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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

An analysis of channel bank erosion and development of a catchment sediment budget model

Janes, Victoria Jennifer Julie January 2013 (has links)
Increased sediment loads within river catchments have well-documented detrimental effects on water quality and catchment management plans are required to address reduction and mitigation of these problems. In order to do this it is essential that tools are available that deliver reliable sediment generation data at appropriate temporal and spatial scales. Currently, most sediment generation models do not include bank erosion individually as a sediment source. Therefore, to enable improved accuracy in predictions of future sediment pressures under environmental change, explicit modelling of the rates of sediment production by the bank erosion is required to provide a more complete representation of the catchment sediment budget. In this study, an existing prototype national bank erosion index has been refined. Using Geographical Information Systems (GIS) digitised overlays, channel migration rates were calculated for several UK catchments. Relationships between the rate of channel bank erosion and factors controlling the rates of channel migration were investigated, including channel sinuosity, slope, upstream catchment area, and restriction of migration due to valley width. Significant correlations between bank erosion and sinuosity, upstream area and channel confinement were observed. The non-linear influence of channel planform geometry (curvature and sinuosity) on migration rates was further investigated using an existing meander migration model. A new bank erosion model was developed to incorporate the influence of both channel confinement and sinuosity. As the model incorporates the key physical controls on bank erosion, hence it is expected that it will have wide applicability in catchment- to national-scale bank erosion assessment. A computationally efficient catchment routing model was developed. Data output from a newly developed catchment overland sediment and runoff estimation model (ADAS APT) was used as input to the routing model. The newly developed bank erosion model and an existing floodplain sedimentation model were incorporated within the routing methodology to provide a catchment sediment budget model. The model was applied to the Exe catchment, Devon, UK and validated against observational data. Model estimations of annual sediment generation through bank erosion, sediment deposition on floodplains, and sediment load at the catchment outlet were within the range of observed values. The catchment sediment budget model developed in this thesis provides a more comprehensive representation of catchment sediment processes than existing alternative methodologies.
2

Georeferenced Riverine Habitat Mapping in the Big South Fork National River and Recreation Area

McConkey, James Bryan 01 May 2010 (has links)
Abstract This project describes the development of a river habitat map of the Big South Fork National River and Recreation Area (BISO NRRA) using GPS-based video mapping and image georeferencing techniques. The Big South Fork of the Cumberland River and major tributaries have been floated and mapped with GPS, sonar, and georeferenced under and above water video cameras. Video footage is interpreted for physical bedforms and compiled in an ArcGIS attribute table that can be queried for species specific habitat location. Underwater video mapping system (UVMS) bedform data includes river characteristic (pool, riffle, run), substrate (bedrock, fines/sand, gravel, cobble, and boulder), embeddedness, sonar depth, rugosity, and sinuosity. The Clear Fork River and New River (3rd order streams), White Oak Creek and North White Oak Creek (2nd order streams), and the Big South Fork of the Cumberland River, a 4th order stream are compared based on the EPA Qualitative Habitat Evaluation Index (QHEI). Relationships between bedform parameters are evident in UVMS data, and large boulder substrate was predicted with 67% accuracy based on sonar depth and river characteristic. The rugosity metric can indicate the location of other habitat characteristics, such as large woody debris and riverbed drop-offs. Embeddedness distribution was modeled using SAS based on UVMS data. The linear, quadratic, and non-linear models poorly fit the embeddedness distribution, with R-squared values of 0.37, 0.42, and 0.33 respectively. Traditional river habitat assessment methods vary in scale from stream length categorization based on satellite imagery and topographic maps (kilometer resolution), to aquatic microhabitat inventory by biologists (0.1 m resolution). Typically, reach scale (10 m resolution) and mesoscale (1 m resolution) studies are limited by accessibility and man-hours in the field. The underwater video mapping system (UVMS) allows for stream scale habitat quantification with mesoscale resolution. Kayak or canoe based UVMS can map river habitat inaccessible from land. Georeferenced river characteristic and substrate video can be evaluated by biologists in the lab, reducing time and labor required for field studies. One limitation of UVMS is that underwater bedform data is recorded only in the thalweg, the deepest continuous line along a watercourse.
3

Georeferenced Riverine Habitat Mapping in the Big South Fork National River and Recreation Area

