Civil Engineering Commons^™

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 …

Mixing Layer Dynamics In Separated Flow Over An Estuarine Sill With Variable Stratification, Stefan A. Talke, Alexander R. Horner-Devine, C. Chris Chickadel

Civil and Environmental Engineering Faculty Publications and Presentations

We investigate the generation of a mixing layer in the separated flow behind an estuarine sill (height H ∼ 4 m) in the Snohomish River, Washington as part of a larger investigation of coherent structures using remote and in situ sensing. During increasing ebb flows the depth d and stratification decrease and a region of sheared flow characterized by elevated production of turbulent kinetic energy develops. Profiles of velocity and acoustic backscatter exhibit coherent fluctuations of order 0.1 Hz and are used to define the boundaries of the mixing layer. Variations in the mixing layer width and its embedded coherent …

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 …

Seismic Vulnerability Of Oregon State Highway Bridges: Mitigation Strategies To Reduce Major Mobility Risks, Albert Nako, Craig Shike, Jan Six, Bruce Johnson, Peter Dusicka, Selamawit Tesfayesus Mehary

Civil and Environmental Engineering Faculty Publications and Presentations

The Oregon Department of Transportation and Portland State University evaluated the seismic vulnerability of state highway bridges in western Oregon. The study used a computer program called REDARS2 that simulated the damage to bridges within a transportation network. It predicted ground motions for a specific location and magnitude of earthquake, resulting bridge damage and the cost of the damage, as well as the cost to the public for traffic delays due to detours around damaged bridges. Estimated damage and delay costs were presented for major highways in the region.

Vertical Boil Propagation From A Submerged Estuarine Sill, C. Chris Chickadel, Alexander R. Horner-Devine, Stefan A. Talke, Andrew T. Jessup

Civil and Environmental Engineering Faculty Publications and Presentations

Surface disruptions by boils during strong tidal flows over a rocky sill were observed in thermal infrared imagery collected at the Snohomish River estuary in Washington State. Locations of boil disruptions and boil diameters at the surface were quantified and are used to test an idealized model of vertical boil propagation. The model is developed as a two-dimensional approximation of a three-dimensional vortex loop, and boil vorticity is derived from the flow shear over the sill. Predictions of boil disruption locations were determined from the modeled vertical velocity, the sill depth, and the over-sill velocity. Predictions by the vertical velocity …

Feedback Between Residual Circulations And Sediment Distribution In Highly Turbid Estuaries: An Analytical Model, Stefan A. Talke, Huib E. De Swart, H. M. Schuttelaars

Civil and Environmental Engineering Faculty Publications and Presentations

Motivated by field studies of the Ems estuary which show longitudinal gradients in bottom sediment concentration as high as O(0.01 kg/m⁴), we develop an analytical model for estuarine residual circulation based on currents from salinity gradients, turbidity gradients, and freshwater discharge. Salinity is assumed to be vertically well mixed, while the vertical concentration profile is assumed to result from a balance between a constant settling velocity and turbulent diffusive flux. Width and depth of the model estuary are held constant. Model results show that turbidity gradients enhance tidally averaged circulation upstream of the estuarine turbidity maximum (ETM), …

An Idealized Model And Systematic Process Study Of Oxygen Depletion In Highly Turbid Estuaries, Stefan A. Talke, Huib E. De Swart, Victor De Jonge

Civil and Environmental Engineering Faculty Publications and Presentations

The sensitivity of oxygen depletion in turbid estuaries to parameters like freshwater discharge, depth, and sediment availability is investigated using an idealized model. The model describes tidally averaged circulation and suspended sediment concentration (SSC), which are input into an advection–diffusion sink module of dissolved oxygen (DO). Based on the analysis of field data collected in the Ems estuary, the modeled oxygen depletion rates are proportional to SSC. The model is calibrated to the observed variation of DO with SSC and temperature. Modeled DO closely tracks changes to the estuarine turbidity zone (ETZ): increased channel depth, decreased freshwater discharge, and decreased …

A Strategy For Reducing The Impact Of Driving Under Influence Of Intoxicants In Portland, Oregon, Christopher Monsere, Delia Chi

Civil and Environmental Engineering Faculty Publications and Presentations

Driving under the influence of intoxicants (DUII) applies to operating a vehicle under the influence of any substance that can impair driving performance. Nationally and locally there is a strong desire to reduce the societal impacts of this significant social problem. The trend in U.S. alcohol-related motor vehicle crashes was generally decreasing in the mid to late 1980’s but has remained fairly flat since the early 1990s. In 1982, approximately 60% of all US traffic fatalities were alcohol-related. By 1994, this had decreased to 43% but in the decade that followed it has changed little. In 2005, nearly 39% of …

