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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.
131

Vulnerabilities to Seismic Hazards in Coastal and River Environments: Lessons post the Canterbury Earthquake Sequence 2010-2012, New Zealand

Kelland, Emma Jean January 2013 (has links)
Coastal and river environments are exposed to a number of natural hazards that have the potential to negatively affect both human and natural environments. The purpose of this research is to explain that significant vulnerabilities to seismic hazards exist within coastal and river environments and that coasts and rivers, past and present, have played as significant a role as seismic, engineering or socio-economic factors in determining the impacts and recovery patterns of a city following a seismic hazard event. An interdisciplinary approach was used to investigate the vulnerability of coastal and river areas in the city of Christchurch, New Zealand, following the Canterbury Earthquake Sequence, which began on the 4th of September 2010. This information was used to identify the characteristics of coasts and rivers that make them more susceptible to earthquake induced hazards including liquefaction, lateral spreading, flooding, landslides and rock falls. The findings of this research are applicable to similar coastal and river environments elsewhere in the world where seismic hazards are also of significant concern. An interdisciplinary approach was used to document and analyse the coastal and river related effects of the Canterbury earthquake sequence on Christchurch city in order to derive transferable lessons that can be used to design less vulnerable urban communities and help to predict seismic vulnerabilities in other New Zealand and international urban coastal and river environments for the future. Methods used to document past and present features and earthquake impacts on coasts and rivers in Christchurch included using maps derived from Geographical Information Systems (GIS), photographs, analysis of interviews from coastal, river and engineering experts, and analysis of secondary data on seismicity, liquefaction potential, geology, and planning statutes. The Canterbury earthquake sequence had a significant effect on Christchurch, particularly around rivers and the coast. This was due to the susceptibility of rivers to lateral spreading and the susceptibility of the eastern Christchurch and estuarine environments to liquefaction. The collapse of river banks and the extensive cracking, tilting and subsidence that accompanied liquefaction, lateral spreading and rock falls caused damage to homes, roads, bridges and lifelines. This consequently blocked transportation routes, interrupted electricity and water lines, and damaged structures built in their path. This study found that there are a number of physical features of coastal and river environments from the past and the present that have induced vulnerabilities to earthquake hazards. The types of sediments found beneath eastern Christchurch are unconsolidated fine sands, silts, peats and gravels. Together with the high water tables located beneath the city, these deposits made the area particularly susceptible to liquefaction and liquefaction-induced lateral spreading, when an earthquake of sufficient size shook the ground. It was both past and present coastal and river processes that deposited the types of sediments that are easily liquefied during an earthquake. Eastern Christchurch was once a coastal and marine environment 6000 years ago when the shoreline reached about 6 km inland of its present day location, which deposited fine sand and silts over this area. The region was also exposed to large braided rivers and smaller spring fed rivers, both of which have laid down further fine sediments over the following thousands of years. A significant finding of this study is the recognition that the Canterbury earthquake sequence has exacerbated existing coastal and river hazards and that assessments and monitoring of these changes will be an important component of Christchurch’s future resilience to natural hazards. In addition, patterns of recovery following the Canterbury earthquakes are highlighted to show that coasts and rivers are again vulnerable to earthquakes through their ability to recovery. This city’s capacity to incorporate resilience into the recovery efforts is also highlighted in this study. Coastal and river areas have underlying physical characteristics that make them increasingly vulnerable to the effects of earthquake hazards, which have not typically been perceived as a ‘coastal’ or ‘river’ hazard. These findings enhance scientific and management understanding of the effects that earthquakes can have on coastal and river environments, an area of research that has had modest consideration to date. This understanding is important from a coastal and river hazard management perspective as concerns for increased human development around coastlines and river margins, with a high seismic risk, continue to grow.
132

The Eight Views: from its origin in the Xiao and Xiang Rivers to Hiroshige.

Baker, Jennifer Helen January 2010 (has links)
This thesis focuses upon the artistic and poetic subject of the Eight Views of the Xiao and Xiang, from its origin in the Xiao-Xiang region in the Hunan province of China throughout its dispersal in East Asian countries such as Korea and Japan. Certain aesthetics and iconography were retained from the early examples, throughout the Eight Views’ transformation from the eleventh to the nineteenth century. The subject‟s close associations with poetry, atmospheric phenomena and the context of exile were reflected in the imagery of the painting and the accompanying verses. This thesis will discuss the historic, geographic and poetic origins of the Eight Views, along with a thorough investigation into the artistic styles which various East Asian artists employed in their own interpretations of the series. Furthermore, the dispersal and diaspora of the subject throughout East Asia are also investigated in this thesis. The work of Japanese artist Ando Hiroshige will serve as the concluding apogee. The Eight Views of the Xiao and Xiang is an important East Asian artistic subject in both poetry and painting and contains many pervasive East Asian aesthetics.
133

