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1
McBride, Maeve. "Riparian Reforestation and Channel Morphology:." ScholarWorks @ UVM, 2007. http://scholarworks.uvm.edu/graddis/151.
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A three part investigation into the effects of riparian reforestation on small streams demonstrated the timing, nature, and processes of morphologic change. First, measurements of two small streams in northeastern Vermont collected in 1966 and 2004 – 2005 documented considerable change in channel width following a period of passive reforestation. Channel widths of several tributaries to Sleepers River were measured in 1966 when the area had more non-forested riparian vegetation than today. A longitudinal survey in 2004 of two of these tributaries, followed by detailed measurements at specific reaches in 2005, provided information on channel size, large woody debris (LWD), and riparian vegetation. Reforested reaches have widened and incised markedly since 1966. Reaches with the oldest forest were widest for a given drainage area, and the non-forested reaches were substantially narrower. A conceptual model was developed that describes a multi-phase process of incision, widening, and recovery following riparian reforestation of non-forested areas. Second, a fixed-bed hydraulic model of one of the streams was developed to evaluate the impact of forested riparian vegetation on near-bank turbulence during overbank flows. Flume experiments with kinematic similitude and a 1:5 scale represented half a channel and its floodplain, mimicking the size of a non-forested reach. Two types of vegetation were simulated: non-forested, with synthetic grass carpet; and forested, where wooden dowels were added. Three-dimensional velocities were measured with an acoustic Doppler velocimeter. Velocities, turbulent kinetic energy (TKE), and Reynolds shear stress showed significant differences between forested and non-forested runs. Forested runs exhibited a narrow band of high TKE in the near-bank region that was roughly two times greater than in non-forested runs. Hydraulic characteristics of forested runs appear to create an environment with higher erosion potential, thereby indicating a possible driving mechanism for channel widening in reforesting stream reaches. Third, Light Detection and Ranging (LiDAR) data from Chittenden County were analyzed to develop a method capable of classifying riparian buffers into broad classes according to forest type and age. The geospatial characteristics of the LiDAR data in forested areas were explored using semivariogram analysis, and LiDAR-based metrics were derived in a geographic information system (GIS) to quantify vegetation height and variance. The LiDAR-based metrics were then used in two discriminant analysis procedures that distinguished: 1) forest type as deciduous or coniferous; and 2) forest age in four age classes. With the resulting linear discriminant functions, a GIS-based classification method was developed. The classification method was highly successful at determining forest type but only moderately successful at determining forest age.
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Niemann, Jeffrey D. (Jeffrey Dean). "Channel network growth and river basin morphology." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/43290.
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Turowski, Jens Martin. "Controls on bedrock channel morphology : experimental and theoretical investigations and comparison with natural channels." Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.613289.
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Miller, Hennessy Felicia, and Hennessy Felicia Miller. "Assessment of Ephemeral Channel Cross-Section Morphology Following Pipeline Construction in Southern Arizona." Thesis, The University of Arizona, 2017. http://hdl.handle.net/10150/624133.
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Morphologic change of ephemeral stream cross-sections is a natural component of fluvial geomorphology but disruptions to natural erosion and deposition by anthropogenic disturbances has the potential for cascading impacts down the channel corridor. The proximal impact of a natural gas pipeline construction on ephemeral stream cross-section geometry in southern Arizona was evaluated from July 2014 (pre-construction) to July 2016 (two years post construction). Cross-sections at three locations (upstream the pipeline Right-Of-Way (ROW)), through the middle of the ROW, and downstream of the ROW) were measured using Light Detection And Ranging (LIDAR) and field methods for 16 ephemeral streams. Results of both the LIDAR and field measurements indicated insignificant difference in cross-sectional area change between upstream, across, and downstream-ROW cross-sections [(F 2,64) = 0.341, p = 0.73; (F2,18)= 0.980, p = 0.395]. Sediment generated during pipeline construction appeared to have moved beyond the physical confines of the study site, which limited the assessment of larger-scale geomorphic impacts. Furthermore, the 2014-2016 study period experienced only small (high-recurrence frequency) precipitation events, indicating the absence of large flows capable of significant morphologic change. To further explain differences in cross-section area change between LIDAR datasets, a linear regression model was used to assess the predictive value of nine variables: year of measurement, drainage area, drainage density, basin slope, upstream-, across-, downstream-ROW cross-section locations, percent bare soil in basin, percent mesquite in basin, total precipitation, and number of storms with average precipitation above 25 mm/hour. Though the amount of bare soil in the basin and the second study period (February 2015-July 2016) at least partially explained the changes in cross-section area, the model was not a strong predictor of morphologic change during the 2014-2016 study period. The majority of the variability in cross-sectional area change in the study basins remained unexplained.
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Adams, Beverley Joanne. "A geomorphological interpretation of saltmarsh channel network morphology and function." Thesis, University College London (University of London), 2001. http://discovery.ucl.ac.uk/1317552/.
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Although tidal channel networks are a near-ubiquitous feature of saltmarsh environments developed on the marine sedimentary shores of Britain, only limited progress has been made towards achieving a scientific understanding of their morphological characteristics and the physical functions that they perform. Based on data acquired from a combination of high resolution aerial photography and field survey, a range of descriptive indices and morphometric measures are used to characterise planimetric, longitudinal and cross-sectional adjustment in saltmarsh channel networks from 29 localities around England and Wales. In accordance with the extensive methodological approach employed during this exploratory phase of the study, regularities and distinguishing features of the selected formations are interpreted in terms of broad-scale environmental controls, which represent the relative intensity of erosional versus resistive forces. While statistical analyses suggest that creek morphology reflects a multiplicity of influences, the strongest bivariate associations, between tidal prism and cross-sectional geometry, are consistent with the finding of earlier process studies that creek morphology is principally adapted to perform a conveyance function. Theoretically-based mathematical models are employed to more fully elucidate relations of causality between creek morphology and function. This intensive investigation utilises Brancaster Marsh, Norfolk as an illustrative case study. The availability of airborne laser altimetry (lidar) for this site facilitates the evaluation of alternative models of channel function. Optimality models of angular geometry are implemented at a network-scale, and cross-sectional adjustments are modelled with reference to the concept of stability shear stress. While of interest from a geomorphological perspective, the insights offered into creek morphology and function are also relevant to the field of coastal engineering. Here, they provide an empirical basis for post-project appraisal, and may lead to theoretical guidelines for the design of tidal channel networks, as an integral component of saltmarsh restoration and flood defence realignment schemes.
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Kozarek, Jessica Lindberg. "Channel Morphology and Riparian Vegetation Influences on Fluvial Aquatic Habitat." Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/77172.
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As public awareness of river degradation has grown in recent years, the number of stream restoration activities has increased dramatically. Anthropogenic influences at a range of spatial scales from watershed landuse to riparian vegetation management to local channel morphology can have hierarchical relationships to local (meso- and macro-) in-stream habitat characteristics. This research examined these influences first by examining the influence of complex channel morphology on meso-scale brook trout (Salvelinus fontinalis) habitat in Shenandoah National Park, VA, and then by examining the combined influence of watershed urbanization and riparian vegetation (100-200 m reaches) on stream temperature.
