+publisher:"Colorado State University" +contributor:("Thornton, Christopher")

Colorado State University

1. Siefken, Seth. Computational fluid dynamics models of Rio Grande bends fitted with rock vanes or bendway weirs.

Degree: MS(M.S.), Civil and Environmental Engineering, 2019, Colorado State University

URL: http://hdl.handle.net/10217/197259

► Rock vanes (also known as stream barbs) and bendway weirs are two types of transverse rock structures used to modify the flow field in river… (more)

▼ Rock vanes (also known as stream barbs) and bendway weirs are two types of transverse rock structures used to modify the flow field in river bends. This study examines the effectiveness of the two types of structures at reducing velocity along the outer bank of river bends to protect the bank from erosion. A numerical model using the commercially available FLOW-3D software was used to evaluate the effect of various rock vane and bendway weir configurations on the flow field through two river bends typical of the Middle Rio Grande. The model was calibrated and validated using data from a previous physical model study of rock vanes. 33 different rock vane configurations were tested in the numerical model to evaluate the effect of altering planform angle, crest slope, projected length, and structure spacing. In addition, 14 different bendway weir configurations were tested to provide a comparison of the relative performance of bendway weirs and rock vanes. The numerical modeling results indicate that rock vanes are more effective at reducing the velocity along the outer bank of a bend than bendway weirs. Modelling showed that the completely submerged crest of bendway weirs allows a substantial amount of flow to pass over the crest, limiting their effectiveness in reducing velocity along the bank. In contrast, rock vanes, with a sloped crest intersecting the waterline at the design flow rate, directed more flow around the tip of the structure rather than over the crest and were much more effective at reducing velocity along the bank. Based on the modeling results, it is recommended that bendway weirs not be installed for the purpose of erosion protection along riverbanks. The reduction in velocity along the bank produced by the various rock vane configurations varied considerably with the geometry of the configuration. Based on the results, the following conclusions are made regarding rock vane geometry: (1) Rock vanes should be installed at a planform angle between 45° and 90° to the river bank. (2) There exists an optimal projected length of rock vane, which lies in the neighborhood of 1/5 to 1/3 of the channel top-width. (3) Rock vanes with a 10% crest slope perform well, although decreasing the crest slope will decrease the velocity along the outer bank and vice versa. (4) Decreasing the spacing of rock vanes decreases the velocity along the outer bank, up to a limit. A design equation was developed to predict the velocity reduction along the bank of a river bend produced by a given configuration of rock vanes, based on the geometry of the rock vanes and the river channel. The equation provided good predictions for the range of configurations tested, having a coefficient of determination r2 = 0.83 and predicting the velocity reduction along the outer bank to within 15 percentage points for all of the tested configurations. Advisors/Committee Members: Ettema, Robert (advisor), Thornton, Christopher (committee member), McGrath, Daniel (committee member).

Subjects/Keywords: bendway weirs; erosion protection; stream barbs; computational fluid dynamics; bank stabilization; rock vanes

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APA (6^th Edition):

Siefken, S. (2019). Computational fluid dynamics models of Rio Grande bends fitted with rock vanes or bendway weirs. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/197259

Chicago Manual of Style (16^th Edition):

Siefken, Seth. “Computational fluid dynamics models of Rio Grande bends fitted with rock vanes or bendway weirs.” 2019. Masters Thesis, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/197259.

MLA Handbook (7^th Edition):

Siefken, Seth. “Computational fluid dynamics models of Rio Grande bends fitted with rock vanes or bendway weirs.” 2019. Web. 27 Jan 2020.

Vancouver:

Siefken S. Computational fluid dynamics models of Rio Grande bends fitted with rock vanes or bendway weirs. [Internet] [Masters thesis]. Colorado State University; 2019. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/197259.

Council of Science Editors:

Siefken S. Computational fluid dynamics models of Rio Grande bends fitted with rock vanes or bendway weirs. [Masters Thesis]. Colorado State University; 2019. Available from: http://hdl.handle.net/10217/197259

Colorado State University

2. Hogan, Taylor. Effects of bend radius on flow around a configuration of bendway weirs: insight from a numerical model, The.

Degree: MS(M.S.), Civil and Environmental Engineering, 2019, Colorado State University

URL: http://hdl.handle.net/10217/197362

► Bendway weirs have been used and refined for decades by hydraulic engineers to control thalweg location within alluvial rivers and to decrease flow velocity along… (more)

▼ Bendway weirs have been used and refined for decades by hydraulic engineers to control thalweg location within alluvial rivers and to decrease flow velocity along the outer bank of channel bends. Although these structures have been used in a variety of applications, there are still a wide range of acceptable design parameters that vary in accordance with the specific design methodology being used. Since the early 2000s, Colorado State University's Hydraulics Lab has assisted The U.S Bureau of Reclamation (USBR) in refining the design of bendway weirs and similar in-stream rock structures. During this period of time, Colorado State University and The USBR have utilized hydraulic and numerical models to develop systematic design guidelines for bendway weirs and other in-stream rock structures. Hydraulic modeling has also provided a large database of velocity and water surface measurements that have been used to calibrate and validate subsequent numerical models. The partnership between Colorado State University and the USBR has led to design recommendations and equations in which the effect of many variables and their sensitivity in overall bendway weir design has been identified. This study investigates the parameter radius of curvature over channel top width, Rc/Tw, and its effect on the flow field around bendway weirs, as its significance in bendway weir design is not well known. To investigate the effects of Rc/Tw on the bendway weir flow field, the 2D numerical model SRH-2D was used in conjunction with AutoCAD Civil3D software. The SRH-2D model was created using the bathymetry of the hydraulic model and then also calibrated and validated using data collected in the hydraulic model. AutoCAD Civil3D was used to create four different bend radii while holding Tw constant, representing Rc/Tw values between 3.0 and 8.0 which are typical of the Middle Rio Grande that the hydraulic model represented. Two additional trapezoidal channel models were also created to isolate the possible effects from specific channel geometry on the bendway weir flow field comparisons. 2D numerical modeling results revealed that the bend radius of curvature had negligible effect on the bendway weir flow field. Velocity patterns in the trapezoidal and native bathymetry channels changed negligibly in location and magnitude across varying bend radii. Cross-sectional velocity distributions were also evaluated and showed that the inner and middle third lateral sections of the channel showed the same (within fractions of a percent) velocity increase after the installation of bendway weirs. The outer fifth of the channel resulted in 6% velocity decrease only varying approximately 0.1% between bend radii. Overall numerical modeling results showed that the bendway weir flow field was negligibly affected by the bend radius of curvature, Rc. Advisors/Committee Members: Thornton, Christopher (advisor), Ettema, Robert (advisor), Williams, John (committee member).

Subjects/Keywords: Change of Bend Radius; Bendway Weirs; SRH-2D

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APA (6^th Edition):

Hogan, T. (2019). Effects of bend radius on flow around a configuration of bendway weirs: insight from a numerical model, The. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/197362

Chicago Manual of Style (16^th Edition):

Hogan, Taylor. “Effects of bend radius on flow around a configuration of bendway weirs: insight from a numerical model, The.” 2019. Masters Thesis, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/197362.

MLA Handbook (7^th Edition):

Hogan, Taylor. “Effects of bend radius on flow around a configuration of bendway weirs: insight from a numerical model, The.” 2019. Web. 27 Jan 2020.

Vancouver:

Hogan T. Effects of bend radius on flow around a configuration of bendway weirs: insight from a numerical model, The. [Internet] [Masters thesis]. Colorado State University; 2019. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/197362.

Council of Science Editors:

Hogan T. Effects of bend radius on flow around a configuration of bendway weirs: insight from a numerical model, The. [Masters Thesis]. Colorado State University; 2019. Available from: http://hdl.handle.net/10217/197362

Colorado State University

3. Keene, Anthony. Estimating interstitial discharge and velocity in flow in riprap and gabion engineering applications.

Degree: MS(M.S.), Civil and Environmental Engineering, 2020, Colorado State University

URL: http://hdl.handle.net/10217/199796

► Interstitial flow is a difficult hydraulic process to measure and predict. Interstitial flow does not follow the same laws as seepage flow in small-grain media… (more)

▼ Interstitial flow is a difficult hydraulic process to measure and predict. Interstitial flow does not follow the same laws as seepage flow in small-grain media (i.e. Darcy's Law), because flow regimes in aggregate rock are often transitional or turbulent at a mild slope. Flow paths and local velocities in open cavities of a rock layer are dynamic, and instrumentation is difficult to place in rock for physical measurement. Due to the dynamic and complicated nature of interstitial flow, limited tools are available for engineering flow through aggregate rock. Flow in aggregate rock is relevant to many hydraulic engineering applications, including riprap and gabions used in designs for drainage, earth retention, and rockfill structures. Riprap and gabion published design guidelines are derived from external flow conditions and often neglect interstitial flow. Discharge in rock directly influences internal forces that can transport loose rock or strain a gabion mattress structure, interstitial velocity also directly influences bed shear stress. However, despite the importance of interstitial velocity and discharge for design, riprap and gabion design guidelines are developed primarily for rock stability. There is a need for interstitial discharge as design criteria; estimating the discharge capacity of aggregate rock can be useful in applications where drainage for a design flow is relevant. Data from laboratory prototype gabion mattress tests are used in tandem with data collected in a previous study on riprap to develop two simple design equations to predict interstitial velocity and interstitial discharge per unit area of a rock layer. A multivariate nonlinear regression was performed as a function of the following key parameters in a rock system: rock size for which 50% of rock is finer than, D₅₀, rock size for which 10% of rock is finer than, D₁₀, coefficient of uniformity (D₆₀/D₁₀), acceleration due to gravity, and bed slope. The regressions yield a coefficient of determination of 0.97 for both interstitial velocity and interstitial discharge predictive equations. Equations are suited for use in rock layers with nominal sizes from ¼-in to 5-in on bed slopes up to 0.15 ft/ft. Advisors/Committee Members: Thornton, Christopher (advisor), Scalia, Joseph (advisor), Williams, John (committee member).

Subjects/Keywords: drainage; gabions and riprap; hydraulic engineering; erosion control; aggregate rock; geotechnical engineering

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APA (6^th Edition):

Keene, A. (2020). Estimating interstitial discharge and velocity in flow in riprap and gabion engineering applications. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/199796

Chicago Manual of Style (16^th Edition):

Keene, Anthony. “Estimating interstitial discharge and velocity in flow in riprap and gabion engineering applications.” 2020. Masters Thesis, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/199796.

MLA Handbook (7^th Edition):

Keene, Anthony. “Estimating interstitial discharge and velocity in flow in riprap and gabion engineering applications.” 2020. Web. 27 Jan 2020.

Vancouver:

Keene A. Estimating interstitial discharge and velocity in flow in riprap and gabion engineering applications. [Internet] [Masters thesis]. Colorado State University; 2020. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/199796.