McConkey, James Bryan 01 May 2010 (has links)
AbstractThis project describes the development of a river habitat map of the Big South Fork National River and Recreation Area (BISO NRRA) using GPS-based video mapping and image georeferencing techniques. The Big South Fork of the Cumberland River and major tributaries have been floated and mapped with GPS, sonar, and georeferenced under and above water video cameras. Video footage is interpreted for physical bedforms and compiled in an ArcGIS attribute table that can be queried for species specific habitat location.Underwater video mapping system (UVMS) bedform data includes river characteristic (pool, riffle, run), substrate (bedrock, fines/sand, gravel, cobble, and boulder), embeddedness, sonar depth, rugosity, and sinuosity. The Clear Fork River and New River (3rd order streams), White Oak Creek and North White Oak Creek (2nd order streams), and the Big South Fork of the Cumberland River, a 4th order stream are compared based on the EPA Qualitative Habitat Evaluation Index (QHEI).Relationships between bedform parameters are evident in UVMS data, and large boulder substrate was predicted with 67% accuracy based on sonar depth and river characteristic. The rugosity metric can indicate the location of other habitat characteristics, such as large woody debris and riverbed drop-offs. Embeddedness distribution was modeled using SAS based on UVMS data. The linear, quadratic, and non-linear models poorly fit the embeddedness distribution, with R-squared values of 0.37, 0.42, and 0.33 respectively.Traditional river habitat assessment methods vary in scale from stream length categorization based on satellite imagery and topographic maps (kilometer resolution), to aquatic microhabitat inventory by biologists (0.1 m resolution). Typically, reach scale (10 m resolution) and mesoscale (1 m resolution) studies are limited by accessibility and man-hours in the field. The underwater video mapping system (UVMS) allows for stream scale habitat quantification with mesoscale resolution. Kayak or canoe based UVMS can map river habitat inaccessible from land. Georeferenced river characteristic and substrate video can be evaluated by biologists in the lab, reducing time and labor required for field studies. One limitation of UVMS is that underwater bedform data is recorded only in the thalweg, the deepest continuous line along a watercourse.
4

Study on Hydro-morphological Characteristics of Meandering Channels with Groynes / 水制工を有する蛇行水路の水成地形特性に関する研究

KARKI, Saroj 24 September 2019 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第22049号 / 工博第4630号 / 新制||工||1722(附属図書館) / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 中川 一, 教授 藤田 正治, 准教授 川池 健司 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
5

Controlling Factors on Bedrock River Sinuosity in the Eastern Tibetan Plateau

Curliss, Lydia January 2013 (has links)
No description available.
6

Effects of Stream Order and Data Resolution on Sinuosity Using GIS

Lohani, Meena 03 July 2008 (has links)
This research focuses on estimation and analysis of stream sinuosity using GIS. Fifty-five streams including 13 streams of order 0, 17 streams of order 1, 15 streams of order 2 and 10 streams of order 3 in Virginia were considered. Several GIS datasets from various sources, including the Virginia Base Mapping Program (VBMP) and United States Geological Survey (USGS), were used to generate stream networks using GIS. Sinuosity was computed using GIS based on a technique comparable to the approach used in an Environmental Monitoring and Assessment Program's (EMAP's) field survey report. Field sinuosity data from EMAP report were used as reference data for analyzing the accuracy of sinuosity values from different GIS data sources and resolutions. The GIS technique was implemented for computing sinuosity for 55 streams in Virginia using vector data including the VBMP Hydro44 and National Hydrography Data (NHD). Insufficient statistical evidence was found to support the hypothesis that the computed sinuosity values using Hydro44 and NHD data are different from EMAP field data for all 55 streams. Sinuosity values computed using Hydro44 and NHD were found to increase with the increase in EMAP sinuosity (positive correlation) for all 55 streams. EMAP data on sinuosity, however, did not predict sinuosity values computed using Hydro44 (R² = 27%) and NHD (R² = 10%) sources well. It was found that the GIS technique of computing sinuosity using digital data such as Hydro44 (VBMP source) and NHD (USGS source 1:24,000) is better suited for stream orders 2 and 3. Insufficient statistical evidence was found that computed sinuosity values for streams derived using various resolutions (i.e., DTM 3m, DTM 10m, DTM 30m, DEM 10m and DEM 30m) are different from EMAP field data. Positive correlation was observed between sinuosity values for streams derived in all resolutions with EMAP field data. DTM 10m resolution data yielded best correlation value (75%) with EMAP field data. / Master of Science
7

Geomorfologické projevy neotektonické aktivity podél úpatního zlomu pohoří Cordillera Blanca, Peru / Geomorphological evidence of neotectonic activity along Cordillera Blanca fault zone, Peru

Masák, Ondřej January 2012 (has links)
Southwest base of Cordillera Blanca mts. in South American Ands belongs to the most tectonically active fault zones. The core of this thesis was making of a detailed geomorphological map based on remote sensing satellite images for the purpose of analysis of direct and indirect manifestations of neotectonics. The greatest emphasis was placed on morphological manifestations of tectonics movements which are fault scarps facets and vertical fault steps deforming other shapes of relief - e.g. lateral moraines, dejection cones. Vertical steps reach from a few meters to tens of meters (max. 60 m) according to the age of influenced landform. Evaluation of measurements from deformometr from locality Pitec shows main trends of movements - moderate rise of massif, slow opening of fault plane and negligible left-lateral slip. Calculation of mountain-front sinuosity index, whose values were found relatively low, confirms high tectonic activity of fault zone. Analysis of longitudinal stream profiles hasn't showed presence of knick-points in the place of crossing with fault zone. Non-continuous process of lifting movements, whose interval is estimated at 1ka to 3ka (while the very last 2ka has been in relative tectonic calm), could be a possible explanation. Deep erosion of water streams wiped the tectonics...
8