Moving beyond one-dimensional (1D) averaged representations of fish habitat, this research explored the distribution of two-dimensional (2D) flow complexity metrics at the meso-habitat scale as explanatory variables for brook trout habitat preferences and as potential metrics to evaluate habitat restoration design. Spatial hydraulic complexity metrics, including area-weighted circulation and kinetic energy gradients, were calculated based on 2D depth averaged modeled velocity distributions in two 100-m reaches on the Staunton River. While there were no statistically significant correlations between kinetic energy gradients or area-weighted circulation and fish density, fish density was positively correlated to the percent of the channel dominated by protruding boulders. The structural complexity of areas with protruding boulders create complex flow patterns suggesting that flow complexity plays an important role in available brook trout habitat preferences at the local scale, although the 2D depth averaged model may not have adequately represented this complexity. The 2D distribution of flow characteristics was then investigated further to quantify areas of flow refugia (low velocity shelters) and the relationship between these areas, traditional measures of habitat quality, and fish biomass. Flow complexity in the vicinity of flow obstructions (in this case, boulders) was investigated further using patch classification and landscape ecology metrics.
The relative influence of riparian vegetation on stream temperature (another important habitat characteristic) in urban and nonurban watersheds was investigated in 27 paired forested and nonforested reaches in PA, MD, and DE. Riparian vegetation and watershed-scale urbanization both influence stream temperature, which can have profound impacts on in-stream ecosystems. Generally, increased urbanization and removal of riparian forest influenced maximum stream temperatures resulting in higher maximum summer stream temperatures (up to 1.8°C); however, the influence of riparian forests (at at 100-200 m reach scale) decreased with increasing urbanization. Extreme maximum summer temperatures, which are a concern for aquatic biota, increased in both frequency and duration in urban nonforested reaches relative to forested reaches indicating that the addition of a forested 100-200 m long buffer partially mitigated these temperature extremes even in urban watersheds. Overall, changes to channel morphology and riparian vegetation had measurable local effects on stream habitat (temperature and hydraulic complexity) yet the implications of restoration efforts at the local scale on ecosystem services at a larger (km +) scale requires further study.Ph. D.
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Gunton, Alan Kenneth. "Beach evolution and environmental forcing factors : Jersey, Channel Islands." Thesis, Lancaster University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337364.
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Badelt, Brad. "Change in channel morphology due to urbanization in Morningside Creek, Ontario." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ47305.pdf.
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Beaumont, Ryan M. "Developing DNS Tools to Study Channel Flow Over Realistic Plaque Morphology." Fogler Library, University of Maine, 2007. http://www.library.umaine.edu/theses/pdf/BeaumontRM2007.pdf.
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Ranganath, Sheila Casaba. "Recovery of Channel Morphology and Benthic Macroinvertebrate Assemblages after Livestock Exclusion." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/33455.
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Measurements in paired stream reaches with and without livestock access in southwestern Virginia suggest that livestock exclusion practices installed on short, isolated stream reaches result in improved geomorphic and riparian vegetation condition, but do not significantly improve the benthic macroinvertebrate assemblage. Detailed longitudinal and cross-sectional surveys, pebble counts, and rapid geomorphic assessments were conducted on contiguous, paired stream reaches (5 pairs) with and without active livestock access across a range of time since livestock exclusion was implemented. In addition, bank characteristics were quantified by measuring groundcover biomass, shrub crown volume, tree density and diameter, soil bulk density, and particle-size analysis. Benthic macroinvertebrates were collected with a D-frame dip net and quantified using the Virginia Stream Condition Index (SCI), and other benthic macroinvertebrate metrics. We determined that: 1) small lengths of livestock exclusion can significantly increase channel depth and decrease the width to depth ratio, and increase groundcover vegetation growth, but do not significantly alter benthic macroinvertebrate assemblages; and, 2) qualitative geomorphic assessment results showed trends over time since exclusion (0 to greater than 50 years), but not in any of the other parameters evaluated. These observations suggest that a more targeted and holistic approach that addresses watershed-wide impacts must be implemented to restore aquatic habitat. (Key Words: CREP, stream channel morphology, livestock exclusion, agriculture, benthic macroinvertebrates, riparian buffers.)Master of Science
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Hanrahan, Timothy Patrick. "Channel morphology, hyporheic exchange, and temperature gradients within Chinook salmon spawning habitat." Online access for everyone, 2006. http://www.dissertations.wsu.edu/Dissertations/Spring2006/t%5Fhanrahan%5F042506.pdf.
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Peakall, Jeffrey. "The influences of lateral ground-tilting on channel morphology and alluvial architecture." Thesis, University of Leeds, 1995. http://etheses.whiterose.ac.uk/2386/.
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This thesis characterises and quantifies the influence of lateral ground-tilting on rivers in terms of: i) channel planform changes and migration style, ii) temporal and spatial patterns of channel movement, and, iii) the preserved alluvial architecture formed by aggrading fluvial systems. A dual field and physical modelling approach is used to examine the impact of tilting on river channels at a range of temporal and spatial scales. Fieldwork was undertaken on the Carson River, Nevada, USA which has been proposed as an example of avulsive downdip channel movement towards an active basin-bounding fault (Leeder, 1993). Froude scale models of both meandering and braided rivers were established in a stream table which could simulate aggradation and be tilted laterally. Quantification of the Holocene history of the Carson River, combined with independent dating of movements on the basin-bounding fault, allows the alluvial-tectonic relationships to be analysed. In addition to local tectonics, factors which may also affect channel movement such as climate change, regional periods of channel incision and intrinsic channel avulsion are investigated. The Carson River is shown to possess a more complex spatial relationship with fault movement and lateral tilting than that envisaged by Leeder (1993). Phases of channel onlap towards the locus of subsidence after fault events are separated by channel offlap during periods of tectonic quiescence. In addition, lag times between faulting and channel movement appear to be short. The preserved alluvial architecture modelled in flume experiments on aggrading braided streams is subdivided into a number of key depositional niches and their geometries quantified. A number of cross-stream and vertical variations in niche geometries can be attributed to the timing, magnitude and frequency of imposed lateral tilting, and confirm Leeder and Alexander's (1987) conceptual model of progressive downdip channel movement in response to lateral tilting. No unambiguous relationship between channel bend parameters and imposed lateral ground-tilting could be defined in the meandering river experiments because the rate and type of bend development masks the impact of tilting. However, the rate of channel movement towards the downtilted margin appears to increase after tilting and be directly related to tilt magnitude. A new model of progressive downdip channel migration in response to lateral tilting is presented which resolves the incompatibility of previous models. In addition, a criterion based on the rate of tilting is proposed in order to distinguish between channels that respond to tectonic tilting either by avulsion or by gradual downdip migration
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Addy, Stephen. "Hierarchical controls on river channel morphology in montane catchments in the Cairngorms, Scotland." Thesis, University of Aberdeen, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=135792.
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The character of montane channel morphology and associated hierarchical controls was investigated in the Dee catchment, Cairngorm Mountains, north-east Scotland. Montane channel morphology in Scotland is of considerable importance given its relatively undisturbed condition in a UK context, variety and for providing habitat for several important lotic species. Nine distinctive sub-catchments were chosen to investigate the linkages between landscape controls and channel morphology distribution. The distribution of channel morphology at the reach scale was mapped using an expanded version of a process-based classification system originally developed in the Pacific northwest, USA. Continuous mapping revealed a wide variety and irregular distribution of channel morphology that is influenced primarily by a suite of glacigenic valley bottom controls. Differences in channel morphology distribution were apparent between catchments reflecting the influence of unique landscape evolution histories. In addition, fifty reaches exhibiting a variety of morphology and associated geomorphic setting, were surveyed in the field to explore in more detail controls on channel morphology. The results generally confirm the relevancy of the typology in the region and the dominant control exerted by slope. However the importance of scale, local controls and the regional geomorphic context was also highlighted. Finally, GIS approaches to channel characterisation at the catchment scale were tested to assess their potential usefulness for catchment management applications. By using a combination of the previous results, GIS models were calibrated and tested to predict the distribution of channel type and Atlantic salmon spawning habitat. The accuracy of channel type predictions were compromised by the model criteria and quality of geospatial data used. However the potential utility of the spawning habitat model as a first order method for screening habitat suitability over large areas was demonstrated.