Council of Science Editors:

Keene A. Estimating interstitial discharge and velocity in flow in riprap and gabion engineering applications. [Masters Thesis]. Colorado State University; 2020. Available from: http://hdl.handle.net/10217/199796

Colorado State University

4. Garfield, Mason. Effects of scour on the flow field at a bendway weir, The.

Degree: MS(M.S.), Civil and Environmental Engineering, 2019, Colorado State University

URL: http://hdl.handle.net/10217/197324

► Bendway weirs (BWs) are rock structures commonly used for controlling the thalweg location in alluvial channels, especially bends. Although there are many studies analyzing the… (more)

▼ Bendway weirs (BWs) are rock structures commonly used for controlling the thalweg location in alluvial channels, especially bends. Although there are many studies analyzing the effect of BWs on bend flow fields, there is little known about the effects of scour on the modified flow field. Many physical and numerical models of BWs use a fixed bed with the existing river bathymetry, assuming that the effects of scour are negligible. This study analyzed the effects of the scour on the flow field using SRH-2D, a 2-dimensional numerical model solving the full St. Venant equation (also termed the dynamic wave equation). In addition, the study used small scale and large scale hydraulic models and a 3-dimensional numerical model, FLOW-3D, to validate and calibrate the 2-D model. Using FLOW-3D, the 3-dimensional flow field was used to identify areas where SRH-2D was accurate and where it was lacking. The small scale hydraulic model was used to determine the effect of streamwise blockage on scour using plates. Results from the small scale hydraulic model indicate that when the degree of streamwise blockage (L/B where L is the width of the plate and B is the width of the flume) and submergence (Y/H where Y is the flow depth and H is the height of the plate) remained the same, but the acute angle to the flume wall varied (α), the maximum scour depth did not change significantly. Accordingly, the scour morphology from the tests with α = 90° could be applied to tests with α = 30° and 60° using the 2-D model. When comparing the flow field using SRH-2D to FLOW-3D, it was found that the maximum depth-averaged velocity was closer to FLOW-3D's when Y/H = 1.25 than when Y/H = 2.0. This finding likely results from the greater effect of blockage directing the flow around the BW than the deeper case, where the flow has a higher vertical velocity over the top of the BW. The 2-D model cannot take this into account, leading to error. The pre- and post-scour maximum velocity magnitude and locations were compared to determine the effect of scour on the flow field using the 2-D model. A deep flow depth (Y/H = 2.0) and a shallower flow depth (Y/H = 1.25) were run for different BW orientations, (α=30°,60°,and 90°) to determine the applicability of the effect of scour on the flow field. The analysis found that, when Y/H = 2.0, the difference in the maximum velocity magnitude and location between pre-and post-scour were fairly negligible for all orientations, whereas when Y/H =1.25, the effects of the scour on the flow field were more prominent. Overall it was found that the scour morphology is important to take into consideration for a fixed bed numerical or physical model when analyzing flow depths slightly overtopping the BW, but has little effect when the flow is twice the size of the BW. Advisors/Committee Members: Ettema, Robert (advisor), Thornton, Christopher (committee member), Wohl, Ellen (committee member).

Subjects/Keywords: FLOW-3D; SRH-2D; Numerical Modeling; Bendway Weirs

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APA (6^th Edition):

Garfield, M. (2019). Effects of scour on the flow field at a bendway weir, The. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/197324

Chicago Manual of Style (16^th Edition):

Garfield, Mason. “Effects of scour on the flow field at a bendway weir, The.” 2019. Masters Thesis, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/197324.

MLA Handbook (7^th Edition):

Garfield, Mason. “Effects of scour on the flow field at a bendway weir, The.” 2019. Web. 27 Jan 2020.

Vancouver:

Garfield M. Effects of scour on the flow field at a bendway weir, The. [Internet] [Masters thesis]. Colorado State University; 2019. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/197324.

Council of Science Editors:

Garfield M. Effects of scour on the flow field at a bendway weir, The. [Masters Thesis]. Colorado State University; 2019. Available from: http://hdl.handle.net/10217/197324

Colorado State University

5. Ubing, Caroline. Baffle-Post Structures for Flow Control in Open Channels.

Degree: MS(M.S.), Civil and Environmental Engineering, 2015, Colorado State University

URL: http://hdl.handle.net/10217/166972

► This thesis presents theory and laboratory findings regarding the hydraulic performance of baffle-post structures used as a means for controlling flow in open channels. Such… (more)

Subjects/Keywords: grade control structures; hydraulic structures; flow control; sediment transport; head loss coefficient

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APA (6^th Edition):

Ubing, C. (2015). Baffle-Post Structures for Flow Control in Open Channels. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/166972

Chicago Manual of Style (16^th Edition):

Ubing, Caroline. “Baffle-Post Structures for Flow Control in Open Channels.” 2015. Masters Thesis, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/166972.

MLA Handbook (7^th Edition):

Ubing, Caroline. “Baffle-Post Structures for Flow Control in Open Channels.” 2015. Web. 27 Jan 2020.

Vancouver:

Ubing C. Baffle-Post Structures for Flow Control in Open Channels. [Internet] [Masters thesis]. Colorado State University; 2015. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/166972.

Council of Science Editors:

Ubing C. Baffle-Post Structures for Flow Control in Open Channels. [Masters Thesis]. Colorado State University; 2015. Available from: http://hdl.handle.net/10217/166972

Colorado State University

6. Chen, Kaiwei. Application of large-scale particle image velocimetry at the Hydraulics Laboratory of Colorado State University.

Degree: MS(M.S.), Civil and Environmental Engineering, 2018, Colorado State University

URL: http://hdl.handle.net/10217/189265

► Large-scale particle image velocimetry (LSPIV) is a nonintrusive technique used to measure free-surface velocities of water flow in a manner that produces a two-dimensional vector… (more)

Subjects/Keywords: Bendway weir; Tracer size; LSPIV; Accuracy

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APA (6^th Edition):

Chen, K. (2018). Application of large-scale particle image velocimetry at the Hydraulics Laboratory of Colorado State University. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/189265

Chicago Manual of Style (16^th Edition):

Chen, Kaiwei. “Application of large-scale particle image velocimetry at the Hydraulics Laboratory of Colorado State University.” 2018. Masters Thesis, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/189265.

MLA Handbook (7^th Edition):

Chen, Kaiwei. “Application of large-scale particle image velocimetry at the Hydraulics Laboratory of Colorado State University.” 2018. Web. 27 Jan 2020.

Vancouver:

Chen K. Application of large-scale particle image velocimetry at the Hydraulics Laboratory of Colorado State University. [Internet] [Masters thesis]. Colorado State University; 2018. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/189265.

Council of Science Editors:

Chen K. Application of large-scale particle image velocimetry at the Hydraulics Laboratory of Colorado State University. [Masters Thesis]. Colorado State University; 2018. Available from: http://hdl.handle.net/10217/189265

Colorado State University

7. Palu, Marcos Cristiano. Floodwave and sediment transport assessment along the Doce River after the Fundão Tailings Dam collapse (Brazil).

Degree: PhD, Civil and Environmental Engineering, 2019, Colorado State University

URL: http://hdl.handle.net/10217/195309

► The collapse of the Fundão Tailings Dam in November 2015 spilled 32 Mm3 of mine waste, causing a substantial socio-economic and environmental damage within the… (more)

▼ The collapse of the Fundão Tailings Dam in November 2015 spilled 32 Mm3 of mine waste, causing a substantial socio-economic and environmental damage within the Doce River basin in Brazil. Approximately 90% of the spilled volume deposited over 118 km downstream of Fundão Dam on floodplains. Nevertheless, high concentration of suspended sediment (≈ 400,000 mg/l) reached the Doce River, where the floodwave and sediment wave traveled at different velocities over 550 km to the Atlantic Ocean. The one-dimensional advection-dispersion equation with sediment settling was solved to determine, for tailing sediment, the longitudinal dispersion coefficient and the settling rate along the river and in the reservoirs (Baguari, Aimorés and Mascarenhas). The values found for the longitudinal dispersion coefficient ranged from 30 to 120 m2/s, which are consistent with those in the literature. Moreover, the sediment settling rate along the whole extension of the river corresponds to the deposition of finer material stored in Fundão Dam, which particle size ranged from 1.1 to 2 μm. The simulation of the flashy hydrographs on the Doce River after the dam collapse was initially carried out with several widespread one-dimensional flood routing methods, including the Modified Puls, Muskingum-Cunge, Preissmann, Crank Nicolson and QUICKEST. All of these methods presented unsatisfactory results, with prediction errors in peak discharge up to 44%, and differences in timing to peak up to 5 hours. A new and more accurate one-dimensional flood routing approach was then used, solving the full dynamic equation into an equivalent diffusive wave format and reformulating the hydraulic diffusion coefficient in terms of the Froude number and floodwave celerity. The numerical solution to this new approach was implemented using Crank Nicolson and QUICKEST schemes. The error in predicted peak discharge along the Doce River was reduced to 2%, and the maximum difference found in time to peak was about 1 hour. Regarding sediment transport, a comprehensive one-dimensional numerical model is developed, coupling the new floodwave propagation algorithm with the numerical solution for advective sediment transport and settling. One of the main features of this model is the ability to simulate the propagation of the floodwave and sediment through the entire Doce River extension with or without reservoirs. A sensitivity analysis showed that a hypothetical decrease in water temperature from 30°C to 5°C would have resulted in a concentration 13 times higher at the outlet. In addition, without the presence of hydropower reservoirs on the Doce River, the sediment concentration at the basin outlet would have been 70,000 mg/l instead of the observed 1,600 mg/l. Finally, a simplified numerical model based on the Doce River measurements can simulate the hypothetical collapse of 56 tailings dams in the Doce River basin to estimate the potential impact on the water supply for the towns along the river. Those simulation results show that tailings dams located in the Piracicaba… Advisors/Committee Members: Julien, Pierre (advisor), Thornton, Christopher (committee member), Ettema, Robert (committee member), Rathburn, Sara (committee member).

Subjects/Keywords: Doce River; Fundão Tailings Dam; transport of suspended sediment; floodwave propagation; dam break; one-dimensional advection-dispersion equation

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APA (6^th Edition):

Palu, M. C. (2019). Floodwave and sediment transport assessment along the Doce River after the Fundão Tailings Dam collapse (Brazil). (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/195309

Chicago Manual of Style (16^th Edition):

Palu, Marcos Cristiano. “Floodwave and sediment transport assessment along the Doce River after the Fundão Tailings Dam collapse (Brazil).” 2019. Doctoral Dissertation, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/195309.

MLA Handbook (7^th Edition):

Palu, Marcos Cristiano. “Floodwave and sediment transport assessment along the Doce River after the Fundão Tailings Dam collapse (Brazil).” 2019. Web. 27 Jan 2020.

Vancouver:

Palu MC. Floodwave and sediment transport assessment along the Doce River after the Fundão Tailings Dam collapse (Brazil). [Internet] [Doctoral dissertation]. Colorado State University; 2019. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/195309.

Council of Science Editors:

Palu MC. Floodwave and sediment transport assessment along the Doce River after the Fundão Tailings Dam collapse (Brazil). [Doctoral Dissertation]. Colorado State University; 2019. Available from: http://hdl.handle.net/10217/195309

8. Ficke, Ashley D. Mitigation Measures for Barriers to Great Plains Fish Migration.

Degree: PhD, Fish, Wildlife, and Conservation Biology, 2015, Colorado State University

URL: http://hdl.handle.net/10217/166913

To view the abstract, please see the full text of the document. Advisors/Committee Members: Myrick, Christopher (advisor), Bestgen, Kevin (committee member), Fausch, Kurt (committee member), Thornton, Christopher (committee member).

