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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.
91

Resilience of large river basins : applying social-ecological systems theory, conflict management, and collaboration on the Mekong and Columbia Basins

MacQuarrie, Patrick R. 11 July 2012 (has links)
River basins provide essential services for both humans and ecosystems. Understanding the connections between ecosystems and society and their function has been at the heart of resilience studies and has become an increasing important endeavor in research and practice. In this dissertation, I define basin resilience as a river basin system's capacity to absorb, manage, and adapt to biophysical, social-economic, and political changes (or stressors) while still maintaining its essential structure, feedbacks, and functional integrity. I address the question of resilience, scale, and development in the Mekong and Columbia River Basins. This dissertation answers the following questions: 1) is systems theory an appropriate model to evaluate basin resilience, 2) is the Mekong Basin resilient, 3) are the Mekong and Columbia River Basins resilient across multiple scales, 4) can conflict management and collaborative learning enhance resilience, 5) can a resilience framework be used for basin comparisons, and 6) what lessons can the Mekong basin take from rapid development in the Columbia basin? In Chapter 2, I create and apply a social-ecological systems (SES) model of the Mekong River Basin to assess resilience at sub-basin (provincial), watershed (national), and basin (regional) scales. Feedbacks, thresholds, vulnerability, and adaptive capacity are determined and used as inputs into an overall basin resilience assessment. Drawing upon field work done in the Mekong Basin, Chapter 3 uses Conflict Management and Collaborative Learning processes to address resilience weaknesses across multiple scales in the Mekong Basin. Chapter 4 uses the basin resilience framework to compare the Mekong and Columbia Basins against physical characteristics, development rate, conflict and cooperation, and institutional responses to development projects. In this dissertation I find the Mekong has medium-low basin resilience and that scale is a critical determinant in basin resilience assessments. I find that in this study, vulnerability is inversely proportional to resilience, and low resilience at one scale, for example fisheries in the Tonle Sap Lake in Cambodia, decreases resilience for the entire basin. I find that Cambodia and Lao PDR are the least resilience and Thailand the most resilient countries in the Mekong Basin ��� Thailand more resilient in some sectors than the Mekong River Commission (MRC). I find that the MRC's conflict management strategy is hampered by a restrictive mandate and weakness in capacity building at tributary and national scales but that Collaborative Learning processes are effective in enhancing resilience at the sub-basin scale. Finally, I demonstrate through the basin comparison that the Mekong has a highly resilient biophysical system and traditionally a resilient institutional system however, the proposed rate of development is unsustainable with trends indicating a significant erosion of resilience. I find the Columbia Basin lacking resilience in fishing, hydropower, and water quality ��� sectors mitigating the effects of development in the Columbia Basin, manifesting as overall negative trends in cooperation. However, the Columbia shows signs of increasing cooperation due recent inclusion of Tribal Nations in water management. Flexible and inclusive institutional responses to water resource development challenges, in the Mekong to rapid development on the mainstream and in the Columbia to negotiations over renewal of the Columbia River Treaty, are key determinants to whether or not each basin can halt the current negative trends and strengthen basin resilience to face the challenges now and those coming in the future. / Graduation date: 2013
92

Estimating ground cover via spectral data

Axness, Daniel S. 29 July 1991 (has links)
Potato ground cover and spectral data were measured in the Columbia Basin during the 1990 growing season. Three spectral were correlated with ground cover; normalized difference, near infrared-red ratio, and the first derivative of the spectral curve at 750 nm. All models were statistically significant at the 99% level. Normalized was most correlated followed by the near infrared-red ratio, and the first derivative of the spectral curve at 750 nm. / Graduation date: 1992
93

Volatile release and atmospheric effects of basaltic fissure eruptions

Thordarson, Thorvaldur January 1995 (has links)
Thesis (Ph. D.)--University of Hawaii at Manoa, 1995. / Includes bibliographical references (leaves 556-580). / Microfiche. / 2 v. (xv, 580 leaves, bound) ill., maps, col. photos. 29 cm
94

The effect of vertical mixing on along channel transport in a layered flow /

Cudaback, Cynthia Nova. January 1998 (has links)
Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographic references (p. [116]-122).
95

Numerical simulations of large river plumes in the Pacific Northwest /

Kilgren, Ryan Wesley. January 2006 (has links)
Thesis (M.S.)--OGI School of Science & Engineering at OHSU, Oct. 2006. / Includes bibliographical references.
96

Power, porous borders and polycentricity: the changing nature of transboundary water governance