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Castele, Michael R. "Modeling sediment transport and quantifying channel morphology of the Sheepscot River, coastal Maine." Restricted access (UM), 2007. http://libraries.maine.edu/gateway/oroauth.asp?file=orono/etheses/37803141.pdf.
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Miller, Scott Nicholas 1969. "An analysis of channel morphology at Walnut Gulch linking field research with GIS applications." Thesis, The University of Arizona, 1995. http://hdl.handle.net/10150/192090.
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Geographic information systems (GIS) have improved our ability to accurately model and assess landscape parameters and processes. These systems offer a significant improvement in time and manpower needed to complete landscape studies. Too often, however, GIS projects have relied heavily on data that has not been integrated with field work or represents an abstraction of reality. A high-resolution database was constructed for the Walnut Gulch Experimental Watershed. New methods for delineating channels and acquiring data were developed to promote field integration. Simultaneously, a field measurement program of over 200 channel cross-sections was undertaken on the same area. The results from the GIS analysis and field research were integrated using statistical analysis. Strong deterministic relationships were derived between channel shape variables and watershed parameters. Channel shape was found to be influenced strongly by channel order and several watershed parameters, principally watershed size and the maximum flow length within a watershed.
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Hogan, Daniel Lewis. "Stream channel morphology : comparison of logged and unlogged watersheds in the Queen Charlotte Islands." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/24685.
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This study compares the morphology of coastal, gravel-bed streams in two unlogged and two logged Queen Charlotte Islands watersheds. This comparison quantifies the influence of logging and related activities on channel morphology and, consequently, the fresh water physical habitat of salmonids. Further, it provides a basis upon which to determine habitat rehabilitation criteria for disturbed channels. Pools and riffles are detailed because: a) they reflect changes in sediment supply; b) they are important fish habitats, and; c) their general character has been documented in previously published literature allowing application of geomorphological results to habitat evaluation.
Longitudinal profiles conducted over relatively long channel segments located within each watershed indicate that channels in watersheds logged to the channel banks by old techniques have reduced pool-to-pool spacings and increased riffle amplitudes and magnitudes. There is an increase in channel stored sediment resulting in proportionally larger riffles and smaller pools. This represents a reduction in available rearing habitat. No significant differences exist in pool and riffle characteristics between unlogged watersheds and those logged by contemporary techniques. In all cases the pool and riffle character differed from most previously published results. Results obtained from detailed study reaches located within each channel segment show that large organic debris is a controlling factor influencing the morphology of these streams. Based upon a comparison of reaches, it is concluded that LOD characteristics are altered in the older logged channels. This includes a shift in the size distribution, with smaller material being more prevalent. Orientation of this material is also altered; more LOD is lying parallel to the flow direction, as opposed to the more common diagonal orientation found in unlogged channels. This shift in orientation is responsible for a reduction in channel width and depth variability, reduced sediment texture, fewer cut banks, smaller pool areas and decreased channel stability. This results in reduced habitat diversity and quality. No morphological differences were detected between unlogged and recently logged reaches.
The architecture of unlogged channels can be duplicated to rehabilitate disturbed streams. Pool and riffle sequences should be spaced approximately 2½ channel widths apart and riffle magnitudes should average 0.013 m/m. LOD should play a major role in rehabilitation. Long pieces of debris should be placed either diagonally across the channel to increase depth and width variability and to store sediment or parallel to the flow if width is to be reduced. Diversity can be increased by placing large root wads to produce small scour holes. Only small debris steps, accounting for approximately 10% of the overall change in elevation should be used. This comparative study of channel morphology emphasizes the importance of critically evaluating basin morphometric properties and the role of LOD orientation. Further, it indicates that previous studies reporting average values and neglecting LOD provide insufficient detail to quantify fish habitat.Arts, Faculty of
Geography, Department of
Graduate
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Lane, Stuart Nicholas. "Monitoring and modelling morphology, flow and sediment transport in a gravel-bed stream." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336765.
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Rakovan, Monica Tsang. "Land use, sediment supply and channel response of southwest Ohio watersheds." Miami University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=miami1321977972.
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DeMarco, Kristyn Anne. "The Effect of Structure and Lithology on Aspect Ratio of Fluvial Channels: A Field-Based Quantitative Study of the New River in Three Geologic Provinces." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/35898.
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Fluvial channel geometry is controlled by the interaction of a number of geologic and hydraulic variables. The width of mixed alluvial-bedrock channels generally is a function of discharge, with variations due to local conditions. The aspect ratio (width/depth) of channels is heavily influenced by substrate size and erodibility. How channel width and aspect ratio vary as a function of other variables, such as structure, lithology, slope, large scale valley topography, and rock uplift, has not been fully quantified. The New River is ideal for examining these relationships because it shows considerable variability in width and aspect ratio and flows through three structurally and lithologically distinct geologic provinces. Through these provinces, the New River does not follow the expected trends of channel widening with increasing drainage area. Topographic maps show that channel width of the New River has a significant variation that far outscores an overall widening downstream. Aspect ratios for the New River are also large, approaching 500. We collected a field data set of 29 sites of the riverâ s channel geometry, along with characteristics of bedrock, sediment, and confinement. Fifteen of the 29 sites are bedrock reaches. The data set allows empirical analysis of how width and aspect ratio of the New River are related to different variables, including slope, discharge, flow velocity, curvature, trend, bedrock type, and structure. Sediment characteristics and confinement of the channel do not affect channel morphology. Bedrock is shown to affect channel width directly through the percent of bedrock exposed in the channel and indirectly through the modified rock mass strength, rock hardness, obliquity to regional strike, dip orientation, and degree of joint intersection.Master of Science
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Rosier, Burkhard. "Interaction of side weir overflow with bed-load transport and bed morphology in a channel /." Lausanne : EPFL, 2007. http://library.epfl.ch/theses/?nr=3872.
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Thèse Ecole polytechnique fédérale de Lausanne EPFL, no 3872 (2007), Faculté de l'environnement naturel, architectural et construit ENAC, Programme doctoral Environnement, Institut des infrastructures, des ressources et de l'environnement ICARE (Laboratoire de constructions hydrauliques LCH). Dir.: Anton Schleiss.
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Diefenderfer, Heida Lin. "Channel morphology and restoration of Sitka spruce (Picea stichensis) tidal forested wetlands, Columbia River, U.S.A. /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/5565.
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Dorn, Taylor C. "Channel Morphology, Streamflow Patterns, and Sediment Transport of Two Intermittent Rivers along the Balcones Escarpment." Thesis, University of Louisiana at Lafayette, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=10811929.