Subjects/Keywords: fish physiology; hydraulics; swimming ability; Great Plains fishes; fish passage; mark recapture

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APA (6^th Edition):

Ficke, A. D. (2015). Mitigation Measures for Barriers to Great Plains Fish Migration. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/166913

Chicago Manual of Style (16^th Edition):

Ficke, Ashley D. “Mitigation Measures for Barriers to Great Plains Fish Migration.” 2015. Doctoral Dissertation, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/166913.

MLA Handbook (7^th Edition):

Ficke, Ashley D. “Mitigation Measures for Barriers to Great Plains Fish Migration.” 2015. Web. 27 Jan 2020.

Vancouver:

Ficke AD. Mitigation Measures for Barriers to Great Plains Fish Migration. [Internet] [Doctoral dissertation]. Colorado State University; 2015. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/166913.

Council of Science Editors:

Ficke AD. Mitigation Measures for Barriers to Great Plains Fish Migration. [Doctoral Dissertation]. Colorado State University; 2015. Available from: http://hdl.handle.net/10217/166913

9. Michalos, Christopher T. Hydraulic effects of biofilms on the design and operation of wastewater forcemains.

Degree: PhD, Civil and Environmental Engineering, 2017, Colorado State University

URL: http://hdl.handle.net/10217/178930

► The impact of biofouling on wastewater forcemains is generally not accounted for in current design practice and little information is available in literature regarding the… (more)

▼ The impact of biofouling on wastewater forcemains is generally not accounted for in current design practice and little information is available in literature regarding the effect of wastewater biofilms on forcemain hydraulics. In practice, many engineers select a clean water, new pipe roughness factor, to perform hydraulic calculations which may lead to under-sizing wastewater lift station pumps. Forcemains have to cope with a particularly challenging task; they have to ensure that solids contained in the wastewater (sand, gravel, organics) are readily transported along with the wastewater. Forcemain design standards generally recommend a velocity of 2.0 ft/s (0.6 m/s) to prevent deposition of solids and a velocity of 3.5 ft/s (1.1 m/s) to re-suspend solids that may have settled. To further complicate forcemain design and operation; wastewater lift station pumps generally operate intermittently which requires remobilization of any material that may have settled while the pumps remain idle. Therefore, forcemains must be designed to be self-cleaning in order to prevent solids deposition which could cause increased sulfide production leading to corrosion and odor issues; loss of capacity through a reduction of cross sectional area; or even blockage at low points, or at the toe of an adversely sloped pipe leading to costly removal. The goal of this research is to identify short-comings in current forcemain design practice by 1) evaluating the hydraulic effect of biofilms on the absolute roughness (ks) of forcemains; 2) evaluating the hydraulic effect of biofilms on Hazen-Williams C factor; and 3) determine critical velocity required for sediment transport, air clearing, self-cleansing, and optimal diameter of forcemains, which are not identified in forcemain design standards. Operational data were collected and evaluated for 20 municipal wastewater forcemains located in the United States. Data from previous studies, academic research, reports, and published papers were used to supplement and support research findings. A total of 415 data points obtained from 68 forcemain systems ranging from 3- to 66 inches in diameter were evaluated as part of this research. Results of the hydraulic analysis determined that 44% of the systems evaluated were operating at velocities between 2- and 3.5 ft/s and 16% of systems were operating at velocities less than 2 ft/s; indicating that these systems are over designed and do not provide sufficient velocity to re-suspend solids promoting sedimentation. The hydraulic effect of biofilms on forcemain flow resistance was evaluated and determined that ks and C factor varied with forcemain velocity. Calculated values of ks ranged from approximately 35 mm to 0.01 mm, with larger values occurring at velocities less than 1 m/s (3.3 ft/s). The upper range of ks values are orders of magnitude larger than the standard clean water, new pipe ks value found in literature. C factor results ranged from approximately 30 to 150; approximately 60% of forcemain systems evaluated are… Advisors/Committee Members: Thornton, Christopher I. (advisor), Grigg, Neil S. (committee member), Julien, Pierre Y. (committee member), Williams, John D. (committee member).

Subjects/Keywords: Forcemain Hydraulics; Forcemain Design; Forcemains

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APA (6^th Edition):

Michalos, C. T. (2017). Hydraulic effects of biofilms on the design and operation of wastewater forcemains. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/178930

Chicago Manual of Style (16^th Edition):

Michalos, Christopher T. “Hydraulic effects of biofilms on the design and operation of wastewater forcemains.” 2017. Doctoral Dissertation, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/178930.

MLA Handbook (7^th Edition):

Michalos, Christopher T. “Hydraulic effects of biofilms on the design and operation of wastewater forcemains.” 2017. Web. 27 Jan 2020.

Vancouver:

Michalos CT. Hydraulic effects of biofilms on the design and operation of wastewater forcemains. [Internet] [Doctoral dissertation]. Colorado State University; 2017. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/178930.

Council of Science Editors:

Michalos CT. Hydraulic effects of biofilms on the design and operation of wastewater forcemains. [Doctoral Dissertation]. Colorado State University; 2017. Available from: http://hdl.handle.net/10217/178930

10. Kim, Hwa Young. Optimization of Sangju weir operations to mitigate sedimentation problems.

Degree: PhD, Civil and Environmental Engineering, 2016, Colorado State University

URL: http://hdl.handle.net/10217/176611

To view the abstract, please see the full text of the document. Advisors/Committee Members: Julien, Pierre Y. (advisor), Fontane, Darrell G. (committee member), Thornton, Christopher I. (committee member), Rathburn, Sara L. (committee member).

Subjects/Keywords: Low-head dams; Reservoir Sedimentation; Weirs; Nakdong River; Dredging; Trap efficiency

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APA (6^th Edition):

Kim, H. Y. (2016). Optimization of Sangju weir operations to mitigate sedimentation problems. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/176611

Chicago Manual of Style (16^th Edition):

Kim, Hwa Young. “Optimization of Sangju weir operations to mitigate sedimentation problems.” 2016. Doctoral Dissertation, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/176611.

MLA Handbook (7^th Edition):

Kim, Hwa Young. “Optimization of Sangju weir operations to mitigate sedimentation problems.” 2016. Web. 27 Jan 2020.

Vancouver:

Kim HY. Optimization of Sangju weir operations to mitigate sedimentation problems. [Internet] [Doctoral dissertation]. Colorado State University; 2016. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/176611.

Council of Science Editors:

Kim HY. Optimization of Sangju weir operations to mitigate sedimentation problems. [Doctoral Dissertation]. Colorado State University; 2016. Available from: http://hdl.handle.net/10217/176611

11. Scholl, Bryan N. Bulking coefficients of aerated flow during wave overtopping simulation on protected land-side slopes.

Degree: PhD, Civil and Environmental Engineering, 2016, Colorado State University

URL: http://hdl.handle.net/10217/176666

► Post hurricane Katrina there has been more interest in erosion on the landward side of levees resulting from wave overtopping during storm events. The development… (more)

▼ Post hurricane Katrina there has been more interest in erosion on the landward side of levees resulting from wave overtopping during storm events. The development of wave overtopping simulators has enabled more rigorous evaluation of levee armoring alternatives under controlled conditions similar to those on levees. Steady state overtopping studies have demonstrated a reduction in shear stress due to air entrainment in the flow. There has not been an evaluation of air entrainment during wave overtopping simulation. For this reason, a study was conducted to quantify flow bulking occurring during wave overtopping simulation. Testing was conducted at the Hydraulics Laboratory at Colorado State University at the Engineering Research Center using a wave overtopping simulator. The simulated levee was 6 ft wide. Levee geometry in the direction of flow was a 13.2 ft. horizontal crest, 30.5 ft levee face with 3:1 (horizontal:vertical) slope and 12.2 ft berm with 25:1 slope. Un-bulked flow thickness was measured with “surfboards” which hydroplane along the surface of flow. Bulked flow thicknesses were measured using visual observations of maximum flow thickness on eight staff gages along the wall of the simulated levee. Wave volumes ranged from 20 ft3/ft to 175 ft3/ft. Conservation of mass and testing repeatability is demonstrated. Bulking values range from zero for the smallest wave volumes to over 100% for the largest wave volumes. An empirical model is developed to estimate bulking on the 3:1 levee slope. A comparison is made to steady state flows with similar air entrainment. The effect of bulking on shear stress is a potential decrease in shear stress over 50% relative to un-bulked flow thickness. A method to incorporate wave overtopping bulking into design is proposed using a cumulative work approach. Advisors/Committee Members: Thornton, Christopher I. (advisor), Abt, Steven R. (advisor), Hughes, Steven A. (committee member), Venayagamoorthy, Subhas K. (committee member), Kampf, Stephanie K. (committee member).

Subjects/Keywords: aeration; levee overtopping; wave overtopping simulation; flow bulking; aerated flow; wave overtopping

…overtopping simulator located at the Engineering Research Center of Colorado State University. Data… …at Colorado State University (CSU). Subsequently, flow bulking predictive… …State University (CSU) Hydraulics Laboratory. The CSU WOS is based on the work of… …wave overtopping simulator (WOS) was designed and constructed at the Colorado…

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APA (6^th Edition):

Scholl, B. N. (2016). Bulking coefficients of aerated flow during wave overtopping simulation on protected land-side slopes. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/176666

Chicago Manual of Style (16^th Edition):

Scholl, Bryan N. “Bulking coefficients of aerated flow during wave overtopping simulation on protected land-side slopes.” 2016. Doctoral Dissertation, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/176666.

MLA Handbook (7^th Edition):

Scholl, Bryan N. “Bulking coefficients of aerated flow during wave overtopping simulation on protected land-side slopes.” 2016. Web. 27 Jan 2020.

Vancouver:

Scholl BN. Bulking coefficients of aerated flow during wave overtopping simulation on protected land-side slopes. [Internet] [Doctoral dissertation]. Colorado State University; 2016. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/176666.

Council of Science Editors:

Scholl BN. Bulking coefficients of aerated flow during wave overtopping simulation on protected land-side slopes. [Doctoral Dissertation]. Colorado State University; 2016. Available from: http://hdl.handle.net/10217/176666

Colorado State University

12. Parker, Thomas Richard. Analysis of riprap design methods using predictive equations for maximum and average velocities at the tips of transverse in-stream structures.

