Dissertations / Theses on the topic 'Floodplain wetlands'
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1
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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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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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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Grulkowski, Darin. "MACROINVERTEBRATE AND HABITAT ASSOCIATIONS IN A REHABILITATED ILLINOIS RIVER FLOODPLAIN: SWAN LAKE, ILLINOIS." OpenSIUC, 2010. https://opensiuc.lib.siu.edu/theses/314.
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Anthropogenic impacts have degraded the function of many large river-floodplain ecosystems. Habitat rehabilitation/management, in the form of water level management, often emphasize the promotion of wetland vegetation. Wetland management is believed to enhance macroinvertebrate populations. To test this assumption, I evaluated macroinvertebrate response to habitat rehabilitation, habitat type, and vegetation density in Swan Lake, an Illinois River floodplain lake located in Calhoun County, Illinois. Results indicated wetland rehabilitation generally enhanced macroinvertebrate availability for spring migrating waterfowl. Results comparing habitats available at Swan Lake indicated moist soil habitats provided greater abundance and biomass of water column macroinvertebrates in the fall season, while spring was more variable. In addition, benthic macroinvertebrate communities indicated inconsistent differences between habitat types. Fall estimates indicated inundation can be an effective mechanism for controlling the timing of water column macroinvertebrate colonization. Vegetation manipulations did not consistently impact macroinvertebrate taxonomic and functional groups, but results indicated some specific taxonomic groups were influenced by vegetation presence/absence and were correlated (positively or negatively) with coarse organic matter. This research supported the principle that management of habitat and hydrologic regime can be effective tools for improving macroinvertebrate populations in order to optimize nutritional resources for waterfowl.
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Zapf, Jeff. "A watershed approach to decrease flooding of Pipe creek in Alexandria, Indiana." Virtual Press, 1996. http://liblink.bsu.edu/uhtbin/catkey/1020171.
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This project explores one method of controlling flooding of Pipe Creek in Alexandria, Indiana. The method used is one of placing wetlands and grass filters within one subwatershed of Pipe Creek to reduce peak discharge and the time to peak discharge. A computer program called Sedimot II was used to determine the peak discharge for the Thurston Ditch subwatershed of Pipe Creek. Both 10 and 50 year 24 hour storms were studied. Following the construction of base line hydrographs for both storm events, four examples of wetland and grass filter placement were shown for the watershed. Hydrographs were then produced for all four alternatives for both 10 and 50 year storms. Recommendations were then made on how these examples could be used in the rest of the Pipe Creek watershed to further reduce the potential for flooding in Alexandria.Department of Landscape Architecture
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Jarvis, Stephanie. "Thecamoebians as an environmental proxy for the Middle Mississippi River floodplain." OpenSIUC, 2014. https://opensiuc.lib.siu.edu/theses/1566.
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Thecamoebian tests from recent lacustrine sediments have been shown to be a useful proxy to study environmental changes such as land-use changes, pollution, and climate shifts. In this study, the usefulness of thecamoebians as an environmental proxy for the Middle Mississippi River (MMR) floodplain is explored. Sediment cores and surface samples were collected from two sites in Alexander County, IL: Southern Illinois University's (SIU) MMR Wetland Field Station near East Cape Girardeau, IL and Horseshoe Lake, a dammed oxbow managed by the IL Department of Natural Resources (DNR), near Olive Branch, IL. These sites represent different floodplain environments, management histories, and flooding patterns. The thecamoebian populations were expected to reflect these differences while also responding to regional signals associated with development, agriculture, and climate. Cores were subsampled at a 5cm interval and all samples were sieved with 150μm and 45μm screens to retain thecamoebian tests. Sieved sediment was examined under a microscope and at least 100 tests were identified in each sample. Pre- and post-land clearing assemblages are recognized at each site, primarily by the increased abundance of the eutrophic-indicating species Cucurbitella tricuspis. Additionally, grab samples collected from the wetlands site during the spring indicate that the site may be influenced by road salt runoff in addition to agricultural activity. These results suggest that thecamoebians are a useful land-use change proxy and more research is needed to better understand the environmental conditions influencing assemblages.
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Burghof, Sonja [Verfasser]. "Hydrogeology and water quality of wetlands in East Africa : case studies of a floodplain and a valley bottom wetland / Sonja Burghof." Bonn : Universitäts- und Landesbibliothek Bonn, 2017. http://d-nb.info/1149154314/34.
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Horton, Kimberly. "Roadway effects on the hydrologic regime of temporary wetlands in the Missouri River floodplain in Missouri." Diss., Columbia, Mo. : University of Missouri-Columbia, 2005. http://hdl.handle.net/10355/4241.
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Thesis (M.S.)--University of Missouri-Columbia, 2005.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (January 11, 2007) Includes bibliographical references.
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Scalero, Noah R. "A SUITABILITY ANALYSIS OF THE WETLANDS ALONG THE MIDDLE MISSISSIPPI RIVER FLOODPLAIN FOR RIVERINE NITRATE ATTENUATION." OpenSIUC, 2020. https://opensiuc.lib.siu.edu/theses/2796.
