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Articles 181 - 210 of 217
Full-Text Articles in Water Resource Management
Lake Whatcom Model Calibration With Variable Stoichiometry In Sediments - Revised, Chris Berger, Scott A. Wells
Lake Whatcom Model Calibration With Variable Stoichiometry In Sediments - Revised, Chris Berger, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
This memorandum discusses model calibration and enhancements made to the Lake Whatcom water quality model. Model development and initial calibration were documented in the report “Lake Whatcom Water Quality Model” (Berger and Wells, 2005). The Lake Whatcom water quality model has been converted from CE-QUAL-W2 version 3.2 to version 3.5 (Cole and Wells, 2006).
Middle Columbia River Aquatic Nuisance Species Survey, Robyn Draheim, Mark D. Sytsma, Rich Miller, Jeffery Cordell
Middle Columbia River Aquatic Nuisance Species Survey, Robyn Draheim, Mark D. Sytsma, Rich Miller, Jeffery Cordell
Center for Lakes and Reservoirs Publications and Presentations
Aquatic nonindigenous species (ANS) in the middle Columbia and lower Snake rivers were surveyed during the summer of 2006. The project area included eight reservoirs and the free-flowing, Hanford Reach on the Columbia River. We also conducted a literature review to create a complete list of ANS for the study area.
Koll Center Wetlands Natural Resources Maintenance Management Plan, Meredith Clayton
Koll Center Wetlands Natural Resources Maintenance Management Plan, Meredith Clayton
Environmental Science and Management Professional Master's Project Reports
The intention of this plan is to provide a vision and guidelines for maintaining and improving the ecological health of Koll Center Wetlands in the short and long term. Although the plan will change over time, the goal is to quantify natural resource needs spatially, temporally, and economically.
Koll Center Wetlands is part of the Greenway/Fanno Creek/Koll Center Wetlands Park complex. The nearly 13 acre park is dominated by aquatic habitats that attract a wide variety of wildlife, particularly birds. The park grounds are not easily traversed and experience limited human use, but there are many viewpoints from which the …
Ce-Qual-W2: A Two-Dimensional, Laterally Averaged, Hydrodynamic And Water Quality Model, Version 3.5, Thomas M. Cole, Scott A. Wells
Ce-Qual-W2: A Two-Dimensional, Laterally Averaged, Hydrodynamic And Water Quality Model, Version 3.5, Thomas M. Cole, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
This manual documents the two-dimensional, laterally averaged, hydrodynamic and water quality model CE-QUAL-W2. This manual was prepared in the Environmental Laboratory (EL), us Army Engineer Waterways Experiment Station (WES), Vicksburg, MS. Bonita Niel and Dr. William Roper, CERD-C provided funding for Version 3.1 of the manual under the Numerical Model Maintenance Program. The principal investigator for Version 3.2 of CE-QUAL-W2 and the User Manual was Mr. Thomas M. Cole of the Water Quality and Contaminant Modeling Branch (WQCMB), Environmental Processes and Effects Division (EPED), EL. This report supersedes the Version 3.2 manual. Revisions made in this V3.5 manual were made …
2005 Diamond Lake Submersed Aquatic Vegetation Survey, Mark D. Sytsma, Mary Pfauth
2005 Diamond Lake Submersed Aquatic Vegetation Survey, Mark D. Sytsma, Mary Pfauth
Center for Lakes and Reservoirs Publications and Presentations
Diamond Lake is a large natural lake having a surface area of some 3214 acres (1300.7 hectares) and a maximum depth of 52 feet (15.8 meters). It is located within the Umpqua National Forest in the Southern Cascade Mountains of Oregon, at an elevation of over 5000 feet (>1524 meters). Diamond Lake is a high-use waterbody that supports angling, public campgrounds, recreational boating, swimming, and water skiing. The human activity associated with the lake has been a significant contributor to the economy of southern Oregon since the early part of the twentieth century.