Degree: MS(M.S.), Civil and Environmental Engineering, 2007, Colorado State University

URL: http://hdl.handle.net/10217/82478

► Transverse in-stream structures are used to enhance navigation, improve flood control, and reduce stream bank erosion. These structures are defined as elongated obstructions having one… (more)

▼ Transverse in-stream structures are used to enhance navigation, improve flood control, and reduce stream bank erosion. These structures are defined as elongated obstructions having one end along the bank of a channel and the other projecting into the channel center and offer protection of erodible banks by deflecting flow from the bank to the channel center. Redirection of the flow moves erosive forces away from the bank, which enhances bank stability. The design, effectiveness, and performance of transverse in-stream structures have not been well documented, but recent efforts have begun to study the flow fields and profiles around and over transverse in-stream structures. It is essential for channel flow characteristics to be quantified and correlated to geometric structure parameters in order for proposed in-stream structure designs to perform effectively. Areas adjacent to the tips of in-stream transverse structures are particularly susceptible to strong approach flows, and an increase in shear stress can cause instability in the in-stream structure. As a result, the tips of the structures are a major focus in design and must be protected. Riprap size is a significant component of the design and stability of transverse in-stream structures, and guidance is needed to select the appropriate size such that the structure remains stable throughout its design life. The U.S. Bureau of Reclamation contracted the Engineering Research Center at Colorado State University to construct an undistorted 1:12 Froude scale, fixed bed, physical model of two channel bend geometries that are characteristic of a reach of the Rio Grande River south of the Cochiti Dam in central New Mexico. A series of factors including the construction of the Cochiti Dam and control levees has caused the historically braided river to meander and become more sinuous. Bank erosion threatens farmlands, irrigation systems, levee function, aquatic habitat, and riparian vegetation. The purpose of the model was to determine the effectiveness of in-stream structures in diffusing the magnitude of forces related to bank erosion. Multiple configurations of transverse in-stream structures with varying x, y, and z parameters were installed in the model, and velocity and shear stress data were collected. A series of twenty-two different configurations of transverse in-stream structures were tested. An analysis of the average and maximum velocities at the tips of the transverse in-stream structures was performed. Utilizing a channel bend approach velocity, average and maximum velocity ratios were calculated using physical model data. A set of dimensionless parameters consisting of influential structure design parameters was organized and arranged for regression analysis. Predictive equations were developed that describe the ratios of maximum and average velocity at the tips of the in-stream structures to bend-averaged velocities. The predictive equations for maximum and average velocity ratios function as a first approximation of in-stream structure riprap design… Advisors/Committee Members: Thornton, Christopher (advisor), Abt, Steven (advisor), Williams, John (committee member).

Subjects/Keywords: tips of in-stream structures; in-stream structures; maximum velocity; predictive equations; riprap; riprap design methods

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APA (6^th Edition):

Parker, T. R. (2007). Analysis of riprap design methods using predictive equations for maximum and average velocities at the tips of transverse in-stream structures. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/82478

Chicago Manual of Style (16^th Edition):

Parker, Thomas Richard. “Analysis of riprap design methods using predictive equations for maximum and average velocities at the tips of transverse in-stream structures.” 2007. Masters Thesis, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/82478.

MLA Handbook (7^th Edition):

Parker, Thomas Richard. “Analysis of riprap design methods using predictive equations for maximum and average velocities at the tips of transverse in-stream structures.” 2007. Web. 27 Jan 2020.

Vancouver:

Parker TR. Analysis of riprap design methods using predictive equations for maximum and average velocities at the tips of transverse in-stream structures. [Internet] [Masters thesis]. Colorado State University; 2007. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/82478.

Council of Science Editors:

Parker TR. Analysis of riprap design methods using predictive equations for maximum and average velocities at the tips of transverse in-stream structures. [Masters Thesis]. Colorado State University; 2007. Available from: http://hdl.handle.net/10217/82478

Colorado State University

13. Ursic, Michael E. Quantification of shear stress in a meandering native topographic channel using a physical hydraulic model.

Degree: MS(M.S.), Civil and Environmental Engineering, 2007, Colorado State University

URL: http://hdl.handle.net/10217/46915

► Current guidelines for predicting increases in shear stress in open-channel bends were developed from investigations that were primarily prismatic in cross section. This study provides… (more)

Subjects/Keywords: shear stress; Rio Grande; physical model; native topography; meandering bend

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APA (6^th Edition):

Ursic, M. E. (2007). Quantification of shear stress in a meandering native topographic channel using a physical hydraulic model. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/46915

Chicago Manual of Style (16^th Edition):

Ursic, Michael E. “Quantification of shear stress in a meandering native topographic channel using a physical hydraulic model.” 2007. Masters Thesis, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/46915.

MLA Handbook (7^th Edition):

Ursic, Michael E. “Quantification of shear stress in a meandering native topographic channel using a physical hydraulic model.” 2007. Web. 27 Jan 2020.

Vancouver:

Ursic ME. Quantification of shear stress in a meandering native topographic channel using a physical hydraulic model. [Internet] [Masters thesis]. Colorado State University; 2007. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/46915.

Council of Science Editors:

Ursic ME. Quantification of shear stress in a meandering native topographic channel using a physical hydraulic model. [Masters Thesis]. Colorado State University; 2007. Available from: http://hdl.handle.net/10217/46915

Colorado State University

14. Sin, Kyung-Seop. Methodology for calculating shear stress in a meandering channel.

Degree: MS(M.S.), Civil and Environmental Engineering, 2007, Colorado State University

URL: http://hdl.handle.net/10217/44952

► Shear stress in meandering channels is the key parameter to predict bank erosion and bend migration. A representative study reach of the Rio Grande River… (more)

Subjects/Keywords: shear stress; Rozovskii; Reynolds Shear; Preston tube; meandering channel; ADV; Shear strength of soils – Testing; River channels; Erosion

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APA (6^th Edition):

Sin, K. (2007). Methodology for calculating shear stress in a meandering channel. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/44952

Chicago Manual of Style (16^th Edition):

Sin, Kyung-Seop. “Methodology for calculating shear stress in a meandering channel.” 2007. Masters Thesis, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/44952.

MLA Handbook (7^th Edition):

Sin, Kyung-Seop. “Methodology for calculating shear stress in a meandering channel.” 2007. Web. 27 Jan 2020.

Vancouver:

Sin K. Methodology for calculating shear stress in a meandering channel. [Internet] [Masters thesis]. Colorado State University; 2007. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/44952.

Council of Science Editors:

Sin K. Methodology for calculating shear stress in a meandering channel. [Masters Thesis]. Colorado State University; 2007. Available from: http://hdl.handle.net/10217/44952

Colorado State University

15. Sclafani, Paul. Methodology for predicting maximum velocity and shear stress in a sinuous channel with bendway weirs using 1-D HEC-RAS modeling results.

Degree: MS(M.S.), Civil and Environmental Engineering, 2007, Colorado State University

URL: http://hdl.handle.net/10217/39342

► The Middle Rio Grande is a 29-mi reach of the Rio Grande River in central New Mexico that extends from downstream of Cochiti Dam to… (more)

▼ The Middle Rio Grande is a 29-mi reach of the Rio Grande River in central New Mexico that extends from downstream of Cochiti Dam to Bernalillo, New Mexico. A series of anthropogenic factors including the construction of flood control levees and Cochiti Dam have altered the historically-braided morphology of the Middle Rio Grande to a more sinuous, degrading reach, with less overall channel migration within a natural floodplain area. Concentration of flow within an incised channel has caused areas of bank erosion and threatened riverside infrastructure, farmland productivity, irrigation systems, levee function, aquatic habitat, and riparian vegetation. Colorado State University (CSU) constructed an undistorted 1:12 Froude scale, fixed bed, physical model consisting of two channel bend geometries that are characteristic of the Middle Rio Grande reach below Cochiti Dam. Small rock structures extending from the outer bank of the bend into the main channel, referred to as bendway weirs, were constructed within each bend to research methods of stabilizing the outer bank with minimal disruption of sensitive habitat and riparian vegetation. Bendway weirs deflect current from the bank in which they are installed to the center of the channel, thus, moving erosive forces away from a degrading bank, establishing a stable channel, and providing or maintaining aquatic habitat between weir structures. Placement of bendway weirs along a river bank effectively creates two zones of flow: 1) the main or constricted flow where the velocity, shear stresses, and potential for channel degradation are increased, and 2) the area between weirs where velocities and shear stresses are greatly reduced and sediment deposition is encouraged. Design criterion to predict increases in velocity and shear stress caused by placement of bendway weirs in a channel bend has not yet been established. Two-dimensional and three-dimensional computer models have been utilized to describe complex flow phenomena associated with bendway weirs in channel bends; however, such computer models may not be practical for typical design projects (Jia et al., 2005; Molls, et al., 1995; Abad et al., 2008; Seed, 1997). Because of historic precedence, continual development, and prevalence in the engineering community, many engineers use one-dimensional (1-D) computer modeling tools, such as Hydrologic Engineering Center's River Analysis System (HEC-RAS), as a first choice in modeling channel flow. 1-D computer models were developed for the trapezoidal channel geometry present in the physical model and for fifteen weir configurations constructed during testing at CSU. Computed results from the 1-D models were compared to data collected from the Middle Rio Grande physical model. Regression relationships were developed to predict velocities and shear stresses in the trapezoidal channel constructed for physical testing at CSU, at the tips of the constructed bendway weirs, and along the inner bank opposite the constructed bendway weirs. From predictive regression relationships for… Advisors/Committee Members: Thornton, Christopher I. (advisor), Watson, Chester C. (committee member), Wohl, Ellen E., 1962- (committee member).

Subjects/Keywords: Weirs – Rio Grande; River channels – Rio Grande; Channels (Hydraulic engineering) – Rio Grande

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Sclafani, P. (2007). Methodology for predicting maximum velocity and shear stress in a sinuous channel with bendway weirs using 1-D HEC-RAS modeling results. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/39342

Chicago Manual of Style (16^th Edition):

Sclafani, Paul. “Methodology for predicting maximum velocity and shear stress in a sinuous channel with bendway weirs using 1-D HEC-RAS modeling results.” 2007. Masters Thesis, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/39342.

MLA Handbook (7^th Edition):

Sclafani, Paul. “Methodology for predicting maximum velocity and shear stress in a sinuous channel with bendway weirs using 1-D HEC-RAS modeling results.” 2007. Web. 27 Jan 2020.

Vancouver:

Sclafani P. Methodology for predicting maximum velocity and shear stress in a sinuous channel with bendway weirs using 1-D HEC-RAS modeling results. [Internet] [Masters thesis]. Colorado State University; 2007. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/39342.