Baltutis, William Jesse 14 May 2018 (has links)
The challenges facing resource management, including transboundary river basins, have become increasingly complex, requiring more holistic readings of governance processes that encompass a range of formal and informal collaborations between diverse actors. Innovation and transformative governance changes hold potential for addressing the increased complexity and multi-scaled nature of the challenges facing the world’s shared rivers. However, significant research gaps exist around this application in practice. This dissertation asks the following questions: Is governance of transboundary waters changing to integrate a more diverse set of actors beyond centralized governments? If so, what is the role of non-central state actors in contributing to innovations and transformative changes to transboundary water governance processes? In working towards answering these questions, the study explores the case of the Columbia River Treaty (North America) and the Lesotho Highlands Water Project (Southern Africa). This study has the following objectives: first, to determine the type of power, albeit conceived from a Euro-western perspective, that non-central state actors mobilize to engage in transboundary water governance processes, and assess if the power these actors mobilize is contributing to changes in governance. Second, to conceptualize the on-going bordering processes for transboundary water governance, and evaluate whether non-central state actors are shaping these processes. And, third, to identify which non-central state actors are involved in transboundary water governance, and examine whether and how these governance systems are becoming more polycentric. This dissertation is composed of five chapters, three of which have been prepared as standalone articles for submission to academic journals. Broadly, the dissertation findings suggest that changes to governance of transboundary waters, away from state-centric processes, may be emerging in some areas, such as the ability of non-central state actors to exercise and mobilize different forms of power to shape water governance processes. Findings illustrate that a clear distinction between international and national processes is no longer sufficient to address transboundary water governance challenges and issues. Further, findings illustrate that some non-central state actors have power and influence in these transboundary water governance processes. However, these insights also highlight that centralized government authority for transboundary waters remains, and evidence of the emergence of polycentric governance systems at the international scale is limited. / Graduate / 2019-04-30
97

Moving at a glacial pace: a biogeomorphological analysis of ecological succession in recently deglaciated terrain in the Selkirk Range, BC

Lincoln, Astra 02 May 2022 (has links)
This research developed a novel workflow for combining different types and scales of data to understand the development of small, steep, and sheltered glacial forefields across space and time using the Avalanche glacier of the Selkirk Range, BC as a case study. As glaciers recede, symbiotic geomorphological and ecological feedback loops determine the ecological succession in recently deglaciated terrain, which can in turn effect landform stability and water quality downstream. In order to describe emergent land cover patterns in the forefield, this research uses Corenbilt’s (2007) fluvial biogeomorphic succession (FBS) framework to interpret a century of land cover changes. To do so, an experimental protocol was developed that combined remotely sensed data – repeat photographs, historic air photographs, satellite imagery, and digital elevation models – and data collected in-situ using a photo transect method. Analysis of more than a century of photographs determined that the Avalanche glacier is receding at a slower rate than has been observed in the region’s larger glaciers, subsequently leading to a slower rate of forefield habitat expansion. Still, all four stages of fluvial biogeomorphological succession were found across the Avalanche glacier’s forefield. It was found that in the Avalanche forefield, terrain age seems to place a limit on which successional stage is possible at any given location within the forefield, but topographic features like slope angle seemed to influence succession patterns within areas that had the same terrain age. Further research is needed to see whether these findings are consistent for similar steep, small, and sheltered glaciers in the region. / Graduate
98

Linking Temporal and Spatial Variability of Millennial and Decadal-Scale Sediment Yield to Aquatic Habitat in the Columbia River Basin

Portugal, Elijah 01 May 2014 (has links)
Eco-geomorphic interactions occur across a range of spatial and temporal scales from the level of the entire watershed to an individual geomorphic unit within a stream channel. Predicting the mechanisms, rates and timing of sediment production and storage in the landscape are fundamental problems in the watershed sciences. This is of particular concern given that excess sedimentation is considered a major pollutant to aquatic ecosystems. Rates of sediment delivery to stream networks are characteristically unsteady and non-uniform. Because of this, conventional approaches for predicting sediment yield provide incomplete and often inaccurate information. Terrestrial cosmogenic nuclides (TCNs) provide an estimate of spatially averaged rates of sediment yield from 101 to 104 km2 and temporally integrated from 103 to 105 years. Here, I used TCNs to constrain unsteadiness and non-uniformity of sediment yield within specific catchments of the Columbia River Basin (CRB). This is in combination with GIS analysis optically stimulated luminescence (OSL), Carbon-14 (C14) dating of fluvial deposits, and rapid geomorphic assessments. Results showed an order of magnitude spatial variability in the rates of millennial-scale sediment yield at the scale of the entire CRB. At the broadest scale long-term rates of sediment yield generally are poorly predicted from topographic and environmental parameters. A notable exception is the observed positive correlation between mean annual precipitation and sediment yield. Where functional relationships exist, the nature of those relationships are scale and situation-dependent. In addition to the broadest scale, each smaller watershed (e.g., ~ 10 – 2,000 km2) has a distinct geologic, geomorphic, and disturbance history that sets the template for the modern sediment dynamics and the physical aspects of aquatic habitat. Chapter 2 presents results of broad-scale trends while Chapter 3 is comprised of case studies from smaller watersheds. Finally, Chapter 4 explores the relationship between long-term sediment yield and modern channel form.
99