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Persistently elevated nitrogen loads discharged to the Gulf of Mexico from the Mississippi and Atchafalaya rivers have been shown by a vast body of literature to be the cause of recurring hypoxic conditions in the Gulf of Mexico. Riverine wetlands have been shown to be important ecosystems capable of substantially reducing nitrogen loads delivered downstream through N removal processes including denitrification, anaerobic ammonium oxidation, and plant uptake. In order to assess the relative potential of wetland sites for nitrogen attenuation, a suitability analysis was performed to identify the relative nitrogen attenuation potential of wetlands within the Middle Mississippi River (MMR) floodplain. For this assessment, the literature on nitrogen cycling in riverine wetlands was used to identify variables which are associated with denitrification potential. Data for these variables were sourced from publicly available geospatial datasets and floodplain inundation frequency estimates using a hydraulic model. The variables compiled for this analysis included flood frequency, soil drainage class, soil hydrologic class, soil pH, soil texture, land use, and soil organic carbon. Principle component analysis was applied to the dataset to reduce the number of variables in the suitability model. The results of the principle components analysis revealed that the first four components explained 77% of the variation within the dataset of potential denitrification variables. As a result of the PCA analysis, the variables Soil Hydrologic Class, Soil Organic Carbon, Land Cover, Soil pH, SSURGO’s Flood Frequency, and Flood Exceedance Probability were used to evaluate riverine wetland areas potential for denitrification under two hydrologic connection scenarios, a “with-levee” and a “no-levee” condition. For the with levee scenario, there were 66,146 ha of floodplain that attained a suitability rating of average potential, an additional 16,937 ha of floodplain attained high potential, and 706 ha of floodplain were rated as having very-high potential. The second scenario assumed removal of levees in the study area. In this scenario, there were 65,897 ha in the floodplain that attained a suitability rating of average potential. There were 34,457 ha in the study segment that attained a rating of high potential, whereas 510 ha attained a very-high potential on the suitability scale. These results were then analyzed by levee system, comparing economic and population data with the results of the suitability analysis. In particular, the amount of area within a levee system achieving a rating of high potential vs. the total property value within the levee system was compared to determine which systems would be best candidates for strategic reconnection. This analysis suggests that the Bois & Brule, the Big Five, and the Grand Tower / Degonia Levee systems are the most suitable systems for strategic reconnection efforts in the study area.
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Diefenderfer, Heida Lin. "Channel morphology and restoration of Sitka spruce (Picea stichensis) tidal forested wetlands, Columbia River, U.S.A. /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/5565.
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Edwards, Katherine E. "Herpetofauna Communities and Habitat Conditions in Temporary Wetlands of Upland and Floodplain Forests on Public Lands in North-Central Mississippi." MSSTATE, 2007. http://sun.library.msstate.edu/ETD-db/theses/available/etd-02222007-143034/.
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Temporary wetlands are important breeding sites for herpetofauna, including species of concern, but are often overlooked in conservation planning and management decisions. I conducted surveys of herpetofauna communities and quantified habitat variables surrounding isolated, upland and stream-connected ephemeral pools on Tombigbee National Forest and Noxubee National Wildlife Refuge in north-central Mississippi from March 2004 ? March 2006 to compare herpetile species assemblages between different classes of temporary wetlands, determine use of pools as reproductive sites for amphibians, and determine faunal-habitat relationships for herpetofauna. Species richness and abundance of terrestrial herpetiles differed significantly between upland and floodplain pools. Upland pools contributed substantially more to the diversity of herpetiles than floodplain pools. Upland pools supported significantly greater abundance of larval Ambystomatid salamanders and central newts (larvae and adults). Forest overstory and ground coverage components influenced amphibian abundance such as abundance of mature trees, standing snags, downed woody debris, and litter depth.
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Mehl, Daniel James Gustav. "Assessing the influence of floodplain wetlands on wet and dry season river flows along the Nuwejaars River, Western Cape, South Africa." University of the Western Cape, 2019. http://hdl.handle.net/11394/7031.
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>Magister Scientiae - MScImproved knowledge is required on the quantity and source of water resources, particularly evident during periods of drought currently being faced in South Africa. There is inadequate knowledge with regards to the flood attenuating properties of wetlands, particularly evident in the ungauged catchments of Southern Africa. This study aims to improve the knowledge on the contribution of flow from tributaries with headwaters in mountainous regions to low lying areas and the effects of wetlands on river flow patterns. Several river flow monitoring sites were established along the major upper tributaries of the Nuwejaars River at which daily water levels were recorded and bi-weekly discharge measurements were conducted. Weather data was collected using four automatic weather stations and three automatic rain gauges’ setup throughout the catchment. Rainfall data coupled with rating curves and daily discharges were used to assess the flow responses of these tributaries to rainfall events. Additionally, stable isotope analysis and basic water quality analysis was used to determine the major sources of flow within the major tributaries. The rainfall and river flow data collected, coupled with the characterization of the wetland was used to determine the flood attenuation capabilities of the wetland. Lastly, a conceptual model based on a basic water balance was developed to further explain the role of the wetland and its effects on river flows. The results showed a 27-hour lag time in peak flows from the upper tributaries at the inflows of the wetland to the outflow. Two of the upper tributaries had flow throughout the year and were fed by springs in the upper mountainous regions of the catchment and all tributaries were largely reliant on rainfall for peak flows. The temporary storage of flows within the wetland occurred as a result of the Nuwejaars River bursting its banks, filling of pools, or ponds and the Voëlvlei Lake. It was concluded that the wetland increased the travel time and decreased the magnitude of flows of the Nuwejaars River. However, due to the fact that wetlands are interlinked on a catchment scale and have a collective effect on flood attenuation this study may be improved by looking at the wetlands within the catchment holistically.