Council of Science Editors:

Sclafani P. Methodology for predicting maximum velocity and shear stress in a sinuous channel with bendway weirs using 1-D HEC-RAS modeling results. [Masters Thesis]. Colorado State University; 2007. Available from: http://hdl.handle.net/10217/39342

Colorado State University

16. Owen, Tracy Elizabeth. Geomorphic analysis of the Middle Rio Grande - Elephant Butte Reach, New Mexico.

Degree: MS(M.S.), Civil and Environmental Engineering, 2007, Colorado State University

URL: http://hdl.handle.net/10217/65348

► The Elephant Butte Reach spans about 30 miles, beginning from the South Boundary of the Bosque del Apache National Wildlife Refuge (River Mile 73.9) to… (more)

▼ The Elephant Butte Reach spans about 30 miles, beginning from the South Boundary of the Bosque del Apache National Wildlife Refuge (River Mile 73.9) to the "narrows" of the Elephant Butte Reservoir (River Mile 44.65), in central New Mexico. Sediment plugs occasionally form along the Middle Rio Grande, completely blocking the main channel of the river. In 1991, 1995, and 2005, the Tiffany Plug was initiated at the upstream end of the Elephant Butte Reach. In 2008, the Bosque del Apache Plug formed just upstream of the Elephant Butte Reach. Sediment plugs occur at the location of a constriction or channel aggradation (Burroughs 2011). As aggradation within the Elephant Butte Reach is known to contribute to a decrease in channel capacity (Reclamation 2007), it is important to understand the influences of Elephant Butte Reservoir levels on channel aggradation/degradation in order to decrease the potential for future sediment plug formation. Further understanding of the historical and spatial changes within Elephant Butte Reach, along with a better understanding of the influences of Elephant Butte Reservoir levels on channel aggradation/degradation, are essential for improvement in future river management practices along the Middle Rio Grande. Using aerial photographs, survey data, reservoir water surface elevation data, and bed material data, the following objectives are addressed in this study: 1. Quantify temporal changes in channel widths and sinuosity from 1935 to 2010. 2. Quantify change in channel slope temporally. 3. Quantify rate of aggradation/degradation in response to a change in base-level (i.e., change in reservoir water surface elevation). 4. Quantify aggradation/degradation wave propagation upstream. 5. Quantify spatial and temporal trends in bed material grain size. From 1935 to 2010, channel widths and sinuosity decrease over time. The majority of the Reach's channel slope decreases from 1935 to 2010; the downstream-most stretch of the channel, closest to Elephant Butte Reservoir, alternates between increasing and decreasing channel slopes. As the Elephant Butte Reservoir level (base-level) increases, the channel aggrades in response. As the base-level decreases, the channel degrades. The rates of aggradation and degradation vary between different periods of base-level changes, and are quantified within the report. When the base-level changes a wave of aggradation/degradation travels upstream. The rate of wave propagation upstream varies relative to the rate of base-level change, and is quantified within the report for four sets of aggradation/degradation waves. Bed material samples obtained from cross-section surveys and at the San Acacia and San Marcial gauges showed a coarsening at a rate of about 0.03 mm/year. In the downstream direction, bed material became slightly finer. The median bed material grain size ranged from 0.11 mm to 0.26 mm. Advisors/Committee Members: Julien, Pierre (advisor), Thornton, Christopher (committee member), Rathburn, Sara (committee member).

Subjects/Keywords: degradation; Rio Grande; geomorphology; Elephant Butte Reach; aggradation; base-line change

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APA (6^th Edition):

Owen, T. E. (2007). Geomorphic analysis of the Middle Rio Grande - Elephant Butte Reach, New Mexico. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/65348

Chicago Manual of Style (16^th Edition):

Owen, Tracy Elizabeth. “Geomorphic analysis of the Middle Rio Grande - Elephant Butte Reach, New Mexico.” 2007. Masters Thesis, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/65348.

MLA Handbook (7^th Edition):

Owen, Tracy Elizabeth. “Geomorphic analysis of the Middle Rio Grande - Elephant Butte Reach, New Mexico.” 2007. Web. 27 Jan 2020.

Vancouver:

Owen TE. Geomorphic analysis of the Middle Rio Grande - Elephant Butte Reach, New Mexico. [Internet] [Masters thesis]. Colorado State University; 2007. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/65348.

Council of Science Editors:

Owen TE. Geomorphic analysis of the Middle Rio Grande - Elephant Butte Reach, New Mexico. [Masters Thesis]. Colorado State University; 2007. Available from: http://hdl.handle.net/10217/65348

Colorado State University

17. Morozko, Zoe. Feasibility assessment of magnetic sensors for measurement of Hall current induced changes to the static magnetic field nearby a Hall thruster.

Degree: MS(M.S.), Mechanical Engineering, 2007, Colorado State University

URL: http://hdl.handle.net/10217/79123

► A Hall thruster is an electric propulsion device that produces thrust electrostatically by accelerating propellant to velocities 5 to 10 times higher than is achievable… (more)

▼ A Hall thruster is an electric propulsion device that produces thrust electrostatically by accelerating propellant to velocities 5 to 10 times higher than is achievable using conventional chemical thrusters. This is accomplished through the application of static, crossed electric and magnetic fields that are concentrated in a region close to the exit plane of the thruster. During operation an azimuthal plasma-electron current develops in the region where the electric and magnetic fields are concentrated. This embedded plasma current is referred to as the Hall current. The thrust produced from accelerating the propellant is transferred to a satellite or spacecraft through interaction between the Hall current and the magnetic coils used to produce the static magnetic field within the thruster. The Hall current can be calculated and the thrust can be determined in real time by measuring the magnetic field produced by the Hall current using sensors located external to the thruster. This work investigates the feasibility of placing magnetic sensors in the regions close to the exit of the thruster to measure the external magnetic field and correlate it to the Hall current. A finite element magnetic solver was used to identify several locations outside of the thrust plume and near the pole piece where the magnetic field magnitude changes by several Gauss in a background field level of ~50 Gauss. Magnetic sensors based on the giant magnetoresistive effect were identified as acceptable with regard to sensitivity, and measurements made with these sensors in a simulated high background magnetic field environment demonstrated that changes of 0.5 Gauss could be easily measured. This work also presents the development of a thrust stand that will be useful in future work to demonstrate the overall concept. Special focus was directed to the design of the data acquisition system and in-vacuum calibration system used to make measurements with the thrust stand. Advisors/Committee Members: Williams, John (advisor), Stansloski, Mitchell (committee member), Thornton, Christopher (committee member).

Subjects/Keywords: electric propulsion; Hall thruster; magnetic field measurement; magnetic sensors; plasma propulsion; thrust stand

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APA (6^th Edition):

Morozko, Z. (2007). Feasibility assessment of magnetic sensors for measurement of Hall current induced changes to the static magnetic field nearby a Hall thruster. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/79123

Chicago Manual of Style (16^th Edition):

Morozko, Zoe. “Feasibility assessment of magnetic sensors for measurement of Hall current induced changes to the static magnetic field nearby a Hall thruster.” 2007. Masters Thesis, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/79123.

MLA Handbook (7^th Edition):

Morozko, Zoe. “Feasibility assessment of magnetic sensors for measurement of Hall current induced changes to the static magnetic field nearby a Hall thruster.” 2007. Web. 27 Jan 2020.

Vancouver:

Morozko Z. Feasibility assessment of magnetic sensors for measurement of Hall current induced changes to the static magnetic field nearby a Hall thruster. [Internet] [Masters thesis]. Colorado State University; 2007. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/79123.

Council of Science Editors:

Morozko Z. Feasibility assessment of magnetic sensors for measurement of Hall current induced changes to the static magnetic field nearby a Hall thruster. [Masters Thesis]. Colorado State University; 2007. Available from: http://hdl.handle.net/10217/79123

Colorado State University

18. Pierce, Adam L. Prediction of selenium in Spring Creek and Fossil Creek, Colorado.

Degree: MS(M.S.), Ecosystem Science and Sustainability, 2007, Colorado State University

URL: http://hdl.handle.net/10217/88587

► The role and importance of selenium as an environmental contaminant has gained widespread attention among research scientists, natural resource managers, and federal and state regulatory… (more)

▼ The role and importance of selenium as an environmental contaminant has gained widespread attention among research scientists, natural resource managers, and federal and state regulatory agencies during the last two decades. Selenium has been listed on Colorado's Clean Water Act Section 303(d) List of Impaired Waters for Spring Creek and Fossil Creek in the city of Fort Collins. Selenium is one of the most hazardous of the trace metals, following mercury, with a narrow range between dietary deficiency and toxicity. Identifying selenium sources and understanding the environmental processes controlling how selenium is introduced to streams is critical to managing and mitigating the effects of elevated concentrations. A modeling approach was used to predict selenium concentrations with exploratory variables including 15 geospatial landscape parameters, precipitation, and streamflow for 5 sub-watersheds within Spring Creek and Fossil Creek watersheds. A correlation analysis was applied with surface water selenium concentrations and the better exploratory variables identified. Selected variables were used in a multiple linear regression model. Various combinations of different variables determined the best performing model, and included the area of shale, area of moderate to strongly alkaline soils, and the length of streams with an adjusted R2 of 0.99, [Se µg/L = 24.038 + 9.516(ALK) - 0.782(STR) -1.039(SHL)]; where ALK = area (km2) of moderate to strongly alkaline soils; STR = length (km) of streams; SHL = area (km2) of shale. Additional multiple linear regression models were developed in ArcGIS® using Ordinary Least Squares (OLS) Regression, and Geographically Weighted Regression (GWR) with area weighted geospatial variables. The best performing OLS model used only area (km2) of wetlands, with an adjusted R2 of 0.98, [Se µg/L = -6.584 + 170.509(wetlands)]. Similarly, the best performing GWR model included area of wetlands, with an adjusted R2 of 0.98. The second best performing GWR model included area of shale, with an adjusted R2 of 0.66. Limitations of this model include a very small sample size of water quality sampling stations, which limits the statistical power of multiple regression models used. Additional techniques applied in basin delineations with landscape element coupling for identification of hydrologic and/or chemical response units can further develop the platform for future modeling efforts targeting unmonitored watersheds. Advisors/Committee Members: Stednick, John D. (advisor), Boone, Randall B. (committee member), Thornton, Christopher I. (committee member).

Subjects/Keywords: water quality; geospatial; GIS; prediction; regression; selenium

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APA (6^th Edition):

Pierce, A. L. (2007). Prediction of selenium in Spring Creek and Fossil Creek, Colorado. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/88587

Chicago Manual of Style (16^th Edition):

Pierce, Adam L. “Prediction of selenium in Spring Creek and Fossil Creek, Colorado.” 2007. Masters Thesis, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/88587.

MLA Handbook (7^th Edition):

Pierce, Adam L. “Prediction of selenium in Spring Creek and Fossil Creek, Colorado.” 2007. Web. 27 Jan 2020.

Vancouver:

Pierce AL. Prediction of selenium in Spring Creek and Fossil Creek, Colorado. [Internet] [Masters thesis]. Colorado State University; 2007. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/88587.