Historically Diamond Lake was fishless but …
Final Report: Evaluation Of The Morphoedaphic Index And Sediment Diatoms For Inference Of Pre-European Settlement Total Phosphorus Concentration In Epa Region 10 Lakes, Rich Miller, Aaron Hook, Richard Petersen, Mark D. Sytsma
Final Report: Evaluation Of The Morphoedaphic Index And Sediment Diatoms For Inference Of Pre-European Settlement Total Phosphorus Concentration In Epa Region 10 Lakes, Rich Miller, Aaron Hook, Richard Petersen, Mark D. Sytsma
Center for Lakes and Reservoirs Publications and Presentations
Water quality in many Northwest lakes has declined over the past century due, in part, to increased anthropogenic nutrient loading (Edmonson and Lehman, 1981). Under the Clean Water Act, resource managers such as the Washington Department of Ecology, Oregon Department of Environmental Quality, and tribes are responsible for restoring and protecting the integrity of these waters. Targets for restoration or criteria for impairment are not well defined, however, and may naturally vary by geology, hydrology, morphometry, and climate.
One way to determine whether lakes are impaired and to identify restoration targets is to assess lake reference conditions (EPA 2000). Reference …
Lake Whatcom Water Quality Model, Chris Berger
Lake Whatcom Water Quality Model, Chris Berger
Civil and Environmental Engineering Faculty Publications and Presentations
A water quality model of Lake Whatcom, Washington was developed as part of a Total Maximum Daily Load Study for the Washington Department of Ecology. Lake Whatcom is a large natural lake which is listed on the 1998 Washington State 303(d) list of waterbodies which do not meet the criterion for dissolved oxygen. Located next to the city of Bellingham, it is approximately 10 miles long and has a surface area of approximately 5000 acres and a maximum depth of over 100 meters. Eutrophication processes in the lake have been accelerated in recent years perhaps by the availability of nutrients …
Sediment Nutrient Accumulation And Nutrient Availability In Two Tidal Freshwater Marshes Along The Mattaponi River, Virginia, Usa, Jennifer L. Morse, J. Patrick Megonigal, Mark R. Walbridge
Sediment Nutrient Accumulation And Nutrient Availability In Two Tidal Freshwater Marshes Along The Mattaponi River, Virginia, Usa, Jennifer L. Morse, J. Patrick Megonigal, Mark R. Walbridge
Environmental Science and Management Faculty Publications and Presentations
Sediment deposition is the main mechanism of nutrient delivery to tidal freshwater marshes (TFMs). We quantified sediment nutrient accumulation in TFMs upstream and downstream of a proposed water withdrawal project on the Mattaponi River, Virginia. Our goal was to assess nutrient availability by comparing relative rates of carbon (C), nitrogen (N), and phosphorus (P) accumulated in sediments with the C, N, and P stoichiometries of surface soils and above ground plant tissues. Surface soil nutrient contents (0.60–0.92% N and 0.09–0.13% P) were low but within reported ranges for TFMs in the eastern US. In both marshes, soil nutrient pools and …
Waldo Lake Research In 2003, Mark D. Sytsma, John Rueter, Richard Petersen, Roy Koch, Scott A. Wells, Rich Miller, Laura Johnson, Robert Leslie Annear
Waldo Lake Research In 2003, Mark D. Sytsma, John Rueter, Richard Petersen, Roy Koch, Scott A. Wells, Rich Miller, Laura Johnson, Robert Leslie Annear
Civil and Environmental Engineering Faculty Publications and Presentations
This report summarizes the first year of an effort to develop a more complete understanding of the physical, chemical, and biological characteristics that drive the ecological processes of Waldo Lake. Modern limnology recognizes the importance of watershed processes as well as in- lake processes in lake ecosystem functioning. Therefore, the approach included consideration of watershed hydrology and forcing functions that determine hydrodynamics of the system as well physical and chemical factors that may be important in regulating primary production in the lake. Data collected since 1998 was summarized and bathymetry of the basin was mapped using state-of-the-art digital depth sounding …
Ce-Qual-W2: A Two-Dimensional, Laterally Averaged, Hydrodynamic And Water Quality Model, Version 3.1, Thomas M. Cole, Scott A. Wells
Ce-Qual-W2: A Two-Dimensional, Laterally Averaged, Hydrodynamic And Water Quality Model, Version 3.1, Thomas M. Cole, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
CE-QUAL-W2 is a two-dimensional, longitudinal/vertical, hydrodynamic and water quality model. Because the model assumes lateral homogeneity, it is best suited for relatively long and narrow waterbodies exhibiting longitudinal and vertical water quality gradients. The model has been applied to rivers, lakes, reservoirs, estuaries, and combinations thereof.