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Despite a recent increase in intermittent river research focusing on the mechanisms driving flow intermittence and the role they play in the biological community, first order controls, such as the geology, land cover, and climate of the watershed, are not well understood. The rise of intermittent river research coincides with them becoming increasingly more prevalent on Earth due to climate change and water abstraction. While these problems are observed more clearly in arid regions, little research is focused in areas with greater rainfall amounts, such as in central Texas, where there are currently no known studies focusing on intermittent rivers. Here, we collected data over the course of nine months (April 2017 ? January 2018) within Schulle Canyon and Spring Lake Preserve, to determine how their morphology changed over time, their capacity to transport sediment, and the drivers of their intermittency. To answer these questions, three methods were used: 1. Ten cross-sectional surveying points were taken in each river to show how each river?s morphology changes over time, 2. Passive Integrated Transponders were inserted into 60 grains varying in size to track, via GPS, how far those grains traveled after a rainfall event, and 3. 30 Stream, Temperature, Intermittency, and Conductivity sensors were longitudinally deployed down each river to determine where and when water is present. From these collected field data, we found that Schulle Canyon?s morphology did not change over nine months, while Spring Lake saw a change in five of its cross sections, most notably cross sections 6, 9, and 10. Water levels were estimated to depths of 30 cm mostly between August 26 - 28, 2017, which coincided with Hurricane Harvey. In each intermittent river, little to no sediment transport was recorded, with all grain sizes staying within 12 m of their starting point. This study provides much-needed data on sediment transport in intermittent rivers.
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Paepke, Betty E. "Controls on Channel Organization and Morphology in a Glaciated Basin in the Uinta Mountains, Utah." DigitalCommons@USU, 2001. https://digitalcommons.usu.edu/etd/6724.
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The organization and morphology of Middle Fork Sheep Creek and South Fork Sheep Creek, two mountain streams in the upper Sheep Creek basin, are controlled by the spatial distribution of glacial moraines. Both channels are organized into a reoccurring sequence of steep-gradient reaches changing downstream to low-gradient reaches. Steep-gradient reaches are located where the channels flow through moraine s. Low-gradient reaches are located in meadows downstream of the steep-gradient reaches and immediately upstream of the next moraine. Knickpoints in the longitudinal profiles of both streams coincide with the location of moraines. Large boulder s, beyond the size transportable by the channel at bankfull discharge, are found within the steep-gradient channels, and are presumed to be glacial lag. Between knickpoints, channel morphology follows the conceptual model of Montgomery and Buffington. Unlike mountain channels elsewhere, landslides, debris flows, and alluvial fans do not influence the morphology or organization of Middle Fork Sheep Creek and South Fork Sheep Creek. Large woody debris loading is less than on channels in Washington and Alaska, with debris dams found mainly in reaches with gradients less than cascade and greater than pool-riffle. Middle Fork Sheep Creek and South Fork Sheep Creek are located in a glaciated basin. At time scales of 103 to 104 years, the channels may be classified as in disequilibrium and the system is not adjusted to present conditions. The presence of large, unmovable boulder s within the steep-gradient channels allows the location of the steep-gradient channels to remain static until the large particles are transported during infrequent large discharges. At time scales of 101 to 102 years, the channels may be thought of as equilibrium systems with channel variables adjusted to the present climate.
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Fisher, Adam Caspian Nebraska. "Power V. Threhsold: Near-Channel Morphology Controls Sediment Rating Curve Shape in Coastal Redwood Watersheds." DigitalCommons@USU, 2019. https://digitalcommons.usu.edu/etd/7654.
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River sediment is one of the most pervasive pollutants in the world. Excess amounts of fine sediment can reduce water quality, damage stream ecosystems, and harm aquatic life. Both natural and human-caused processes can add sediment to a river, such as tectonic uplift, landslides, and timber harvesting. Therefore, it is important to understand how fine sediment enters and moves through a rive system to inform policymakers and land-managers on effective ecosystem management.
In this study, we determined how the relationship between river flow and suspended sediment changed among watersheds along the North Coast of California. We found a rise in suspended sediment concentration at median flows following extreme timber harvesting. Additionally, our results indicate that river flow and suspended sediment relationships are influenced by timber harvest activity, tectonic uplift, rainfall patterns, and near-channel environments.
These results support previous findings that extreme land disturbance in a watershed, be it natural or human-caused, can change river flow and suspended sediment relationships. Our results suggest that policymakers and land-managers should take into account tectonic uplift when making regulation and should prioritize protecting near-channel environments.
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Bill, Michael D. "Channel morphology and substrate responses to high flows and road construction in forested mid-Appalachian watersheds /." Available to subscribers only, 2005. http://proquest.umi.com/pqdweb?did=1079664441&sid=25&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Duffin, Jenna. "Effects of Engineered Log Jams on Channel Morphology, Middle Fork of the John Day River, Oregon." Thesis, University of Oregon, 2015. http://hdl.handle.net/1794/19338.
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Engineered log jams (ELJs) were constructed on the Middle Fork of the John Day River in eastern Oregon as part of a large restoration project. These log structures were designed to address many of the restoration goals including creating scour pools, inhibiting bank erosion, creating and maintaining a sinuous river planform, and increasing complexity of fish habitat. This study uses geomorphic change detection techniques to monitor topographic change under and around the 26 log structures in two different river reaches over a six to seven year period. This study finds that the ELJs are remaining stable within the river and maintaining deep pool habitat. The study provides insight into which log structure variables are most related to the patterns and amounts of aggradation and degradation. Understanding the geomorphic changes to the riverbed in response to the placement of the ELJs can influence the design and future effectiveness of ELJs.
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Procopio, Nicholas Anthony III Kilham Susan Soltau. "An evaluation of landscapes, hydrology, and channel morphology of coastal plain drainages with different cranberry agriculture histories /." Philadelphia, Pa. : Drexel University, 2006. http://dspace.library.drexel.edu/handle/1860%20/896.
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Chen, Feng. "Study of Channel Morphology and Infill Lithology in the Wilcox Group Central Louisiana Using Seismic Attribute Analysis." Thesis, University of Louisiana at Lafayette, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10002413.
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The fluvial and deltaic Wilcox Group is a major target for hydrocarbon and coal exploration in northern and central Louisiana. However, the characterization and delineation of fluvial systems is a difficult task due to the variability and complexity of fluvial systems and their internal heterogeneities.
Seismic geomorphology is studied by recognizing paleogeographic features in seismic stratal slices, which are seismic images of paleo-depositional surfaces. Seismic attributes, which are extracted along seismic stratal slices, can reveal information that is not readily apparent in raw seismic data. The existence and distribution of fluvial channels are recognized by the channel geomorphology in seismic attributes displayed on stratal slices. The lithologies in the channels are indicated by those seismic attributes that are directly related to the physical properties of rocks. Selected attributes utilized herein include similarity, spectral decomposition, sweetness, relative acoustic impedance, root mean square (RMS) amplitude, and curvature. Co-rendering and Red/Green/Blue (RGB) display techniques are also included to better illuminate the channel geometry and lithology distribution. Hydrocarbons may exist in the channel sand-bodies, but are not explicitly identified herein. Future drilling plans for oil and gas exploration may benefit from the identification of the channels and the lithologies that fill them.
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Dominick, DeWitt S. "Effects of Flow Augmentation on Channel Morphology and Riparian Vegetation in the Upper Arkansas River Basin, Colorado." DigitalCommons@USU, 1997. https://digitalcommons.usu.edu/etd/6543.
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This study examined historic change of riparian plant communities and fluvial geomorphic response of gravel-bedded streams and their floodplains to over 50 years of hydrologic disturbance. Four tributary basins of the Arkansas River were analyzed. Lake Creek, Clear Creek, and Cottonwood Creek are drainages similar in area, physiography, and vegetation composition. However, Lake Creek may receive an instantaneous discharge of approximately 28 m3sec-1 from the Twin Lakes tunnel, over three times the normal flow of the stream during spring runoff. By contrast, Clear Creek and Cottonwood Creek, nonaugmented streams, were used as controls to compare the historic and present condition of natural flowing streams with Lake Creek. Lake Fork was also examined, another augmented stream that carries transmountain water stored in a reservoir to the Upper Arkansas River.
