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Articles 391 - 420 of 424
Full-Text Articles in Civil and Environmental Engineering
Using Custom Transportation Data Collection Software With Handheld Computers For Education, Research, And Practice, Robert Bertini, Christopher Monsere, Andrew Byrd, Michael Rose, Tarek El-Seoud
Using Custom Transportation Data Collection Software With Handheld Computers For Education, Research, And Practice, Robert Bertini, Christopher Monsere, Andrew Byrd, Michael Rose, Tarek El-Seoud
Civil and Environmental Engineering Faculty Publications and Presentations
In an effort to facilitate data collection for research, give students first-hand experience collecting data for course projects, and generate interest in the transportation field through outreach, the Intelligent Transportation Systems Laboratory of Portland State University, Oregon, has developed custom data collection software for handheld computers using the Palm OS platform. The software is designed to export the collected data to desktop computers in common file formats suitable for analysis in spreadsheet and geographic information systems applications. Data collection problems addressed include recording position over time, recording geographic location of features, and performing cumulative vehicle or pedestrian counts.
Decadal-Scale Changes In West Coast Shelf Internal Tides (The Tides, They Are A Changin'), David A. Jay, Thomas A. Chisholm, A. Krause, K. Leffler
Decadal-Scale Changes In West Coast Shelf Internal Tides (The Tides, They Are A Changin'), David A. Jay, Thomas A. Chisholm, A. Krause, K. Leffler
Civil and Environmental Engineering Faculty Publications and Presentations
The National Science Foundation (NSF) Co-OP (Coastal Ocean Program) Project RISE (River-Influenced Shelf Ecosystems) seeks to understand how primary and secondary productivity are enhanced by large river plumes in upwelling regions, using the Columbia River plume as a case study. Columbia River plume waters are rich in silicate and iron, but relatively depleted in nitrate. Mixing of nitrate-rich upwelled water with the plume is, therefore, important to plume primary production. Large internal tidal currents cause part of the necessary mixing. Accordingly, any long-term changes in these internal tides could impact productivity. Because no decadal-scale current observations are available to evaluate …
Willamette River Basin Temperature Tmdl Model: Model Calibration, Chris Berger, Michael Lee Mckillip, Robert Leslie Annear, Sher Jamal Khan, Scott A. Wells
Willamette River Basin Temperature Tmdl Model: Model Calibration, Chris Berger, Michael Lee Mckillip, Robert Leslie Annear, Sher Jamal Khan, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
The State of Oregon Department of Environmental Quality (DEQ) is developing a TMDL for temperature in the Willamette River basin shown in Figure 1. The study area included the Willamette River and all major tributaries (except the Tualatin River where a TMDL process was already concluded). A large section of the Columbia River was also modeled to provide adequate boundary representation of tidal flows in the lower Willamette River. The Willamette River below the Oregon City Falls in the Portland metropolitan area has a typical diurnal tidal range of 1 m. The development of a dynamic model of temperature and …
Green River Ce-Qual-W2 Project: A Hydrodynamic And Water Quality Study Of The Green River King County, Washington, Tim Kraft, Robert Leslie Annear, Chris Berger, Scott A. Wells
Green River Ce-Qual-W2 Project: A Hydrodynamic And Water Quality Study Of The Green River King County, Washington, Tim Kraft, Robert Leslie Annear, Chris Berger, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
This report describes the data processing and model calibration performed for a hydrodynamic and water quality model of the Green River, located in King County, Washington. Figure 1 shows the location of the river, and the limits of the section of river that was modeled.