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Francis, Cathy, and n/a. "A multi-scale investigation into the effects of permanent inundation on the flood pulse, in ephemeral floodplain wetlands of the River Murray." University of Canberra. Health, Design & Science, 2005. http://erl.canberra.edu.au./public/adt-AUC20061128.153926.
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Using a multi-scale experimental approach, the research undertaken in this thesis investigated the role
of the flood pulse in ephemeral floodplain wetlands of the River Murray, in order to better understand
the impact of river regulation (and permanent inundation) on these wetlands.
An ecosystem-based experiment was conducted on the River Murray floodplain, to compare changes
in nutrient availability and phytoplankton productivity in three ephemeral wetlands (over a drying/reflooding
cycle) with three permanently inundated wetlands. In the ephemeral wetlands, both drying
and re-flooding phases were associated with significant increases in nutrient availability and, in some
cases, phytoplankton productivity. It was demonstrated that the ?flood pulse?, as described by the
Flood Pulse Concept (FPC), can occur in ephemeral wetlands in dryland river-floodplain systems,
although considerable variation in the nature of the pulse existed amongst these wetlands. Results of
this experiment suggest that factors such as the degree of drying and length of isolation during the dry
phase, the rate of re-filling, timing of re-flooding and the number of drying/re-flooding cycles may be
potentially important in producing the variation observed.
Permanent inundation of ephemeral wetlands effectively removed these periods of peak nutrient
availability and phytoplankton productivity, resulting in continuously low levels (of nutrient availability
and phytoplankton productivity). It was concluded that alteration of the natural hydrological cycle in
this way can significantly reduce nutrient availability, primary production and secondary production,
essentially changing the structure and function, the ecology, of these wetlands. Equally, the results of
this experiment indicate that some of the changes resulting from river regulation and permanent
inundation can be somewhat reversed, within a relatively short period of time, given re-instatement of
a more natural hydrological regime.
A mesocosm experiment was used to examine the influence of the dry phase, specifically the effect of
the degree of wetland drying, on patterns of nutrient availability and primary productivity comprising
the flood pulse. Compared to permanent inundation, re-flooding of completely desiccated sediments
increased carbon (C) and nitrogen (N) availability while partial drying generally decreased, or had little
effect on, C and N availability after re-flooding. However, degree of drying had little effect on
phosphorus availability or rates of primary production measured after re-flooding, and it is possible
that these two factors are related. Partial drying reduced rates of community respiration after reflooding,
possibly a reflection of the reduced carbon concentrations measured in these mesocosms in
this phase of the experiment. Degree of drying also influenced the macrophyte community (measured
after three months of flooding), with plant biomass generally decreasing and species diversity
increasing as the degree of drying increased (with the exception of complete sediment desiccation
which had lasting negative effects on both macrophyte biomass and species diversity).
The results of the ecosystem and mesocosm experiments were utilised, in addition to results collected
from the same experiment conducted at two smaller scales (minicosms and microcosms), to assess
whether the effects of hydrological regime on nutrient availability at the ?wetland? scale could be
replicated in smaller-scale experiments. None of the smaller-scaled experiments included in this
investigation were able to replicate the specific response to hydrological regime recorded at the
ecosystem scale, however the mesocosm experiment did produce results that were more similar to
those at the ecosystem scale than those produced by the mini and microcosm experiments. The
results of this study indicated that extrapolation of results from small-scale experiments should be
undertaken with caution, and confirmed that a multi-scale approach to ecological research is wise,
where large-scale field experimentation and/or monitoring provides a check on the accuracy, and
hence relevance, of conclusions reached via mesocosm experiments.
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Teixeira, Raquel Reis. "Dinâmica de macroinvertebrados em duas classes de àreas úmidas (formação palustre e meandro antigo de rio) de uma planície de inundação da bacia do Rio dos Sinos." Universidade do Vale do Rio do Sinos, 2005. http://www.repositorio.jesuita.org.br/handle/UNISINOS/2293.