Hydrologic data collected from U.S.G.S. gaging stations were used in an attempt to identify relations between specific flow events and corresponding changes in fluvial landforms, riparian vegetation patterns, and channel morphology. Topographic cross sections of the channel and floodplain were surveyed and hydraulic geometry at each field site was examined. Aerial photographs from 1938-39, 1956-57 , and 1988 were incorporated into a Geographic Information System (GIS) to prepare a series of land cover maps of the river corridor at eight field sites on augmented and nonaugmented streams.
Results indicate channel morphology and riparian vegetation cover on the active floodplains of Lake Creek and Lake Fork have experienced substantial change from natural physical and biologic conditions as a result of historic and present flow augmentation practices. The increase in water discharge without a natural sediment load in Lake Creek and Lake Fork appears to have caused accelerated rates of channel bank erosion, incision, and bank retreat below transbasin diversion releases. In some downstream reaches characterized by gentler slopes and wider valley bottoms, the width-depth ratio of the channel has increased and sinuosity has decreased. Sites carrying transmountain water were characterized by higher shear stress and specific stream power values and larger bed material compared to control sites. Consequently, the Lake Creek and Lake Fork drainages show temporal and spatial loss of riparian vegetation adjacent to the stream channel in response to historic and present flow augmentation practices. Control watersheds, Clear Creek and Cottonwood Creek, where natural flow regimes exist, did not experience similar magnitudes of change in channel morphology or spatial distribution of riparian vegetation.
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Marston, Bryce Kendrick. "Influence of the Mountain Pine Beetle disturbance on large wood dynamics and channel morphology in mountain streams." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/35499.
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Doctor of PhilosophyDepartment of Geography
Charles W. Martin
Disturbance regimes are important determinants of both terrestrial and aquatic ecosystem structure and function. Disturbances may linger in the landscape and lag temporally, influencing stream ecosystem form and function for decades, if not centuries. The recent enhanced Mountain Pine Beetle (MPB) infestation in pine forests of the Rocky Mountain region has resulted in extensive tree mortality, producing the potential for significant increases in carbon supply to stream channels. To better understand MPB impacts on in-stream large wood (LW), a census was conducted in 30 headwater streams within the Medicine Bow National Forest in south-central Wyoming, across the temporal spectrum from early- to late-stage MPB-infestation. A subset of those streams exhibiting mean conditions at each level of infestation was surveyed to determine any significant differences in channel morphology or aquatic ecosystem function. Results indicate that wood loads related to the MPB-infestation significantly increase with time since initial infestation. However, even in late-stage infestation streams, many of the fallen MPB-killed trees are bridging across the channels and have yet to break and ramp down sufficiently enough to enter between the channel margins. Wood loads will continue to increase as more trees fall and bridging pieces decompose, break and then enter the channel. Measurable increases in the amount of LW with time since initial beetle infestation have both positive and negative effects on channel form and function. Although forest MPB-infestation has peaked in the study area, streams are still early on a curve of rapidly increasing wood loads that are beginning to affect streams and have the potential to dramatically increase the carbon base of regional stream ecosystems.
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Schoonover, Jon E. "Hydrology, water quality, and channel morphology across an urban-rural land use gradient in the Georgia Piedmont, USA." Auburn, Ala., 2005. http://repo.lib.auburn.edu/2005%20Fall/Dissertation/SCHOONOVER_JON_14.pdf.
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Papangelakis, Elli. "The effects of channel morphology on the mobility and dispersion of sediment in a small gravel-bed stream." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/54003.
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The role of channel morphology in sediment transport is poorly understood due to the complexity of the interactions between morphology, sediment characteristics and flow. A better understanding of the ways in which channel morphology affects sediment transport at all scales and under varying flow conditions can improve predictions of channel behavior and provide insights for better stream restoration applications. This study aimed to capture the effects of morphology on bed mobility and sediment dispersion in a small gravel-bed stream through the use of a 10 year tracer dataset. The characterization of bed mobility and sediment dispersion conducted at three spatial scales (the reach, morphological unit and local scale), revealed the importance of scale when examining the role or morphology on sediment transport. East Creek was found to be in conditions of marginal sediment transport, remaining near the critical conditions for sediment mobilization the majority of the time, and falling within a low sediment transport regime common in small gravel-bed streams. Both bed mobility and tracer travel distances increased with increasing flow conditions, and measures of cumulative flow energy had stronger relations to both variables than peak discharge. Grain size was not found to play no role in bed mobility or travel distance in East Creek. At the reach scale, morphology did not affect bed mobility, and influenced the travel distance of tracers only during high flows, or when averaged over long time periods. Although burial rates were high, burial depths were shallow, and burial showed no relation to flow or mobility. At the morphological unit scale, differences were observed in the rate of increase of bed area under mobility with increasing flow between reaches and between morphological units. Finally, at the local scale, bed mobility was highly localized and sporadic. Results of this study allow for the description of the role of morphology on bed mobility and sediment dispersion in a low sediment transport regime and throughout various spatial and temporal scales. Further research opportunities include the exploration of the role of morphology on bed mobility and sediment dispersion in a variety of morphological and sediment transport settings.Arts, Faculty of
Geography, Department of
Graduate
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Chen, Yan. "SINGLE CRYSTAL ENGINEERING OF AMORPHOUS-CRYSTALLINE BLOCK COPOLYMERS CRYSTALLIZATION, MORPHOLOGY AND APPLICATIONS." University of Akron / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=akron1133226076.
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Schmitt, Thierry Gilles. "Morphology and dynamics of headland connected sandbanks from high resolution bathymetric surveys : Helwick and Nash Sands, Bristol Channel, U.K." Thesis, Cardiff University, 2006. http://orca.cf.ac.uk/56116/.
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Morphology and movements of sand dunes are studied using repeated high-resolution bathymetric data in areas where banner banks approach the shore. Two sites in the Bristol Channel were selected for their contrasting environments. The Helwick Sands is characterised by deeper water-depths, stronger wave climates and weaker tidal currents than the Nash Sands. At the Helwick, migrations of the dunes were measured ranging between 21 and 109 hlv"1. Dunes crossing its crest and connecting despite opposite direction of migration on either flank were observed. This geometry is interpreted to be the result of the strong wave climate coupled with a nearly rectilinear tidal flow, which are leading to dune crests extension. A morphometric study of the sand dunes has revealed the tendency for the dunes to flatten in shallow water, which can also be attributed to the effect of the waves. At the Nash, strong currents and breaking waves have created a strong crestal escarpment. Dune migration rates along the flanks were measured to range from 34 to 180 m.y"1 {Text not available}, based on a comparison of surveys 263 days apart. However, in the Nash Passage (between East Nash and the coast) short term (19 days) sand dunes migration measurements revealed very fast moving (up to 715 m.y_1) small short-living sand dunes. Celerity and morphology of the dunes were used to compute sand transport specific fluxes. Such fluxes are broadly compatible with fluxes computed from tidal current data using bedload transport formulae. For both banks, the geometry of the flux vector field suggests a clockwise sand transport pattern around the banks. Although different intensities of the fluxes were expected at the two sites, the fluxes of corresponding morphological areas are similar. Differences in the tidal current asymmetry and reduced effective threshold of sand transport due to the wave energy are invoked to explain theses similarities. Pattern of erosion and deposition were evaluated from the divergence of sand fluxes. This partem has revealed the occurrence of transients in the sand transport, which are the result of complex interactions between the flow, the headland and the bed morphology.