The Green River flows from its headwaters in the Cascade Mountain foothills through the King County, Washington communities of Auburn, Kent, and Tukwila before discharging into the Duwamish River. Two sections of the river were modeled in this project. The Middle Green River begins in the Cascade Mountain foothills east of Tacoma, and continues downstream …
Willamette River Basin Temperature Tmdl Model: Model Scenarios, Robert Leslie Annear, Michael Lee Mckillip, Sher Jamal Khan, Chris Berger, Scott A. Wells
Willamette River Basin Temperature Tmdl Model: Model Scenarios, Robert Leslie Annear, Michael Lee Mckillip, Sher Jamal Khan, Chris Berger, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
The State of Oregon Department of Environmental Quality (DEQ) is developing a TMDL for temperature in the Willamette River basin shown in Figure 1. The study area included the Willamette River and all major tributaries (except the Tualatin River where a TMDL process was already concluded). A large section of the Columbia River was also modeled to provide adequate boundary representation of tidal flows in the lower Willamette River. The Willamette River below the Oregon City Falls in the Portland metropolitan area has a typical diurnal tidal range of 1 m. The development of a dynamic model of temperature and …
Review Of Spokane River Model For Washington Department Of Ecology, Chris Berger, Robert Leslie Annear, Scott A. Wells
Review Of Spokane River Model For Washington Department Of Ecology, Chris Berger, Robert Leslie Annear, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
This memorandum discusses changes made to the Spokane River model calibration since the original calibration of the model discussed in the following reports: Annear et al. (2001), Berger at al. (2002), Slominski et al. (2002), and Berger et al. (2003). The first group of refinements was made by the Washington Department of Ecology. Additional changes were made by Portland State University (PSU) and were discussed in this report along with the results of two alternative calibrations. The last section displays the original calibration results from Berger et al. (2003) as a basis for comparison to the changes made by Ecology …
Willamette River Basin Temperature Tmdl Model: Boundary Conditions And Model Setup, Robert Leslie Annear, Michael Lee Mckillip, Sher Jamal Khan, Chris Berger, Scott A. Wells
Willamette River Basin Temperature Tmdl Model: Boundary Conditions And Model Setup, Robert Leslie Annear, Michael Lee Mckillip, Sher Jamal Khan, Chris Berger, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
The State of Oregon Department of Environmental Quality (DEQ) is developing a TMDL for temperature in the Willamette River basin shown in Figure 1. The study area included the Willamette River and all major tributaries (except the Tualatin River where a TMDL process was already concluded). A large section of the Columbia River was also modeled to provide adequate boundary representation of tidal flows in the lower Willamette River. The Willamette River below the Oregon City Falls in the Portland metropolitan area has a typical diurnal tidal range of 1 m. The development of a dynamic model of temperature and …
Impacts Of Columbia River Discharge On Salmonid Habitat: 2. Changes In Shallow-Water Habitat, David A. Jay, Tobias Kukulka
Impacts Of Columbia River Discharge On Salmonid Habitat: 2. Changes In Shallow-Water Habitat, David A. Jay, Tobias Kukulka
Civil and Environmental Engineering Faculty Publications and Presentations
This is the second part of an investigation that analyzes human alteration of shallow-water habitat (SWH) available to juvenile salmonids in the tidal Lower Columbia River. Part 2 develops a one-dimensional, subtidal river stage model that explains ~90% of the stage variance in the tidal river. This model and the tidal model developed in part 1 (Kukulka and Jay, 2003) uncouple the nonlinear interaction of river tides and river stage by referring both to external forcing by river discharge, ocean tides, and atmospheric pressure. Applying the two models, daily high-water levels were predicted for a reach from rkm-50 to rkm-90 …
Impacts Of Columbia River Discharge On Salmonid Habitat: 1. A Nonstationary Fluvial Tide Model, David A. Jay, Tobias Kukulka
Impacts Of Columbia River Discharge On Salmonid Habitat: 1. A Nonstationary Fluvial Tide Model, David A. Jay, Tobias Kukulka
Civil and Environmental Engineering Faculty Publications and Presentations
This is the first part of a two-part investigation that applies nonstationary time series analysis methods and the St. Venant equations to the problem of understanding juvenile salmonid access to favorable shallow-water habitat in a tidal river. Habitat access is a function of river stage, tidal range, and the distribution of bed elevation. Part 1 models nonstationary tidal properties: species amplitudes and phases and tidal range. Part 2 models low-frequency river stage in the Lower Columbia River and reconstructs historical water levels, using the tidal model from part 1. To incorporate the nonstationary frictional effects of variable river discharge into …
Modeling Carrier Behavior In Sequential Auction Transportation Markets, Miguel Andres Figliozzi, Hani S. Mahmassani, Patrick Jaillet
Modeling Carrier Behavior In Sequential Auction Transportation Markets, Miguel Andres Figliozzi, Hani S. Mahmassani, Patrick Jaillet
Civil and Environmental Engineering Faculty Publications and Presentations
Online markets for transportation services, in the form of Internet sites that dynamically match shipments (shippers? demand) and transportation capacity (carriers? offer) through auction mechanisms are changing the traditional structure of transportation markets. A general framework for the study of carriers? behavior in a sequential auction transportation marketplace is provided. The unique characteristics of these marketplaces and the sources of difficulty in analyzing the behavior of these marketplaces are discussed. Learning and behavior in a sequential Vickrey auction marketplace is analyzed and simulated. Some results and the overall behavioral framework are also discussed.