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Este trabalho teve como objetivo avaliar os efeitos das perturbações hidrológicas (inundação e seca) na riqueza, densidade e composição da comunidade de macroinvertebrados em duas classes de áreas úmidas (formação palustre e meandro antigo de rio) de uma planície de inundação do Rio dos Sinos. A área de estudo localiza-se no município de Novo Hamburgo (Lomba Grande), no Estado do Rio Grande do Sul. Em cada classe de área úmida, um total de 12 coletas foi realizada ao longo de um ciclo anual (16/abril/2003 a 12/março/2004), onde 5 amostradas foram coletadas aleatoriamente utilizando um core (75 mm de diâmetro) inserido 5 cm no substrato. Um total de 1.229 espécimes de macroinvertebrados distribuídos em 50 taxa no meandro antigo de rio e 1.930 espécimes distribuídos em 48 taxa na formação palustre foram coletados. A maioria dos organismos observados eram insetos aquáticos (67,3% no meandro antigo de rio e 69,4% na formação palustre). A riqueza (F11,44 = 3,161; p < 0,05, meandro antigo de rio e F11,44 = 7,290; p
The objective of this study was to evaluate the effects of floods and drought on the macroinvertebrate richness, density and composition in two wetland classes (palustrine wetland and oxbow lake) associated to a floodplain system of the Sinos River basin over an annual cycle (2003-2004). The studied area was located in Novo Hamburgo city (Lomba Grande), in the South of the Brazil (Rio Grande do Sul). In each wetland class, twelve collections were carried out during an annual cycle (Apr 16/2003 to Mar 12/2004). In each collection, five samples were collected at random along an transect. The collections were developed using a corer (75 mm diameter) inserted 5 cm into the substratum. A total of 1,229 macroinvertebrates representing 50 taxa was observed in the oxbow lake and 1,930 macroinvertebrates distributed in 48 taxa were collected in the palustrine wetland. The majority of the taxa corresponded to aquatic insects (67.3% in the oxbow lake and 69.4% in the palustrine wetland). The macroinvertebrate richness (
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Widing, felicia, and Nina Rubensson. "Methane fluxes from tree stems in Amazon floodplains : Evaluating methodological aspect of measuring spatial and seasonal variability in a flooded system." Thesis, Linköpings universitet, Tema Miljöförändring, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-153908.
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Träd i tropiska våtmarker har uppmärksammats som en viktig källa till regionala och globala metan (CH4) utsläpp, då träd fungerar som utsläppskanaler för metan som bildas i sedimenten. Dock finns det en osäkerhet gällande säsongsvariation och rumslig variation samt mängden CH4 utsläpp från träd, eftersom kunskapen kring regionala flöden är begränsad. Därför strävar vi efter att optimera provtagningsinsatser för att öka möjligheten till representativa uppskattningar för olika typer av skogsekosystem och förbättra kunskapen om rumslig och temporär variabilitet för framtida mätningar i Amazonas. Vi undersökte variabiliteten i flöden av CH4 från träd belägna i tre periodvis översvämmade platser (Solimões, Negro and Tapajós) längs Amazonfloden, med olika karaktäristiska egenskaper. Studien genomfördes in situ med slutna kammare på 36 träd vid de tre provplatserna, under olika hydrologiska säsonger. Platserna visade en stor säsongsvariation i CH4-flöden, med de största bidragen under högvattensäsong. En signifikant skillnad mellan två av platserna upptäcktes endast under högvatten och detta kan vara ett resultat av vattnets varierande fysikaliska och kemiska egenskaper. Med hänsyn till variation inom studieplatserna har indelning av zoner betydelse för mätning av CH4-flöden i träd, då vattennivån är en påverkande faktor. En stor rumslig variation upptäcktes, med lägre flöden i zonen närmast land och med det högsta flödet i zonen där förhållanden varierar mest mellan blött och torrt. Detta mönster kan beaktas genom att utföra provtagningar längs zonerna med hänsyn till vattenavståndet.Tropical wetland-adapted trees are recognized as an important source of regional and global methane (CH4) emissions, by transport of soil gas through wetland trees. However, spatiotemporal variability and controls on the magnitude of tree-mediated CH4 emissions remain unknown as fluxes are poorly constrained. Therefore, we aim to optimize sampling efforts to yield representative emission estimates for distinct types of forest ecosystems and improve knowledge on spatial and temporal variability. We examined the variability in tree stem mediated CH4 fluxes in situ, located in three different floodplains (Solimões, Negro and Tapajós) with various characteristics, during different hydrological seasons. The sampling was conducted by measuring fluxes from 36 trees at each location using closed chambers. All the three study sites, situated in the Amazon region, displayed seasonal variability in CH4 fluxes, with the largest contributions observed during the wet season. A significant difference between Solimões and Negro was detected during the wet season and this may be a result of the different chemical and physical characteristics between the sampling locations. As for within the study sites, zones played a significant role for CH4 flux from trees since the water level influences the fluxes. A strong spatial variability (lower fluxes in the land zone, and the highest flux obtained in the zone with greatest variability between dry and wet conditions) was found. This pattern can be addressed by sampling along flooded and non-flooded zones.
The Global Methane Budget
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Anderson, Christopher John. "The influence of hydrology and time on productivity and soil development of created and restored wetlands." Columbus, Ohio : Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1132540084.
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Drinkard, Maureen Katherine. "IMPACTS OF A FLOOD PULSING HYDROLOGY ON PLANTS AND INVERTEBRATES IN RIPARIAN WETLANDS." Kent State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=kent1342805313.
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Amaral, José Americo Bordini do. "Estudo de várzea da planície de inundação da bacia do Ribeirão do Feijão - SP." Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-01122016-120047/.