Coupling The Hydrodynamic And Water Quality Model Ce-Qual-W2 With A Multi-Trophic Fish Bio-Energetics Model For Lake Roosevelt, Washington, Michael Lee Mckillip

Dissertations and Theses

Grand Coulee Dam created Franklin D. Roosevelt Lake as part of the Columbia Basin Project. Located in northeastern Washington State, the Project provides economically important hydropower (19 billion kilowatt hours per year), irrigation (225,000 ha), flood control, and sport fishing ($5 to 20 million annually). A good system understanding aids in balancing these beneficial uses for the 230 km long reservoir. The reservoir's atypical 45-day mean residence time is much shorter than a typical lake, and much longer than for a riverine dam. The spring freshet requires drawdowns of 15 to 20 m for flood control—the driving characteristic of reservoir …

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 …

Optimal Bus Stop Spacing For Minimizing Transit Operation Cost, Huan Li, Robert L. Bertini

Civil and Environmental Engineering Faculty Publications and Presentations

With the increasing attention to finance issues relative to transit operation, a bus stop spacing model is generated with the aim at minimizing the operation cost without impact on transit accessibility. Two cost functions are considered in the model including passenger access cost and in-vehicle passenger stopping cost aiming at minimizing total cost. A bus route in Portland, Oregon, USA is examined as an example using Archived Bus Dispatch System (BDS) data provided by TriMet, the regional transit provider for the Portland, Oregon metropolitan area. Based on the optimization model, the theoretical optimized bus stop spacing is 930 feet comparing …

Improving Arterial Performance Measurement Using Traffic Signal System Data, Michael Wolfe, Christopher Monsere, Peter Koonce, Robert L. Bertini

Civil and Environmental Engineering Faculty Publications and Presentations

The characterization of the performance of freeways in real time and on a historical basis has been successfully achieved for many years. The ability to characterize arterial performance has been more elusive. Currently numerous applications of traffic management and traveler information systems include freeways but lack the ability to extend their operation to major arterials. This paper describes methods for quantifying arterial performance using data from signal system loop detectors. Included in the array of metrics are traffic density, total delay, predicted travel time, and signal coordination effectiveness. Methods for determining performance in these areas are adapted for use in …

Evaluating And Adaptive Signal Control System In Gresham, James M. Peters, Jay Mccoy, Robert L. Bertini

Civil and Environmental Engineering Faculty Publications and Presentations

Cities and Counties are faced with increasing traffic congestion due to rapidly increasing population. Like many agencies, the City of Gresham has struggled with how to manage the increasing congestion with limited funds for major roadway widening projects. Gresham has recognized the need to optimize existing system capacity to get the most out of their current transportation system infrastructure investment.

In 2005, the City of Gresham, in cooperation with numerous agencies in the Portland metropolitan area, evaluated a variety of signal control systems including traditional time-of-day coordination, traffic responsive, and adaptive signal control systems. Based on that evaluation, the steering …

Enhancing Targeted Traffic Enforcement Efforts In Portland, Oregon, Max Coffman, Christopher Monsere

Civil and Environmental Engineering Faculty Publications and Presentations

Enforcement is a key component of any comprehensive traffic safety program, and through a unique effort the Portland Office of Transportation (PDOT) partners with schools, the court system, community groups and the Police Bureau to develop a coordinated citywide program to improve traffic safety. However, like many government agencies, the Police Bureau faces constraints that limit the resources it can devote to traffic safety. In response, PDOT and the Police Bureau’s Traffic Division have instituted a program of Strategic and Focused Enforcement (SAFE) to better allocate limited traffic safety personnel and resources. Using historical crash data, PDOT identified 30 high …

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 …

Improved Regression-Based Streamflow Forecasting Considering Large-Scale Climate Variability, Austin R. Fisher

Dissertations and Theses

The Natural Resources Conservation Service (NRCS) produces water supply forecasts for most of the streams in the western United States. The NRCS produces forecasts starting in January, when snow course measurements of snow water equivalent were available. Although the seasonal streamflow volume forecasts made by the NRCS are useful, many water supply managers need information at the beginning of the water year in October and would like to see forecasts in the form of a monthly hydrograph.

