flood events. Over the past decade, RFID (radio frequency identification) technology has emerged as a useful method for tracking the movement and transport of coarse sediment clasts. This approach has been used to measure the transport of large clasts in mid-sized streams, ephemeral channels, and laboratory flume settings. However, this research utilized finite transport of sediment and focused on accurately …

Theoretical Model For Shields Diagram And Its Application, Jichao Jiang

Department of Environmental Engineering: Theses and Student Research

The transition from the condition of “no motion” to initial sediment moment, defined as sediment initiation, has been related to practical engineering (channel degradation, stable channel design), oceanographic (dredging, pipelines, cables), sedimentologic (sediment mobility, transport rates), geologic (the hydraulic interpretation of paleoenvironments), geochemical (pollutant transport), and gained considerable interest since nineteenth century.

Shields diagram for sediment initiation in terms of critical shear stress is a classic problem in sediment transport, but it is still an empirical law without a simple and practical theory despite extensive research since the 1930s. Hence, this research presents a simple theoretical model for critical shear …

A Comprehensive Method Of Calculating Maximum Bridge Scour Depth, Rupayan Saha, Seung Oh Lee, Seung Ho Hong

Faculty & Staff Scholarship

Recently, the issues of scour around a bridge have become prominent because of the recurrent occurrence of extreme weather events. Thus, a bridge must be designed with the appropriate protection measures to prevent failure due to scour for the high flows to which it may be subjected during such extreme weather events. However, the current scour depth estimation by several recommended equations shows inaccurate results in high flow. One possible reason is that the current scour equations are based on experiments using free-surface flow even though extreme flood events can cause bridge overtopping flow in combination with submerged orifice flow. …

Sediment Transport Modelling On The River Bandon, John Gamble, Joseph R. Harrington

Conference Papers

In November 2009 Ireland was subject to a severe weather event, causing widespread flooding nationwide. One of the worst effected towns was the town of Bandon in County Cork which regularly floods. The River Bandon is located in the South Western River District (SWRBD) with a catchment area of 608km2 . The River Bandon offers a positive environment for biodiversity, facilitating habitats for some endangered species. The River Bandon is planned to undergo significant river improvement works. This paper presents the findings of an extensive sediment sampling, testing and analysis programme, including for suspended and bed sediments and sediment loadings. …

A Literature Review Of The Beneficial Use Of Dredged Material And Sediment Management Plans And Strategies, Portland State University. Hatfield School Of Government. Center For Public Service, Michelle Welch, Eric Thomas Mogren, Lauren Beeney

Center for Public Service Publications and Reports

This report identifies lessons learned from the body of existing literature on dredge sediment beneficial uses. It also examines the constructive role collaborative processes can play in development of sediment management plans. The authors reviewed approximately 100 documents and reports for this project. Seventeen of those were reviewed in detail based on their relevance in identifying sediment beneficial uses and/or the use of collaborative processes in the development of sediment management plans. A number of these documents were sediment management plans and strategies for specific projects and programs in other locations. The report presents findings and lessons for the consideration …

Sediment Transport Modelling On The River Bandon - Abstract, John Gamble

Conference Papers

No abstract provided.

Sediment Transport Modelling On The River Bandon, John Gamble, D. Barnett, Joseph R. Harrington

Conference Papers

No abstract provided.

Numerical Modeling Of The Effects Of Hydrologic Conditions And Sediment Transport On Geomorphic Patterns In Wetlands, Mehrnoosh Mahmoudi

FIU Electronic Theses and Dissertations

This dissertation focused on developing a numerical model of spatial and temporal changes in bed morphology of ridge and slough features in wetlands with respect to hydrology and sediment transport when a sudden change in hydrologic condition occurs. The specific objectives of this research were: (1) developing a two-dimensional hydrology model to simulate the spatial distribution of flow depth and velocity over time when a pulsed flow condition is applied, (2) developing a process-based numerical model of sediment transport coupled with flow depth and velocity in wetland ecosystems, and (3) use the developed model to explore how sediment transport may …

Circulation, Sediment Concentration And Oxygen Depletion In The Tidal Ems River, Stefan A. Talke, Huib E. De Swart

Civil and Environmental Engineering Faculty Publications and Presentations

We present measurements which show that the tidal Ems River in Germ any is extremely muddy over a 30 km + turbid zone, with fluid mud o f 1-2 m thickness covering the bed with suspended sediment concentrations (SSC) o f greater than 50 kg.m^-3. Moreover, we show that these elevated SSC contain large quantities of organic material which deplete dissolved oxygen (DO) and produce summertime hypoxic zones. Using mathematical modeling, we develop simplified representations o f the estuary physics that reproduce the tidally-averaged circulation, SSC distribution, and oxygen depletion. These models show that SSC and oxygen concentrations …

