Ubing, Caroline, authorThornton, Christopher, advisorEttema, Robert, advisorBledsoe, Brian, committee memberWohl, Ellen, committee member2015-08-272015-08-272015http://hdl.handle.net/10217/166972This 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 structures comprise one to two parallel rows of posts that extend slightly higher than the anticipated depth of flow, and offer a useful means for retarding flow in various channel situations where there is a need to reduce flow energy, possibly to reduce flow capacity to transport bed sediment and manage channel morphology. Observations and data regarding headloss and discharge coefficients and backwater flow profiles associated with varying structure geometry were obtained so as to determine the extent to which a baffle-post structure will retard an approach flow and reduces its capacity to convey bed sediment. The creation of a M₁ gradually varied flow profile in the upstream reach complicates the use of headloss to characterize hydraulic performance of the baffle-post structures. Instead, the parameter, y₁/y₀, offers a practical means for describing such performance; y₁= flow depth at the upstream face of the structure, and y₀= the depth of uniform flow prior to use of a structure. The most influential geometric variable was influencing structure performance was the lateral spacing between posts, s; it is expressed non-dimensionally as s/D, where D = post diameter. Qualitative results regarding sediment transport confirm a reduction in bed-sediment transport rate upstream of the structure. However, the turbulent flow structures at the baffle-post structures promote local scour at the base of such structures. Due to the flow acceleration between posts, baffle-posts structures could potentially obstruct fish and other aquatic life passage along the channel.born digitalmasters thesesengCopyright 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.grade control structureshydraulic structuresflow controlsediment transporthead loss coefficientText