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A partir de setembro de 1999 até novembro de 2000 estudou-se a várzea da margem direita da planície de inundação do Ribeirão do Feijão, com objetivo de verificação da várzea funcionando como filtro natural na contenção de matéria orgânica utilizando-se para esse estudo, um modelo de simulação desenvolvido com o software Stella. Foram coletados dados climatológicos oriundos de estação climatológica automática (temperatura do ar, umidade relativa, precipitação, radiação solar, velocidade e direção do vento e pressão barométrica), em piezômetros instalados na várzea (em número de 9) e coleta de amostras de água no rio, dados limnológicos: físicos (temperatura da água, turbidez, oxigênio dissolvido, condutividade e profundidade); químicos (fósforo total, fósforo total dissolvido, silicato, nitrogênio total, nitrato, nitrito e amônia), além de dados obtidos pelo estudo da literatura e trabalhos próximos da área de estudo já publicados. A partir do estudo da inter-relação dos processos existentes na várzea de inundação do Ribeirão do Feijão, elaborou-se modelo de simulação. As conclusões que se obtiveram indicam bom comportamento do modelo de simulação e, também, que estudos em escala de tempo mais reduzida sejam utilizados em trabalhos futuros para estudos de várzeas. Outra conclusão refere-se ao funcionamento da várzea como filtro natural, onde houve armazenamento de carbono (matéria orgânica). Constatou-se grande amplitude da variação diária da altura da lâmina d\'água devido à evapotranspiração. Recomenda-se a preservação desse rio porque 40% da água de superfície que abastece a cidade de São Carlos é oriunda desse manancial.From September 1999 up to November 2000 a wetland of the right margin of Feijão river floodplain was studied with the objective to verify its activity as an natural filter to retain organic matter making use of a simulation model constructed with the help of the Stella software. Were collected climatological data from an automatic climatological station (air temperature, air moisture, rain, solar radiation, speed and wind direction and atmospheric pressure), from piezometers installed within the wetland (number of 9) and samples collected of river water, limnological data: physical data (water temperature, turbidity, dissolved oxygen, conductivity and depth); chemical data (total phosphorus, total dissolved phosphorus, silicate, total nitrogen, nitrate, nitrite and ammonium), moreover data obtained from literature and papers published of sites near the study area. From the interrelationship of processes occurring within the Feijão river floodplain wetland was constructed the simulation model. The obtained conclusions indicate the good simulation model behavior and show that time scales should be shorter in future wetland studies. Other conclusion refer to wetland conduction as a natural filter where occurred carbon storage (organic matter). Great amplitude of water table diary variation have been verified within the wetland due to evapotranspiration. Is possible to recommend the river preservation because 40% of the surface city supply is from this site.
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Benassi, Roseli Frederigi. "Dinâmica espaço-temporal de um sistema de áreas alagáveis na planície de inundação do rio Jacupiranguinha, Vale do Ribeira de Iguape, SP." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-26012007-101647/.
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O objetivo principal deste estudo foi verificar a dinâmica espaço-temporal das variáveis limnológicas de um sistema de áreas alagáveis naturais, em microbacia no Vale do Ribeira de Iguape, rio Jacupiranguinha, sob influências de pulsos hidrológicos distintos, para inferir a capacidade destes sistemas em depurar e ou aprisionar carga de nutrientes potencialmente poluidoras que aportam nestas áreas. Para tanto, foram selecionados 11 pontos de amostragem: 1 e 2 no rio Jacupiranguinha; 3 no córrego Serrana; 4 a 10 no sistema de áreas alagáveis; e 11 saída do sistema, próximo ao rio Jacupiranguinha. Amostras de água foram coletadas em 4 períodos, em todas as estações de coleta, e determinadas as concentrações de nutrientes, DBO, DQO, coliformes fecais e totais. No sedimento foram determinadas as concentrações de nitrogênio total, fósforo total e matéria orgânica. Nas estações do sistema de áreas alagáveis foram coletadas macrófitas aquáticas. Medidas de temperatura, condutividade elétrica, pH, OD foram realizadas utilizando-se sonda multiparamétrica. Realizou-se um levantamento topográfico, estudo batimétrico na planície e foram instaladas réguas hidrométricas na área. As vazões e os níveis hidrométricos do rio Jacupiranguinha tiveram relação direta com a precipitação. As lagoas da planície não apresentam comunicação permanente com o rio, são necessários valores acima de 2,47 m para que ocorra o transbordamento e, consequentemente, a fertilização do sistema de áreas alagáveis. Com a utilização do software PULSO foram observados 5 e 3 pulsos completos, nas cotas topográficas 2,47 m e 2,97 m, respectivamente. A duração de ambas as fases dos pulsos (potamofase e limnofase) foram diferentes, a limnofase prevaleceu no período estudado. O regime de pulsos parece ter um efeito homogeinizador no sistema. Diferenças espaciais e sazonais foram observadas nas variáveis limnológicas da água. O sedimento não apresentou diferenças sazonais e espaciais significativas, entretanto, mostrou-se o compartimento de maior armazenamento de nitrogênio, fósforo e matéria orgânica nas estações das lagoas I e II. Números mais elevados de coliformes foram registrados nos pontos 1 e 2. As macrófitas aquáticas presentes no sistema de áreas alagáveis apresentaram importante participação na determinação dos padrões de ciclagem e aprisionamento de nitrogênio e fósforo total, pois estocam quantidades significativas destes nutrientes em sua biomassa. Em termos de reduções de cargas, no período seco, o sistema de áreas alagáveis apresentou reduções consideráveis levando em consideração a série nitrogenada, fosfatada e DBO. Assim, o regime de pulso mantém a conectividade do rio Jacupiranguinha com o sistema de áreas alagáveis e determinam a dinâmica dos fatores abióticos e