Upper Spokane River Model In Idaho: Boundary Conditions And Model Setup For 2001, Scott A. Wells, Robert Leslie Annear, Chris Berger
Upper Spokane River Model In Idaho: Boundary Conditions And Model Setup For 2001, Scott A. Wells, Robert Leslie Annear, Chris Berger
Civil and Environmental Engineering Faculty Publications and Presentations
The Spokane River in Idaho originates in Coeur d’Alene Lake (Figure 1 and Figure 2). The section of the Spokane River from Coeur d’Alene Lake to the Washington state line is the subject of a water quality study for the US Environmental Protection Agency. The objective of this study is to create a water quality and hydrodynamic model of the Spokane River in Idaho using CE-QUAL-W2 Version 3.1 (Cole and Wells, 2002).
Since the Spokane River is water quality limited, a hydrodynamic and water quality model for the Spokane River in Washington was developed by Portland State University for the …
Interfacial Mixing In A Highly Stratified Estuary: 1. Characteristics Of Mixing, David J. Kay, David A. Jay
Interfacial Mixing In A Highly Stratified Estuary: 1. Characteristics Of Mixing, David J. Kay, David A. Jay
Civil and Environmental Engineering Faculty Publications and Presentations
This article is Part I of a set of papers addressing mixing in a highly stratified estuary. Measurements of interfacial turbulence were made in Columbia River estuary under conditions of moderate river flow and neap tides. A flux correlation method was used to determine buoyancy fluxes, and fits to theoretical velocity and temperature variance spectra were used to measure turbulent kinetic and potential energy dissipation rates. At the measurement site in the interior of the estuary, mixing along the top of the salt wedge is found to occur only on ebb, during periods when the internal Froude number is supercritical. …
Interfacial Mixing In A Highly Stratified Estuary: 2. A "Method Of Constrained Differences" Approach For The Determination Of The Momentum And Mass Balances And The Energy Of Mixing, David J. Kay, David A. Jay
Interfacial Mixing In A Highly Stratified Estuary: 2. A "Method Of Constrained Differences" Approach For The Determination Of The Momentum And Mass Balances And The Energy Of Mixing, David J. Kay, David A. Jay
Civil and Environmental Engineering Faculty Publications and Presentations
This article is Part 2 of a set of papers addressing mixing in a highly stratified estuary. In Part 2, turbulence and mean flow measurements are together used to understand the role of mixing in the overall dynamics of the system. Estimates of the partition of energy dissipation between bed-generated and internal mixing suggest that internal mixing accounts for about two thirds of the total turbulent kinetic energy (TKE) produced in the salt-wedge reach of the Columbia River estuary during the neap-tide, moderate river-flow observation period. This suggests that internal mixing plays a larger role in the energetics of such …
Particle Trapping In Stratified Estuaries - Definition Of A Parameter Space, David A. Jay, Philip M. Orton, Thomas A. Chisholm, Douglas J. Wilson, Annika M. Fain, John Mcginity
Particle Trapping In Stratified Estuaries - Definition Of A Parameter Space, David A. Jay, Philip M. Orton, Thomas A. Chisholm, Douglas J. Wilson, Annika M. Fain, John Mcginity
Civil and Environmental Engineering Faculty Publications and Presentations
Estuarine turbidity maxima (ETM) retain suspended particulate matter (SPM) through advection, settling, aggregation and non-linearities in bed processes. This contribution defines for the first time a parameter space descriptive of ETM water-column particle trapping processes through a scaling analysis of the local and integral SPM balances. In the absence of long-term deposition, there are five primary parameters for the large particles or aggregates that are typically trapped. Rouse number P, the ratio of settling velocity WS of the SPM relative to the shear velocity U*, describes the material trapped in the ETM in terms of the local vertical balance between …
A Multi-Class Suspended Particulate Matter Calibration For Bottom Boundary Layers, Philip M. Orton, David A. Jay, D. J. Wilson
A Multi-Class Suspended Particulate Matter Calibration For Bottom Boundary Layers, Philip M. Orton, David A. Jay, D. J. Wilson
Civil and Environmental Engineering Faculty Publications and Presentations
We present a multi-class suspended particulate matter (SPM) calibration for use with in situ water sample SPM concentration data and backscatter (or transmission) from one or more acoustic and optical sensors. The output of this calibration is high-resolution SPM concentration data in several discrete settling velocity (Ws) classes. Separately for each sensor, the calibration involves three steps: (1) a calibration of backscatter to total SPM concentration; (2) a decomposition of resulting concentration data into several Wsclasses, utilizing a dynamical vertical SPM profile model; and (3) a sensor bias calibration where water sample concentration data are used to correct for the …
Upper Spokane River Model: Model Calibration, 2001, Chris Berger, Robert Leslie Annear, Benjamin Welle
Upper Spokane River Model: Model Calibration, 2001, Chris Berger, Robert Leslie Annear, Benjamin Welle
Civil and Environmental Engineering Faculty Publications and Presentations
The Upper Spokane River system under consideration is located in the Northeastern part of Washington State and runs from the Stateline with Idaho, River mile (RM) 96.0, downstream to Long Lake dam at RM 32.5. Figure 1 shows the river system and an outline the boundaries of the City of Spokane.