An investigation into the effect of decadal scale variability, as reflected by the Pacific Decadal Oscillation (PDO), show important relationships that may be …

Modeling Improvements For Water Supply Forecasting In The Columbia River Basin, Daniel Albert Buller

Dissertations and Theses

The purposes of this study were twofold. The first was to explore possible improvements that could be made over existing methods by applying alternative modeling approaches, including the one developed by Garen to forecast runoff volumes in the Columbia River at The Dalles, Oregon. The second was to use the Southern Oscillation as one of the variables to forecast spring and summer runoff and to evaluate whether this variable adds significant information early in the season before any snow has accumulated. The Columbia River basin's mountainous topography and northern latitude are ideally suited for water supply forecasting because much of …

Settlements Due To Arid Collapsible Soils, Heather L. Devine

Dissertations and Theses

The arid alluvial deposits common to the western United States frequently undergo moderate to severe collapse when wetted that can threaten or destroy the stability of structures that are founded on such soils. Additionally, in some areas collapse has been known to occur due to overburden stresses alone. As development expands in these areas a method to estimate the degree of this collapse is essential.

Current settlement methods are reviewed and evaluated as they apply to collapsible soils, providing a basis for the development of a proposed settlement method for determining collapse. To aid in the determining the basis for …

A Telescopic Approach To Modeling Leachate Dynamics And Migration At The St. Johns Landfill, Portland, Oregon, Thomas Stephen Lowry

Dissertations and Theses

The St. Johns Landfill is a 225-acre site that lies near the confluence of the Columbia and Willamette Rivers, in the North Portland Industrial District of Portland, Oregon. A slough system surrounds the landfill on three sides with the fourth side adjacent to a shallow lake. The landfill first opened in 1930 when it was operated as an open dump. It operated as an open dump until 1969 when it was converted to a sanitary landfill, employing daily cover and compaction. The landfill was closed in 1991.

The landfill sits directly on top of a thick layer of silty overbank …

Numerical Simulation Of Contaminated Sediment Transport In The Upper Columbia Slough System, Binghong Wu

Dissertations and Theses

An integrated modeling system has been developed to simulate sediment and contaminated sediment transport in the Upper Columbia Slough System during the Flood of 1996. The modeling system consists of a hydrodynamic model, a sediment transport model, and a contaminant transport model. The hydrodynamic model predicts the Slough flow dynamics and sediment transporting power; the sediment transport model predicts flow-induced sediment transport; and the contaminant transport model predicts the migration of contaminated sediments in the Slough system.

The Upper Columbia Slough modeling system is characterized by its recognition of the complex interplay of Slough hydrology, hydrodynamics, sediment transport, contaminant transport. …

Water Quality Model For South Slough, Coos Bay, Oregon, Holly Kay Juza

Dissertations and Theses

The South Slough Estuary is located off Coos Bay along the southern coast of Oregon. It is divided into two channels that meet and continue to Coos Bay at the Charleston Harbor. There are six major contributing streams to South Slough. After rainfall events, the level of coliform bacteria in the slough increases because of stream bacteria loading. This is due to cattle grazing in the drainage areas, failed septic systems from private homes, and sewage sludge applied to the County landfill, which drains into the slough. The Oregon Health Division has enforced a Sanitation Management Plan for Commercial Shellfish …

Improved Finite Analytic Methods For Solving Advection-Dominated Transport Equation In Highly Variable Velocity Field, Wei Cuifeng

Dissertations and Theses

Solute transport studies frequently rely on numerical solutions of the classical advection-diffusion equation. Unfortunately, solutions obtained with traditional finite difference and finite element techniques typically exhibit excessive numerical diffusion or spurious oscillation when advection dominates, especially when velocity field is highly variable.

One recently developed technique, the finite analytic method, offers an attractive alternative. Finite analytic methods utilize local analytic solutions in discrete elements to obtain the algebraic representations of the governing partial differential equations, thus eliminating the truncation error in the finite difference and the use of approximating functions in the finite element method. The finite analytic solutions have …

Predicting Solute Transport In Natural Streams - A Stochastic Approach, Xueqing Zhou

Dissertations and Theses

The existing theories for predicting longitudinal dispersion in straight open channels have long been recognized as inadequate when applied to natural rivers. These theories tend to grossly underestimate dispersion in real streams since an important mixing mechanism due to nonuniform river cross-section variations is not explicitly taken into account. Recognizing the important role of stream irregularities on solute transport and the analytical difficulties of classical deterministic analysis, we develop a stochastic approach for analyzing solute transport in natural streams. Variations in river width and bed elevation are conveniently represented as one-dimensional random fields, characterized by their autocorrelation functions. Advection and …

Two Dimensional Finite Element Modeling Of Swift Delta Soil Nail Wall By "Abaqus", Richard James Barrows

