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Xavier, Patricia Anne. "Floodplain woodland hydrodynamics." Thesis, Cardiff University, 2009. http://orca.cf.ac.uk/54961/.
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Floodplain woodlands are valuable environments, providing a diverse habitat for many riparian and land-based species. It is now recognised that the continual loss of floodplain woodland has impoverished the national biodiversity of riparian environments, and measures have been brought in both nationally and through the European Commission to halt the decline. This has however, highlighted a deficiency that has existed for many years in the field of river hydraulics. The representation of complex riparian vegetation environments within river models remains an area not adequately addressed. This research presents experimental investigations into floodplain woodland vegetation, with a view to improving the representation of these vegetations within numerical models. Floodplain woodland hydrodynamics were explored with scaled-down (1:8) stag gered arrays of single stem and multi-stem model trees at planting densities of 8.8, 19.8 and 80.6 plants per m 2. The planting densities investigated correspond to the recommended planting densities cited by the Forestry Commission UK. Roughness factors, including Manning's n, the Darcy-Weisbach friction factor / and the bulk drag coefficient Ca were computed for the different model tree and planting density combinations. Velocity measurements within the arrays were investigated, and a study to determine the optimum sampling strategy was carried out to obtain representative velocity and turbulent kinetic energy measurements within the model tree arrays. The optimum sampling locations for streamwise velocity appeared to be clustered around 0.3 s and 0.7 s, where s is the lateral or longitudinal spacing between the model trees, while for turbulent kinetic energy the optimum location was 0.5 s. Full scale drag force versus velocity tests of floodplain woodland trees were carried out and a drag area parameter CdA.Uo derived. The trees experienced little to no bending at low velocities, with force varying linearly with the square of velocity, while considerable deflection was observed at higher velocities, with force varying linearly with the velocity. Physical parameters including height, diameter, mass and volume of the wood are compared against the drag area parameter, with mass and volume showing a stronger correlation than height or diameter. The increase in the drag area parameter due to the presence of foliage was also investigated. The numerical incorporation of floodplain woodland vegetation is presented with respect to two-dimensional depth-averaged numerical modelling. A reach of the River Laver in North Yorkshire, England was modelled to assess the hydraulic impact of the conversion of arable land to floodplain woodland.
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Holowaty, Nadja Deyglun. "Floodplain management in Quebec : a case study of the Mille Iles River floodplains." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63232.
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Wolfe, Brian Paul. "Floodplains and the Proximate Principle: A Case for Floodplain Linear Parks in Roanoke, Virginia." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/33151.
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The intention of this paper is to argue a position for the use of floodplain linear parks as a means of urban flood mitigation. Current approaches often focus on protecting existing and future structures via the use of costly-engineered solutions such as dams and floodwalls. My argument is that the same money can be used to restore the floodplain by removing such structures and establishing a park system that will serve as a valuable public amenity, while allowing flooding to occur with minimal damage produced. In the long run, such a park will provide a greater return on the investment than other potential solutions. A discussion of the â Proximate Principleâ will describe how this works. From an environmental perspective, the importance of such a park will be discussed by placing it in the context of the green infrastructure concept, which is essentially an umbrella term for ongoing efforts to better integrate human and natural systems. Three case studies are presented that demonstrate examples of such park systems and the effects they had on local economies and communities. These studies begin demonstrating the social connotations for such a project as well. Throughout this paper, ties are made to the city of Roanoke, Virginia (where the project portion of this thesis takes place) to demonstrate the relevance of floodplain linear parks to the city. All arguments made are supported by a conceptual floodplain park plan for the city of Roanoke.Master of Landscape Architecture
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Jones, Charles Nathaniel. "Floodplain Hydrology and Biogeochemistry." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/75169.
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River-floodplain connectivity is defined as the water mediated transfer of materials and energy between a river or stream and its adjacent floodplain. It is generally accepted that restoring and/or enhancing river-floodplain connectivity can reduce the downstream flux of reactive solutes such as nitrogen (N) and phosphorus (P) and thus improve downstream water quality. However, there is little scientific literature to guide ecological engineering efforts which optimize river-floodplain connectivity for solute retention. Therefore, the aim of my dissertation research was to examine feedbacks between inundation hydrology and floodplain biogeochemistry, with an emphasis on analyzing variation experienced along the river continuum and the cumulative effects of river-floodplain connectivity at the basin scale. This was completed through four independent investigations. Field sites ranged from the Atchafalaya River Basin, the largest river-floodplain system in the continental US, to the floodplain of a recently restored headwater stream in Appalachia. We also developed a method to examine river-floodplain connectivity across large- river networks and applied that methodology to US stream network. Largely, our results highlight the role floodwater residence time distributions play in floodplain biogeochemistry. In headwater streams, residence times restrict redox dependent processes (e.g. denitrification) and downstream flushing of reactive solutes is the dominant process. However, in large-river floodplains, redox dependent processes can become solute limited because of prolonged residence times and hydrologic isolation. In these floodplains, the dominant process is often autochthonous solute accumulation. Further, results from our modeling study suggest large-river floodplains have a greater impact on downstream water quality than floodplains associated with smaller streams, even when considering cumulative effects across the entire river network.Ph. D.
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Sorg, Jonathan Earl. "FLOODPLAIN MANAGEMENT: AN INTERNSHIP WITH THE OHIO DEPARTMENT OF NATURAL RESOURCES' FLOODPLAIN MANAGEMENT PROGRAM." Connect to this document online, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1133361272.
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Thesis (M. En.)--Miami University, Institute of Environmental Sciences, 2005.Title from first page of PDF document. Document formatted into pages; contains [1], v, 169, [1] p. : ill. Includes bibliographical references (p. 36).
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Castenson, Karen Lynn. "Hydromorphology of Piedmont Floodplain Soils." College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/1354.
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Thesis (M.S.) -- University of Maryland, College Park, 2004.Thesis research directed by: Dept. of Plant Science and Landscape Architecture. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Trigg, Mark Adam. "Amazon River and floodplain hydrodynamics." Thesis, University of Bristol, 2010. http://hdl.handle.net/1983/a11db296-b2d8-4c75-95e4-7c94816345c0.
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The annual monomodal flood pulse of the Amazon River is a key driver for this globally important hydrological system. Understanding the behaviour and characteristics of this flood wave and its influence on the dynamics of river and floodplain interaction is important to many studies attempting to quantify processes dependent upon it, including estimates of carbon fluxes from the wetlands and sediment movement to the ocean. The main aim of the research presented in this thesis was to investigate the hydrodynamic behaviour of the Amazon River and its floodplain, in order to better understand its components and processes. The key scientific question underpinning this aim is: How do the floodplain storage and fluxes affect the passage of the Amazon flood wave and in turn how does the passage of the flood wave control the dynamics on the floodplain? Research was carried out using a synthesis of hydraulic characterisation, numerical modelling, spatial analysis of remote sensing data and field surveys. In combination with information from published floodplain studies, these results were then used to inform the development of a conceptual hydrodynamics framework for the Amazon floodplain. Hydraulic characterisation of the Amazon flood wave was undertaken showing that it is subcritical and diffusive in nature with dominating backwater effects. Experiments with the main channel using hydraulic models showed that main channel water levels were relatively insensitive (0.5 m error on a 12 m flood wave amplitude) to the geometric representation of the channel and that simplified bathymetry is adequate for calibrated predictions, provided the mean cross sectional area can be reasonably well approximated. Hydraulic model results compare well with observed data despite explicit exclusion of the floodplain, indicating that the storage volume of the floodplain has a minimal affect on the passage of the Amazon flood wave for this reach. The spatial analysis of Landsat TM images shows a total of 1,762 floodplain channels in the study area with a mean width of 47 m. Shuttle radar topography mission data has difficulty in resolving many of these floodplain channels due to 96% of the channels having a width less than the SRTM spatial resolution of 90 m. Comparing floodplain channel widths with their frequency reveals a power law relationship, showing patterns of structure that are self-similar over many orders of magnitude. Analysis of the floodplain channel network connectivity showed that the complex floodplain can be divided into floodplain hydrologic units (FHU) and that each unit type has different geomorphic characteristics resulting from a different mixture of water inputs, with each unit isolated from other units for much of the flood cycle by sediment barriers. A field survey of the floodplain channels was conducted in order to measure and characterise their morphology. The findings of this survey together with numerical connectivity experiments, demonstrate that floodplain channels could be playing a much more significant role in the floodplain hydrodynamics then previously acknowledged. Floodplain channels were grouped into three types by depth: (i) for channels carrying only river flood water, depth was strongly correlated with the flood wave’s mean annual range of 11.4 m; (ii) for channels which carried river flood water and local runoff, the mean depth was substantially deeper at 15.9 m; and, (iii) main river island channels were deeper again, with a mean depth of 17.7 m. Finally, a coherent, evidence based, conceptual floodplain hydrodynamics framework was developed to inform a broad range of future Amazon wetland research. The framework represents an extension to the macro level understanding available in the scientific literature and provides an important link between the macro and detailed level study scale.