The application of CE-QUAL-W2 requires knowledge in the following areas: 1. Hydrodynamics 2. Aquatic biology 3. Aquatic chemistry 4. Numerical methods 5. Computers and FORTRAN coding 6. Statistics 7. Data assembly and reconstruction.
Water quality modeling is in many ways an art requiring not only knowledge in these areas but also experience in their …
The Bull Run River–Reservoir System Model, Robert Leslie Annear, Scott A. Wells
The Bull Run River–Reservoir System Model, Robert Leslie Annear, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
The Bull Run watershed is located 41.8 kilometers east of Portland, Oregon in the Mt. Hood National Forest and consists of two reservoirs supplying drinking water to over 840,000 people in the Portland metropolitan area. In March 1998 Steelhead and Spring Chinook were listed as threatened in the Lower Columbia basin under the Endangered Species Act. Historical reservoir operations during the summer released no water downstream resulting in stream temperatures exceeding the state water quality standard for salmonids. CE-QUAL-W2 Version 3 is a two-dimensional water quality and hydrodynamic model capable of modeling watersheds with interconnected rivers, reservoirs and estuaries. CE-QUAL-W2 …
Basis Of The Ce-Qual-W2 Version 3 River Basin Hydrodynamic And Water Quality Model, Scott A. Wells
Basis Of The Ce-Qual-W2 Version 3 River Basin Hydrodynamic And Water Quality Model, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
CE-QUAL-W2 Version 3, a 2-D (longitudinal-vertical) hydrodynamic and water quality model for river basins combining both river and stratified river-estuary and lake-reservoir flow, is a development product of the Waterways Experiment Station in Vicksburg, MS, USA. With the development and release of any revised or reformulated model codes, significant model validation is required. This includes comparison of model results to simple analytical solutions for hydrodynamics and water quality transport, as well as comparison to laboratory and field data. In this paper, the model is compared to numerous analytical solutions for mass transport (1- D advective mass transport) and hydrodynamics (impulsive …
Willamette River And Columbia River Waste Load Allocation Model, Chris Berger, Robert Leslie Annear, Scott A. Wells
Willamette River And Columbia River Waste Load Allocation Model, Chris Berger, Robert Leslie Annear, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
A hydrodynamic and water quality model of the Lower Willamette River was developed to evaluate management alternatives designed to improve water quality. The Lower Willamette River is located in Oregon and drains a watershed covering 11500 square miles consisting of forested, agricultural, and urban lands. Inflows include treated municipal wastes and industrial effluents along with non-point sources from agricultural, silvicultural and urbanized land. The model was designed to address temperature, dissolved oxygen, algae, pH and bacteria concerns. The Corps of Engineers two-dimensional, laterally averaged, hydrodynamic and water quality model CE-QUAL-W2, Version 3 was applied. CE-QUAL-W2 consists of directly coupled hydrodynamic …
Validation Of The Ce-Qual-W2 Version 3 River Basin Hydrodynamic And Water Quality Model, Scott A. Wells
Validation Of The Ce-Qual-W2 Version 3 River Basin Hydrodynamic And Water Quality Model, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
CE-QUAL-W2 Version 3, a 2-D (longitudinal-vertical) hydrodynamic and water quality model for river basins combining both river and stratified river-estuary and lakereservoir flow, is a development product of the Waterways Experiment Station in Vicksburg, MS, USA. With the development and release of any revised or reformulated model codes, significant model validation is required. This includes comparison of model results to simple analytical solutions for hydrodynamics and water quality transport, as well as comparison to laboratory and field data. In this paper, the model is compared to numerous analytical solutions for mass transport (1-D advective mass transport) and hydrodynamics (impulsive wind …
Watershed Solutions: Collaborative Problem Solving For States And Communities, National Policy Consensus Center
Watershed Solutions: Collaborative Problem Solving For States And Communities, National Policy Consensus Center
National Policy Consensus Center Publications
In July 2002, the National Policy Consensus Center (NPCC) hosted a colloquium for people involved in watershed collaborations, academics, and other experts from government and non-profit organizations. Its aim was to identify lessons learned from successful watershed initiatives, and to develop recommendations for governors and other state officials on ways to enhance the use and effectiveness of watershed partnerships. This report is an outgrowth of that conference.