The Washington Department of Ecology (Ecology) is interested in a water quality model for the Upper Spokane River system for use in developing Total Maximum Daily Loads (TMDLs). As a result, Ecology and the Corps of Engineers funded a study to develop a water quality and hydrodynamic model of …
Upper Spokane River Model: Boundary Conditions And Model Setup, 2001, Spencer Slominski, Robert Leslie Annear, Chris Berger, Scott A. Wells
Upper Spokane River Model: Boundary Conditions And Model Setup, 2001, Spencer Slominski, Robert Leslie Annear, Chris Berger, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
The Washington Department of Ecology is interested in a water quality model for the Upper Spokane River system for use in developing Total Maximum Daily Loads (TMDLs). The goals of this modeling effort are to:
• Gather data to construct a computer simulation model of the Spokane River system including Long Lake Reservoir and the pools behind Nine Mile dam, Upper Falls dam and Upriver dam for 2001 based on the calibration conducted for 1991 and 2000 data sets, (Annear et al, 2001).
• Ensure that the model accurately represents the system hydrodynamics and water quality (flow, temperature, dissolved oxygen …
Tmdls: Statistical Correlations Or Mechanistic Modeling?, Scott A. Wells, Thomas M. Cole
Tmdls: Statistical Correlations Or Mechanistic Modeling?, Scott A. Wells, Thomas M. Cole
Civil and Environmental Engineering Faculty Publications and Presentations
In developing TMDL waste-load allocations for the Snake River-Reservoir system in Western Idaho and Eastern Oregon, determinations of the assimilative capacity of the system and the impact of pollutant reduction strategies has been performed using both a statistical-correlation approach and a mechanistic modeling approach. The system included the Lower Snake River, Brownlee Reservoir, Oxbow Reservoir, and Hells Canyon Reservoir with the focus was on Brownlee Reservoir.
The statistical approach used on Brownlee Reservoir divided the system into riverine and lacustrine zones. Field data were then averaged over season and location to provide statistical correlations, such as between total phosphorus (TP) …
Upper Spokane River Model: Model Calibration, 1991 And 2000, Chris Berger, Robert Leslie Annear, Scott A. Wells
Upper Spokane River Model: Model Calibration, 1991 And 2000, Chris Berger, Robert Leslie Annear, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
The Washington Department of Ecology is interested in a water quality model for the Upper Spokane River system for use in developing Total Maximum Daily Loads (TMDLs). The goals of this modeling effort are to:
• Gather data to construct a computer simulation model of the Spokane River system including Long Lake Reservoir and the pools behind Nine Mile dam, Upper Falls dam and Upriver dam. • Ensure that the model accurately represents the system hydrodynamics and water quality (flow, temperature, dissolved oxygen and nutrient dynamics)
This report evaluates the model calibration and discusses issues relative to that calibration effort. …
Lower Willamette River Model: Model Calibration, Chris Berger, Robert Leslie Annear, Scott A. Wells
Lower Willamette River Model: Model Calibration, Chris Berger, Robert Leslie Annear, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
Water Environment Services of Clackamas County is in the process of planning upgrades on several of its wastewater treatment plants (WWTPs) which discharge into the Lower Willamette River. The goals of the modeling effort were to:
• Gather data to construct a computer simulation model of the Lower Willamette River system in order to evaluate the impact of the WWTP discharges on water quality
• Ensure that the model accurately represents the system physics and chemistry (flow, temperature, dissolved oxygen and nutrient dynamics) by model calibration
• Use the model to evaluate how to meet various future discharge scenarios for …
Upper Spokane River Model: Boundary Conditions And Model Setup, 1991 And 2000, Robert Leslie Annear, Chris Berger, Scott A. Wells
Upper Spokane River Model: Boundary Conditions And Model Setup, 1991 And 2000, Robert Leslie Annear, Chris Berger, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
The Washington Department of Ecology is interested in a water quality model for the Upper Spokane River system for use in developing Total Maximum Daily Loads (TMDLs). The goals of this modeling effort are to:
• Gather data to construct a computer simulation model of the Spokane River system including Long Lake Reservoir and the pools behind Nine Mile dam, Upper Falls dam and Upriver dam
• Ensure that the model accurately represents the system hydrodynamics and water quality (flow, temperature, dissolved oxygen and nutrient dynamics)
A hydrodynamic and water quality model, CE-QUAL-W2 Version 3 (Wells, 1997), is being applied …
Lower Willamette River Model: Boundary Conditions And Model Setup, Herman G. Rodriguez, Robert Leslie Annear, Scott A. Wells, Chris Berger
Lower Willamette River Model: Boundary Conditions And Model Setup, Herman G. Rodriguez, Robert Leslie Annear, Scott A. Wells, Chris Berger
Civil and Environmental Engineering Faculty Publications and Presentations
Water Environment Services of Clackamas County is in the process of planning upgrades on several of its sewage treatment plants which discharge into the Lower Willamette River. The goals of the modeling effort are to:
• Gather data to construct a computer simulation model of the Lower Willamette River system including part of the Lower Columbia River and the Willamette River above the Oregon City Falls; Because of the tidal influence in the Lower Willamette River, portions of the Columbia River that might affect the Lower Willamette River water quality were also modeled. Also, a section of the Willamette River …
Tidal Asymmetry In An Estuarine Pycnocline 2. Transport, David A. Jay, Cynthia N. Cudaback
Tidal Asymmetry In An Estuarine Pycnocline 2. Transport, David A. Jay, Cynthia N. Cudaback
Civil and Environmental Engineering Faculty Publications and Presentations
Flood currents in shallow estuaries are driven by an along-channel barotropic and baroclinic pressure gradient that increases monotonically toward the bottom, while friction retards near-bottom currents. Therefore, in many estuaries there is a middepth maximum in flood currents. We explore this phenomenon using a simple three-layer model in which each layer has vertically uniform currents and constant density. In this model the middle layer is of intermediate density and grows by shear-induced entrainment from the other two layers. This very simple model produces a middepth maximum in flood currents and simulates observed currents in the Columbia River entrance channel within …
Tidal Asymmetry In An Estuarine Pycnocline: Depth And Thickness, Cynthia N. Cudaback, David A. Jay
Tidal Asymmetry In An Estuarine Pycnocline: Depth And Thickness, Cynthia N. Cudaback, David A. Jay
Civil and Environmental Engineering Faculty Publications and Presentations
Tidal variations in estuarine stratification are revealed by the depth and thickness of the density interface. The depth of the interface may be predicted using an inviscid two-layer model that combines baroclinic estuarine circulation with barotropic tidal currents [Helfrich, 1995]. Here we present results from a two-layer model modified to include the effects of bottom friction and interfacial mixing. Modeled layer thickness and speed compare favorably with prior analytic studies [Farmer and Armi, 1986; Pratt, 1986]. We use a bulk Richardson number criterion to estimate the thickness of the pycnocline from two-layer model results; the predicted pycnocline depth and thickness …
Improvements In Modeling Dissolved Oxygen In Activated Sludge Systems, Jacek Makinia, Scott A. Wells
Improvements In Modeling Dissolved Oxygen In Activated Sludge Systems, Jacek Makinia, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
The aim of this research was to show the impact of the flow conditions and variations in the aeration intensity on changes in the predicted dissolved oxygen (DO) concentrations in a full-scale activated sludge reactor. The Activated Sludge Model No. 1 was used to describe the biochemical processes. The studies were performed at the Rock Creek wastewater treatment plant in Hillsboro, OR (USA). The simulation results were compared with data originating from two 24-hour experiments. The model that best reflected the spatial and diurnal distributions of the DO concentrations was the one-dimensional advection-dispersion equation with a variable overall oxygen mass …
The Columbia River Plume Study: Subtidal Variability In The Velocity And Salinity Fields, B. M. Hickey, Leonard J. Pietrafesa, David A. Jay, William C. Boicourt
The Columbia River Plume Study: Subtidal Variability In The Velocity And Salinity Fields, B. M. Hickey, Leonard J. Pietrafesa, David A. Jay, William C. Boicourt