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Leigh, Catherine. "Floodplain river function in Australia's wet/dry tropics, with specific reference to aquatic macroinvertebrates and the Gulf of Carpentaria." Thesis, Griffith University, 2009. https://eprints.qut.edu.au/119606/1/Leigh_2009_02Thesis.pdf.
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This thesis provides significant insight into our understanding of river function in highly seasonal systems. In north Australia’s vast wet/dry tropics, large rivers and associated wetlands are regarded among the continent’s most biologically diverse and ecologically healthy. Until recently however, research on the hydrology, biodiversity and function of Australian rivers has focussed on the south. My thesis investigates floodplain river function in Australia’s wet/dry tropics, more specifically in the Gulf of Carpentaria drainage division, and is the first to present a dynamic conceptual model of river function for these systems. Three major themes reside within riverine ecology: flow, pattern and process. These themes feature within existing conceptual models of large river function, for example, the River Continuum Concept, the Flood Pulse Concept and the Riverine Productivity Model. These themes and models were used as a template to explore river function in the study region: flow, as broad-scale hydrology and more localised hydrological connectivity; patterns, as spatiotemporal variation in aquatic macroinvertebrate biodiversity; and processes, as organic carbon flow through aquatic macroinvertebrate food webs. The flow regime is major driver of river function, and as such, a multivariate analysis of daily flow data from large, Gulf of Carpentaria rivers was conducted. Two major classes of river were found, each with a distinct flow regime type: ‘tropical’ rivers were characterised by flow regularity and permanent hydrological connection, ‘dryland’ rivers by high levels of flow variability and ephemerality, similar to rivers in Australia’s central and semi-arid zones. However, both river types experienced seasonal change, associated with higher flow magnitudes in the wet and lower flow magnitudes in the dry, with ‘dryland’ rivers typified by greater numbers of zero flow days. These features—flow regularity and permanence for ‘tropical’ rivers, flow variability and absence for ‘dryland’ rivers, and wet/dry seasonality for both river types—were proposed as the broad-scale hydrological drivers of river function in the Gulf region and are expected to be found as important drivers throughout the wet/dry tropics.
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Brill, Katie Ellen. "Impacts of inundation and season on greenhouse gas fluxes from a low-order floodplain." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/19213.
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The global climate is changing and much of this is attributed to the greenhouse effect, which has been exacerbated by increased anthropogenic releases of greenhouse gases (GHGs). However, important GHGs, carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4), are produced naturally in the soil during the metabolism of many soil microbial and plant communities. The generation rate of GHGs depends on many factors, including soil community composition, nutrient availability, temperature, and soil moisture. Predicted climate variability is expected to alter temperature and rainfall patterns, which can impact the factors regulating natural generation of GHGs. With changing fluxes of GHGs, the natural feedback loops between GHG generation and climate may change. Increased emissions from natural sources would exacerbate climate change, whereas decreased emissions may mitigate its impacts. Floodplains may be particularly susceptible to climate change, as their biogeochemical processing is driven by hydrology. For this study, ten mesocosms were installed on the floodplain of Stroubles Creek in southwest Virginia. A flood event was simulated in half of these mesocosms in both early spring and mid-summer, which represent extremes in soil moisture and primary productivity on the floodplain. Headspace gases were monitored for CO, N2O, and CH4. Efflux of CO2 and N2O was higher in summer than spring, and also increased following wetting events. Methane production was greater in the spring, with no detectable change with wetting. Increases in summer rainfall events could increase the release of important GHGs to the atmosphere, potentially at levels significant to climate change.Master of Science
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Schmidt, Casey A. "Floodplain impacts from channelization and urbanization a characterization of the Tumblin Creek Delta Floodplain, Gainesville, Florida /." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0010261.
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Huthoff, Fredrik. "Modeling hydraulic resistance of floodplain vegetation." Enschede : University of Twente [Host], 2007. http://doc.utwente.nl/58016.
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Kunjikutty, Sobhalatha Panangattu. "Floodplain filtration for treating municipal wastewaters." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100641.
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The effectiveness of a cheap, low-tech, environmentally and technically favorable treatment of secondary treated municipal wastewater by contaminant removal through a floodplain-soil filter was evaluated using floodplain-simulating field lysimeters, packed with a sandy soil in 2002 and sand in 2003 and 2004. Secondary treated wastewaters from Vaudreuil (2002 and 2003) and Pincourt (2004) Wastewater Treatment Plants were used as influent. This was applied at rates of 0.06, 0.19, and 0.31 m3 m-2 d -1 to vegetated lysimeters, and at a rate of 0.19 m3 m-2 d-1 to bare-soil lysimeters.Removal of NH4+-N, NO3--N, and COD from the influent was studied in all three years. Irrespective of flow rate or year, the system removed 62~84%, 96~99%, and 6~67% of TKN, NH4+-N, and COD, respectively, from the influent. Under 0.19 m3 m-2 d-1 flow rate, vegetated systems removed slightly more of these constituents from the influent, than did bare-soil lysimeters. Organic degradation mainly occurred in the top 0.1 m soil depth. Degradation of organic and inorganic influent nitrogen increased NO3--N levels in the effluent. Only minimal increases in soil-N levels and N2O emissions occurred with increasing application rates. The nitrogen mass balance accounted for 85∼98% (2003) and 67∼96% (2004) of input nitrogen (through leaching, soil retention, and N2O emissions), the remaining portion being attributable to vegetative effects and volatilization of non-N2O nitrogenous gases. The under established vegetation on the lysimeters reduced nitrogen leaching through soil, being 6% (2003) and 60% (2004) more effective than bare soil.
Effluent water quality improved with decreasing levels of heavy metals. Compared to influent levels, in vegetated lysimeters, under all flow rates, mean effluent As, Cd, Cu, Ni, Pb, and Zn levels had dropped by 58%, 9%, 3%, 37%, 63%, and 52% in 2003, and by 20%, 63%, 5%, 23%, 18%, 57%, and 79% for As, Cd, Cr, Cu, Ni, Pb, and Zn, in 2004. In both years, similar decreases in heavy metal levels occurred in the bare soil lysimeters. Across all flow rates and influent concentrations, soil heavy metal levels increased. In 2004, even low heavy metal content influent further increased (6∼179%) their accumulation in soil. As inputs of heavy metals to the soil increased with the increase in application rates, their associated times to reach maximum permissible limits also decreased.
LEACHN simulation of NO3--N in leachate arising from wastewater application, showed lowered levels with increasing flow rates, due to enhanced denitrification in the resulting anoxic upper soil zones. The simulation under continuous wastewater application at different range of nitrogen concentrations (low, medium, high) showed an increase of NO 3--N levels in the leachate with increasing N-levels. For all flow rates, and under tropical or humid conditions, the effluent NO 3--N levels remained below permissible limits for the low-N content wastewater applications. Intermittent applications, under all wastewater N-contents and flow rates, reduced NO3--N levels in the leachate by 51∼89% compared to continuous wastewater application, and permissible limits were not exceeded. Hence, wastewater with high levels of nitrogenous compounds, as occurs in most developing countries, could be treated by land under an intermittent application pattern, allowing a considerable reduction in nitrate pollution.
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Bates, Paul David. "Finite element modelling of floodplain inundation." Thesis, University of Bristol, 1992. http://hdl.handle.net/1983/edf8eb51-e701-4c18-a482-7f0dac785f84.
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Flood inundation phenomena typically occur over reach lengths of 5- 30 km and incorporate a number of complex flow mechanisms. These include a momentum transfer between the main channel and floodplain and turbulent mixing caused by the delivery of water to the floodplain from the channela nd its subsequenrte turn. However, currently available one dimensional schemes applicable at scales appropriate to floodplain inundation processes cannot effectively simulate such processes. This is due to both an incomplete description of the flow physics and a failure to treat floodplain areas in realistic fashion. More complex two and three dimensional models, which have these capabilities, have only been applied over very short reach lengths (c. 0.5 -2 km) and rarely to compound meandering channels. This thesis reports on the further development of a generalized two dimensional, finite element code (RMA-2) to meet this research need. This is achieved via a series of modifications to the numerical model and to the physical representation by finite elements that enable river channel/floodplain flow at the long reach scale to be effectively simulated. Evaluationo f the enhancedR MA-2 schemef ollows a three stages trategy. Firstly, the assumptions underlying the scheme are examined to identify possible inconsistencies. Secondly, tests are undertaken to assess whether the specified physical model has been correctly transferred into computer code. This is achieved via sensitivity analysis, examination of numerical stability issues and investigation of model response to abnormal parameterization. Thirdly, model predictions of flow field information are compared to observed field data in the context of an application of the enhanced model to an 11 km reach of the River Culm, Devon, UK. Results from this evaluation process indicate that the enhanced RMA-2 model is capable of simulating main channel/floodplain momentum transfer and the two dimensionale ffects associatedw ith compoundm eanderingc hannelsa t this scale. Model simulations compare favourably to field data, both for specific cross sections and over the entire mesh. Finally, extension of this core modelling capability is begun via the development of two model application scenarios. These demonstrate the likely utility of the enhanceds chemef or the assessmenotf flood risk and the investigationo f sediment depositionp rocessesin floodplain systems.