Council of Science Editors:

Pierce AL. Prediction of selenium in Spring Creek and Fossil Creek, Colorado. [Masters Thesis]. Colorado State University; 2007. Available from: http://hdl.handle.net/10217/88587

Colorado State University

19. Kim, Jaehoon. Hazard area mapping during extreme rainstorms in South Korean mountains.

Degree: PhD, Civil and Environmental Engineering, 2007, Colorado State University

URL: http://hdl.handle.net/10217/80350

► The concern for climate change has increased worldwide. Localized rain storms with high intensity and short duration have been observed in the United States, Europe,… (more)

▼ The concern for climate change has increased worldwide. Localized rain storms with high intensity and short duration have been observed in the United States, Europe, Australia, and China. South Korea is one of the countries that have also been impacted by extreme rainfall events during typhoons. Extreme rainstorms have caused major damage from landslides and debris flows in the South Korean mountains. The Duksan Creek watershed in South Korea was selected to simulate surface runoff using TREX during the extreme rainstorm precipitation event from July 14 to July 16, 2006. The maximum hourly rainfall was 62 mm on July 15 in 2006. The three hour rainfall from 08:00 AM to 11:00AM on this day was 168 mm. This rainstorm triggered 518 landslides and caused major infrastructure damage from debris flows. The three hour rainfall precipitation has a 100 year return period. The TREX model was calibrated in two mountainous regions of South Korea. The relative percent difference of time to peak and peak discharge on the Naerin Stream and the Naesung Stream were 6.25 %, -2.58 % and 1.90 %, -0.25 %, respectively. The TREX simulation at the Duksan Creek was performed at a 30 m resolution with distributed data on topography (DEM), soil type, and land use. The peak discharge from the TREX simulation at the Duksan Creek watershed was 452 m3/s. This value was compared to the results of several other methods and the relative percent difference was -1.1 %. The peak discharge was also compared with specific peak discharge measurements and this value corresponds to the range of values for similar watersheds. The TREX model can calculate the distribution of infiltration depth. The infiltration depth calculation typically ranged from 0.2 m to 0.3m with maximum value of 1.2 m. Based on the infinite slope analysis, such infiltration depths correspond to a critical slope angle of 25° to 29°. This range of the critical slope angle was comparable to the angle of 26° from the field investigations and from the analysis of satellite images and aerial photographs at the Duksan Creek. Several different hazard mapping methods were compared including a landslide hazard map from the Korea Forest Institute (KFRI), SINMAP, and TREX. The result of the relative predictability of TREX was slightly better an improvement of 24.6 % than the result of SINMAP. The maximum shear stress could also be calculated by the TREX model. Values of shear stress typically ranged between 0.223 kPa to 0.895 kPa in the tributaries and 1.79 kPa to 17 kPa in the main channel. Based on a critical shear stress analysis, a 1 m diameter boulder reaches incipient motion at a shear stress of 0.895 kPa. Advisors/Committee Members: Julien, Pierre Y. (advisor), Watson, Chester C. (committee member), Thornton, Christopher I. (committee member), MacDonald, Lee H. (committee member).

Subjects/Keywords: debris flow; extreme event; hazard area; landslide; mapping; mountains

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APA (6^th Edition):

Kim, J. (2007). Hazard area mapping during extreme rainstorms in South Korean mountains. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/80350

Chicago Manual of Style (16^th Edition):

Kim, Jaehoon. “Hazard area mapping during extreme rainstorms in South Korean mountains.” 2007. Doctoral Dissertation, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/80350.

MLA Handbook (7^th Edition):

Kim, Jaehoon. “Hazard area mapping during extreme rainstorms in South Korean mountains.” 2007. Web. 27 Jan 2020.

Vancouver:

Kim J. Hazard area mapping during extreme rainstorms in South Korean mountains. [Internet] [Doctoral dissertation]. Colorado State University; 2007. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/80350.

Council of Science Editors:

Kim J. Hazard area mapping during extreme rainstorms in South Korean mountains. [Doctoral Dissertation]. Colorado State University; 2007. Available from: http://hdl.handle.net/10217/80350

Colorado State University

20. An, Sang Do. Interflow dynamics and three-dimensional modeling of turbid density currents in Imha Reservoir, South Korea.

Degree: PhD, Civil and Environmental Engineering, 2007, Colorado State University

URL: http://hdl.handle.net/10217/70434

► This study reports a detailed research identifying the turbid density flow regimes and propagation dynamics of density currents in Imha Reservoir in South Korea during… (more)

▼ This study reports a detailed research identifying the turbid density flow regimes and propagation dynamics of density currents in Imha Reservoir in South Korea during Typhoon Ewiniar. We employ a high resolution 3-D numerical model (FLOW-3D), based on nonhydrostatic Navier-Stokes equations, to investigate the propagation of density flows resulting from the complicated reservoir morphometry and various mixing processes. The 3-D numerical model was modified to simulate particle-driven density currents. The particle dynamics algorithm builds upon the original FLOW-3D code in two ways: (1) improve the original buoyant flow model to compute the changes in density via particle deposition; and (2) include multiple sediment sizes in mixtures as a function of particle size. The influences of inflow characteristics and seasonal changes of thermal structure of the reservoir on the turbid density currents intruding into Imha Reservoir are studied. A series of numerical simulations of lock-exchange are validated with laboratory experiments on: (1) gravity currents propagating into a two-layered fluid; (2) gravity currents propagating into a stratified fluid; and (3) particle-driven gravity currents. The model predictions of propagation speed compared very well with laboratory experiments and analytical solutions. Two numerical approaches (Reynolds Averaged Navier-Stokes model and large-eddy simulation) are equally effective and robust in predicting propagation speed and interfacial instability compared to the laboratory experiments. The simulation of gravity currents intruding into a stratified fluid matched the theoretical solution derived from an energy model. The modified FLOW-3D model successfully captured the decreasing propagation speed due to the different deposition rates of different particle sizes, compared to experimental measurements. We extended our simulations to include the effects of particle sizes on the propagation dynamics of gravity currents. The type of gravity currents depends on particle sizes and can be subdivided into three zones: (1) When ds, is less than about 10 μm, the particle-driven gravity currents behave like IGC (Intrusive Gravity Currents) and all sediments can remain in suspension. Thus the suspended sediments can increase the density of the currents enough to travel a longer distance; (2) When ds > 40 μm, particles will rapidly settle, resulting in a decrease in excess density of the gravity currents. So, such density currents lose their momentum quickly and rapidly vanish; and (3) When 10 μm ds 40 μm, some particles will settle quickly, but others remain suspended for a long time, affecting the propagation dynamics of the currents. Modeling gravity currents in this regime particle sizes must account for particle dynamics and settling. We applied the FLOW-3D coupled with the particle dynamics algorithm to Imha Reservoir in South Korea. The model application was validated against field measurements during Typhoon Ewiniar in 2006. In the field validation, absolute mean error (AME) and root mean… Advisors/Committee Members: Julien, Pierre Y. (advisor), Thornton, Christopher I. (committee member), Venayagamoorthy, Subhas K. (committee member), Wohl, Ellen E. (committee member).

Subjects/Keywords: computational fluid dynamics (CFD); density currents; environmental engineering; gravity currents; reservoir; turbidity currents

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APA (6^th Edition):

An, S. D. (2007). Interflow dynamics and three-dimensional modeling of turbid density currents in Imha Reservoir, South Korea. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/70434

Chicago Manual of Style (16^th Edition):

An, Sang Do. “Interflow dynamics and three-dimensional modeling of turbid density currents in Imha Reservoir, South Korea.” 2007. Doctoral Dissertation, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/70434.

MLA Handbook (7^th Edition):

An, Sang Do. “Interflow dynamics and three-dimensional modeling of turbid density currents in Imha Reservoir, South Korea.” 2007. Web. 27 Jan 2020.

Vancouver:

An SD. Interflow dynamics and three-dimensional modeling of turbid density currents in Imha Reservoir, South Korea. [Internet] [Doctoral dissertation]. Colorado State University; 2007. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/70434.

Council of Science Editors:

An SD. Interflow dynamics and three-dimensional modeling of turbid density currents in Imha Reservoir, South Korea. [Doctoral Dissertation]. Colorado State University; 2007. Available from: http://hdl.handle.net/10217/70434

Colorado State University

21. Robeson, Michael D. Pressure flow effects on scour at bridges.

Degree: MS(M.S.), Civil Engineering, 2007, Colorado State University

URL: http://hdl.handle.net/10217/37826

► Scour caused by the occurrence of pressure flow requires a comprehensive understanding. Pressure flow can be defined as flow in which the low chord of… (more)

▼ Scour caused by the occurrence of pressure flow requires a comprehensive understanding. Pressure flow can be defined as flow in which the low chord of a bridge becomes inundated and the flow through the bridge opening transitions from free surface flow to a pressurized condition, leading to a submerged or partially submerged bridge deck condition. A pressure flow condition often occurs at a bridge during a flood, potentially leading to bridge failure. Scour of bridge foundations (piers and abutments) represents the largest single cause of bridge failure in the United States (ASCE, 1999). Methodical scour research began in 1949 with the research of E.M. Laursen. Unfortunately, the application of scour research to the design of bridges did not occur until several bridges failed due to local scour. Over the years, bridge scour research has focused on the study of free surface flow. During the past decade, research related to pressure flow scour has become increasingly important. A testing program was developed and performed at the Hydraulics Laboratory of Colorado State University to examine pressure flow effects on scour at and around bridges. Flume experiments were conducted incorporating a physical model of a generic bridge with supporting abutments constructed at an approximate scale of 8:1. In an effort to simulate varying magnitudes of a pressure flow condition, the model was constructed in a manner that permitted the bridge deck to be lowered into the flow. By lowering the bridge deck and holding the level of the approach flow constant, multiple levels of deck submergence could be examined. Six vertical bridge positions, three discharges, two abutment widths and two sediment sizes were incorporated into a matrix comprising 69 tests. Data collected included hydraulic parameters and topographic surveys. Analysis of data collected during the study resulted in the formulation of a set of multivariate linear regression equations enabling the user to estimate abutment, local and deck scour depths during a pressure flow condition. Results of a dimensional analysis indicate that the dominant variables in predicting scour depths for a pressure flow condition include; the critical velocity of a given sediment size, the average velocity under the bridge deck, the height of the bridge deck above the initial and final bed surface, the depth of flow upstream of the bridge and the Froude number of the approach flow. Coefficients of determination for the developed equations ranged from 0.82 to 0.95. Advisors/Committee Members: Thornton, Christopher I. (advisor), Abt, Steven R. (committee member), Arneson, Larry A. (committee member), Doe, William W. (committee member).

Subjects/Keywords: Scour at bridges; Scour (Hydraulic engineering)

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APA (6^th Edition):

Robeson, M. D. (2007). Pressure flow effects on scour at bridges. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/37826

Chicago Manual of Style (16^th Edition):

Robeson, Michael D. “Pressure flow effects on scour at bridges.” 2007. Masters Thesis, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/37826.

MLA Handbook (7^th Edition):

Robeson, Michael D. “Pressure flow effects on scour at bridges.” 2007. Web. 27 Jan 2020.

Vancouver:

Robeson MD. Pressure flow effects on scour at bridges. [Internet] [Masters thesis]. Colorado State University; 2007. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/37826.

Council of Science Editors:

Robeson MD. Pressure flow effects on scour at bridges. [Masters Thesis]. Colorado State University; 2007. Available from: http://hdl.handle.net/10217/37826

Colorado State University

22. Holmquist-Johnson, Christopher Lee. Numerical analysis of river spanning rock U-weirs: evaluating effects of structure geometry on local hydraulics.

