Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 69 for “"Streambed"”.
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Characterizing Groundwater Discharge from a Cobble Armored Streambed, Alder Creek, Ontario, Canada
… with cobbles 1-15 cm in diameter lining the streambed and a straight channel with minimal cobbles visibly present on the sediment surface. The reaches were surveyed to determine the velocities of water crossing the GWSWIn for the purpose of assessing the mechanics of flow in the shallow …
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Prediction of Gravel Streambed Embeddedness Using Explainable AI and Machine Learning Techniques
Excess fine sediments (<2 mm) in gravel streambeds can negatively impact river habitats by reducing porosity and interparticle flow. Human activities have increased fine sediment inputs into river systems, leading to higher embeddedness in gravel streambeds. Embeddedness, also called colmation or …
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The Role of Streambed Biofilms in The Removal of Biodegradable Contaminants From Shallow Streams
Previous research has demonstrated that streambed biofilms are important in contaminant removal in shallow streams. However, the ability to predict the rate at which this removal occurs did not exist. To develop a model describing streambed biofilm activity, experiments were conducted in an 8-meter …
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Comparing Reach Scale Hyporheic Exchange and Denitrification Induced by Instream Restoration Structures and Natural Streambed Morphology
… exchange and on denitrification, including streambed hydraulic conductivity, natural or background stream topography and slope, and groundwater levels. Type and number of instream structures also influenced surface water-groundwater exchange and denitrification, but to a lesser degree, and …
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A three dimension hyporheic model of the River Bure: Understanding the nutrient dynamics and the role of streambed heterogeneity
… hydraulic modeling results indicate that streambed discharge significantly influences hyporheic exchange. Especially, the residence times under average stream discharge conditions are higher than the ones under the high discharge conditions mostly on the part that has riffle - pool …
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Seepage of Groundwater into the St. Clair River Near Sarnia, Ontario, Canada
… and source(s) of groundwater seepage from the streambed into the St. Clair River in the vicinity of Sarnia, Ontario, Canada. Seventeen survey lines were installed on the bed of the St. Clair River in a 100 m by 7 km band between Sarnia Bay and the Sarnia Indian Reserve. The survey lines …
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Relations among benthic macroinvertebrates and concentrations and distributions of trace elements using water chemistry, streambed sediment, transplanted bryophytes on the Uncompahgre River, Colorado
Includes bibliographical references (pages 100-111).
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Multi-scale hydrogeomorphic influences on bull trout spawning habitat in snowmelt-dominated headwater streams
… finest available textural facies. In subreach streambed sections hosting bull trout redds, redd density was significantly (at α=0.05) positively related to bankfull Shields stress (τ*bf, p=0.04) and bankfull Shields stress adjusted for grain stress only (τ**bf, p=0.02). In stream reaches …
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Multi-scale hydrogeomorphic influences on bull trout spawning habitat in snowmelt-dominated headwater streams
… finest available textural facies. In subreach streambed sections hosting bull trout redds, redd density was significantly (at α=0.05) positively related to bankfull Shields stress (τ*bf, p=0.04) and bankfull Shields stress adjusted for grain stress only (τ**bf, p=0.02). In stream reaches …
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Flow and reactive transport modeling at the stream-groundwater interface
… transformation and attenuation of these solutes. Streambed structures enhance these processes by increased water and solute exchange across this interface, denoted as hyporheic exchange. This thesis investigates the influence of hydrological and morphological factors on hyporheic water and solute …
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Experimental Evaluation of Three Backward Transit Time Distributions (bTTD) for Solute Storage and Release During Hyporheic Exchange
… by trapping less reactive contaminants in streambed sediments that are then slowly released back to the stream over time. In this study we evaluated three different analytical representations of the backward transit time distribution (bTTD) of water leaving the hyporheic zone, corresponding …
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Spatial Variability in Seepage from Unlined, Open Channels
… pressure information collected in surface water, streambed porous media, and groundwater in one-dimensional analytical or one-, two-, or even three-dimensional (1D, 2D, or 3D) numerical models that combine heat transport and fluid flux equations. This work compared the advantages and limitations …
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Legacies of Early 20th Century Logging in Southern Appalachian Streams
… streams and averaged 417 m³ of wood/ha of streambed. Logged streams had significantly less wood (1.1 m³ of wood/ha of stream), probably because of the construction of railroads in streambeds used to remove timber. Fine substrates (<5.6 mm diameter) were less abundant in logged streams and …
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Water flow and heat transport modelling at the interface between river and aquifer
… water. Characterizing the flow conditions in the streambed is challenging as flow patterns are often complex and multidimensional, driven by surface hydraulic gradients and groundwater discharge. This thesis presents the results of an integrated approach of studies, ranging from the acquisition of …
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Microbial activity on wood in streams: exploring abiotic and biotic factors affecting the structure and function of wood biofilms
… colonizer. Comparing wood incubated on the streambed surface to wood buried beneath the streambed, fungal hyphae dominated the biofilm but actinomycetes and bacteria were also present. An assay of microbial activity (¹⁴C glucose uptake) indicated that surface biofilms were more active than …
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Assessing Macroinvertebrate Community Recovery in Post Restoration Silver Bow Creek, Montana
… activities have contaminated the floodplain and streambed of Silver Bow Creek, Montana, resulting in a streambed devoid of life and severely contaminated with heavy metals. In the mid nineteen seventies, up-stream water treatment facilities were upgraded and water quality improved, bringing …
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Assessing Macroinvertebrate Community Recovery in Post Restoration Silver Bow Creek, Montana
… activities have contaminated the floodplain and streambed of Silver Bow Creek, Montana, resulting in a streambed devoid of life and severely contaminated with heavy metals. In the mid nineteen seventies, up-stream water treatment facilities were upgraded and water quality improved, bringing …
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