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Michalková, Monika. "Human influences on floodplain lake sedimentation." Lyon 3, 2010. http://www.theses.fr/2010LYO31027.
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L'érosion latérale du fleuve Sacramento, Californie: les influences humaines et les conséquences sur l'habitat des lônes L'étude est basée sur l'analyse spatiale et temporelle d'un chenal actif et des lônes associées. On a utilisé une série de photographies aériennes (prises en 1942, 1962, 1985 et 1999) représentant plus de 140 km de longueur. Les changements planimétriques ont été analysés longitudinalement (analyse synchronique) et temporellement (analyse diachronique) pour souligner les structures spatiales et leur évolution temporelle. La révitalisation du Haut Rhône et les premiers résultats de la sédimentation dans les lônes : Des travaux de revitalisation sur le Rhône ont été réalisés en Chautagne, en Belley et Brégnier-Cordon. L'étude des formes et des processus permet d'en évaluer la sédimentation. On considère notamment les trois points suivants: i) la définition du nombre de connexions par an (la fréquence de connexion débordante); ii) les mesures des taux de sédimentation; iii) les analyses statistiques des relations et l'analyse intra-bras (caractérisant les fréquences de connexion et définissant l'espérance de vie des bras morts). Les différents groupes ont été définis par des analyses en composantes principales normées (ACPn). Morphodynamic de la sortie du cut-off méandre: l'analyse expérimentale du terrain et d'études en laboratoire Les expérimentations sur l'évolution morphodynamique à l'embouchure aval d'un bras mort connecté par l'aval et pas par l'amont ont été menées sur un modèle physique de méandres recoupés de la Morava, au VUVH à Bratislava. Les fonnes d'écoulement et de dépôt/érosion pour deux géométries contrastées d'embouchure aval ont été observées, mesurées et simulées par modélisation hydrosédimentaire 2DLateral Erosion of the Sacramento River, California: Human influences and consequences for floodplain lake habitats This study is based on a spatial and temporal analysis of the active channel and associated flood plain lakes using aerial photographs spanning five decades (1942, 1962, 1985, 1999) over the entire 140 km long reach. Planimetric changes were analysed longitudinally (synchronic analysis) and temporally (diachronic) to highlight the spatial structures and their evolution through time. Revitalisation of Ht. Rhône and First Feedbacks on Revitalised Floodplain Lakes Sedimentation along the Rhône River The revitalisation work on Rhône River has been done on three different localities: Chautagne, Belley and Brégnier-Cordon. The morphologic form as a result of processes become consequently the control factor. Three steps were considered: i) to define the number connexions by year (the frequency of overbank connexion) ; ii) the measurement 1 of the sedimentation rates iii) the statistical analysis of the relationships and inter-lake analysis (the characterise of connexion frequency and to define the life expectancy of floodplain lakes). The diffèrent groups were defined by nPCA analysis. Morphodynamics of the Exit of a Cut-off Meander: Experimental Findings from Field and Labora tory Studies The morphological evolution of the entrances and exits of abandoned river channels govems their hydrological connectivity. The study focusses on flow and sediment dynamics in the exit of a cut-off meander where the downstream entrance Îs still connected to the main channel, but the upstream entrance is closed. Two similar field and laboratory cases were investigated using innovative velocimetry techniques (acoustic Doppler profiling, image analysis). Laboratory experiments were conducted with a mobile-bed physical model of the Morava river (Slovakia). Field measurements were performed in the exit of the Port-Galland cut-offmeander, Ain river (France)
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Leigh, Catherine. "Floodplain River Function in Australia's Wet/Dry Tropics, With Special Reference to Aquatic Macroinvertebrates and the Gulf of Carpentaria." Thesis, Griffith University, 2009. http://hdl.handle.net/10072/367453.
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This thesis provides significant insight into our understanding of river function in highly
seasonal systems. In north Australia’s vast wet/dry tropics, large rivers and associated
wetlands are regarded among the continent’s most biologically diverse and ecologically
healthy. Until recently however, research on the hydrology, biodiversity and function of
Australian rivers has focussed on the south. My thesis investigates floodplain river
function in Australia’s wet/dry tropics, more specifically in the Gulf of Carpentaria
drainage division, and is the first to present a dynamic conceptual model of river
function for these systems.
Three major themes reside within riverine ecology: flow, pattern and process. These
themes feature within existing conceptual models of large river function, for example,
the River Continuum Concept, the Flood Pulse Concept and the Riverine Productivity
Model. These themes and models were used as a template to explore river function in
the study region: flow, as broad-scale hydrology and more localised hydrological
connectivity; patterns, as spatiotemporal variation in aquatic macroinvertebrate
biodiversity; and processes, as organic carbon flow through aquatic macroinvertebrate
food webs.
The flow regime is major driver of river function, and as such, a multivariate analysis of
daily flow data from large, Gulf of Carpentaria rivers was conducted. Two major classes
of river were found, each with a distinct flow regime type: ‘tropical’ rivers were
characterised by flow regularity and permanent hydrological connection, ‘dryland’
rivers by high levels of flow variability and ephemerality, similar to rivers in Australia’s
central and semi-arid zones. However, both river types experienced seasonal change,
associated with higher flow magnitudes in the wet and lower flow magnitudes in the
dry, with ‘dryland’ rivers typified by greater numbers of zero flow days. These
features—flow regularity and permanence for ‘tropical’ rivers, flow variability and
absence for ‘dryland’ rivers, and wet/dry seasonality for both river types—were
proposed as the broad-scale hydrological drivers of river function in the Gulf region and
are expected to be found as important drivers throughout the wet/dry tropics.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
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Gallup, Douglas J. "Floodplain and Flood Probability Mapping Using Geodatabases." Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd736.pdf.
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Reid, Brian. "Energy Flow in a Floodplain Aquifer Ecosystem." The University of Montana, 2007. http://etd.lib.umt.edu/theses/available/etd-05232007-165824/.
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We developed an energy budget to identify energy sources for the invertebrate community of a large 20 km2 floodplain aquifer, based on biomass distributions, organismal respirometry, in situ community respiration, mesocosm and microcosm experiments, stable isotopes and invertebrate gut contents. The invertebrate respiration scaling exponent was 0.474 (+/- 0.068, 95% CI) across six orders in body mass, which is significantly lower than the ¾ power scaling predicted by metabolic theory. Invertebrate production was dominated by copepods (Diacyclops, Acanthocyclops, Bryocamptus), Stygobromus amphipods, and amphibiont stoneflies, and ranged from 26.9 to 4200 mg C/m3 sediment/year. Production and density showed a U-shaped response to dissolved oxygen (high production at both low and high oxygen concentrations). Production declined exponentially with depth for most sites, but at sites with orthograde oxygen profiles there was an exponential increase at the oxycline. Aerobic microbial community production ranged from 1210 to 2020 mg C/m3 sediment/year, also showing a U-shaped response to oxygen. System respiratory quotient (RQ) ranged from ≈ 0 to 9.5, indicating a significant contribution of anaerobic production to system energy flow. We documented multiple lines of evidence for DOC (soil, river) and buried POM carbon sources, however POM was by far the largest carbon reservoir in the aquifer at ≈ 108 (to 1010) mg C/ m3 sediment. Energy from POM breakdown was the only source sufficient to explain microbial and invertebrate production. Carbon stable isotope signatures showed strong levels of depletion for invertebrates (δ13C -25 to -70). These results suggest a significant anaerobic subsidy of aerobic food webs in the subsurface, and a potential methane subsidy of 10% to 99% of invertebrate energy flow. Oxygen showed high, non-random, spatial and temporal variation across the aquifer, with a large scale decline in oxygen along the axis of the floodplain, and distinct hotspots of low oxygen. Low oxygen hotspots corresponded with migration of stonefly nymphs 100s of meters into the aquifer. The U-shaped responses and biogeochemical trends suggest a major threshold at bulk oxygen concentrations of 3-5 mg/l. Collectively, these findings indicate the role of dissolved oxygen as a key variable in groundwater ecosystems.
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Bechtold, James Scott. "Fluvial sediment influences on floodplain soil biogeochemistry /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/5358.
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Pernik, Maribeth. "Mixing processes in a river-floodplain system." Thesis, Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/19514.
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Flynn, Nicola Jane. "Nitrogen interactions between floodwater and floodplain soils." Thesis, Royal Holloway, University of London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311972.
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Ludwig, Andrea L. "Constructed Floodplain Wetland Effectiveness for Stormwater Management." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/28460.
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A 0.2-hectare wetland was constructed in the floodplain of Opequon Creek in Northern Virginia as a best management practice (BMP) for stormwater management. The research goals were to 1) determine if wetland hydrology existed and quantify the role of groundwater exchange in the constructed wetland (CW) water budget, 2) estimate wetland hydraulic characteristics during overbank flows, and 3) quantify the event-scale nutrient assimilative capacity of the constructed wetland. CW water table elevations and hydraulic gradients were measured through an array of nested piezometers. During controlled flooding events, stream water was pumped from the creek and amended with nutrients and a conservative tracer in two seasons to determine hydraulic characteristics and nutrient reduction. Samples were collected at the inlet, outlet structure, and at three locations along three transects along the wetland flowpath.
