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Morphodynamic modeling of flow and sediment transport over low-head, Run-of-River dams

dc.contributor.authorQueen, Robert William, author
dc.contributor.authorNeslon, Peter A., advisor
dc.contributor.authorRathburn, Sara L., committee member
dc.contributor.authorMorrison, Ryan R., committee member
dc.date.accessioned2018-09-10T20:05:45Z
dc.date.available2018-09-10T20:05:45Z
dc.date.issued2018
dc.description.abstractLow-head or Run-of-River (RoR) dams exist on all types of rivers throughout the United States, yet the exact mechanisms of how sediment moves around the structures have not been well researched. Due to the increasing use of RoR dams in small hydroelectric projects, there is a need to better understand the controlling factors of how sediment passes over these dams. A one-dimensional morphodynamic model was developed to investigate the effects of RoR dams on channel morphology over long time scales. The model solves the gradually varied flow equations to compute the flow field in the vicinity of the dam, computes grain-size-specific sediment transport rates, and uses sediment mass conservation and vertical storage bookkeeping to calculate the evolution of bed elevation, the bed surface grain-size distribution, and the vertical pattern of stratigraphy. The model's hydraulic calculations were calibrated using data collected from a series of flume experiments performed with a model RoR dam to better capture the non-hydrostatic flow over a dam. Numerical experiments designed to investigate how the grain-size distribution of the sediment supply rate, flow rate (steady and unsteady), and dam height act as controls on sediment passage over RoR dams were conducted using parameters reported in the literature for a RoR dam in northern Delaware.These one-dimensional simulations were complemented with a few simulations using, a two-dimensional morphodynamic model, Nays2DH. The 1D simulation results show that the stored sediment upstream of RoR dams does depend on the sediment supply, dam height, grain-size and flow discharge. Once sedimentation in the reservoir has reached equilibrium, high flow events will reduce or scour the sediment while lower flows will typically increase the amount of sediment behind the dam. Finally, a dam that stores more sediment will have greater downstream effects in terms of changes to grain-sizes and bed elevation due to the increased time it takes to pass sediment over the dam and reach an equilibrium condition on the upstream side of the dam.
dc.format.mediumborn digital
dc.format.mediummasters theses
dc.identifierQueen_colostate_0053N_15072.pdf
dc.identifier.urihttps://hdl.handle.net/10217/191474
dc.languageEnglish
dc.language.isoeng
dc.publisherColorado State University. Libraries
dc.relation.ispartof2000-2019
dc.rightsCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.
dc.subjectmorphodynamic modeling
dc.subjectrun-of-river dams
dc.subjecthydraulics
dc.subjectsediment transport
dc.subjectnumerical modeling
dc.titleMorphodynamic modeling of flow and sediment transport over low-head, Run-of-River dams
dc.typeText
dcterms.rights.dplaThis Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).
thesis.degree.disciplineCivil and Environmental Engineering
thesis.degree.grantorColorado State University
thesis.degree.levelMasters
thesis.degree.nameMaster of Science (M.S.)

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