Civil and Environmental Engineering Faculty Publications and Presentations
A comprehensive study of the strongly wind driven midlatitude buoyant plume from the Columbia River, located on the U.S. west coast, demonstrates that the plume has two basic structures during the fall/winter season, namely, a thin (~5~15 m), strongly stratified plume tending west to northwestward during periods of southward or light northward wind stress and a thicker (~10~40 m), weakly stratified plume tending northward and hugging the coast during periods of stronger northward stress. The plume and its velocity field respond nearly instantaneously to changes in wind speed or direction, and the wind fluctuations have timescales of 2-10 days. Frictional …
Interaction Of Fluctuating River Flow With A Barotropic Tide: A Demonstration Of Wavelet Tidal Analysis Methods, David A. Jay, Edward P. Flinchem
Interaction Of Fluctuating River Flow With A Barotropic Tide: A Demonstration Of Wavelet Tidal Analysis Methods, David A. Jay, Edward P. Flinchem
Civil and Environmental Engineering Faculty Publications and Presentations
Wavelet transforms provide a valuable new tool for analysis of tidal processes that deviate markedly from an assumption of exact periodicity inherent in traditional harmonic analysis. A wavelet basis adapted to nonstationary tidal problems is constructed and employed to analyze the modulation of the external tide in a river by variations in streamflow. Interaction of a surface tide with river flow is the best available demonstration of the continuous wavelet transform (CWT) methods developed. It is the simplest and perhaps the only nonstationary tidal process for which both sufficient data and dynamical understanding exist to allow detailed comparisons between CWT …
Data Assimilation In Models With Convective Adjustment, Robert N. Miller, Edward D. Zaron, Andrew F. Bennett
Data Assimilation In Models With Convective Adjustment, Robert N. Miller, Edward D. Zaron, Andrew F. Bennett
Civil and Environmental Engineering Faculty Publications and Presentations
Practical hydrostatic ocean models are often restricted to statically stable configurations by the use of a convective adjustment. A common way to do this is to assign an infinite boat conductivity to the water at a given level if the water column should become statically unstable. This is implemented in the form of a switch. When a statically unstable configuration is detected, it is immediately replaced with a statically stable one in which heat is conserved. In this approach, the model is no longer governed by a smooth set of equations, and usual techniques of variational data assimilation must be …
Particle Trapping In Estuarine Tidal Flows, David A. Jay, Jeffery D. Musiak
Particle Trapping In Estuarine Tidal Flows, David A. Jay, Jeffery D. Musiak
Civil and Environmental Engineering Faculty Publications and Presentations
Particle trapping in estuarine turbidity maxima (ETM) is caused primarily by convergent mean and/or tidal fluxes of sediment. The result is an approximately bell-shaped along-channel distribution of vertically integrated, tidal cycle mean suspended sediment concentration. Observations from the Columbia River estuary suggest that (1) strong two-layer or internal along-channel residual and overtide flows are generated by time-varying stratification and (2) correlations between the near-bed velocity and the suspended sediment fields at these frequencies are important in landward transport of sediment. A new spatially and temporally integrated form of the sediment conservation equation has been derived to analyze this trapping process. …
Green's Law Revisited: Tidal Long-Wave Propagation In Channels With Strong Topography, David A. Jay
Green's Law Revisited: Tidal Long-Wave Propagation In Channels With Strong Topography, David A. Jay
Civil and Environmental Engineering Faculty Publications and Presentations
Green's Law states that tidal long-wave elevation ζ and tidal transport Q vary with width b and depth h according to ζ ≌ b−1/2h−1/4 and Q ≌ b+1/2h+/4. This solution is of limited utility because it is restricted to inviscid, infinitesimal waves in channels with no mean flow and weak topography (those with topographic scale L ≫ wavelength λ). An analytical perturbation model including finite-amplitude effects, river flow, and tidal flats has been used to show that (1) wave behavior to lowest order is a function of only two nondimensional parameters representing, respectively, …