Water table elevation monitoring demonstrated that wetland hydrology existed on the site. The mean residence time of the wetland was found to be 100 min for flow-rates of 4.25-5.1 m3/min. Residence time distributions of the high and low marsh features identified a considerable degree of flow dispersion. Manningâ s n varied between macrotopographic features and was significantly higher in the spring event as compared to the fall event, likely due to the presence of rigid-stem vegetation. Average wetland n was 0.62. Total suspended solid concentrations decreased with increasing residence time during both experiments. Mass reduction of pollutants were 73% total suspended solids (TSS), 54% ammonia-nitrogen (NH3-N), 16% nitrate-N (NO3-N), 16% total nitrogen (TN), 23% orthophosphate-phosphorus (PO4-P), and 37% total P (TP) in the fall, and 69% TSS, 58% NH3-N, 7% NO3-N, 22% TN, 8% PO4-P, and 25% TP in the spring. Linear regression of mass flux over the event hydrograph was used to determine pollutant removal rates between the wetland inlet and outlet. Pollutant removal rates were determined through linear regression of mass flux and were higher in the spring event than in the fall. Dissolved nitrogen species were more rapidly removed than dissolved phosphorus. TSS, TP, and TN removal were greater and faster than dissolved nutrient species, suggesting that physical settling was the dominant removal mechanism for stormwater pollutants.Ph. D.
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Botha, Mark. "Dynamics of two South African floodplain forests." Master's thesis, University of Cape Town, 2001. http://hdl.handle.net/11427/10165.
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Including bibliographical references.Riverine systems are an important component of landscape diversity because of the interaction of biodiversity patterns, disturbance regimes and environmental gradients therein. They stabilise migrating river channels and ameliorate hydrological extremes. Concern is growing over the degradation of riparian environments through upstream abstraction, impoundments, altered flood regimes and increased incidence of low flows. These processes may lead to subtle or significant vegetation changes that will affect the understanding, management and conservation of these systems. This is particularly true in semi-arid environments where a functioning river is a vital source of water and nutrients for the maintenance of riparian biota, especially riverine forests. There remains, however, a lack of ecological understanding of riparian forests in Africa, especially tree regeneration requirements, community level patterns and water relations. The major determinants of tree distribution have yet to be fully elucidated for many riverine systems, particularly in tropical areas, and the potential consequences of changes in causal agents are unquantified.
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Baugh, Calum Alexander. "The hydraulics of the Amazon River floodplain." Thesis, University of Bristol, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.683694.
Full textAbstract:
The Amazon River is the largest by discharge and basin area globally, annually it delivers large volumes of water to the oceans through a mono modal flood cycle. During this cycle an unknown quantity of water is exchanged with the adjacent floodplain. The volume and duration of this exchange plays an important natural function for sedimentological, biogeochemical and ecological processes. It is known that hydraulic processes within the floodplain, including water depths, flow discharges and inundation timings, influence this exchange of water between the Amazon River and its floodplain. Hence the overall aim of this thesis was to investigate how water was routed through the Amazon floodplain and the hydraulic processes behind this routing. Floodplain water routing and hydraulics are influenced by three key aspects in the Amazon: 1) the volume of water, 2) the pathways along which this volume is routed, and 3) the influence oflocal water sources in the floodplain upon water derived from the Amazon River. Addressing these aspects led to three key scientific questions around which this thesis was structured: 1) What volume of water was exchanged between the Amazon River and its floodplain? 2) Along what flow pathways does this exchange occur? and 3) How does water from local hydrological sources influence the floodplain hydraulic processes? Investigations in this thesis were focussed upon a 30,000 km2 study site situated in the middle reach of the floodplain, ~250 km upstream of Manaus, Brazil. Within this area a two-dimensional hydraulic model was constructed from and tested against data from insitu gauges, satellite data and field work observations. The model was then used to address each of the above scientific questions. Before investigating the first question, it was necessary to develop a method to minimise the vegetation canopy distortion errors which had degraded the accuracy of the Digital Elevation Model (OEM), used by the model to represent floodplain topography. After this method, volumetric exchanges between the river and the floodplain were quantified by assessing the volume of water which filled and drained annually from the floodplain. Then the volume of flow routed through the floodplain as a proportion of the total flow was assessed by identifying cross sectional flow differences from simulations with and without floodplain storage components. Between 1995 - 1997 the floodplain filled during rising water by 93 - 113 km3 , whilst during falling water the floodplain drained 75 - 113 km3. Annual flows through the floodplain represented 6.4% - 10.7% of the total flow via the Amazon River, this increased to 9.0% - 18.8% at high water and decreased to 1.3%- 2.3% at low water. The role of floodplain channels as preferential flow pathways for water entering and exiting the floodplain was investigated by incorporating their geometry into the hydraulic model using a subgrid methodology. The overall effect of all these channels was to increase the duration of connection between the Amazon River and the floodplain. Consequently floodplain inundation volume increased by 7.3% - 11.3% at high water, and decreased at low water by 4.0% - 16.6%. These floodplain channels tended to function in networks, whereby smaller channels delivered flow into the floodplain, these collected into larger channels which then drained back into the main river. In total, these networks served as a net drainage mechanism taking flow from the floodplain back to the main river. The influence of local hydrological water inputs from terrafirme catchments which bounded the floodplain, were represented from simulated outflows from a hydrological rainfall-runoff model. Over the entire domain floodplain hydraulics were insensitive to these additional inputs, however a more significant influence could be observed int the areas surrounding the input locations. Temporally, the most significant influence was during falling and low water, when some areas witnessed flow increases of 15% - 400%. During this time, water in the floodplain could be composed of up to 10% - 15% from these local water sources. In answering the thesis aim, the work that will be presented shows that the Amazon floodplain routes a large proportion of the total flow within the study domain. This large exchange of water is aided by the existence of flow pathways, afforded from floodplain channel features, which play an important role in connecting the river and floodplain during early rising water and late falling water. Floodplain hydraulic processes are subtly influenced by local water inputs, which can be important in sustaining flows during falling and low water.
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Strick, Robert John Paul. "Floodplain geomorphology and topography in large rivers." Thesis, University of Brighton, 2016. https://research.brighton.ac.uk/en/studentTheses/a61e4805-4874-4cec-a1d8-e019aefd3053.
Full textAbstract:
Rivers are essential components of the earth surface. The world’s largest rivers have been studied much less than to smaller rivers. They are dominated by meandering channels – whether these are individual km-wide meander bends or ‘accessory’ meandering channels in an anabranching system. Large rivers, specifically ones with laterally migrating bends, can build a variety of floodplain elements that are represented by a complex surface topography, the dynamics and characteristics of which are not yet fully understood. This research brings a greater understanding to, and quantification of, the floodplain topography and geomorphology of large rivers. The project uses remote sensing imagery of the World’s largest rivers, LiDAR datasets of meandering scroll bar topography, and global coverage elevation data. Novel analytical methods are created, involving image manipulation and GIS processing, to quantify these landforms in a way that was not possible until recent technological and computational advancements. A new hierarchical classification schema of meandering floodplain deposits is presented and applied to quantify meandering deposits for two large rivers, the Amazon and the Ob. Both floodplains show similar downstream morphological changes to their floodplains despite their different sizes and locations. The new classification schema works well to describe meandering floodplain deposits. The geomorphology of scroll bars is investigated for the Mississippi River, revealing the heterogeneity of these deposits and that local meander bend conditions are important in determining scroll bar formation and preservation on the floodplain. The periodicity of scroll bars from a range of rivers is investigated and it is shown that scroll bars are intrinsically linked with the width of the adjacent river channel and respond to local planform changes. Floodplains of large rivers have complex overbank sedimentation processes that create spillage sedimentation phenomena. Spillage sedimentation was quantified down a 1700 km reach of the Amazon River and a 1400 km reach for the River Ob, revealing spatial discontinuities in spillage phenomena. Spillage dominance depends on diverse sediment loadings, hydrological sequencing, and morphological opportunity. Understanding spillage dynamics is important in quantifying overbank sedimentation rates and the spatial distribution of fine-grained deposits. The findings of this thesis highlight that despite the incredible complexity and heterogeneity of large river floodplains, order can be inferred via classification schemas and fundamental relationships identified. The thesis uses novel methods and conceptual models to bring a greater understanding and quantification to this complex floodplain geomorphology.
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Sims, Neil C. "The landscape-scale structure and functioning of floodplains." Connect to this title online, 2004. http://cicada.canberra.edu.au/public/adt-AUC20050706.095439/.
Full textAbstract:
Thesis (Ph. D.)--University of Canberra, 2004.Title from PDF title page (viewed on July 20, 2005). Pages 185-194 lacking in digital version of thesis. Includes bibliographical references (p. 155-184).
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Kruske, Montana L., and Dr Eileen G. Ernenwein. "Paleochannel or Palisade? Preliminary Geophysical Investigations of a Linear Feature at the Runion Archaeological Site, Washington County, Tennessee." Digital Commons @ East Tennessee State University, 2019. https://dc.etsu.edu/asrf/2019/schedule/74.