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Stirling, James R. "Channel morphology and riffle-poll sequences in natural reaches of an urbanized alluvial system, the East Don River, Toronto, Ontario." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0012/MQ34049.pdf.
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Musselman, Zachary Allen. "TRIBUTARY RESPONSE TO THE LAKE LIVINGSTON IMPOUNDMENT -- LOWER TRINITY RIVER, TEXAS." Lexington, Ky. : [University of Kentucky Libraries], 2006. http://lib.uky.edu/ETD/ukygeog2006d00404/zamusselman.pdf.
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Thesis (Ph. D.)--University of Kentucky, 2006.Title from document title page (viewed on June 1, 2006). Document formatted into pages; contains ix, 173 p. : ill. (some col.), maps (some col.). Includes abstract and vita. Includes bibliographical references (p. 159-170).
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Dion, Kenneth Michael. "Channel morphology and the distribution of juvenile Atlantic salmon habitat in the Ste. Marguerite River following the historic Saguenay flood of July 1996." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0006/MQ44157.pdf.
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Castillo-Rodríguez, Miguel E. "Base-level fall, knickpoint retreat and transient channel morphology : the case of small bedrock rivers on resistant quartzites (Isle of Jura, western Scotland)." Thesis, University of Glasgow, 2011. http://theses.gla.ac.uk/2880/.
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Understanding the link between tectonics and climate and their consequences in landscape evolution is a major current issue in Earth sciences. Bedrock rivers are an important component of the landscape because they transmit changes in tectonic and/or climatic conditions by setting bedrock incision rates to which the landscape must be adjusted. Nevertheless, there remain unresolved issues in relation to bedrock river processes and response to perturbation. The effects caused by propagation of a knickpoint triggered by a sudden drop in base-level remain to be fully clarified. Questions about rates of knickpoint recession, the control exerted by structure and lithology, the morphological response of rivers after knickpoint recession and whether bedrock incision rates are re-established after the passage of a knickpoint, as theory predicts, are all issues that need to be clarified. Moreover, the estimation of bedrock incision, which is key to understand transience in landscapes, has relied on the stream power model, mainly tested on large fluvial settings. Whether the stream power model is valid for small bedrock rivers is not well understood. Some of these questions are tackled in this research, by studying small bedrock river catchments. The case of a knickpoint propagation on a homogeneous resistant lithology (quartzite), triggered by an instantaneous base-level lowering ( 18 m in 13.6 ka), is evaluated here, as well as the effect of structure and the morphological response of rivers to base-level fall. Two approaches were followed: (1) stream profile analysis using slope-area and distance-slope plots and (2) the analysis of terrestrial cosmogenic nuclides to obtain erosion rates. The Isle of Jura, located in the west coast of Scotland, was selected as natural laboratory because bedrock rivers incise the landscape and rapid rock uplift resulting from glacio-isostatic rebound after the Last Glacial Maximum has left the Jura landscape in transience. The present research is organised in seven chapters. In chapter 1, the motivation for this research is presented. In chapter 2, a review of theory underpinning research on bedrock rivers, landscape evolution and knickpoint generation, is detailed. The relevant studies in the field are also reviewed. The physical setting of Jura is characterised in chapter 3, as well as the morphometry of catchments, stressing the effect of Quaternary glaciation on the landscape of Jura. Unpublished exposure ages and analysis of the resultant raised beaches (~35 m OD) of Jura’s west coast are used to demonstrate a sudden drop in base-level in Jura ~13.6 ka. Chapter 4 details how stream long profiles were extracted and how the slope-area (SA) and distance-slope (DS) analyses were undertaken. This chapter 4 shows that the Jura rivers have strong imprints related to glacial processes and base-level fall, making it difficult to use SA and DS models to estimate channel incision as has been done for large fluvial settings. Chapter 5 is explains how the base-level fall knickpoints were identified and it is shown that stream discharge is a first-order control on knickpoint propagation. Structure and lithology, on the other hand, are not first-order controls on knickpoint recession. Chapter 5 also evaluates the vertical distribution of knickpoints and morphological response of rivers after knickpoint migration, with the results indicating that stream power controls the vertical distribution of knickpoints and the morphological response of rivers to base-level fall. A threshold of ~5 km2, where rivers’ ability to modify their channel, resulting in a channel convex profile, is also identified. In chapter 6 the problem of bedrock incision and the role of sediment is tackled. Based on the sampling of sediment in fieldwork, it is demonstrated that the median fraction in the rivers of Jura is ≈45 mm and grain-size neither fines nor increases with stream discharge and channel slope, strongly indicating that detachment-limited conditions are likely to control bedrock incision. In the second part of chapter 6, the incision rates upstream and downstream of the base-level fall knickpoint are obtained to test whether incision rates are re-established after knickpoint propagation. Incision rates were obtained from the concentrations of cosmogenic 10Be in samples extracted from the river bed. The results indicate that incision rates are not re-established at an expected value of ≈ 0.1 m/k yr after knickpoint migration. Rather, incision rates below the knickpoint remain somewhat elevated (≈ 0.5 m/k yr) reflecting: (1) ongoing base-level fall, and/or (2) the propagation of younger knickpoints (< 13.6 ka) in those transient reaches. The cosmogenic-derived incision rates were tested with different bedrock incision rules. The results indicate that the stream power model is a good predictor for channel incision, even for the case of small catchments. In chapter 7 the conclusions of this research are provided.
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Yuill, Brendan Thomas. "Sediment Transport and Bed Mobility in a Low-ordered Ephemeral Watershed." Diss., The University of Arizona, 2009. http://hdl.handle.net/10150/195269.
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This dissertation reports the results of a field based study examining sediment transport and bed mobility in a low-ordered, ephemeral watershed. Runoff and sediment transport concentrations were sampled at the watershed outlet to determine flow discharge and sediment flux during approximately 21 flow events, from 1998 - 2007. Sediment collected in flow was measured for grain-size distribution to determine if specific grain-size fractions behave differently while in transport. The coarse sediment yield was measured for mass and grain-size distribution at the watershed outlet for two years, 2005 - 2006. Further, the arrangement and composition of the channel bed material was comprehensively mapped using terrestrial-based photogrammetry for the years, 2005 - 2006. Results show that patterns of sediment transport are complex, controlled in part by flow hydraulics but also by other phenomena. Some of the variation in sediment transport is determined by grain-size. Grain-sizes with different sources within the watershed and that transported by different transport modes were observed to follow different patterns of transport. Also, the channel bed, which serves as the source for the coarse fraction of the sediment transport, was observed to change in grain composition during periods of flow. This tendency for the bed material to evolve in time likely affected the amount and composition of the sediment grains that were entrained from it.An additional objective of this dissertation was to determine how unique the observed patterns of sediment transport were to low-order ephemeral channels. Sediment transport and yield were modeled using bed load transport formulae designed to capture the physical mechanics of transport as observed in perennial streams. Results show that contemporary transport models predict transport within the field site with similar accuracy as that in many perennial systems but not well enough to rely on their predictions for many engineering applications.
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Nellis, Shelley. "EFFECTS OF ALTERNATIVE PREY AS A BUFFER TO PREDATION OF CHANNEL CATFISH (ICTALURUS PUNCTATUS) BY LARGEMOUTH BASS (MICROPTERUS SALMOIDES)." VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/129.
