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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.
11

Spatial heterogeneity of soil nutrients, nitrogen dynamics and vegetation in a 3rd order stream floodplain in southwestern West Virginia

Dick, David Allen. January 2003 (has links)
Thesis (M.S.)--Marshall University, 2003. / Title from document title page. Document formatted into pages; contains ix, 140 p. including illustrations. Includes vita. Includes bibliographical references (p. 104-108).
12

The use of ⁷Be as a tracer in sediment budget investigations

Blake, William Henry January 2000 (has links)
No description available.
13

Turbulent diffusion in channels of complex geometry

Kearney, Dominic January 2000 (has links)
This thesis examines turbulent diffusion processes in rectangular and compound open channels, with particular attention to the effect of secondary flow and the relationship between eddy viscosity and eddy diffusivity. Three dimensional velocities and concentration were measured using 3 component Laser Doppler Velocimetry (LDV) combined with Laser Induced Fluorescence (LIF) from three laboratory flumes: one rectangular simple channel and a deep and a shallow compound channel. (Continues...).
14

Investigation of flood probability and regionalization

Sun, Hongyong. January 1992 (has links)
Thesis (M.S.)--Ohio University, November, 1992. / Title from PDF t.p.
15

Some new approaches to measuring willingness to pay : a case study of flood risk reduction in Roanoke, Virginia /

Dietz, Brian C., January 1992 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 101-104). Also available via the Internet.
16

Transboundary river floods : vulnerability of continents, international river basins and countries /

Bakker, Marloes H. N. January 1900 (has links)
Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 167-175). Also available on the World Wide Web.
17

Ecology of the marsh rice rat (Oryzomys palustris) in southern Illinois: wetland dynamics, metapopulations, and trophic position

van der Merwe, Jorista 01 December 2014 (has links)
Wetlands occurring on natural river floodplains typically have more dynamic hydrology, because of influences from the river, than man-made wetlands or those associated with reclaimed minelands. For wetland-associated species, fluctuating water levels can affect patch availability, connectivity and potentially habitat quality, and therefore drive metapopulation dynamics. Differences in hydrology between wetland complexes could change food webs and consequently the trophic diversity of the communities occupying these areas. My first objective was to assess the spatial and temporal variation in occupancy and turnover rates of a semi-aquatic small mammal at 2 hydrologically distinct wetland complexes over 3 years in southern Illinois. My second objective was to determine spatio-temporal variation in the trophic structure of small mammals at 2 wetland complexes (floodplain and mineland) in southern Illinois. To address my first objective, I live-trapped marsh rice rats (Oryzomys palustris) during 2011-2013 at 9 wetland patches on the Mississippi River floodplain and 14 patches at a reclaimed mineland. I used multi-season occupancy modeling to estimate initial occupancy, detection, colonization and extinction rates. Catch per unit effort differed markedly between the 2 sites (27 captures/1,000 trap-nights at the floodplain site vs. 8 at the mining site). Estimates of detection probability increased with an increase in effort (number of traps per night per wetland patch). Occupancy probability was similar between sites and positively related to patch size. Patch colonization probability at both sites was related negatively to total rainfall 3 weeks prior to trapping. In addition, the variation in colonization probability among years, was different between sites, with colonization in 2013 being much lower at the mining site than at the floodplain. An increase in total rainfall 3 months prior to trapping led to a substantial increase in extinction probability on the floodplain, but not at the mining site. Differences in metapopulation dynamics and relative abundance between the 2 sites can be attributed to differences in hydrology and habitat quality. Although rice rats were present at the mining site in much lower numbers than at the floodplain site, these less-natural wetland complexes might serve as valuable refuges for species occurring in increasingly fragmented landscapes. For my second objective, I collected hair samples from 6 species of small mammals (n = 416) occurring at these wetland complexes. I analyzed C and N stable isotopes for 3 mammal taxa (Oryzomys palustris, Peromyscus spp,, Microtus ochragaster) to compare diet between species, sites, and, times. Food sources (vegetation and invertebrates) were collected at each site to form the isotopic baseline. Using stable isotope mixing models, I found no seasonal difference in diet composition, but signatures varied between sites. Oryzomys palustris at both wetland complexes incorporated primarily (70-80%) invertebrates in their diet, and used more C4 vegetation (30%) than C3 (0%). Isotope signatures of Peromyscus diets at the floodplain site were similar to that of Oryzomys, with ~80% invertebrates and >C4 vegetation than C3 vegetation (~20% and 0%, respectively). At the mining site, Peromyscus were at a much lower trophic level and consumed 70% vegetation with C3 plants making up a greater part of their diet than C4 vegetation (50% and 20%, respectively). Microtus was at a lower trophic position than the other 2 species at both sites. These isotope results point to reduced niche overlap between Oryzomys and Peromyscus at the mining site, perhaps due to lower habitat quality and limited suitable resources. Although small mammals had narrower diet breadths at the mining site, none of the species was at a higher trophic position at the mining site than at the floodplain site. At the floodplain site, the more dynamic hydrology might have given rise to higher biodiversity and consequently provided more resources to allow small mammals to use similar food items.
18