Full textAbstract:
Runion is a protohistoric Native American village located on the floodplain of the Nolichucky River in western Washington County. Previous archaeological excavations and radiocarbon dates suggest that the village was occupied during the mid-16th to mid-17th century. The Nolichucky River, in contrast, has been flowing through the area for millennia. Geophysical surveys are used to image the subsurface non-invasively, without disturbing protected land and/or organisms. Preliminary geophysical data collected at Runion include ground penetrating radar (GPR), electromagnetic induction (EMI), and magnetometry. These data show a linear feature surrounding the protohistoric village. Given its placement around the margins of the village, the feature could be interpreted as a fortification ditch, which is often paired with a palisade wall to defend a village from attack. The feature is also consistent with typical meandering floodplain stratigraphy, where sections of channel are often abandoned to form oxbow lakes. Over time these abandoned channels fill in and are called paleochannels.
Each geophysical method measures the properties and characteristics of the linear feature, a presumed paleochannel. GPR sends electromagnetic radar waves into the ground, which reflect off different subsurface layers and are recorded as radargrams. Magnetometry measures subtle changes in earth magnetism, including the magnetization of rocks, soils, and/or ferrous objects. EMI systems transmit low frequency electromagnetic waves to measure both electrical conductivity (EC) and magnetic susceptibility (MS). Each of these instruments are used to collect data in transects and then processed to produce profiles, maps and, in the case of GPR, three-dimensional datasets of the subsurface.
It is anticipated that GPR will reveal details about the stratigraphy of the linear feature. Magnetic, EC, and MS measurements will further help to interpret the GPR data by distinguishing between different types of sediments. These data may show if the feature is a paleochannel or a ditch excavated into older stratigraphic layers by village inhabitants for fortification. Ultimately, the feature will be tested with soil cores to study the sediments directly.
At this preliminary stage the feature is interpreted to be a paleochannel. The stratigraphic layers revealed by GPR show a broad depression with stratigraphic layers characteristic of a paleochannel. In addition, magnetic readings are anomalously low on the eastern margin (closer to the modern river channel) and high on the western margin. This could indicate paired point bar sands and paleochannel fill, respectively. This interpretation is still tentative, however, because we have not yet integrated the EMI data, extracted soil cores, or dated the feature. Radiocarbon dates might help determine the relative age of the feature if organic carbon is present. In conclusion, preliminary data currently suggests that the structure is geological rather than archaeological. In the coming months we will collect more GPR data with different frequency GPR antennas, integrate the EMI data, and test the findings by extracting soil cores and reconstructing the stratigraphy.
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Sweet, Robert John. "Computer modelling of flood flows and floodplain sedimentation." Thesis, University of Exeter, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400860.
Full textAbstract:
Past studies of overbank flow and sediment deposition have identified the importance of basin scale and reach scale controls. In addition, floodplain topography has been identified as an important control on overbank flow sequences and associated sediment transport and deposition. Recently, the adoption of combined numerical modelling and field-based approaches have provided an effective means of quantifying reach scale processes operating in floodplain environments. However, there is a need to investigate these processes both at the reach and catchment scale. In this study, a twostage procedure has been developed in an attempt to investigate these processes at a range of spatial scales. First, an existing two-dimensional hydraulic model that solves the depth-averaged shallow water equations was used to predict distributed flow depths and velocities over high-resolution topographic grids representing each of the study reaches. These grids were generated from detailed field survey data of floodplain topography collected using a Global Positioning System (GPS) within three study catchments where between six to eight contrasting reaches were chosen to investigate basin and reach scale morphological controls on overbank flows. The results of the hydraulic model indicate three stages in floodplain inundation. First, initial inundation of low-lying areas adjacent to channel margins. Second, a rapid increase in inundation extent via interconnected low-lying areas as threshold discharges are exceeded. Third, complete inundation where floodwater is conveyed as a single unit in a downstream direction. These patterns were also observed using ground and oblique aerial photography of floodwater inundation patterns. The second stage in the procedure utilised a sediment transport and deposition model that was developed using these hydraulic data. This model was used to estimate patterns and rates of floodplain sedimentation at a reach scale and then extended to the catchment scale. Parameter combinations used in this stage were investigated using a Generalised Likelihood Uncertainty Estimation (GLUE) framework and predictions were compared with estimates of medium-term sedimentation rates derived from 137Cs analysis of floodplain sediment cores. The results of the sediment transport and deposition model indicate that within reach variability of floodplain sedimentation is influenced by small-scale local topographic controls. Typically, 15 % of the inundated floodplain area receives ~50% of the total sedimentation amount and reflects the low-lying areas adjacent to the channel. In contrast, 40% of the inundated floodplain area receives < 20% of the total sedimentation, reflecting distal floodplain areas that are inundated for short periods of time.
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Millington, Catherine. "The geomorphological dynamics of a restored forested floodplain." Thesis, University of Southampton, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443031.
Full textAbstract:
This thesis investigates geomorphological processes within the forested floodplain of the Highland Water, a small, lowland river in the New Forest, southern England. Geomorphological processes were monitored (a) before restoration, in order to define reference conditions, and (b) after restoration, in order to monitor the performance of the restoration against the reference conditions. The results demonstrate that the restoration was successful at moving the restored system towards target reference conditions by re-connecting the channel and floodplain, and consequently floodplain geomorphological dynamics were increased after restoration. However, the restored floodplain was considerably more connected and more dynamic than an upstream semi-natural reference reach, indicating that the restored channel was perhaps undersized. Floodplain channels were an important geomorphological feature observed on semi-natural floodplains, particularly in association with hydraulically effective wood jams. Experiments into sedimentation and erosion showed that overbank flow scoured the surface and distributed sediment, and rates of erosion and deposition were higher within floodplain channels than elsewhere on the floodplain surface. These channels were therefore a major control over the spatial distribution of energy and materials on the floodplain at the patch, feature and reach scale (10-1 to 102 m). The formation of in-channel wood jams, which force flow overbank, relies on the accumulation of wood. Experiments to investigate transport of small wood recorded travel distances ranging from 0 to over 1000 m. Shorter travel distances were associated with higher in-channel geomorphological diversity, particularly the presence of in-channel wood jams. This thesis therefore provides a greater understanding of the geomorphological processes operating on a forested floodplain in conjunction with monitoring the performance of a river restoration project that incorporated a forested floodplain.
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McCann, David Michael. "Basin-scale spatiotemporal analysis of hydrologic floodplain connectivity." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/64179.
Full textAbstract:
Floodplain inundation often provides water quality benefits by trapping sediment and biogeochemically transforming other pollutants. Hydrologic floodplain connectivity is a measure of water exchanges and interactions between the main channel and the floodplain via surface (inundation) and subsurface (groundwater) connections. Using an automated model combining GIS and numerical analysis software, this study examined floodplain inundation patterns and measured floodplain connectivity for the Mahantango Creek watershed (Pennsylvania, USA). Connectivity was quantified by developing a metric that included inundation area and duration. Long-term hydrographs at each reach in the watershed were developed via QPPQ (Flow-Percentile-Percentile-Flow) methodology using regional regression analysis to calculate the ungauged flow duration curves (FDC). Inundation area (normalized to stream length) was found to increase with drainage area, suggesting larger streams have more area available for biogeochemical activity. Annual connectivity increased with drainage area, suggesting larger streams, having higher connectivity, should be the focus of individual reach restoration projects due to higher potential for water quality benefits. Across the watershed as a whole, however, the total annual connectivity across first order streams was greater than higher order streams, suggesting the collection of small streams in a watershed may have a stronger effect on outlet water quality. Connectivity was consistently higher during the non-growing season, which was attributed to higher flows. Despite higher connectivity during the non-growing season, increased floodplain biological activity may be negated by low temperatures, reducing microbial activity. Correlations between land use and connectivity were also found, emphasizing dynamics between flow, channel morphology, and floodplain inundation.Master of Science
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Cook, Benjmain O. "Lower Scotts Creek Floodplain and Habitat Enhancement Project." DigitalCommons@CalPoly, 2016. https://digitalcommons.calpoly.edu/theses/1647.
Full textAbstract:
Scotts Creek, located in northern Santa Cruz County, maintains the southernmost persistent population of Central California Coast (CCC) Coho Salmon (endangered) in addition to CCC steelhead (threatened). Fisheries biologists believe overwinter mortality due to lack of refuge habitat is the primary factor limiting salmonid production. Instream rearing habitat may also be limiting, especially during drought years. The legacy effects of historic land use practices, including dredging, wood removal, and the construction of levees, continued to limit refuge and rearing opportunities. A restoration project was implemented to improve refuge and rearing opportunities for salmonids along lower Scotts Creek by removing portions of the deteriorating levee, grading new connections with existing off-channel features, enhancing tributary confluences, constructing alcove habitat features at the margins of the stream channel, and constructing large wood complexes (LWCs) instream.