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Channel catfish have pectoral spines that lock to defend against gape-limited predators such as largemouth bass. Previous work indicated that spines increase survival of channel catfish exposed to bass but did not determine whether bass avoid catfish if less dangerous species are available. We presented bass with channel catfish and two alternatives, bluegill and goldfish, and compared order of ingestion, ingestion time, percent of successful strikes, and time spent chasing each prey species. We also presented the three species in a jar study that standardized position in the water column as well as in a net-pen study. The order of ingestion was suggestive of a preference for goldfish, then bluegill and finally channel catfish. Handling time was greater for channel catfish, less for bluegill, and the least for goldfish. Fewer catfish were eaten when other prey were available. Bass appear to avoid channel catfish if alternative prey is available.
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Clark, Chase. "THE IMPACTS OF LOGGING WITH CURRENT AND MODIFIED BEST MANAGEMENT PRACTICES ON WATERSHED CHARACTERISTICS IN EASTERN KENTUCKY." UKnowledge, 2015. http://uknowledge.uky.edu/forestry_etds/25.
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In Kentucky, Best Management Practices (BMPs) were developed to protect the integrity of water resources during and after silvicultural operations, but their effectiveness is largely unknown. The study objectives were to (1) quantify the extent to which current BMPs minimized logging-related changes in stream water quality, channel morphology, and the content of woody debris and (2) quantify the extent to which modified BMPs influenced these characteristics. Six watersheds in eastern Kentucky were commercially logged in 2008-2009. In each watershed, one of three treatments was implemented (each replicated once). Treatment 1 (BMP) was based on current Kentucky BMPs. In treatments 2 (BMP+) and 3 (BMP++), current BMPs were modified with additional protective measures. Before the harvest, sampling sites were established in each watershed. Channel morphology and woody debris data were collected at each site in 2006 and again 2014. Data for water chemistry were retrieved from ongoing sampling records. BMP watersheds were compared to one another and to unharvested control watersheds in each year independently. Data within each individual watershed were also compared across years. The results indicate that current BMPs were effective in minimizing changes in the watershed characteristics examined here, and the benefits of modified BMPs were highly variable.
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Gu, Xiaohan, and Ling Yang. "Face detection based on skin color." Thesis, Högskolan i Gävle, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-13767.
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This work is on a method for face detection through analysis of photos. Accurate location of faces and point out the faces are implemented. In the first step, we use Cb and Cr channel to find where the skin color parts are on the photo, then remove noise which around the skin parts, finally, use morphology technique to detect face part exactly. Our result shows this approach can detect faces and establish a good technical based for future face recognition.
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Farrell, Hannah Lucia, and Hannah Lucia Farrell. "Reclamation Practices and Impacts of a Pipeline Corridor in Southern Arizona: Seeding and Vehicle Trampling Impact Vegetation Establishment: Construction Alters Short-term Ephemeral Channel Morphology Trends." Thesis, The University of Arizona, 2016. http://hdl.handle.net/10150/620633.
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Anthropogenic disturbances are increasing in arid lands, as are expectations to successfully minimize impacts to natural resources and reclaim sites to publicly acceptable levels. This research explores the effectiveness of reclamation practices on a 60 mile natural gas pipeline constructed in September of 2014 that spans from west of Tucson to the border of Mexico. First, a controlled field experiment was conducted to assess the effects of seeding, grazing, and trampling (vehicular, cattle, and human foot traffic) on the reclaimed pipeline Right-Of-Way (ROW). Vegetation establishment (native plant cover; undesirable plant cover; species richness; herbaceous biomass), soil movement, and plant functional group community development was compared among the treatments. Reclaimed ROW areas left to recover without seeding resulted in similar vegetation cover, species, and community composition as undisturbed desert areas, although the presence of undesirable species was greater. The combined impacts of grazing and trampling resulted in reduced vegetation establishment and increased soil erosion. Second, the impacts of the pipeline construction on ephemeral wash channels were analyzed in terms of channel morphology and riparian vegetation changes. Channel cross section dimensions were measured upstream of the ROW, downstream of the ROW, and within the ROW before and after the 2015 Monsoon season to evaluate impacts on channel morphology and erosion processes. High resolution aerial imagery taken before and after pipeline construction was used to evaluate changes in riparian vegetation cover. Reduced herbaceous vegetation cover downstream of the ROW was detected, which may have been the result of increased channel scour within the ROW and increased sediment deposition downstream of the ROW. This research improves our understanding of and may aid in selection of appropriate reclamation practices.
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Werner, Shelly D. "An assessment for the case of shared traditions in the North Channel region : site morphology and settlement distribution during the 1st Millennium BC to 1st Millennium AD." Thesis, University of Edinburgh, 2007. http://hdl.handle.net/1842/3197.
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The seaways appear to have been a prevalent means of travel in the past as observed in the evidence of contact and trade between regions. The Irish Sea between Britain and Ireland was part of a maritime network traditionally termed the Atlantic Seaways that linked these islands and the Continent. Communication across the North Channel between Western Scotland and northern part of Ireland may have been demonstrably easier during the later prehistoric period than movement looking eastwards across the Central Highlands of Scotland. Thus, these areas possibly developed into a ‘North Channel’ region as opposed to the sea creating a cultural divide. This idea is explored through a series of comparisons between sites either side of the North Channel. Three specific areas are targeted for the overall research, Argyll, the coastline of Northern Ireland and Co. Donegal. Both the individual architectural features and site distributions in relation to their locations within the landscape are investigated through an integrated approach. Firstly, a fine scale examination of the morphology of settlement sites using a common classification scheme explores the degree of structural comparability between these areas. The second approach is at a broader scale that statistically tests the distribution of site types with regards to specific landscape variables, including elevation, slope and aspect to identify spatial patterns. The third approach statistically tests the location of sites with regards to visibility to determine whether or not the locations of sites have particular visibility features and the comparability between the three study areas. This technique uses the Viewshed tool available in GIS software. It is argued that broad comparisons exist between Scotland and Ireland in site classifications, their distributions and vistas, which illustrate the degree of communication occurring between the study areas. Sites dating to the 1st millennium BC in Argyll and Co. Donegal exemplify similar distributions with regards to vistas and to a lesser extent the environmental variables. A few general structural features are similar between sites in Northern Ireland and Co. Donegal during this period; however, interpretations on the former also indicate that possible influences are also coming from outside the study region. Around the turn of the millennium to the beginning of the 1st millennium AD, communication links between Co. Donegal and Argyll appear to dwindle and the number of sites in Northern Ireland begins to increase. Around mid 1st millennium AD, sites in Co. Donegal illustrate features and distributions comparable to both Argyll and Northern Ireland, suggesting communication links are re‐established during this period.
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Omar, Mohamed Yussuf. "Assessment of the effects of stream channel incision on soil water levels, soil morphology and vegetation in a wetland in the Hogsback area, Eastern Cape, South Africa." Thesis, University of Fort Hare, 2015. http://hdl.handle.net/10353/3132.