bióticos, fundamentais para que esse sistema possa funcionar como armazenador e ou depurador de cargas poluidoras advindas deste rio. Entretanto, recomenda-se a construção de sistema de áreas alagáveis artificial para a complementação do tratamento de esgoto existente na área.The aim of this study was to verify the spatial and temporal dynamics of natural wetland limnological variables, in Jacupiranguinha river, a micro basin from Ribeira de Iguape Valley, under distinct hydrological pulses. This was made to infer these systems capacity in depurating or retaining potentially polluting nutrients in wetlands. It was selected 11 sample points: 1 and 2 in Jacupiranguinha river; 3 in Serranas brook; 4 to 10 in wetland system and 11 in the exit of the system, next to Jacupiranguinha river. Samples were collected in four different periods for nutrients determination, BOD, COD, fecal and total coliforms analysis. In sediment was determined nitrogen and phosphorus concentrations and organic matter. It was collected aquatic macrophytes too. Temperature, electric conductivity, pH and dissolved oxygen were measured with YSI probe. Topography was determined and a batimetric study was made in floodplain; besides, it was installed hydrometric rulers in the area. Discharge and hydrometric levels of Jacupiranguinha river were positively related with precipitation. The floodplain ponds were not permanently connected with fluvial course; it is necessary values above 2,47 meters to overflow the wetland and connect it with the river. With the software PULSO was observed 5 and 3 complete pulses, with respectively 2,47 m and 2,97 m of topographic level. Duration of pulse phases (potamophase and limnophase) was different, and limnophase had predominated. Pulse regime seems to homogenize the system. Seasonal and spatial differences were observed in water limnological variables. The differences in sediment were not significant; however it showed the higher nitrogen, phosphorus and organic matter concentrations in the two ponds. Higher coliform concentrations were registered in points 1 and 2. The aquatic macrophytes present in the studied wetland were very important in nitrogen and phosphorus cycle and retention of these nutrients in their biomass. In terms of load reduction, nitrogen, phosphorus and BOD were considerable reduced in dry season. Thus, pulse regime maintains the wetland connected with Jacupiranguinha river and guide the biotic and abiotic factors dynamics, very important factors for a better operation of the system, serving as nutrient storage and depurative. However, we recommend the construction of an artificial wetland system to complement the waste treatment in the studied area.
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Neto, Paulino de Almeida. "Hidrogramas experimentais de área alagada da micro bacia do rio Jacupiranguinha, Baixo Ribeira do Iguape, SP." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-20112007-155108/.
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Ao longo dos anos, vêm sendo desenvolvidos trabalhos comprovando a importância de áreas alagadas naturais para a manutenção e preservação da qualidade das águas e do ecossistema fluvial. Este fato, associado à importância dos sistemas rios-planícies de inundação, fazem com que sua investigação e preservação sejam consideradas prioritárias. O objetivo desta pesquisa é analisar experimentalmente fatores que influenciam hidrogramas, conforme a ecologia fluvial de áreas alagadas da microbacia do rio Jacupiranguinha localizado no Baixo Ribeira do Iguape, SP. A concretização deste objetivo iniciou-se com a definição da área de estudo, bem como sua importância para a região. Foram então instaladas cinco estações linimétricas e uma estação climatológica, e em seguida, com os dados de vazão coletados em campo, foram construídas a curva-chave da entrada da área alagada e as incertezas relativas aos seus parâmetros. A partir desses estudos e com o levantamento topográfico de toda planície de inundação, foi determinada a relação entre áreas inundáveis, vazões e cotas hidrométricas do rio. Além disso, com os dados climatológicos, vazões e vegetação superficial foi possível determinar as componentes (precipitação, escoamento superficial, evaporação e armazenamento) do balanço hídrico da micro-bacia. O monitoramento linimétrico do rio Jacupiranguinha, junto com suas séries históricas e curvas de permanência, possibilitou também o cálculo de sua vazão ecológica. Finalmente foram construídos quadros síntese-conceituais, integrando as relações entre todas as variáveis hidrológicas e limnológicas selecionadas, demonstrando assim a forte associação entre o sistema rio-áreas alagadas.It is very important to improve our knowledge about the floodplains, which have been proved by studies, since these areas are vital to the maintenance and preservation of the quality of waters and the fluvial ecosystem. This fact, associated with the importance of the wetlands-river system, makes its investigation and preservation to be considered number one priority. The objective of this research is to analyze factors that may influence hydrographs, according to the fluvial ecology of wetlands in micro basin of Baixo Ribeira do Iguape Valley, SP. The work began with the definition of the studied field and its importance to the area. Subsequently, five hydrometric station and one meteorological station were installed, and therefore the rating curve in the entrance of floodplain was calculated along with the uncertainties related to its parameters. With these studies and with the topographic survey, it was possible to find the relation between wetlands, river stage and flow. The climatologically information, the river stage and the superficial covering vegetation are essential factors to determinate the components (precipitation, superficial flow, evaporation and the storage) of the water balance at the micro basis of Jacupiraguinha river. The hydrometric observation of the river along with historical series and the probability-duration curve make it possible to calculate the ecological flow. Finally, conceptual charts integrating the relations between hydrological and limnologicals factors were built showing the strong association with the wetlands-river system.