Novel restoration techniques were employed on an experimental basis. Whole in-situ alder trees were pushed into the stream channel with their root systems left partially intact to establish living key pieces. Individual log, boulder, and rootwad LWC components were attached together with couplers that permitted some freedom of independent movement among the individual components. LWCs were braced against live, standing trees and stabilized with boulder ballasts placed on the streambed, which eliminated excavation of the streambed/banks and the need to dewater or divert the stream during construction.
Project performance, changes to physical habitat characteristics, and changes to stream morphology associated with implementation were monitored using habitat assessment methods derived from the California Department of Fish and Wildlife’s (CDFW) salmonid habitat survey protocol (Flosi et al. 2010), and topographic survey techniques and data analysis adapted from Columbia Habitat Monitoring Protocol (Bouwes et al. 2011). Preliminary results indicated that LWCs remained stable and functional. In addition, implementation of the restoration project increased pool frequency, low-flow pool volume, instream cover, frequency of instream, alcove, and off-channel refuge habitat features, and frequency of points of connectivity with the floodplain. Long-term monitoring will be required to determine the survivorship, decay rates, and overall persistence of alder recruits.
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Newman, Sonia K. "Management of dominant Carex species on floodplain meadows." Thesis, Open University, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.606954.
Full textAbstract:
Carex acuta and Carex acutiformis have been identified as problem plant species on floodplain meadows in the UK and western Europe and invasive plants in wetland habitats in North America and Canada. A double-cut treatment has been proposed as a control method, however this has not been scientifically tested. This thesis explores the ecology of C. aeuta and C. aeutiformis, the effectiveness of a double cut treatment on their control, the effects of the cutting treatment on the plant community and potential mechanisms regulating the expansion and persistence of the dominant sedge species in sub-optimal conditions. Field trials were set up to monitor the effects of cutting treatment on the meadow vegetation and pot experiments assess the effects of cutting on Carex plant traits. Mesocosm experiments were also undertaken to explore the relationships between water regime, microbial community and plant competition. The field trials revealed that a double cut was a successful treatment to control C. aeuta and C. aeutiformis on ftoodplain meadows. The frequency of the cutting treatment was more important than the timing of the additional cut in controlling C. aeufa and C. aeutiformis. Carex traits were not affected by the timing of defoliation, however flowering in C. aeufa significantly decreased with a double cut compared to a single cut. The microbial community had no effect on the plant community in the mesocosm experiment, the reasons for this are discussed. Drying stress decreased the yield, but not necessarily the percentage cover of the studied sedges and increased the cover of drought tolerant plants in the field and in the mesocosm experiments. Recommendations of short-term treatments to control C. aeuta and C. aeutiformis are presented in this study.
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Fritsche, Jessica R. "Living on a Mississippi floodplain : rural occupants' perspective /." Available to subscribers only, 2007. http://proquest.umi.com/pqdweb?did=1456286051&sid=1&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Estrup, Andersen Hans. "Hydrology, nutrient processes and vegetation in floodplain wetlands." Copenhagen : Den kgl. Veterinær- og Landbohøjskole, 2002. http://www2.dmu.dk/1_viden/2_Publikationer/3_Ovrige/rapporter/Phd_HEA.pdf.
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Joyce, Christopher Brian. "Management of European floodplain grasslands for plant biodiversity." Thesis, Loughborough University, 1998. https://dspace.lboro.ac.uk/2134/6988.
Full textAbstract:
European floodplain grasslands are characterized by periodic flooding and regular management, usually cutting and grazing as part of an agricultural system. Past losses and ecological degradation have been due largely to river regulation and either agricultural intensification or abandonment and have resulted in a substantial reduction in area across Europe. Nevertheless, the remaining resource supports considerable biodiversity and a high level of biological production. A better quantitative understanding of the functioning of these grasslands is required in order to establish effective conservation management within a sustainable land use system. The thesis examines the impact of key management factors on three important functional characteristics of the biodiversity of floodplain plant communities, namely plant diversity (measured by species diversity), cover (%) and primary production (above-ground biomass), on two floodplain grasslands of the River Trent, UK and a third on the the Luznice river, the Czech Republic. Field investigations of the effects of cutting, grazing, cessation of management, the influence of floodborne litter, and the impact of fertilizer nitrogen were undertaken over periods of between one and three seasons. These demonstrated that floodplain grassland plant communities are sensitive to variations in management and that impacts on communities are mediated particularly through effects on plant competition. Productive competitive species were encouraged both by abandonment and fertilizer application whereas cutting and grazing management, and the imposition of litter, favoured stress-tolerating perennials. Species diversity decreased both with high inputs of litter and additions of fertilizer. Plant community responses and competitive strategies of key species are discussed in the context of biodiversity conservation, ecological restoration and management of European floodplain grasslands.
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Wang, Jincheng. "Mercury Exposure Assessment of South River Floodplain Birds." W&M ScholarWorks, 2011. https://scholarworks.wm.edu/etd/1539617902.
Full textAbstract:
The studies involved in this thesis expanded the current project being conducted in Dr. Newman’s laboratory that aimed to define and quantify the impacts of mercury movement in contaminated aquatic and terrestrial food webs in the South River watershed (Virginia, USA). This expansion involved a two phase study, which fulfilled the requirement of a master thesis.
Previous research in our lab documented mercury biomagnification in the river itself and two floodplain locations on the South River watershed. Predictive models were built for mercury concentration in members of these food webs. These studies reached a preliminary conclusion that mercury biomagnification in members of floodplain food webs was faster than that of the aquatic food web. To substantiate this finding and further understand the factors that might produce the differences observed among floodplain locations, two additional floodplain locations were sampled and modeled in 2010. Overall, the models constructed in this study for predicting methylmercury were superior to models for total mercury or the percentage of the mercury present as methylmercury. Including previous models for other sites, four of five attempted methylmercury models based on δ15N met the criterion for useful prediction. For the floodplain models, thermoregulatory strategy was found to have substantial influence on mercury concentrations of food web members. The food web biomagnification factors for the four floodplain locations were consistently higher than that of the contiguous aquatic food web.
The second phase of this research focused on description and determination of current mercury exposure to adults of three avian species during nesting on the South River floodplain and judgment of the risk of harmful mercury exposure to these species by comparing the mercury exposure distributions to published toxicity test results. This study incorporated a formal expert elicitation involving a modified Delphi framework and a Monte Carlo simulation to accomplish a probabilistic risk assessment. Simulations from this study predicted the probability that an adult bird during breeding season would ingest harmful amounts of mercury during daily foraging and also the probability that the average mercury ingestion rate for the breeding season of an adult bird would exceed published rates found to cause harm to other birds (>100 ng total Hg/g body weight per day).The probabilities that these species’ averaged ingestion rates exceeded the threshold value were all less than 0.01.
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Godber, Allison Maree. "Urban floodplain land-use - acceptable risk? : A case study of flood risk perception on the Guragunbah (Carrara-Merrimac) floodplain, Gold Coast." Thesis, Queensland University of Technology, 2005. https://eprints.qut.edu.au/16140/1/Allison_Godber_Thesis.pdf.
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In Australia, the developments of hazard-specific legislation, policy and guidelines aims to minimise community exposure to the adverse effects of natural hazards. This occurs under policies of ecologically sustainable development land-use planning processes, which must also now involve the assessment of hazard-risk. However the development occurring in potentially hazardous environments, for example urban floodplains susceptible to flooding, continues to occur as a result of contemporary land-use planning and risk management processes. Why is this an outcome of past and present risk management and land-use planning processes? This thesis finds that a significant factor contributing to this outcome is the discrepancy between the perception and management of risk, particularly acceptable risk, by stakeholders (Local Government, the development industry, risk managers and floodplain occupants). The research is based on an Australian example of an urban floodplain currently under considerable development pressure, but at risk from flooding – Guragunbah (Carrara Merrimac Floodplain) and surrounding suburbs within the Nerang River catchment on the Gold Coast. A case study methodology was adopted, involving a combination of survey data and secondary documents.
A basis for the thesis was the modelling of the actual risk decision-making processes operating within the case study Local Government, and the comparison between actual observed process and the theoretical framework outlined by the existing hazard risk management and land-use planning policy, guidelines and legislation. This enabled the identification of key stakeholders and their roles within the risk management and land-use planning processes operating within the case study area.
The scope of the results of this thesis indicate that a large proportion of stakeholders external to the Local Government (such as residents and some members of the development industry) do not understand the risks of flooding represented by the standards formally adopted by local government (1-in-100 year flood, for example) and as a result, misinterpret their levels of flood risk exposure. Importantly, the results also indicate that contrasts exist in the flood risks considered to be ‘acceptable’ by the stakeholders, particularly when the potential consequences associated with events are described or illustrated in ‘non-technical’ terms. The extent to which the formal standards are misinterpreted suggests that many stakeholders may potentially be exposed to risks greater than they consider to be ‘acceptable’, but they are assuming that the Local Government (in particular) is setting risk standards that are acceptable to them.