Degree: PhD, Civil and Environmental Engineering, 2007, Colorado State University

URL: http://hdl.handle.net/10217/50677

► River spanning rock weirs are being constructed for water delivery as well as to enable fish passage at barriers and provide or improve the aquatic… (more)

▼ River spanning rock weirs are being constructed for water delivery as well as to enable fish passage at barriers and provide or improve the aquatic habitat for endangered fish species. Many design methods are based upon anecdotal information applicable to narrow ranges of channel conditions and rely heavily on field experience and engineering judgment. Without an accurate understanding of physical processes associated with river spanning rock weirs, designers cannot address the failure mechanisms of these structures. This research examined the applicability of a Computational Fluid Dynamics (CFD) model, U2RANS, to simulate the complex flow patterns associated with numerous U-weir configurations. 3D numerical model simulations were used to examine the effects of variations in U-weir geometry on local hydraulics (upstream water surface elevations and downstream velocity and bed shear stress). Variations in structure geometry included: arm angle, arm slope, drop height, and throat width. Various combinations of each of these parameters were modeled at five flow rates: 1/10 bankfull discharge, 1/5 bankfull discharge, 1/3 bankfull discharge, 2/3 bankfull discharge and bankfull discharge. Numerical modeling results duplicated both field observations and laboratory results by quantifying high shear stress magnification near field and lab scour areas and low shear stress magnification near field and lab depositional areas. The results clearly showed that by altering the structure geometry associated with U-weirs, local flow patterns such as upstream flow depth, downstream velocity, and bed shear stress distributions could be altered significantly. With the range of parameters tested, the maximum increase in channel velocity ranged from 1.24 to 4.04 times the reference velocity in the channel with no structure present. Similarly, the maximum increase in bed shear stress caused by altering structure geometry ranged from 1.57 to 7.59 times the critical bed shear stress in the channel for a given bed material size. For the range of structure parameters and channel characteristics modeled, stage-discharge relationships were also developed utilizing output from the numerical model simulations. These relationships are useful in the design process when estimating the backwater effect from a structure for irrigation diversion as well as determining the spacing between structures when multiple structures are used in series. Recommendations were also made, based on the analysis and conclusions gathered from the current study, for further research. The analysis and results of the current study as well as laboratory studies conducted by Colorado State University and field reconnaissance by the Bureau of Reclamation provide a process-based method for understanding how structure geometry affects flow characteristics, scour development, fish passage, water delivery, and overall structure stability. Results of the numerical modeling allow designers to utilize the methods and results of the analysis to determine the appropriate U-weir… Advisors/Committee Members: Watson, Chester C. (advisor), Abt, Steven R. (committee member), Thornton, Christopher I. (committee member), Doe, William (committee member).

Subjects/Keywords: River restoration; Rock weirs

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APA (6^th Edition):

Holmquist-Johnson, C. L. (2007). Numerical analysis of river spanning rock U-weirs: evaluating effects of structure geometry on local hydraulics. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/50677

Chicago Manual of Style (16^th Edition):

Holmquist-Johnson, Christopher Lee. “Numerical analysis of river spanning rock U-weirs: evaluating effects of structure geometry on local hydraulics.” 2007. Doctoral Dissertation, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/50677.

MLA Handbook (7^th Edition):

Holmquist-Johnson, Christopher Lee. “Numerical analysis of river spanning rock U-weirs: evaluating effects of structure geometry on local hydraulics.” 2007. Web. 27 Jan 2020.

Vancouver:

Holmquist-Johnson CL. Numerical analysis of river spanning rock U-weirs: evaluating effects of structure geometry on local hydraulics. [Internet] [Doctoral dissertation]. Colorado State University; 2007. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/50677.

Council of Science Editors:

Holmquist-Johnson CL. Numerical analysis of river spanning rock U-weirs: evaluating effects of structure geometry on local hydraulics. [Doctoral Dissertation]. Colorado State University; 2007. Available from: http://hdl.handle.net/10217/50677

Colorado State University

23. Park, Kiyoung. Mechanics of sediment plug formation in the Middle Rio Grande, NM.

Degree: PhD, Civil and Environmental Engineering, 2007, Colorado State University

URL: http://hdl.handle.net/10217/80965

► The Rio Grande is a dynamic river system which has experienced significant hydraulic and geomorphic changes through recorded history from the early 1900's to the… (more)

▼ The Rio Grande is a dynamic river system which has experienced significant hydraulic and geomorphic changes through recorded history from the early 1900's to the present. These changes stem, for the most part, from natural and human interventions to the river system, which experienced channel bed elevation changes, lateral migration, straightening, channel realignment, etc. Sediment plugs have formed in the Tiffany area near San Marcial in 1991, 1995, and 2005, and in the Bosque Reach 14 miles upstream from the Tiffany plug location in 2008. Many authors have investigated the cause of sediment plugs in the Middle Rio Grande but the previous studies do not provide a complete criteria for sediment plug formation. Better understanding of the complex mechanics of plug formation on the Middle Rio Grande is therefore pursed. Based on the historic flow and geometric characteristics of plug areas, seven parameters were identified as major causing factors of sediment plug formation in the Middle Rio Grande: (1) two geometric factors: variability of channel widths and roughness; (2) two water and sediment loss factors: perching/overbanking and sediment concentration distribution profiles; and (3) three backwater effect factors: backwater effects from a reservoir, a bridge, and sharp bends. The purpose of this research is to analyze possible sediment plug parameters and to assess the primary causing factors. The specific objectives are to: (1) investigate the mechanics of sedimentation effect due to each factor; (2) simulate the historic sediment plugs using a numerical aggradation/degradation program; and (3) determine which factors contribute the most to the formation of sediment plugs. Geometric factors show that the channel has narrowed 40% between 1962 and 2002 and channel capacity has 77% decreased over time. The representative composite roughness increased 50 % between 1992 and 2002. Accordingly sediment transport capacity has decreased 45%. The narrowing (40%) with increase in roughness (50%) causes considerable loss of sediment transport capacity (45%). Therefore geometric factors induce more overbank flows and channel bed aggradation. Sedimentation factors show that the perching ratio increased from 13% to 87% between 1992 and 2002. Bank depth has decreased 51% between 1992 and 2002. The perching and lower bank depth facilitated more overbank flows and 13 ~ 20% loss of water. As particle sizes have coarsened (0.2mm in 1992 → 0.25mm in 2002) and width/depth ratios have increased (129 in 1992 → 229 in 2002), leading to higher rouse numbers and more near-bed concentration profiles. High Rouse number (Ro >1.2) and near-bed sediment concentration profile speed up the aggradation rates (4 ~ 7 times faster) than for a uniform-concentration profile. The high near-bed concentrations shorten the plug formation time from 90 to 20 days. Since snowmelt floods exceed bankfull discharges less than 2 months, the acceleration factors are essential for sediment plugs to form. Backwater effects from the Elephant… Advisors/Committee Members: Julien, Pierre Y. (advisor), Thornton, Christopher I. (committee member), Venayagamoorthy, Subhas K. (committee member), Wohl, Ellen E. (committee member).

Subjects/Keywords: perching; Rouse number; Rio Grande; channel width; numerical models; sediment transport capacity

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APA (6^th Edition):

Park, K. (2007). Mechanics of sediment plug formation in the Middle Rio Grande, NM. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/80965

Chicago Manual of Style (16^th Edition):

Park, Kiyoung. “Mechanics of sediment plug formation in the Middle Rio Grande, NM.” 2007. Doctoral Dissertation, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/80965.

MLA Handbook (7^th Edition):

Park, Kiyoung. “Mechanics of sediment plug formation in the Middle Rio Grande, NM.” 2007. Web. 27 Jan 2020.

Vancouver:

Park K. Mechanics of sediment plug formation in the Middle Rio Grande, NM. [Internet] [Doctoral dissertation]. Colorado State University; 2007. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/80965.

Council of Science Editors:

Park K. Mechanics of sediment plug formation in the Middle Rio Grande, NM. [Doctoral Dissertation]. Colorado State University; 2007. Available from: http://hdl.handle.net/10217/80965

Colorado State University

24. Cox, Amanda L. Moment stability analysis method for determining safety factors for articulated concrete blocks.

Degree: PhD, Civil and Environmental Engineering, 2007, Colorado State University

URL: http://hdl.handle.net/10217/39324

► Articulated concrete block (ACB) revetment systems are widely used for channel lining and embankment protection. Available information pertaining to testing and analysis of ACB systems… (more)

Subjects/Keywords: revetment; moment stability analysis; factor of safety; embankment stability; articulated concrete blocks; Concrete blocks – Stability; Slopes (Soil mechanics) – Stability; Embankments – Design and construction – Testing; Retaining walls – Design and construction – Testing

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APA (6^th Edition):

Cox, A. L. (2007). Moment stability analysis method for determining safety factors for articulated concrete blocks. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/39324

Chicago Manual of Style (16^th Edition):

Cox, Amanda L. “Moment stability analysis method for determining safety factors for articulated concrete blocks.” 2007. Doctoral Dissertation, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/39324.

MLA Handbook (7^th Edition):

Cox, Amanda L. “Moment stability analysis method for determining safety factors for articulated concrete blocks.” 2007. Web. 27 Jan 2020.

Vancouver:

Cox AL. Moment stability analysis method for determining safety factors for articulated concrete blocks. [Internet] [Doctoral dissertation]. Colorado State University; 2007. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/39324.

Council of Science Editors:

Cox AL. Moment stability analysis method for determining safety factors for articulated concrete blocks. [Doctoral Dissertation]. Colorado State University; 2007. Available from: http://hdl.handle.net/10217/39324

Colorado State University

25. Ahn, Jungkyu. Numerical modeling of reservoir sedimentation and flushing processes.

Degree: PhD, Civil and Environmental Engineering, 2007, Colorado State University

URL: http://hdl.handle.net/10217/70431

► As rivers flow into reservoirs, part of the transported sediment will be deposited. Sedimentation in the reservoir may significantly reduce reservoir storage capacity. Reservoir capacity… (more)

▼ As rivers flow into reservoirs, part of the transported sediment will be deposited. Sedimentation in the reservoir may significantly reduce reservoir storage capacity. Reservoir capacity can be recovered by removing deposited sediment by dredging or flushing. Generally speaking, the latter is preferable to the former. An accurate estimation sedimentation volume and its removal are required for the development of a long term operation plan in the design stage. One-dimensional, 1D, models are more suitable for a long term simulation of channel cross section change of a long study reach than two or three dimensional models. A 1D model, GSTARS3, was considered, because this study focuses on sedimentation and flushing in the entire reservoir over several years and GSTARS3 can predict channel geometry in a semi-two dimensional manner by using the stream tube concept. However, like all 1D numerical models, GSTARS3 is based on some simplified assumptions. One of the major assumptions made for GSTARS3 is steady or quasi-steady flow condition, which is valid for most reservoir operation. If there is no significant flow change in a reservoir, such as rapid water surface drop during flushing, steady model can be applied. However, unsteady effect due to the flushing may not be ignored and should be considered for the numerical modeling of flushing processes. Not only flow characteristics but also properties of bed materials in reservoir regime may be different from those in a river regime. Both reservoir and river regimes should be considered for a drawdown flushing study. Flow in the upper part of a reservoir may become river flow during a drawdown flushing operation. A new model, GSTARS4 (Yang and Ahn, 2011) was developed for reservoir sedimentation and flushing simulations in this study. It has the capabilities of simulating unsteady flow and coexistence of river and reservoir regimes in the study area. GSTARS4 was applied to the Xiaolangdi Reservoir, located on the main stream of the Yellow River. The sediment concentration in the reservoir is very high, 10 ~ 100 kg/m3 for common operation and 100 ~ 300 kg/m3 for flushing operation, with very fine materials about 20 ~ 70 % of clay. Stability criteria for computing sediment transport and channel geometric changes by using GSTARS4 model was derived and verified for the Xiaolangdi Reservoir sedimentation and flushing computations. Han's (1980) non-equilibrium sediment transport equation and the modified unit stream power equation for hyper-concentrated sediment flows by Yang et al. (1996) were used. Both unsteady and quasi-steady simulations were conducted for 3.5 years with calibrated site-specific coefficients of the Xiaolangdi Reservoir. The computed thalweg elevation, channel cross section, bed material size, volume of reservoir sedimentation, and gradation of flushed sediments were compared with the measured results. The unsteady computation results are closer to the measurements than those of the steady flow simulation results. Advisors/Committee Members: Yang, Chih Ted (advisor), Julien, Pierre Y. (committee member), Thornton, Christopher I. (committee member), Wohl, Ellen E. (committee member).