The Effect Of Tidal Asymmetry And Temporal Settling Lag On Sediment Trapping In Tidal Estuaries, Alexander S. Chernetsky, Henk M. Schuttelaars, Stefan A. Talke

Civil and Environmental Engineering Faculty Publications and Presentations

Over decades and centuries, the mean depth of estuaries changes due to sea-level rise, land subsidence, infilling, and dredging projects. These processes produce changes in relative roughness (friction) and mixing, resulting in fundamental changes in the characteristics of the horizontal (velocity) and vertical tides (sea surface elevation) and the dynamics of sediment trapping. To investigate such changes, a 2DV model is developed. The model equations consist of the width-averaged shallow water equations and a sediment balance equation. Together with the condition of morphodynamic equilibrium, these equations are solved analytically by making a regular expansion of the various physical variables in …

Suspended Sediment Fluxes At An Intertidal Flat: The Shifting Influence Of Wave, Wind, Tidal, And Freshwater Forcing, Stefan A. Talke, Mark T. Stacey

Civil and Environmental Engineering Faculty Publications and Presentations

Using in situ, continuous, high frequency (8–16 Hz) measurements of velocity, suspended sediment concentration (SSC), and salinity, we investigate the factors affecting near-bed sediment flux during and after a meteorological event (cold front) on an intertidal flat in central San Francisco Bay. Hydrodynamic forcing occurs over many frequency bands including wind wave, ocean swell, seiching (500–1000 s), tidal, and infra-tidal frequencies, and varies greatly over the time scale of hours and days. Sediment fluxes occur primarily due to variations in flow and SSC at three different scales: residual (tidally averaged), tidal, and seiching. During the meteorological event, sediment fluxes are …

Water Erosion Prediction Project (Wepp): Development History, Model Capabilities, And Future Enhancements, Dennis C. Flanagan, John E. Gilley, Thomas G. Franti

Biological Systems Engineering: Papers and Publications

The Water Erosion Prediction Project (WEPP) was initiated in August 1985 to develop new‐generation water erosion prediction technology for use by federal action agencies involved in soil and water conservation and environmental planning and assessment. Developed by the USDA‐ARS as a replacement for empirically based erosion prediction technologies, the WEPP model simulates many of the physical processes important in soil erosion, including infiltration, runoff, raindrop and flow detachment, sediment transport, deposition, plant growth, and residue decomposition. The WEPP project included an extensive field experimental program conducted on cropland, rangeland, and disturbed forest sites to obtain data required to parameterize and …

A Spatially Distributed Model For The Dynamic Prediction Of Sediment Erosion And Transport In Mountainous Forested Watersheds, Colleen O. Doten, Laura C. Bowling, Jordan S. Lanini, Edwin P. Maurer, Dennis P. Lettenmaier

Civil, Environmental and Sustainable Engineering

Erosion and sediment transport in a temperate forested watershed are predicted with a new sediment model that represents the main sources of sediment generation in forested environments (mass wasting, hillslope erosion, and road surface erosion) within the distributed hydrology-soil-vegetation model (DHSVM) environment. The model produces slope failures on the basis of a factor-of-safety analysis with the infinite slope model through use of stochastically generated soil and vegetation parameters. Failed material is routed downslope with a rule-based scheme that determines sediment delivery to streams. Sediment from hillslopes and road surfaces is also transported to the channel network. A simple channel routing …

Hydrodynamics And Morphology In The Ems/Dollard Estuary: Review Of Models, Measurements, Scientific Literature, And The Effects Of Changing Conditions, Stefan A. Talke, Huib E. De Swart

Civil and Environmental Engineering Faculty Publications and Presentations

The Ems estuary has constantly changed over the past centuries both from man-made and natural influences. On the time scale of thousands of years, sea level rise has created the estuary and dynamically changed its boundaries. More recently, storm surges created the Dollard sub-basin in the 14th -15th centuries. Beginning in the 16th century, diking and reclamation of land has greatly altered the surface area of the Ems estuary, particularly in the Dollard. These natural and anthropogenic changes to the surface area of the Ems altered the flow patterns of water, the tidal characteristics, and the patterns of sediment deposition …

A Sediment Transport Model For Incising Gullies On Steep Topography, Erkan Istanbulluoglu, David G. Tarboton, Robert T. Pack, Charles H. Luce

Civil and Environmental Engineering Faculty Publications

We have conducted surveys of gullies that developed in a small, steep watershed in the Idaho Batholith after a severe wildfire followed by intense precipitation. We measured gully length and cross sections to estimate the volumes of sediment loss due to gully formation. These volume estimates are assumed to provide an estimate of sediment transport capacity at each survey cross section from the single gully-forming thunderstorm. Sediment transport models commonly relate transport capacity to overland flow shear stress, which is related to runoff rate, slope, and drainage area. We have estimated the runoff rate and duration associated with the gully-forming …