The thesis questions the true ‘acceptability’ of the formal standards being adopted through floodplain management policy at the Local, State and Federal levels of Government and identifies management opportunities and constraints in addressing the issue. Obstacles to management change include resource availability, lack of political will and stakeholder consultation. Opportunities for management change include modifying: the approach adopted by Local Governments when constructing planning schemes; the existing planning standards and decisions associated with permissible individual land-use; the mitigation of existing flood risks and exposure; and the communication of flood risk information. In the ‘real-world’ Local Government context, as illustrated by this case study, the issue may be practically addressed by modifying the standards and processes followed to establish acceptable risk.
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Godber, Allison Maree. "Urban floodplain land-use - acceptable risk? : A case study of flood risk perception on the Guragunbah (Carrara-Merrimac) floodplain, Gold Coast." Queensland University of Technology, 2005. http://eprints.qut.edu.au/16140/.
Full textAbstract:
In Australia, the developments of hazard-specific legislation, policy and guidelines aims to minimise community exposure to the adverse effects of natural hazards. This occurs under policies of ecologically sustainable development land-use planning processes, which must also now involve the assessment of hazard-risk. However the development occurring in potentially hazardous environments, for example urban floodplains susceptible to flooding, continues to occur as a result of contemporary land-use planning and risk management processes. Why is this an outcome of past and present risk management and land-use planning processes? This thesis finds that a significant factor contributing to this outcome is the discrepancy between the perception and management of risk, particularly acceptable risk, by stakeholders (Local Government, the development industry, risk managers and floodplain occupants). The research is based on an Australian example of an urban floodplain currently under considerable development pressure, but at risk from flooding – Guragunbah (Carrara Merrimac Floodplain) and surrounding suburbs within the Nerang River catchment on the Gold Coast. A case study methodology was adopted, involving a combination of survey data and secondary documents.
A basis for the thesis was the modelling of the actual risk decision-making processes operating within the case study Local Government, and the comparison between actual observed process and the theoretical framework outlined by the existing hazard risk management and land-use planning policy, guidelines and legislation. This enabled the identification of key stakeholders and their roles within the risk management and land-use planning processes operating within the case study area.
The scope of the results of this thesis indicate that a large proportion of stakeholders external to the Local Government (such as residents and some members of the development industry) do not understand the risks of flooding represented by the standards formally adopted by local government (1-in-100 year flood, for example) and as a result, misinterpret their levels of flood risk exposure. Importantly, the results also indicate that contrasts exist in the flood risks considered to be ‘acceptable’ by the stakeholders, particularly when the potential consequences associated with events are described or illustrated in ‘non-technical’ terms. The extent to which the formal standards are misinterpreted suggests that many stakeholders may potentially be exposed to risks greater than they consider to be ‘acceptable’, but they are assuming that the Local Government (in particular) is setting risk standards that are acceptable to them.
The thesis questions the true ‘acceptability’ of the formal standards being adopted through floodplain management policy at the Local, State and Federal levels of Government and identifies management opportunities and constraints in addressing the issue. Obstacles to management change include resource availability, lack of political will and stakeholder consultation. Opportunities for management change include modifying: the approach adopted by Local Governments when constructing planning schemes; the existing planning standards and decisions associated with permissible individual land-use; the mitigation of existing flood risks and exposure; and the communication of flood risk information. In the ‘real-world’ Local Government context, as illustrated by this case study, the issue may be practically addressed by modifying the standards and processes followed to establish acceptable risk.
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Anderson, Michelle Louise. "The edge effect lateral habitat ecology of an alluvial river flood plain /." Diss., [Missoula, Mont.] : The University of Montana, 2009. http://etd.lib.umt.edu/theses/available/etd-10012008-134442/.
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Smemoe, Christopher M. "Floodplain Risk Analysis Using Flood Probability and Annual Exceedance Probability Maps." Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd379.pdf.
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Necsoiu, Dorel Marius. "A Data Fusion Framework for Floodplain Analysis using GIS and Remotely Sensed Data." Thesis, University of North Texas, 2000. https://digital.library.unt.edu/ark:/67531/metadc2557/.
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Throughout history floods have been part of the human experience. They are recurring phenomena that form a necessary and enduring feature of all river basin and lowland coastal systems. In an average year, they benefit millions of people who depend on them. In the more developed countries, major floods can be the largest cause of economic losses from natural disasters, and are also a major cause of disaster-related deaths in the less developed countries. Flood disaster mitigation research was conducted to determine how remotely sensed data can effectively be used to produce accurate flood plain maps (FPMs), and to identify/quantify the sources of error associated with such data. Differences were analyzed between flood maps produced by an automated remote sensing analysis tailored to the available satellite remote sensing datasets (rFPM), the 100-year flooded areas "predicted" by the Flood Insurance Rate Maps, and FPMs based on DEM and hydrological data (aFPM). Landuse/landcover was also examined to determine its influence on rFPM errors. These errors were identified and the results were integrated in a GIS to minimize landuse / landcover effects. Two substantial flood events were analyzed. These events were selected because of their similar characteristics (i.e., the existence of FIRM or Q3 data; flood data which included flood peaks, rating curves, and flood profiles; and DEM and remote sensing imagery.) Automatic feature extraction was determined to be an important component for successful flood analysis. A process network, in conjunction with domain specific information, was used to map raw remotely sensed data onto a representation that is more compatible with a GIS data model. From a practical point of view, rFPM provides a way to automatically match existing data models to the type of remote sensing data available for each event under investigation. Overall, results showed how remote sensing could contribute to the complex problem of flood management by providing an efficient way to revise the National Flood Insurance Program maps.
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Heatlie, Fiona. "Turbulent flow around bluff bodies at the floodplain edge." Thesis, Loughborough University, 2010. https://dspace.lboro.ac.uk/2134/8517.
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This thesis examines the flow around bluff bodies placed at the floodplain edge in a compound, open channel. The floodplain edge location is associated with a strong shear layer between lower velocity floodplain flow and high velocity flow in the main channel. The drag force exerted by a bluff body is dependant on the way in which the flow separates around the body and subsequently recovers but the drag coefficients typically used to represent the effects of bluff bodies are based on experiments on bodies in geometrically simple channels. The differences induced in the wake structures and therefore in the drag coefficients of bluff bodies when they are placed in the shear layer at the floodplain edge are little understood. In this study, experimental data is gathered that allows direct comparison of the wakes of identical bluff bodies, both emergent (surface-piercing) and submerged, in simple and compound open channels. For the compound channel scenarios, for both single and multiple block arrangements, turbulence data is also reported. These results are augmented using a computational model based on the solution of the 3D Reynolds Averaged Navier Stokes equations, using a non-linear turbulence model. The results show that the changes induced in the wake structures due to their location at the floodplain edge of the compound channel can have a significant effect on the drag coefficient. For the emergent bodies, the proximity of the deep main channel flow is shown to impact in a complex manner upon the processes of reattachment and re-separation, changing the formation of vorticity in the wake. For the submerged bodies, this is complicated by asymmetry in the same processes on the block top. For both body types, separation on the main channel side results in the creation of a strong axial circulation at the floodplain edge and the decay of the wake is asymmetrically affected by the differing behaviour of the turbulence on the two sides.
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Milne, Judith May. "Plant community ecology of a major subtropical riverine floodplain." Thesis, University of Glasgow, 2004. http://theses.gla.ac.uk/4057/.
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This project described the vegetation of a stretch of the Parana River and investigated which natural or human-imposed factors might be controlling its characteristics, its capacity for biodiversity support and its potential to provide an economic resource. This information is of value in the planning of management strategies aiming to conserve biodiversity and develop sustainable ways in which the floodplain resources can be utilised. Central to this study were the surveys of vegetation and environmental characteristics of aquatic, terrestrial and transitional habitats of the Parana floodplain near Porto Rico. These produced extensive data sets which helped to reveal the types of vegetation-environment relationships structuring the floodplain plant communities. To complement this investigative approach, three aspects of the functioning of floodplain vegetation were chosen for closer study. These were the impacts of livestock grazing on wetland and island vegetation, competitive interactions between pairs of free-floating aquatic plant species and the role of aquatic macrophytes in contributing carbon to aquatic food webs. Three major community types were identified in the aquatic habitats of the floodplain, one which included Eichhornia azurea in mixture with several free-floating and emergent species, a second in which E. azurea was strongly dominant and a third comprised purely of submerged species. Two strongly contrasting broad vegetation communities were identified at bank and shore environments. Polygonum and Ludwigia species were important in one group and Poaceae, creepers, woody plants and ferns in the other group. Sub-groups of these communities could also be suggested, but these are less distinct. Most of the floodplain sites supported a Poaceae-creeper community type with the remaining sites supporting a community indicated by Polygonum species. The Poaceae group was comprised of a number of sub-communities in which the importance of Poaceae relative to other species varied. The aquatic vegetation communities differed structurally with contrasting community biomass, canopy height, canopy cover, species richness and stem density. They were associated with waterbodies with different water depth and pH and different sediment nitrogen and phosphorus contents. Water flow rate category and underwent light availability also differed between the sites that tended to support the different vegetation types. The two major bank and shore vegetation communities differed in canopy cover, in the soil nitrogen, phosphorus and calcium levels with which they were associated and in the steepness of the bank on which they tended to grow. Floodplain vegetation communities contrasted in species richness and differed in the soil nitrogen and calcium levels and river systems with which they were associated.