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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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Thomas, David Haydon Lewis. "Environment, socioeconomic change and sustainability in a Nigerian floodplain wetland." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320352.
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Roberts, Susan Jane. "Gunak, Gapalg Dja Gungod ('Fire, floodplain and paperbark') : a study of fire behaviour in the Melaleuca-floodplain communities of Kakadu National Park, Northern Territory, Australia." Thesis, SOAS, University of London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245216.
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In the past fire ecology literature in the tropics has focused mostly on the role of fire within the savanna biome. The fire ecology of tropical wetlands has been largely neglected. This thesis attempts to redress this imbalance by examining the fire behaviour of the wetlands in Kakadu National Park, northern Australia. Wetland burning has become a critical management issue in the Park, particularly since the eradication of the feral Asian water buffalo (Bubalus bubalis Linnaeus) from the Park. Fuel loads, which had been previously suppressed by grazing and trampling, have increased substantially, and this has subsequently affected the fire ecology of the region. This thesis investigates aspects of fire ecology in the Mclaleucafloodplain communities of Kakadu. It examines Aboriginal people's contemporary use and knowledge of fire, as well as the fire behaviour and impact of fires both set by Aboriginal people and from other sources of ignition. In addition, a 'Wetland Burning Index' (WBI) is compiled in order to examine some of the interactions between wetland fuel, weather and fire behaviour. A range of ecological and ethnoecological methodologies are employed in order to measure fire behaviour in situ rather than approximating specific fire regimes under experimental conditions. The thesis assesses the effectiveness and practicability of these methods. A description of wetland fire behaviour is also given, and includes a range of fire types and phenomena. Aboriginal names of fires, and related terms, are also detailed (in the Gundjeihmi language), some of which have not been previously documented. The study concludes by discussing how indigenous people's knowledge of fire can contribute to the field of wetland fire ecology. It also discusses how different fire types can be used to manage tropical wetland ecosystems.
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Farrelly, Tina Schantz. "Long-term Responses of Phalaris arundinacea and Columbia River Bottomland Vegetation to Managed Flooding." PDXScholar, 2012. https://pdxscholar.library.pdx.edu/open_access_etds/787.
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I sought to determine the effect of managed flooding on Phalaris arundinacea L. and other plant species distributions in a large wetland complex, Smith and Bybee Wetlands (SBW), in northwestern Oregon. Altered hydrology has reduced historically high spring flow and prematurely initiated the historic summer drying period at SBW. This alteration has increased the coverage of invasive plants (e.g., P. arundinacea) causing a decrease in native plant cover and thus degrading ecological functions. SBW managers installed a water control structure (WCS) between SBW and the Columbia Slough/River system to impound winter rainfall and thus approximate the ecological benefits that natural flooding provided as well as reduce the abundance of P. arundinacea. Prior researchers conducted intensive vegetation and hydrological monitoring in 2003 (during the season immediately before WCS installation) and 2004. I conducted similar analysis in the fifth and sixth years, 2008 and 2009, following establishment of the WCS. Both study years, I determined percent cover of all vegetation on transects established in 2003. The results, including 2004, as well as 2008 and 2009 showed a reduced cover of P. arundinacea in areas experiencing at least 0.6 meters of inundation and an increased cover of native plant communities when compared to the 2003 baseline data. Native Carex aperta Boott. cover increased 7-fold from 0.3% to 2.3%; Polygonum species cover increased from 20.0% to 52.6%; and Salix lucida Muhl. ssp. lasiandra (Benth.) E. Murray cover increased from 10.9% to 15.5% cover. P. arundinacea declined by over one-third from 44.4% to 28.1% cover following water management. Since hydrology management began, the native Polygonum species community replaced P. arundinacea as the dominant species in the emergent zone. The results of this study refined the suggested depth of inundation needed to reduce P. arundinacea cover in such lake-wetland complexes as SBW from 0.85 meters (based on 2004 study results) to 0.6 meters. Shannon Diversity decreased following water management. The findings of this study demonstrated that water management can enhance native bottomland communities, especially those comprised of obligate wetland species, and reduce P. arundinacea cover in areas experiencing at least 0.6 meters of inundation.
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Kennedy, Thomas Brian. "Aquatic community organization in a diverse floodplain river fish fauna of the southeastern United States." Thesis, [Tuscaloosa, Ala. : University of Alabama Libraries], 2009. http://purl.lib.ua.edu/37.