Elevation based classification of streams and establishment of regime equations for predicting bankfull channel geometry

Jha, Rajan 06 September 2013 (has links)
Since past more than hundred years, fluvial geomorphologists all across the globe have been trying to understand the basic phenomena and processes that control the behavioral patterns of streams. A large number of stream classification systems has been proposed till date, but none of them have been accepted universally. Lately, a large amount of efforts have been made to develop bankfull relations for estimating channel geometry that can be employed for stream restoration practices. Focusing on these two objectives, in this study a new stream classification system based on elevation above mean sea level has been developed and later using elevation as one of the independent and nondimensionalising parameters, universal and regional regime equations in dimensionless forms have been developed for predicting channel geometry at bankfull conditions. To accomplish the first objective, 873 field measurement values describing the hydraulic geometry and morphology of streams mainly from Canada, UK and USA were compiled and statistically analyzed. Based on similar mode values of three dimensionless channel variables (aspect ratio, sinuosity and channel slope), several fine elevations ranges were merged to produce the final five elevation ranges. These final five zones formed the basis of the new elevation based classification system and were identified with their unique modal values of dimensionless variables. Performing joint probability distributions on each of these zones, trends in the behavior of channel variables while moving from lowland to upland were observed. For the completion of second objective, 405 data points out of initial 873 points were selected and employed for the development of bankfull relations by using bankfull discharge and watershed variables as the input variables. Regression equations developed for width and depth established bankfull discharge as the only required input variable whereas all other watershed variables were proved out to be relatively insignificant. Channel slope equation did not show any dependence on bankfull discharge and was observed to be influenced only by drainage area and valley slope factors. Later when bankfull discharge was replaced by annual average rainfall as the new input variable, watershed parameters (drainage area, forest cover, urban cover etc.) became significant in bankfull width and depth regression equations. This suggested that bankfull discharge in itself encompasses the effects of all the watershed variables and associated processes and thus is sufficient for estimating channel dimensions. Indeed, bankfull discharge based regression equation demonstrated its strong dependence on watershed and rainfall variables. / Master of Science
9

Submarine Channel Evolution Linked to Rising Salt Dome, Mississippi Canyon, Gulf of Mexico

Carter, Rachel C 18 December 2015 (has links)
By examining halokinetics and channel evolution in a deep-water system, we investigate how submarine channel morphology is affected by changing seascape linked to diapirism. The study area is located in Mississippi Canyon, Gulf of Mexico (GOM), situated directly off the continental slope in a prominent salt dome region. Interactions of salt domes with submarine channels in the GOM are poorly documented. Utilizing 3D seismic data and seismic geomorphology techniques, a long-lived Plio-Pleistocene submarine channel system has been investigated to develop a relationship between variable phases of salt movement and plan-form morphology of preserved channels. We suggest that halokinetics acts as a driver for topographic-channel evolution in the study area. We show how submarine channel morphology can be directly controlled by halokinetics, where salt movement can act as a structural control on both location and morphology of meandering channel complexes. Channels are able to move towards an equilibrium state only when holokinetics decreases.
10

Odezva vybraných řek Českého masivu na litologické a tektonické podmínky / Response of selected rivers of the Bohemian Massif to lithological and structural conditions

Flašar, Jan January 2012 (has links)
Three groups of streams were selected in the area of the Bohemian Massif: the Berounka river with its source streams; the Vltava river with its tributaries the Malše and the Lužnice; the Labe river with its tributaries the Cidlina, the Bystřice and the Javorka. The lithological and tectonical influences to several parameters of the streams were studied. These parameters include: stream gradient, orientation of the stream and sinuosity of the stream. Data were obtained from digital elevation models, aerial photographs, topographical and geological maps. The longitudinal profiles of the streams (in the combination with geological cross-sections), the SL indexes and the gradient/sinuosity graphs were created on the basis of the obtained data. These tools were used for evaluation of the influence of lithology and the tectonics to the streams. The evolution of the streams and the stream-groups was evaluated and compared as well. A strong influence of lithology on the stream gradient was found on most of the analysed streams. The tectonic situation, on the contrary, had strong influence on the orientation of the streams, especially in the resistant rocks. Also, there were selected areas, where was a higher probability of quaternary vertical movements influencing the streams (mountainous areas of the Novohradské...

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