The role of fine sediment as a vector for contaminant transport in fluvial systems : a case study of heavy metals in the River Aire, Yorkshire, UK

Carton, Julie January 2000 (has links)
No description available.
134

The Role of Vorticity, Turbulence and Three-dimensional Flow Structure on the Development of Scour

Jamieson, Elizabeth Clare 09 September 2011 (has links)
Fundamental to the understanding of how rivers transform and shape our environment is the role of turbulence and complex, three-dimensional flow, such as vorticity, in sediment transport and erosion. However, classical sediment transport models (or formulae) are based, for the most part, on boundary shear stress and do not incorporate these natural phenomena. This is understandable given that the relationship between turbulence generation, intensity and form; the influence of turbulence on mobile sediment; and the magnitude and patterns of deposition and erosion are complex and difficult to quantify. Nevertheless, the failure to incorporate turbulence and complex, three-dimensional flow into existing models means that our understanding of sediment transport remains incomplete. The central hypothesis of this thesis is that vortical motion is the main factor in the development of local scour. To examine this, a comprehensive experimental approach was taken. This approach involved detailed measurements of the unique three-dimensional patterns of velocity, turbulence and bed morphology associated with flow in an open channel with and without the presence of submerged groyne-like structures (stream barbs and wing dikes) at both the laboratory and field scales. Using densely spaced velocity data and new techniques for processing and analyzing these data, it was possible to identify complex features of the flow field at both scales, such as the presence of vortex cores, and correlate these with changes in bed levels. These data provide a unique perspective of the spatial variability of velocity, turbulence and bed morphology in open channels (and in particular in channel bends, where flow is highly three-dimensional). In particular, it was found that, of the flow parameters analyzed, turbulent stresses were most correlated to scour in channel bends without the presence of structures. In contrast, vorticity was found to be the dominant factor in local scour hole development in the vicinity of submerged structures at both the laboratory and field scale. Such data are rare (if non-existent) in existing experimental research, particularly at the scale of a large natural river. This research also examines stream barb design and performance. Stream barbs (also known as submerged groynes or spur dikes) are a relatively novel approach to stream bank protection and are not common in Canada. The design and installation of stream barbs in a creek in Ottawa (Sawmill Creek) was undertaken to serve as a demonstration project for the use of these structures in a semi-alluvial channel, for which no such case studies exist. Three years of monitoring the site and the performance of these structures to reduce bank erosion and improve aquatic habitat have been carried out. Laboratory testing of stream barb performance was also undertaken and showed that with improper design, the outer bank in a channel bend may be more susceptible to erosion due to excessive local scour downstream of the barb. In particular, to avoid bank erosion downstream of the barb, barbs should be small, such that they create minimum flow obstruction, and include a bank key that is wider than the barb itself and extends in the downstream direction.
135

Deepwater vee

Siebert, Melanie 03 June 2011 (has links)
Deepwater Vee began as a meditation on the rivers I have worked on as a wilderness guide—the Nahanni, the Thelon, the Burnside, the Tatshenshini / Alsek, and others. The lyric poems take wobbly bearings and try to track the phenomenal world. This collection of nature poetry also considers two of Canada’s most threatened waterways—the Athabasca, which runs through the heart of the Alberta tar sands, and the North Saskatchewan, the river that ran by my home but which I had never paddled until recently, a river stressed by dams and upgraders, sewage and pesticides. These rivers push the poems into a contemplation of loss and into the terrain of Alexander MacKenzie’s dreams, a busker’s street riffs and the imagined wanderings of a grandmother who returns to inhabit the earth. / Graduate / 10000-01-01
136

Self organisation in braided systems : DEM analysis of the River Feshie, Scotland

Langham, Joseph Anthony January 2004 (has links)
No description available.
137

The management of a national environmental problem 'toxic cyanobacteria'

Pearson, Michael John January 1996 (has links)
No description available.
138

The evolution of alluvial systems in the south central Pyrenees, Spain

Jones, Stuart Jason January 1998 (has links)
No description available.
139

River channel adjustment to hydrologic change

Tilleard, John W. Unknown Date (has links) (PDF)
The size of an alluvial river channel can adjust in response to changes in the pattern of flows that it carries. An important case of such channel change occurs downstream of dams or water diversions where flow regulation has been observed to cause morphological and ecological impacts. (For complete abstract open document)
140

The effects of a modified flow regime on fish assemblages in a third-order Piedmont stream in Lee County, Alabama

Gleason, James Edmund. January 2007 (has links) (PDF)
Thesis (M.S.)--Auburn University, 2007. / Abstract. Includes bibliographic references (ℓ. 105-123)

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