Studies on watershed collaborations are beginning to identify what makes them successful and what some of the barriers are to greater success. For example, contrary to the fears of some observers, successful collaborations …
Reconnaissance Of Pharmaceutical Chemicals In Urban Streams Of The Tualatin River Basin, Oregon, 2002, Stewart A. Rounds, Micelis C. Doyle, Patrick M. Edwards, Edward T. Furlong
Reconnaissance Of Pharmaceutical Chemicals In Urban Streams Of The Tualatin River Basin, Oregon, 2002, Stewart A. Rounds, Micelis C. Doyle, Patrick M. Edwards, Edward T. Furlong
Environmental Science and Management Faculty Publications and Presentations
A reconnaissance of pharmaceutical chemicals in urban streams of the Tualatin River basin was conducted in July 2002 in an effort to better understand the occurrence and distribution of such compounds, and to determine whether they might be useful indicators of human-related stream contamination. Of the 21 pharmaceutical chemicals and metabolites tested, only 6 (acetaminophen, caffeine, carbamazepine, codeine, cotinine, and sulfamethoxazole) were detected in filtered stream samples from 10 sites. The concentrations of most of the detected compounds were relatively low (less than 0.05 microgram per liter). The most frequently detected compounds were cotinine (a nicotine metabolite, 8 of 10 …
Water Rights As Contested Terrain: The Case Of Tenmile Creek, Oregon, Marcie L. Allen
Water Rights As Contested Terrain: The Case Of Tenmile Creek, Oregon, Marcie L. Allen
Dissertations and Theses
This thesis examines the complex conflict over water rights at Tenmile Creek, located along the south central Oregon Coast. The research is an exploratory case study identifying the main motivations of actors, the constraints they faced, and the conditions that encouraged or dissuaded collaborative behavior.
The main objectives are (1) to refine the understanding of the relationship between societies and their physical environment in market societies that are both motivated to exploit and preserve natural resources and, (2) to explore the kinds of institutional arrangements that may be required to manage the water supply in a collaborative and sustainable manner. …
The Impact Of Fine Sediment On Stream Macroinvertebrates In Urban And Rural Oregon Streams, Raymond S. Hoy
The Impact Of Fine Sediment On Stream Macroinvertebrates In Urban And Rural Oregon Streams, Raymond S. Hoy
Dissertations and Theses
Urbanization, often characterized by high impervious surface area, can result in excessive inputs of fine sediments into urban streams. Excessive fine sediments can blanket the stream bed filling the interstitial space in the substratum, which may have adverse effects on stream biota. A field survey was conducted in Oregon urban and non-urban basins to investigate the relationship between fine sediments and stream macroinvertebrates. Physical, chemical, and biological data were collected from 59 stream sites in two urban and two rural streams. The stream sites fulfilled a continuous sediment gradient, which ranged from a low of 2% of fine sediment in …
Theoretical Basis For The Ce-Qual-W2 River Basin Model, Scott A. Wells, Thomas M. Cole
Theoretical Basis For The Ce-Qual-W2 River Basin Model, Scott A. Wells, Thomas M. Cole
Civil and Environmental Engineering Faculty Publications and Presentations
The primary objective of this research is to integrate a riverine model into the existing W2 code that would provide the capability for modeling entire watersheds. This task was accomplished by the following steps:
• Formal derivation of governing equations and solution algorithm with general channel slope
• Detailed analysis of algorithm for linking branches and smooth implementation of boundary conditions between branches
• Algorithm development and changes to basic model code (including branch definitions with slope, slope correction to solution algorithm, transfer of momentum between internal branches)
These tasks were performed with the following constraints and initiatives:
• Utilize …
Ce-Qual-W2, Version 3, Scott A. Wells, Thomas M. Cole
Ce-Qual-W2, Version 3, Scott A. Wells, Thomas M. Cole
Civil and Environmental Engineering Faculty Publications and Presentations
CE-QUAL-W2 is a two-dimensional water quality and hydrodynamic code supported by the U.S. Army Engineer Research and Development Center (Cole and Buchak 1995). The model has been widely applied to stratified surface water systems such as lakes, reservoirs, and estuaries and computes water levels, horizontal and vertical velocities, temperature, and 21 other water quality parameters (such as dissolved oxygen, nutrients, organic matter, algae, pH, the carbonate cycle, bacteria, and dissolved and suspended solids). A typical model grid is shown in Figure 1 where the vertical axis is aligned with gravity.