Dissertations and Theses

Soil nail walls are a form of mechanical earth stabilization for cut situations. They consist of the introduction of passive inclusions (nails) into soil cut lifts. These nailed lifts are then tied together with a structural facing (usually shotcrete) . The wall lifts are constructed incrementally from the top of cut down. Soil nail walls are being recognized as having potential for large cost savings over other alternatives. The increasing need to provide high capacity roadways in restricted rights of way under structures such as bridges will require increasing use of techniques such as combined soil nail and piling walls. …

Water Quality Modeling Of The Tualitin River, Christopher John Berger

Dissertations and Theses

Water quality problems related to excessive algal growth, high nutrient loading, and low flows have been occurring along Oregon's Tualatin River. The Tualatin River is 86 miles long and has a drainage basin of 711 square miles. The drainage basin incorporates forest, agricultural, and urban areas. Located in the Portland metropolitan area, these problems have been acerbated by the effects of urban growth. To help analyze pollution control alternatives, a river model study, funded by the Oregon Department of Environmental Quality (DEQ}, was undertaken. An in-stream model of hydraulics and water quality was developed. The Corps of Engineer's CE-QUAL-W2 model, …

Modeling Of Flow And Water Quality In Henry Hagg Lake Near Forest Grove, Oregon, Michael T. Knutson

Dissertations and Theses

Increased population growth in Washington County, Oregon, has helped cause the water quality of the Tualatin River to decline. Henry Hagg Lake is a storage reservoir which was built to augment summer low flows in the Tualatin River. Hagg Lake also supplies the Tualatin River Basin with both irrigation and municipal water in the summer. Using the U.S. Army Corps of Engineer's model CE-QUAL-W2 (a two-dimensional hydrodynamic and water quality model) , a model of Henry Hagg Lake was created. The model was calibrated using water quality and hydraulic data for 1990 at the Hagg Lake outflow in Scoggins Creek. …

Predicting Seepage Of Leachate From The St. Johns Landfill To Ground And Surface Water Systems, Kevin A. Schock

Dissertations and Theses

Determination of the vertical and horizontal groundwater hydraulic gradient within a landfill is the first step in determining the potential of groundwater contamination from the landfill leachate. The length of a study and the frequency at which measurements are recorded can greatly affect the description of the local groundwater environment. A more comprehensive analysis can be preformed for longer periods of study and greater measurement frequency. The intent of this study was to install a continuous groundwater level monitoring system around the st. Johns Landfill for a minimum study length of one year. This would allow a more thorough study …

Gravity Sedimentation: A One-Dimensional Numerical Model, Joanna Robin Karl

Dissertations and Theses

A large fraction of the current cost of wastewater treatment is from the treatment and disposal of wastewater sludge. Improved design, energy efficiency, and performance of dewatering facilities could significantly decrease transport and disposal costs.

Dewatering facilities are designed based on field experience, trial and error, pilot plant testing, and/or full scale testing. Design is generally time-consuming and expensive. A full-scale test typically consists of side-by-side operation of 4 to 5 full-scale dewatering units for several weeks to more than 6 months. Theoretical modeling of the physics of dewatering units such as the belt filter press, based on laboratory determined …

One-Dimensional Computer Modeling Of Thermal And Water Quality Characteristics Of Coldwater Lake, Wa, David Kevin Whitaker

Dissertations and Theses

Coldwater Lake is a new lake formed when a massive mudflow down the Toutle River Valley, caused by the eruption of Mount St. Helens on May 18, 1980, blocked the natural outlet of Coldwater Creek. This research utilizes physical, biological and chemical data collected at Coldwater Lake during the sun1mers of 1989 and 1990 to calibrate and verify the one-dimensional computer models CE-THERMRl and CE-QUAL-Rl for Coldwater Lake. CE-THERM-R1 was used to simulate thermal characteristics in Coldwater Lake during the summer stratification periods of 1989 and 1990. The model was calibrated to 1989 data and was verified with 1990 data. …

The Use Of Laboratory Testing To Understand The Behavior Of Collapsible Soil Upon Wetting, Martha H. Denham

Dissertations and Theses

In developing a constitutive model that could predict the settlement due to the collapse, several goals needed to be met. These were to gain an understanding of the collapse phenomenon, knowing the soil properties at the natural water content and how they change after collapse, and develop and test the new model. It was felt that laboratory testing could be of use. The types of test conducted included use of the Oedometer, Pressuremeter, and Triaxial tests. The material that was used for the testing was a "generic" soil manufactured out of diatomite. In all of the tests the soil was …