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Wetland degradation in the form of channel incisioning can significantly alter the hydrological functioning of a wetland. In this study in a small headwater wetland in the Hogsback area, Eastern Cape Province, the impact of channel incisioning on soil water levels and soil morphology was examined. A good correlation (R2 = 0.89) exists between the depth of channel incisioning and average water table depths in most of the 21 installed piezometers. In localised cases the upslope supply of water was in equilibrium with drainage from the piezometers. Although all the studied soils show hydromorphic characteristics, those continuously saturated close to the surface exhibit redox accumulations in oxygen supplying macropores, whereas gleyic colour patterns occur deeper in soils where the water table has been lowered by channel incision. The nature and occurrence of different hydromorphic soil indicators observed confirm the contribution of soil morphology as a valuable indicator of long-term average soil water conditions. The study evaluates the effects of hydrological processes on plant species composition and distribution in a Hogsback wetland. Twenty-four circular plots with a radius of 2 m were established between March and August 2013. Within each sample plot, the habitat information and species present were recorded including Braun-Blanquet cover-abundance value for each and every species present in the plot. Plant species were identified in the field and the unknown plant species were collected, pressed, oven-dried and identified at the National Herbarium, South African Biodiversity Institute (SANBI), Pretoria and Schonland Herbarium, Rhodes University, Grahamstown. A total of 39 taxa belonging to 19 families and 34 genera were recorded from the Hogsback wetland. Of the documented taxa, three were exotic and three endemic to South Africa, indicating diversity and dynamic nature of Hogsback wetland flora. Plant families with the highest number of species were: Poaceae (11 species), Asteraceae (5 species), Onagraceae and Cyperaceae with 3 taxa each. The low number of exotic plant species in Hogsback wetland (three taxa in total) indicates limited anthropogenic influence. Unique species recorded in Hogsback wetlands are three species that are endemic to South Africa, namely, Alchemilla capensis, Helichrysum rosum and Lysimachia nutans. Five main floristic associations were identified from the Hierarchical Cluster Analysis whilst Detrenched .Correspondence Analysis (DCA) identified four groups. The Canonical Correspondence Analysis (CCA) indicates that edaphic factors, particularly in an area covered with water, erosion category, organic matter content and water table depth were the most important environmental variables measured accounting for the vegetation pattern present in the Hogsback wetland.
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Greve, Adrienne I. "Toward a more complex understanding of urban stream function : assessing post-developmental recovery period and channel morphology and the relationship between urban built form, land cover pattern, and hydrologic flow regime /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/10815.
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Enell, Lina E. "Chemical signalling in the Drosophila brain : GABA, short neuropeptide F and their receptors." Doctoral thesis, Stockholms universitet, Zoologiska institutionen, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-56476.
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Gamma-aminobutyric acid (GABA) and short neuropeptide F (sNPF) are widespread signalling molecules in the brain of insects. In order to understand more about the signalling and to some extent start to unravel the functional roles of these two substances, this study has examined the locations of the transmitters and their receptors in the brain of the fruit fly Drosophila melanogaster using immunocytochemistry in combination with Gal4/UAS technique. The main focus is GABA and sNPF in feeding circuits and in the olfactory system. We found both GABA receptor types in neurons in many important areas of the Drosophila brain including the antennal lobe, mushroom body and the central body complex. The metabotropic GABAB receptor (GABABR) is expressed in a pattern similar to the ionotropic GABAAR, but some distribution differences can be distinguished (paper I). The insulin producing cells contain only GABABR, whereas the GABAAR is localized on neighbouring neurons. We found that GABA regulates the production and release of insulin-like peptides via GABABRs (paper II). The roles of sNPFs in feeding and growth have previously been established, but the mechanisms behind this are unclear. We mapped the distribution of sNPF with antisera to the sNPF precursor and found the peptide in a large variety of interneurons, including the Kenyon cells of the mushroom bodies, as well as in olfactory sensory neurons that send axons to the antennal lobe (paper III). We also mapped the distribution of the sNPF receptor in larval tissues and found localization in six median neurosecretory cells that are not insulin-producing cells, in neuronal branches in the larval antennal lobe and in processes innervating the mushroom bodies (paper IV). In summary, we have studied two different signal substances in the Drosophila brain (GABA and sNPF) in some detail. We found that these substances and their receptors are widespread, that both sNPF and GABA act in very diverse systems and that they presumably play roles in feeding, metabolism and olfaction.At the time of doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.
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Weichert, Roman. "Bed morphology and stability in steep open channels /." Zürich : ETH, 2005. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=16316.
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Richardson, Keith. "Morphology, hydraulics and bedload transport in bedrock channels." Thesis, Lancaster University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.441370.
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Ewald, Karl Heins. "Caracterização de formas topográficas em fundos de vale no Planalto de Cascavel, Região Oeste do Estado do Paraná." Universidade Estadual do Oeste do Paraná, 2013. http://tede.unioeste.br:8080/tede/handle/tede/1655.
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Previous issue date: 2013-05-09Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Rivers are important agents working in the sculpturing of relief, through its high transport capacity of sediments originary from slopes and marginal erosion. The modeling occurs through the processes of erosion and deposition of sediments, which depend on variables such as lithological composition, slope, and flooding. The processes that originate topographic forms are widely described in the literature of alluvial-bed rivers, however little is known about the occurrence of these forms in mixed bed channels (alluvial-rock) and bedrock channel. In this context, this research aims to describe the topographic forms of the valleys on the Cascavel Plateau. The method for the recognition of these forms is the topographic mapping of cross sections in different parts of the channel located at the top, middle and lower course. The mapping is performed with a set level and optical sights. Were mapped four fluvial channels, two channels in areas with altimetric elevations below 400 meters, and two other channels with elevations above 700 meters. The channels have floodplains with varying lengths. Topographic forms were found as dikes, point bars, flood inundation basins, pools and riffles. The data collected show strong channel incision in the sections corresponding to the upper parts of the channels, and that in the course stretches of low flood plains are well developed. Channel meandering is a characteristic feature of the Cascavel Plateau. The formation of point bars is directly associated with the channel marginal erosion, whereas the dikes are the result of sediment settling. The pool-riffle sequences occur by the reduction of the flow velocity in some places, and, in others, by the presence of woody debris. In some parts of the river where are rock outcrop was observed the formation of pot-holes
Os rios são importantes agentes atuando na esculturação do relevo por meio da sua alta capacidade de transporte de sedimentos originários das vertentes e dos processos de erosão marginal. A modelagem ocorre através dos processos de erosão e deposição de sedimentos, que dependem de variáveis como composição litológica, declividade e cheias. Os processos que originam as formas topográficas são descritos vastamente na literatura sobre rios de leito aluviais, no entanto pouco se sabe sobre a ocorrência dessas formas em canais de leitos mistos (aluviais-rochosos) e leitos rochosos. Nesse contexto esta pesquisa objetiva a descrição das formas topográficas de fundos de vale no Planalto de Cascavel. O método para o reconhecimento dessas formas topográficas consiste no mapeamento de seções transversais em trechos distintos do canal localizados no alto, médio e baixo curso. O mapeamento é realizado com um conjunto de nível ótico e mira. Foram mapeados quatro canais fluviais, sendo dois canais em áreas com cotas altimétricas inferiores a 400 metros e, outros dois canais com cotas superiores a 700 metros. Os canais apresentam planícies de inundação com extensões variadas. Foram encontradas formas topográficas como diques, barras em pontal, bacias de inundação, soleiras e depressões. Os dados coletados mostram que há forte incisão do canal nos trechos correspondentes ao alto curso dos canais, e, que nos trechos de baixo curso as planícies de inundação são bem desenvolvidas. O meandramento de canais é uma característica do Planalto de Cascavel. A formação de barras em pontal está associada diretamente a erosão marginal, enquanto que os diques são resultantes da decantação de sedimentos. As sequências de soleiras-depressões ocorrem pela diminuição da velocidade do fluxo em alguns trechos, e, em outros, pela presença de detritos lenhosos. Nos trechos rochosos onde há afloramento rochoso foi observada a formação de marmitas