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.
Results
Showing 1 to 20 of 53 for “"riverbed"”.
-
Nanoparticle - Heavy Metal Associations in Riverbed Sediments
… coupled plasma mass spectroscopy (HR-ICPMS). Riverbed sediment samples were taken from the Clark Fork River in Montana, USA where a large-scale dam removal project has released reservoir sediment contaminated with toxic trace metals (namely Pb, Zn, Cu and As) which accumulated from one and a …
-
Controls on arsenic mobility in contaminated wetland and riverbed streams
… arsenic retention in contaminated wetland and riverbed sediments. A sequential extraction procedure was designed and tested to differentiate solid phase arsenic speciation, including adsorbed As and As coprecipitated with amorphous and crystalline oxides and sulfides. The sequential extraction …
-
Effect of Unsteady Surface Water Hydraulics on Mixing-Dependent Hyporheic Denitrification in Riverbed Dunes
… unsteady hyporheic flow and transport through a riverbed dune using MODFLOW and SEAM3D, and varied SW depth, degree of sediment heterogeneity, amplitude and frequency of sinusoidal fluctuations, among others to determine these effects. We found that increasing steady state surface water depth …
-
Investigation Of Pressure Fluctuations In The Hyporheic Zone In Response To Flow Around A Hydraulic Structure
… are typically studied from above 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 …
-
Hydrological factors influencing the ecology of riverbed breeding birds on the plains' reaches of Canterbury's braided rivers : a thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy in the University of Canterbury
The wide, unstable, braided riverbeds of the eastern South Island, New Zealand, have been inhabited by a diverse avifauna. Several species including the wrybill breed only on these rivers. Use is restricted mainly to the breeding season from September to December, so this was the critical study …
-
The impact of urban groundwater upon surface water quality : Birmingham - River Tame study, UK
… data was collected from installed riverbed piezometers and existing monitoring across the aquifer. Field data and supporting computer modelling indicated the convergence of groundwater flows from the sandstone/drift deposits and variable discharge to the river (0.06 to 10.7 …
-
Urban accupuncture: Architecture as a catalyst for environmental and water conservation in the context of the Kilimanjaro Informal Settlement
… in the natural and urban landscapes of the riverbed, its rivers' edges and its man-made peripheries. This research locates itself at the northern boundary of the city of Windhoek along a stretch of polluted riverbed in the Kilimanjaro Informal Settlement (KIS) where public environments are …
-
Remote sensing and localization of smart rocks with orientation-controlled magnets for real-time monitoring of bridge scour and riprap effectiveness
… The spherical smart rock placed directly on riverbed at Roubidoux Creek successfully demonstrated its movement to the scour hole during the December 27, 2015, flood. The smart rocks deployed at Waddell Creek and at Gasconade River, however, were washed away. Thus, additional smart rocks were …
-
HYPORHEIC FLOW, RESIDENCE TIMES AND NITROGEN REACTIONS IN A RIFFLE-POOL SEQUENCE, TRUCKEE RIVER, NV.
… to fine particulate organic matter that reduces riverbed porosity and permeability and promotes microbial activity that stimulates nitrogen transformations. In the hyporheic zone, physical and biogeochemical processes controlling nitrification and denitrification processes are directly linked. …
-
Effects of rigid stems on sediment transport
… On the other hand, the presence of vegetation in riverbed modifies flow structure, flow resistance, sediment transport and morphology. Each single modification has been largely studied, but the knowledge on the mutual relationships are still limited. This project faces a part of these …
-
Investigating the habitat selection and dietary preferences of a largely sedentary population of blue wildebeest in the Kgalagadi Transfrontier Park – impacts of permanent surface water provision in a semi-arid environment
… distribution of this resident herd within the riverbeds of the Park. I explore the effects of water quality, forage abundance, tree density and river width on wildebeest habitat selection. I do this through a combination of an analysis of two years of wildebeest census data, published water …
-
Taxonomy, faunistics and life-history traits of Dytiscidae and Noteridae (Coleoptera) in a West African savannah
… of these adult beetles. In a rocky area in the riverbed of the permanent Comoé River four sets of studies were performed during dry and beginning rainy season. According to the working hypothesis beetles should be searching for adequate aquatic habitats as long as temporary savannah waters are …
-
Surface-water groundwater interaction and arsenic mobilization in south and southeast Asia
… of arsenic mobilization in freshly deposited riverbed sediments are up to 1000 times those of inland aquifer sediments and measured arsenic concentrations in riverbed porewaters that exceeded the aquifer concentrations. We found the effect of riverine recharge is controlled by the geomorphic …
-
Characterization of Pre and Post Re-Naturalized Surface Water/Groundwater Exchange, Jocko River, Flathead Indian Reservation, Montana
… range from 7 to 280 ft/day whereas, riverbed vertical hydraulic conductivities range from 0.1 to 187 ft/day. Initial channel restoration increased the riverbed elevation (~ 3 ft). A correlation exist between river discharge and water table elevation changes near the river whereas, …
-
Characterization of Pre and Post Re-Naturalized Surface Water/Groundwater Exchange, Jocko River, Flathead Indian Reservation, Montana
… range from 7 to 280 ft/day whereas, riverbed vertical hydraulic conductivities range from 0.1 to 187 ft/day. Initial channel restoration increased the riverbed elevation (~ 3 ft). A correlation exist between river discharge and water table elevation changes near the river whereas, …
-
An assessment of wetland vulnerability to artisanal mining in Zimbabwe
… including habitat loss, biodiversity decline, riverbed sedimentation, and heavy metal pollution. Subsequently, the study investigated in the Umzingwane Catchment, located in southern Zimbabwe as a case study, to analyse variations in water nutrient and metal concentrations in wetlands affected …
-
Controls on and Morphodynamic Effects of Width Variations in Bed-load Dominated Alluvial Channels: Experimental and Numerical Study
… controlling factors, and quantification of the riverbed morphodynamic response to width variability is of crucial importance to support effective river management. The practical and engineering interest on stable cross-sections of alluvial channels has attracted a considerable amount of …
-
Water flow and heat transport modelling at the interface between river and aquifer
… of the measured diurnal temperature variation in riverbed sediments provided detailed information about the exchange flux between river and groundwater. Beyond the one-dimensional vertical water flow in the riverbed sediment, hyporheic and parafluvial flow patterns were identified. Subsurface flow …
-
Modelling local scour around bridge piers using TELEMAC
… If not adequately designed for, local scour of a riverbed at a bridge pier may become deep enough to undermine the pier foundation and eventually cause the bridge to collapse. Complete protection against scour is expensive and therefore not a favourable design option. It is generally cheaper to …
-
Reevaluation of the southwestern end of the Salem synclinorium
… oblique-slip faults and thrusts in a riverbed exposure within the southwestern portion of the Salem synclinorium, offers a structural model for the Salem synclinorium. Thrusting induced extensional fractures and veins. Oblique-slip faults which cut the thrusts may have nucleated on …
Page 1 of 3