This technical note documents the development of CE-QUAL-W2, Version 3, …
Modeling The Bull Run River-Reservoir System, Scott A. Wells
Modeling The Bull Run River-Reservoir System, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
The City of Portland, Water Bureau currently operates 2 Bull Run reservoirs, Reservoir #2 and Reservoir #1 as a water supply source in the Bull Run watershed shown in Figure 1 and Figure 2. The Water Bureau wants to operate their water supply system in order to meet both water supply objectives and fish habitat objectives downstream of the Bull Run reservoirs in Bull Run River. In addition, a third Bull Run reservoir has been proposed as an additional water supply source. This reservoir also may be used to meet water supply and fish habitat objectives in Bull Run River. …
Ce-Qual-W2 Version 3: Hydrodynamic And Water Quality River Basin Modeling, Scott A. Wells
Ce-Qual-W2 Version 3: Hydrodynamic And Water Quality River Basin Modeling, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
CE-QUAL-W2 is a two-dimensional (longitudinal-vertical) water quality and hydrodynamic computer simulation model that was originally developed for deep, long, and narrow waterbodies. The current model, Version 2, has been used in over 200 river, reservoir/lake, and estuary applications throughout the U.S. and abroad. Version 2, though, cannot accommodate systems that have a significant sloping water surface since the vertical coordinate system is aligned with gravity and vertical accelerations are neglected. The governing equations for CE-QUAL-W2 were re-derived so that it could be applied to entire river basins including river-estuary, lake-river, and reservoir-river systems with channel slopes. This re-derivation is one …
Variation Of Constitutive Model Formulation On Analytical Cake Filtration Models, Scott A. Wells
Variation Of Constitutive Model Formulation On Analytical Cake Filtration Models, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
Constitutive properties are required to model porosity, effective stress, porewater pressure, or permeability during cake filtration. By using an analytical cake filtration model based on Tiller (1975) with various constitutive property formulations, predictions of effective stress, permeability, and porosity distributions in a filter cake can be made. This analytical approach was only valid when spatially average values of porosity and pressure differential were constant over time. Several different constitutive property formulations were compared to data of effective stress and permeability as a function of porosity for kaolin clay in water. Also the spatial distribution of porosity in a filter cake …
Modeling Macrophytes Of The Columbia Slough, Oregon, Chris Berger, Scott A. Wells
Modeling Macrophytes Of The Columbia Slough, Oregon, Chris Berger, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
The Columbia Slough is a tidally influenced freshwater system of wetlands, channels, and lakes located within the Portland, Oregon metropolitan area at the confluence of the Willamette and Columbia Rivers. It is a eutrophic water body susceptible to algae blooms and crashes and periods of high pH which violate water quality standards. High nutrient loads from groundwater principally controls algae productivity. Past structural changes to the Columbia Slough have included filling of wetlands and lakes and the construction of levees, dikes, culverts and irrigation channels. These changes have altered the natural flow dynamics creating an environment more conducive to eutrophication. …
Continuous Deflection Separation Of Stormwater Particulates, Tracy S. Schwarz, Scott A. Wells
Continuous Deflection Separation Of Stormwater Particulates, Tracy S. Schwarz, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
Capture of stormwater particulate matter is of concern to watershed managers trying to meet water quality guidelines by removing toxics associated with particulates from natural water bodies. A laboratory investigation into particle removal efficiency of a prototype Continuous Deflective Separation (CDS) device was made in the laboratory. Particle size distributions were obtained for roadway drainage surfaces. These distributions were used to assess the predicted performance of a CDS unit in the field.