Subjects/Keywords: flushing; GSTARS; modeling; reservoir; sedimentation; sediment

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Ahn, J. (2007). Numerical modeling of reservoir sedimentation and flushing processes. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/70431

Chicago Manual of Style (16^th Edition):

Ahn, Jungkyu. “Numerical modeling of reservoir sedimentation and flushing processes.” 2007. Doctoral Dissertation, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/70431.

MLA Handbook (7^th Edition):

Ahn, Jungkyu. “Numerical modeling of reservoir sedimentation and flushing processes.” 2007. Web. 27 Jan 2020.

Vancouver:

Ahn J. Numerical modeling of reservoir sedimentation and flushing processes. [Internet] [Doctoral dissertation]. Colorado State University; 2007. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/70431.

Council of Science Editors:

Ahn J. Numerical modeling of reservoir sedimentation and flushing processes. [Doctoral Dissertation]. Colorado State University; 2007. Available from: http://hdl.handle.net/10217/70431

Colorado State University

26. Scurlock, Stephen Michael. Quantification of hydraulic effects from transverse instream structures in channel bends.

Degree: PhD, Civil and Environmental Engineering, 2007, Colorado State University

URL: http://hdl.handle.net/10217/82534

► Meandering river channels possess hydraulic and geomorphic characteristics that occasionally place anthropogenic interests at risk. Loss of valuable land holdings and infrastructure due to outer-bank… (more)

▼ Meandering river channels possess hydraulic and geomorphic characteristics that occasionally place anthropogenic interests at risk. Loss of valuable land holdings and infrastructure due to outer-bank channel encroachment from erosion processes and complications for channel-bend navigation have prompted development of techniques for reconfiguration of instream hydraulics. Transverse instream structures are one type of technique and have been implemented in channel bends to reduce outer-bank erosivity and improve navigability. Instream structures use less material and have ecological and habitat benefits over traditional revetment type bank protection. Structures are typically constructed in series, extend from the outer-bank into the channel center, and are designed with various crest heights and slopes. Current design recommendations for the structures in natural channels provide generalized ranges of geometric parameters only; no specific information pertaining to hydraulic reconfiguration is provided. Understanding specific hydraulic response to alteration of geometric structure parameters is requisite for educated structure design. Focusing on two types of transverse instream structures, the spur-dike and vane, a mathematical design tool was developed for the quantification and prediction of induced hydraulic response. A series of dimensionless groupings were formulated using parameters obtainable from field data of natural channels and grouped using dimensional analysis. Each dimensionless grouping had an identifiable hydraulic influence on induced hydraulics. A conglomerate mathematical expression was established as the framework for induced instream structure quantification. The mathematical model was tailored to produce twenty-four hydraulic relationships through regression analysis utilizing a robust physical model dataset collected within rigid-bed, trapezoidal channel bends. Average and maximum velocity and boundary shear-stress data were segmented into outer-bank, centerline, and inner-bank regions and then normalized by bend-averaged baseline conditions. Velocity equations were developed for an all-structure dataset, a spur-dike dataset, and a vane dataset. Boundary shear-stress equations were developed for spur-dike structures only. Regression equations quantified laboratory hydraulics to a high level of accuracy. Equation response to independent parameter alteration coincided with continuity principles and physical hydraulic expectations. Methods performed well in application to extraneous natural channel data from the literature. Developed methodologies from this research presented a fundamental addition to the current design procedures for the installation of structures in migrating channel bends. Quantification of the reduction of outer-bank erosive potential and increase at the shifted conveyance zone within natural channels was made possible using readily measured field data and the proposed methodology. Equations allow for previously unattainable investigation of… Advisors/Committee Members: Thornton, Christopher I. (advisor), Abt, Steven R. (committee member), Venayagamoorthy, Subhas K. (committee member), Wohl, Ellen E. (committee member).

Subjects/Keywords: restoration; rivers; spur dike; vane; hydraulics

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APA (6^th Edition):

Scurlock, S. M. (2007). Quantification of hydraulic effects from transverse instream structures in channel bends. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/82534

Chicago Manual of Style (16^th Edition):

Scurlock, Stephen Michael. “Quantification of hydraulic effects from transverse instream structures in channel bends.” 2007. Doctoral Dissertation, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/82534.

MLA Handbook (7^th Edition):

Scurlock, Stephen Michael. “Quantification of hydraulic effects from transverse instream structures in channel bends.” 2007. Web. 27 Jan 2020.

Vancouver:

Scurlock SM. Quantification of hydraulic effects from transverse instream structures in channel bends. [Internet] [Doctoral dissertation]. Colorado State University; 2007. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/82534.

Council of Science Editors:

Scurlock SM. Quantification of hydraulic effects from transverse instream structures in channel bends. [Doctoral Dissertation]. Colorado State University; 2007. Available from: http://hdl.handle.net/10217/82534

Colorado State University

27. Robeson, Michael D. Unification of large-scale laboratory rainfall erosion testing.

Degree: PhD, Civil and Environmental Engineering, 2007, Colorado State University

URL: http://hdl.handle.net/10217/88533

► Water pollution degrades surface waters making them unsafe for drinking, fishing, swimming, and other activities. The movement of sediment and pollutants carried by sediment over… (more)

Subjects/Keywords: testing; erosion; laboratory; rainfall

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Robeson, M. D. (2007). Unification of large-scale laboratory rainfall erosion testing. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/88533

Chicago Manual of Style (16^th Edition):

Robeson, Michael D. “Unification of large-scale laboratory rainfall erosion testing.” 2007. Doctoral Dissertation, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/88533.

MLA Handbook (7^th Edition):

Robeson, Michael D. “Unification of large-scale laboratory rainfall erosion testing.” 2007. Web. 27 Jan 2020.

Vancouver:

Robeson MD. Unification of large-scale laboratory rainfall erosion testing. [Internet] [Doctoral dissertation]. Colorado State University; 2007. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/88533.

Council of Science Editors:

Robeson MD. Unification of large-scale laboratory rainfall erosion testing. [Doctoral Dissertation]. Colorado State University; 2007. Available from: http://hdl.handle.net/10217/88533

Colorado State University

28. Sin, Kyung-Seop. Three-dimensional computational modeling of curved channel flow.

Degree: PhD, Civil and Environmental Engineering, 2007, Colorado State University

URL: http://hdl.handle.net/10217/88539

► Investigating flow dynamics in curved channels is a challenging problem due to its complex three-dimensional flow structure. Despite the numerous investigations that have been performed… (more)

▼ Investigating flow dynamics in curved channels is a challenging problem due to its complex three-dimensional flow structure. Despite the numerous investigations that have been performed on this important topic over the last several decades, there remains much to be understood. The focus of this dissertation is on flow around curved channel bends with an emphasis on the use of three-dimensional numerical simulations to provide insights on the flow dynamics in channel bends. In particular, the answers to the following two main questions are sought: 1) when is it appropriate to use the rigid lid assumption for simulating flow around bends?; and 2) what is (are) the most relevant parameters for quantifying the enhanced shear stress in channel bends from a practical standpoint? A computational fluid dynamics framework was developed using the ANSYS Fluent code and validated using experimental flume data. Following the validation study, a total of 26 simulations were performed and the results analysed in an attempt to answer the two main questions. In an attempt to answer the first question, a broad parametric study was conducted using both free surface resolving simulations as well as simulations that make use of the rigid lid assumption. It is shown that the two main parameters that appear to control the flow dynamics in a bend are the maximum bend angle, expressed as the ratio of the length of the channel bend Lc to its radius of curvature Rc, and the upstream Froude number. Analysis reveal when that Lc/Rc ≥ π/2, the curvature effects begin to dominate the dynamics and the error between the free surface model and the rigid lid model dramatically increases regardless of the value of the Froude number. The study calls for caution to be used when using the rigid lid assumption and indicates that this assumption should not be used for simulating flows when Lc/Rc ≥ π/2, especially for sharply curved channels with a radius of curvature to top width ratio Rc/Tw < 2. The increase in shear stress is commonly expressed as a Kb value, which is simply the ratio of shear stress in a bend of the channel to the averaged approach shear stress in a straight channel. The results from the parametric study show that the conventional approach for parameterizing Kb as a function of Rc/Tw, where Rc is the radius of curvature and Tw is the channel top width, appears to be inadequate because the distributions in the Kb values exhibit significant scatter for small changes in Rc/Tw i.e. for flow around sharply curved bends. Dimensional analysis reveals that for a given channel cross-section, constant flow rate, bed slope and channel bed roughness, Kb depends on both Lc/Rc and Rc/Tw. In this study, the combined effects of these two parameters were investigated. It is shown from the parametric study that the magnitude of the shear stress increases as a function of Lc/Rc and reaches an asymptotic limit as Lc/Rc > π/2, for Rc/Tw < 2. The study also highlights that the location of the maximum shear stress occurs in the inner (convex) side of the bend… Advisors/Committee Members: Venayagamoorthy, Subhas K. (advisor), Thornton, Christopher I. (advisor), Abt, Steven R. (committee member), Julien, Pierre Y. (committee member), Dasi, Lakshmi P. (committee member).

Subjects/Keywords: computational fluid dynamics; curved channel flow; free surface model; rigid-lid model; RNG k-e model; shear stress

Record Details Similar Records Cite « Share

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Sin, K. (2007). Three-dimensional computational modeling of curved channel flow. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/88539

Chicago Manual of Style (16^th Edition):

Sin, Kyung-Seop. “Three-dimensional computational modeling of curved channel flow.” 2007. Doctoral Dissertation, Colorado State University. Accessed January 27, 2020. http://hdl.handle.net/10217/88539.

MLA Handbook (7^th Edition):

Sin, Kyung-Seop. “Three-dimensional computational modeling of curved channel flow.” 2007. Web. 27 Jan 2020.

Vancouver:

Sin K. Three-dimensional computational modeling of curved channel flow. [Internet] [Doctoral dissertation]. Colorado State University; 2007. [cited 2020 Jan 27]. Available from: http://hdl.handle.net/10217/88539.

Council of Science Editors:

Sin K. Three-dimensional computational modeling of curved channel flow. [Doctoral Dissertation]. Colorado State University; 2007. Available from: http://hdl.handle.net/10217/88539

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