The role of information in the development of floodplain policies : the Southlands case study

Huhtala, Kari Edward January 1988 (has links)
Increasing development of floodplain lands has led to the need for government officials to be more discerning about the quality and distribution of flood hazard information during the formulation of floodplain management policies. This thesis examines the relationship between flood hazard awareness and the adoption of floodplain policies, and includes a case study in the Southlands area of the City of Vancouver, British Columbia. The research points to methods for improving the quality and distribution of hazard information and education in the public decision-making process. A literature review of natural hazard research presents the available evidence on the relationship between hazard awareness and response, and general information principles that should be followed in developing a successful hazard advisory program. The thesis presents the necessary information to understand the full range of flood adjustment measures available to deal with flood hazard, as well as the formal institutional and legislative framework and government programs that affect flood management decisions in the Province of British Columbia and City of Vancouver. Background information on the study area is provided, including its location, flood hazard, history of flood management and the planning program used to develop floodplain management policies. The empirical research involved interviews of government officials and a survey of floodplain residents in the Southlands area to establish flood-related perceptions. The findings from the interviews and surveys are integrated to demonstrate the perceptions of the government's and community's awareness of flood risk and responses as a result of information that has been provided as part of the Southlands Local Area Planning Program. Recommendations are made for improvements in information approaches that could be used in future flood management programs. / Applied Science, Faculty of / Community and Regional Planning (SCARP), School of / Graduate
19

The Role of Floods in Particulate Organic Matter Dynamics of a Southern Appalachian River/Floodplain Ecosystem

Neatrour, Matthew Aaron 09 September 1999 (has links)
I investigated the role of a flood in particulate organic matter (POM) dynamics of the Little Tennessee river/floodplain ecosystem in western North Carolina, USA. I measured litter inputs, leaf breakdown, floodplain litter, and aboveground herbaceous net primary production at 12 sites. Annual litter inputs (274-625 g m-2 y-1) were typical of a temperate deciduous forest, but lower than other floodplain forests in the eastern United States. Mean aboveground herbaceous net primary production ranged from 61-439 g m-2 y-1 and leaf breakdown rates of 4 tree species ranged from 0.001-0.010 d-1. Following a flood on 8 January 1998, sites were separated into three inundation classes: inundated, partially-inundated, and non-inundated. Sites inundated by a January flood had significantly less forest floor leaf litter and coarse woody debris after the flood. There was no significant change at the partially-inundated or non-inundated sites. In addition, there was no significant difference in herbaceous material between pre- and post-flood collections for any inundation classes. Litter input, leaf breakdown, and floodplain litter standing crop data suggest that flood entrainment of POM from the floodplain of Little Tennessee River is a source of POM to the active channel. The impact of floods on the floodplain POM dynamics, however, is highly dependent on the time of year and magnitude of the flood, and on the structure of floodplain tree assemblages, which is strongly influenced by anthropogenic land use. Compared to direct litterfall and instream primary production, the floodplain may be a small annual source of POM for the river. / Master of Science
20

Centrarchid assemblages in oxbow lakes of the Mississippi Alluvial Valley with perspectives for fisheries management

Alfermann, Ted Joseph 06 August 2011 (has links)
Surrounding land-use and in-lake data were collected to determine environmental variables influential in structuring centrarchid assemblages in oxbow lakes of the Mississippi Alluvial Valley (MAV) and to suggest environmental manipulation strategies that may improve the fisheries of these systems. I sampled 53 oxbow lakes using boat electrofishing and land-use data were summarized using ArcView GIS. Non-metric Multidimensional Scaling separated centrarchids according to water quality tolerance. Centrarchid composition was related to land-use, water clarity, maximum depth, connectivity, primary productivity, and physicochemistry as determined by Canonical Analysis of Principal Coordinates. Canonical Correspondence Analysis rejected the null hypothesis of no relationship between land-use and centrarchid proportional composition. Environmental variables were related significantly to centrarchid composition. Based on these data, a general fisheries management plan for oxbow lakes of the MAV was proposed.

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