Flow rates in the laboratory tests ranged from 125 GPM (7.9 l/s) to 270 GPM (17.0 l/s). Screen sizes used for testing were 1200 m and 2400 m. …
Analytical Modeling Of Cake Filtration, Scott A. Wells
Analytical Modeling Of Cake Filtration, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
The specific resistance model of cake filtration is based on the assumption that the average cake resistance is constant over time. This implies also that the spatially average values of porosity and pressure differential are also constant over time since specific resistance is a function of both parameters.
An analytical cake filtration model based on Tiller (1975) was derived using constitutive properties of kaolin suspensions in distilled water. Constitutive properties were determined by experiments performed using high-energy X-rays and porewater pressure probes to determine the spatial and temporal distributions of porosity and porewater pressure. Using these constitutive properties, predictions were …
Application Of Mathematical Modeling And Computer Simulation For Solving Water Quality Problems, Jacek Makinia, Scott A. Wells, David Crawford, Marian Kulbik
Application Of Mathematical Modeling And Computer Simulation For Solving Water Quality Problems, Jacek Makinia, Scott A. Wells, David Crawford, Marian Kulbik
Civil and Environmental Engineering Faculty Publications and Presentations
Deteriorated water resources in Central and Eastern Europe call for actions that should be undertaken to improve current conditions and to protect human and environmental health. Mathematical modeling and computer simulation is often an integral part of the decision-making process. Models and simulations allow rapid and varied evaluation of causes and effects and the principal advantage is that they enable an analysis of even long-term actions with limited investment costs. This paper provides an overview of popular models used for simulation of major elements of a water quality system: surface water quality (QUAL2E), wastewater treatment (Activated Sludge Model No.1), sewer …
Filtration Modeling Of A Plate-And-Frame Press, Scott A. Wells
Filtration Modeling Of A Plate-And-Frame Press, Scott A. Wells
Civil and Environmental Engineering Faculty Publications and Presentations
The porosity distribution and filtrate production during cake filtration in a plate-and-frame filter press were simulated mathematically. The model considered filtration that occurs after the filling process, not filtration that occurs as the suspension fills the cell. Governing equations for the temporal porosity distribution were developed for a plateand- frame press. The governing equations were solved numerically using an alternating-direction-implicit scheme. Appropriate initial and boundary conditions were determined based on characteristics of the plate-and-frame press and of the suspension properties. Predicted porosity and velocity distributions were calculated for assumed constitutive parameters.
Modeling Density Currents In Circular Clarifiers, Scott A. Wells, David M. Laliberte
Modeling Density Currents In Circular Clarifiers, Scott A. Wells, David M. Laliberte
Civil and Environmental Engineering Faculty Publications and Presentations
Design of sedimentation tanks for solid-liquid separation is often dependent on assuming ideal flow conditions. But the geometry of the tank and density currents as a result of temperature and suspended solids influences the fluid mechanics of the tank and can result in significant deviations from ideal flow.
A two-dimensional radial flow model was proposed which incorporated the effect of density currents resulting from temperature and suspended solids differentials within the tank. The numerical model predicted the steady-state, layer-averaged radial flow and layer depth.
The model solution and field data showed that the momentum and suspended solids of the inflow …
Gravity Drainage Prior To Cake Filtration, Scott A. Wells, Gregory K. Savage
Gravity Drainage Prior To Cake Filtration, Scott A. Wells, Gregory K. Savage
Civil and Environmental Engineering Faculty Publications and Presentations
During the initial stages of a Buchner funnel or specific resistance test, gravity drainage occurs prior to application of the pressure differential. Some allow time for a small cake to form by gravity drainage. Filtrate data from the gravity drainage period can be used to determine constitutive properties of the cake under a hydrostatic pressure gradient. The constitutive properties that define the structure of the cake include the permeability and porosity as functions of the applied stress. Equations governing the drainage rate during a gravity filtration experiment assuming a constant and a non-constant average cake permeability and cake porosity were …