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 60 for “"hyporheic"”.
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Mixing Processes in Hyporheic Sediments
L'abstract è presente nell'allegato / the abstract is in the attachment
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Elemental Stoichiometry of Freshwater Hyporheic Microorganisms
… including elemental stoichiometry along a hyporheic flowpath underlying the Nyack floodplain. We isolated and characterized 44 bacterial strains, sampled microbial biofilm communities across the floodplain, characterized the bacterial isolates and determined elemental ratios (C:N:P). We …
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Elemental Stoichiometry of Freshwater Hyporheic Microorganisms
… including elemental stoichiometry along a hyporheic flowpath underlying the Nyack floodplain. We isolated and characterized 44 bacterial strains, sampled microbial biofilm communities across the floodplain, characterized the bacterial isolates and determined elemental ratios (C:N:P). We …
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Hyporheic flow in a mountainous riverine system
Investigation into the effects of beaver dams on hyporheic exchange in peat dominated mountainous streams is needed to better understand stream-floodplain connections and improve our overall conceptual model of water storage and flow through riverine valleys. The objective of this study was to …
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Physical, chemical, and microbial dynamics in the hyporheic zone
… where surface water mixes with groundwater (the hyporheic zone), is an important biogeochemical reactor, providing a variety of ecosystem services. In addition to hosting ecologically and economically important microbial processes, it is subject to dynamics in terms of inputs from the surface. In …
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Characterization of hyporheic zone processes of a northern prairie stream
<p> A hyporheic zone occurs beneath and adjacent to streams where surface water and groundwater mix. This zone is known to be a reservoir for solutes and a habitat for interstitial organisms. Hyporheic zone boundaries in the Tongue River, North Dakota, were investigated through examination of the …
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Mixing and Attenuation of Upwelling Groundwater Contaminants in the Hyporheic Zone
The hyporheic zone is the reactive interface between surface water and groundwater found beneath streams and rivers, where chemical gradients and an abundant biological presence allow beneficial attenuation of contaminants. Such attenuation often requires reactants from surface water and …
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The effects of augmentation of coarse particulate organic matter in hyporheic sediments
Metabolic and biogeochemical processes in hyporheic zones may depend on inputs of coarse particulate organic matter. Our research focused on how differing quantity and quality of organic matter affects metabolism and nutrient retention in the hyporheic zone of a low-order Appalachian stream. We …
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Effect of Urbanization on the Hyporheic Zone: Lessons from the Virginia Piedmont
… are a cause of increasing concern. The hyporheic zone is an important part of stream ecosystems, and here we focus on the effect of urbanization on the hyporheic zone from ten first-to-second-order streams within the Virginia Piedmont. We use sediment hydraulic conductivity and stream …
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Controls on Mixing and Non-Mixing Dependent Denitrification in River Hyporheic Zones
… processes in aquatic systems. The hyporheic zone has unique biogeochemical conditions, and is known to attenuate contaminants originating from SW and traveling through the hyporheic zone, together with necessary reactants. However, the ability of the hyporheic zone to attenuate …
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Using temperature profiles to investigate the hyporheic zone in an agricultural drainage ditch
… on ground water/surface water interaction and hyporheic zone processes in natural rivers and streams. Research into natural systems has revealed significant ground water/surface water interaction and a complex variability that depends primarily on surface conditions, subsurface composition, and …
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Effect of Unsteady Surface Water Hydraulics on Mixing-Dependent Hyporheic Denitrification in Riverbed Dunes
… affects surface water (SW) quality. The hyporheic zone, where SW and groundwater interact, possesses unique biogeochemical conditions that can attenuate contaminants (e.g., denitrification), including mixing-dependent reactions that require components from both water sources. Previous …
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Cumulative Impacts of Watershed-Scale Hyporheic Stream Restoration on Nitrate Loading to Downstream Waterbodies
… of the eastern USA. We simulated restoration of hyporheic exchange as one increasingly popular technique that receives dissolved nitrate-nitrogen (NO3--N) mitigation credit under the Chesapeake Bay TMDL. We populated the model with hyporheic exchange (0.3% of surface flow per hyporheic-exchange …
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HYPORHEIC FLOW, RESIDENCE TIMES AND NITROGEN REACTIONS IN A RIFFLE-POOL SEQUENCE, TRUCKEE RIVER, NV.
… that stimulates nitrogen transformations. In the hyporheic zone, physical and biogeochemical processes controlling nitrification and denitrification processes are directly linked. Thus, this dissertation investigates hyporheic flow, residence times, oxygen dynamics and nitrogen transformations of …
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Assessment of Hyporheic Exchange at In-stream Restoration Structures on Savage River, Garrett County, Maryland
… that in-stream restoration structures alter hyporheic exchange dynamics in restored channels; this study assessed hyporheic exchange at a recently constructed stream reach, including the effects of in-stream restoration structures. Hydrometric and thermal data were collected in the streambed …
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Investigation Of Pressure Fluctuations In The Hyporheic Zone In Response To Flow Around A Hydraulic Structure
… the water-riverbed interface. This study maps hyporheic pressure fluctuations as they are related to surface water velocity. The pressure map is used to evaluate lift enhancement and destabilization forces on the riverbed. High pressure events in the subsurface help generate a destabilizing …
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Comparing Reach Scale Hyporheic Exchange and Denitrification Induced by Instream Restoration Structures and Natural Streambed Morphology
… may be attempted. One strategy is increasing hyporheic zone flow at baseflow by addition of instream structures. The hyporheic zone can be an area of increased biogeochemical activity, with potential enhancement of reactions such as denitrification. However, the comparative effects of various …
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Experimental Evaluation of Three Backward Transit Time Distributions (bTTD) for Solute Storage and Release During Hyporheic Exchange
Hyporheic exchange in streams supports many important ecosystem services but can also contribute to legacy pollution, 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 …
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Arsenic transport in groundwater, surface water, and the hyporheic zone of a mine-influenced stream-aquifer system
… arsenic in groundwater, surface water and the hyporheic zone in a stream-aquifer system influenced by an abandoned arsenopyrite mine. Mine tailing piles consisting of a host of arsenic-bearing minerals including arsenopyrite and scorodite remain adjacent to the stream and represent a continuous …
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Preferential and Non-Darcy Flows in the Hyporheic Zone: Surface Water-Groundwater Hydraulics and Effects on Stream Functions
… the dominance of hydraulic conductivity (K) on hyporheic hydraulics and implications to hyporheic zone functions through a series of modeling studies and field experiments. Computational Fluid Dynamics (CFD) software was used to model the effect of varying K on weir-induced hyporheic exchange …
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