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Musgrave, Heather. "Water sources to floodplain wetlands in the Lambourn catchment." Thesis, Open University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.437771.
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Jobe, Addison Scott. "CONSERVATION RESERVE PROGRAM EFFECTS ON FLOODPLAIN LAND COVER MANAGEMENT." OpenSIUC, 2018. https://opensiuc.lib.siu.edu/theses/2433.
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Growing populations and industrialized agriculture practices have eradicated much of the United States wetlands along river floodplains. One program available for the restoration of floodplains is the Conservation Reserve Program (CRP). The current research explores the effects CRP land change has on flooding zones, utilizing Flood Modeller and HEC-RAS. Modelling in both one-dimensional and two-dimensional approaches were tested and analyzed for the same river reach. Flood Modeller is proven a viable tool for flood modeling within the United States when compared to HEC-RAS. Application of the software is used in the Nodaway River system located in the western halves of Iowa and Missouri, to model the effects of introducing new forest areas within the region. Flood stage during the conversion first decreases in the early years, before rising to produce greater heights. Flow velocities where CRP land is present are reduced for long-term scopes. Velocity reduction occurs as the Manning’s roughness values increase due to tree diameter and brush density. Flood zones become more widespread with the implementation of CRP. Comparing one-dimensional and two-dimensional flood mapping zones, the two-dimensional model shows less inundation. CRP land cover effects evolve over time, with the greatest impact appearing at the end of the contract.
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Bradley, Christopher. "The hydrology of a floodplain wetland, Narborough Bog, Leicestershire." Thesis, University of Leicester, 1994. http://hdl.handle.net/2381/34504.
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A combination of fieldwork and numerical modelling is used to examine the hydrology of a floodplain wetland, Narborough Bog in Leicestershire. The hydrogeological conditions which maintain floodplain wetlands are considered by describing floodplain hydrostratigraphies and deriving a simplified model of wetland hydrology. The hydrological processes which provide water inflow and outflow to a wetland system are reviewed. The mathematics of subsurface water flow are described to provide the background for application of a full groundwater model to the site. The processes are considered by reviewing studies on wetland hydrology. Regular monitoring of field water tables was undertaken, from November 1990 to June 1993; and the spatial and temporal relationship of these records to rainfall, evapotranspiration and river stage are described. Regression models and a response function are used to quantify the relationship of water tables to meteorological parameters, and also to examine the extent of temporal variations in model explanation. Experiments investigating water flow through in-situ peat deposits and alluvial sediments are described. These included an artificial flood experiment and the study of infiltration through an isolated peat column. The results enable approximate values for hydraulic parameters to be estimated for organic and alluvial deposits. The groundwater model MODFLOW was used to develop a calibrated transient model, the ability of which to replicate water table responses to isolated recharge and evapotranspiration events was examined. The results enable an assessment of the significance of influent and effluent water flows, and the contribution of overbank water flow to Narborough Bog. Suggestions for further refinement to the model are advanced. The model is used to derive approximate water budgets for 1991 and 1992 to demonstrate the sensitivity of Narborough Bog to periods of drought, and examine the current significance of the river to site hydrology.
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Claxton, Amanda Jane. "Modelling water flow and chemical transport through floodplain systems." Thesis, University of Bristol, 2002. http://hdl.handle.net/1983/83c59baf-994b-43f1-b7be-660152b25ea7.
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This study uses a fieldwork-modelling research methodology to investigate hydrological pathways and chemical transport in floodplains and riparian zones, which occupy a key position in the landscape at the catchment-river interface. A numerical model is developed (ESTEL2D-SUBIEF2D) that is capable of modelling subsurface water and chemical movement at a high spatial and temporal resolution. The model is used in conjunction with data from two field sites (a lowland floodplain on the River Severn, UK, and a headwater riparian zone on Sleepers River, USA), and with hypothetical tracers, to quantify the effect of a range of factors on the operation of hydrological and biogeochemical processes in floodplain systems. This study shows the relative importance of river and hillslope inputs of water and chemicals to the floodplain, and how the scale of hydrological event (overbank flow, bankfull flow and low flow) affects the interaction of these sources. For example, in the case of an overbank flood event, hillslope inputs can be held back by the steep hydraulic gradient induced by flood water for up to 10 days. A comparison of headwater and lowland floodplains is attempted for the first time and indicates that different hydrological processes operate in these two environments. This implies that results from existing smaller scale riparian zone studies cannot simply be 'scaled up' to larger, lowland floodplain zones. The operation of the denitrification process within the floodplain is investigated as a relevant example of the more general transport modelling capability of the numerical code. This supports and extends the results of previous studies which have suggested that denitrification in the floodplain may be fundamentally limited by the interaction of hydrological processes and carbon availability. This comprehensive exploration of the full range of subsurface flow pathways through the floodplain highlights the importance of an understanding of hydrological pathways as critical to understanding chemical transport within the floodplain system.
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Palmer, Laura Michelle. "Impacts of Stationarity Assumption in Floodplain Management: Case Studies." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1483386481824778.
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Soong, Oliver. "Vegetation Establishment Following Floodplain Restoration in Mediterranean-climate California." Thesis, University of California, Santa Barbara, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10254066.
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Although herbaceous communities are important components of floodplain ecosystems, the factors constraining their restoration and post-restoration dynamics are poorly understood. Over the decade following restoration of a 3.2 km reach of the Merced River and floodplain in California, we tracked herbaceous community composition to distinguish floodplain habitats and utilized perturbations from revegetation treatments and post-restoration flooding to generate community assembly rule hypotheses regarding treatment effectiveness and persistence, with a particular interest in native perennials capable of suppressing non-natives over time if undisturbed. Revegetation treatments comprised combinations of sowing a sterile cover crop, sowing native species, and inoculating mycorrhizae. Most surveyed floodplain areas comprised a low terrace characterized by exceptionally droughty soils, relatively deep groundwater, and occasional flooding lasting into summer. Few species could tolerate both flood and drought to this extent, and the flood year community was generally distinct from that in non-flood years. Both communities were dominated by ruderals capable of avoiding stress and re-establishing following disturbance, including many non-native annual grassland species. Only Artemisia douglasiana responded to the treatments, as most seeded native species failed to establish, including those native perennial grasses expected to suppress non-native annuals, while other seeded native species either established adequately from natural dispersal or failed to persist through moderate flooding. Neither the cover crop nor mycorrhizal inoculation had any meaningful effect. Restoration efforts in naturally ruderal-dominated habitats may be better spent allowing natural regeneration, addressing particularly noxious invasives, and identifying or constructing habitats supporting long-lived native perennials.
Although originally developed for population sizes and population growth rates, modern capture-recapture models can estimate demographic rates in complex situations: multistate models for multiple study sites and stage-structured populations, superpopulation entry probability models for recruitment, and multievent models when state assessments are uncertain. However, combinations of these complications, such as recruitment studies with uncertain state assessments, are common, yet no single model has explicitly incorporated all of these elements. Ultimately, these models estimate the same fundamental population process with the same general approach, and we combine them in a generalized hidden process model based upon a simple discrete state and transition population model with Poisson recruitment that can estimate how recruitment and survivorship rates vary with respect to measured covariates from uncertain state assessments for a stage-structured population at multiple sites. Although closely related to the motivating models, the generalized model relaxes the Markov assumption. While we provide the distributions necessary to implement Bayesian data augmentation methods, we also provide an efficient analytical likelihood with a compact parameter space that is applicable in the absence of density-dependent mortality. As a demonstration, we estimate the influence of several covariates on recruitment and survivorship rates from uncertain observations of Salix gooddingii seedlings at different locations along a riparian gradient, and we use simulations to examine variation in the precision of estimated parameters.
In Mediterranean climates, cottonwoods and willows often exhibit high germination and seedling mortality rates, with recruitment occurring primarily in the occasional year when favorable spring floods improve survivorship. However, along the Robinson Reach of the Merced River, both germination and mortality rates appeared to be atypically low. To understand why these rates were so low along this recently restored flow-regulated, gravel-bedded stream, we surveyed Populus fremontii, Salix exigua, and Salix gooddingii, estimated germination and survivorship rates, and examined their correlations with factors expected to constrain recruitment, namely seed release, seed arrival, moist germination beds, light levels, groundwater depth, groundwater recession rates, and shear stress. Germination/initial establishment rates were low due in part to low seed arrival rates. Only Salix gooddingii was abundant enough to model in detail, and while moist germination surfaces increased germination/initial establishment, rates were low overall. Survivorship rates for Salix gooddingii seedlings and for small individuals were not correlated with any examined covariates. Seedlings tolerated moderate competition, and the absence of major scouring, even during 6 year flows, enabled survival at sites with sufficiently shallow groundwater that seedlings were unaffected by groundwater recession rates.
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Trowbridge, Wendy Bryan. "The influence of restored flooding on floodplain plant distributions /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2002. http://uclibs.org/PID/11984.
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McManus, Erin Michael. "Primary succession of lianas in an Amazonian floodplain forest /." Electronic thesis, 2003. http://etd.wfu.edu/theses/available/etd-11292003-151813/.
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