Structural and biological analysis of faults in basalts in Sheepshead Mountains, Oregon as an Earth analogue to Mars

Bohanon, Allison 13 May 2022 (has links) (PDF)
Microbial life on Mars is not visible from orbit or by rover cameras, but the fracture networks and scarp morphologies associated with fractures they could live in are measurable. We conducted a field analogue study of 92 normal fault scarps in the Sheepshead Mountains, Oregon to examine the correlation between scarp morphology and vegetation growth in the Steens Basalt. While vegetation is not expected on Mars, the fracture networks that sustain vegetation offer the same micro-environment that would support and protect endoliths. Structural variables were measured in the field and infrared spectra of fault scarps were measured using a handheld multispectral camera and vegetation indices were calculated from these images. Statistical analysis of the scarp morphologic parameters indicate that interconnectedness of fractures is key for elevated vegetation and is represented by a range of parameters. Results support a model for ideal slopes to investigate for preserved biological activity on Mars.
100

Trophically transmitted parasites as ecosystem indicators : relationships among parasite community structure, juvenile salmon diet composition, and ocean conditions

Losee, James P. 29 May 2012 (has links)
Recent research conducted throughout the Northern California Current (NCC) on the ecology of Pacific salmon (Oncorhynchus spp.) indicates that variable ocean conditions affect the community composition of zooplankton in the nearshore environment which, in turn, can affect the quality of prey for fish, sea birds and mammals. Interannual variability in the quality and composition of the copepod community in the NCC during early marine residency of some Pacific salmon populations is related to survival to adulthood. However, copepods make up a small portion of the diet of coho and Chinook salmon, and the mechanistic linkages between ocean climate, zooplankton composition and salmon prey remain unclear. Parasite analysis provides a supplement to traditional diet analysis that can describe the foraging history of a host species. Coho salmon (O. kisutch) and Chinook salmon (O. tshawytscha) serve as hosts to an array of marine parasites acquired through consumption of infected intermediate hosts such as copepods, euphausiids, and planktivorous fishes. Causing little or no harm to their salmon host, the presence of trophically transmitted parasites provides information on the dietary history of their salmonid host beyond the 24 hours associated with traditional diet analysis. This study (1) examined differences in feeding behavior of coho and Chinook salmon during their early marine residency using both stomach and parasite community analyses and (2) tested the hypothesis that variability in ocean circulation patterns (measured through the Pacific Decadal Oscillation, sea surface temperature (SST) and Bakun's upwelling index) and copepod species composition are related to variability in the community structure of trophically transmitted marine parasites found in juvenile salmon. I compared the abundance and species composition of parasites recovered from juvenile Columbia River coho and upper Columbia River summer and fall Chinook salmon captured off the coast of Washington from 2002 to 2009. I also compared interannual variability in parasite assemblages to physical and biological indices of ocean conditions. Coho and Chinook salmon consumed similar prey taxa; however, the species richness and abundance of trophically transmitted parasites indicated that Chinook salmon consumed a greater diversity and abundance of infected prey. In addition, differences in the abundance of fish in the diet and Anisakis simplex, a parasitic nematode known to infect salmon through fish consumption, suggest that Chinook salmon consistently consumed more fish prey than coho. In contrast, coho appeared to consume more euphausiids as indicated by stomach content analysis and increased abundance of the euphausiid parasite, Rhadinorhynchus trachuri. Shifts in the parasite community composition of both coho and Chinook salmon were related to interannual variability in SST and the biomass of southern-origin copepods (r > 0.7, P < 0.05). The acanthocephalan R. trachuri and a tetraphyllid cestode were associated with "warm" SSTs and greater biomass of lipid-poor, subtropical copepods while the nematode A. simplex was more abundant in years of "cold" SST and a relatively low biomass of subtropical copepods. These results provide novel insight into differences in the diet of Columbia River coho and Chinook salmon and illustrate linkages between ocean climate, zooplankton community composition and salmon diet during early marine residency. / Graduation date: 2012

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