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Mansell, Lauren Joanne. "Floodplain-mire interactions and palaeoecology : implications for wetland ontogeny and Holocene climate change." Thesis, Queen's University Belfast, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.579790.
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There has been increasing interest in combining proxy records from raised mire and floodplain ecosystems in order to provide greater clarity concerning Holocene climate and environment change. However, there are a number of questions still to be addressed concerning this approach. Perhaps most pertinent is that there has been limited research as to how these systems interact and react to change in a local landscape context. For instance, do ecosystems register events such as increased wetness in a synchronous manner and to what extent do they experience different thresholds? It has become increasingly apparent that chronologically aligning these records is challenging. This study provides a palaeoenvironmental reconstruction across a transect from raised mire to floodplain, using the Humberhead Levels in South Yorkshire as a case study. Coleoptera and pollen were used as environmental indicators, while multiple fraction dating and Bayesian modelling were used to produce age-depth models. These results were compared with previous research undertaken in the region in order to explore wider environmental signals. Floodplain-peat development (c. 8000-3000 cal BC) was intrinsically linked to rising sea-levels, causing base-levels to rise, leading to plaudification and the formation of rheotrophic mire-peat communities, from at least c. 5000 cal BC. The mire communities reached ombrotrophy by c. 2800 cal BC and were no-longer influenced by base-level flow. Consequently, the floodplain and mire ecosystems stopped registering synchronous episodes of change, such as increased wetness. Although the floodplain and lagg fen ecosystems continued to experience similar changes, they also recorded a number of asynchronous hydrological events. These systems may have experienced different thresholds. That floodplain, mire and lagg fen communities do not always register similar or simultaneous environmental changes highlights that more caution should be taken when combining different datasets in order to infer wider regional reconstructions.
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Cooper, Dylan Morgan. "Nutrient release potential during floodplain reconnection: Comparison of conventional and ecological stream restoration approaches." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/82487.
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In the last few centuries, many streams in the eastern United States have been severely disturbed by land use change and are now disconnected from their original floodplain due to the aggradation of legacy sediment. Currently, stream-floodplain reconnection is advocated as a stream restoration practice to take advantage of ecosystem services. The objective of this study is to compare two current stream restoration approaches for their nutrient flushing ability: 1) a conventional approach leaves legacy sediment on the floodplain; and 2) an ecological approach that involves removing the accumulated legacy sediment in order to restore the original floodplain surface wetland, revealing a buried A soil horizon. Soil cores were taken from the surficial legacy sediment layer and the buried A soil horizon in the floodplain of a 550-meter reach of Stroubles Creek in the Valley and Ridge province near Blacksburg, VA, to evaluate potential for flushable DOC, TDN, NO3-, NH4+, and SRP content. In addition, an inundation model was developed to evaluate the extent of flooding under the two restoration scenarios. The inundation model results and nutrient flushability levels were then used to simulate the release of nutrients as a function of stream restoration approach. Results indicate that the buried A horizon contained less flushable nutrients, but the ecological restoration would have a higher frequency of inundation that allows for more flushable nutrient release at the annual scale. Understanding the nutrient release potential from the floodplain will provide the ability to estimate net nutrient retention in different stream-floodplain reconnection strategies.Master of Science
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van, der Merwe Jorista. "Ecology of the marsh rice rat (Oryzomys palustris) in southern Illinois: wetland dynamics, metapopulations, and trophic position." OpenSIUC, 2014. https://opensiuc.lib.siu.edu/dissertations/974.
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Wetlands occurring on natural river floodplains typically have more dynamic hydrology, because of influences from the river, than man-made wetlands or those associated with reclaimed minelands. For wetland-associated species, fluctuating water levels can affect patch availability, connectivity and potentially habitat quality, and therefore drive metapopulation dynamics. Differences in hydrology between wetland complexes could change food webs and consequently the trophic diversity of the communities occupying these areas. My first objective was to assess the spatial and temporal variation in occupancy and turnover rates of a semi-aquatic small mammal at 2 hydrologically distinct wetland complexes over 3 years in southern Illinois. My second objective was to determine spatio-temporal variation in the trophic structure of small mammals at 2 wetland complexes (floodplain and mineland) in southern Illinois. To address my first objective, I live-trapped marsh rice rats (Oryzomys palustris) during 2011-2013 at 9 wetland patches on the Mississippi River floodplain and 14 patches at a reclaimed mineland. I used multi-season occupancy modeling to estimate initial occupancy, detection, colonization and extinction rates. Catch per unit effort differed markedly between the 2 sites (27 captures/1,000 trap-nights at the floodplain site vs. 8 at the mining site). Estimates of detection probability increased with an increase in effort (number of traps per night per wetland patch). Occupancy probability was similar between sites and positively related to patch size. Patch colonization probability at both sites was related negatively to total rainfall 3 weeks prior to trapping. In addition, the variation in colonization probability among years, was different between sites, with colonization in 2013 being much lower at the mining site than at the floodplain. An increase in total rainfall 3 months prior to trapping led to a substantial increase in extinction probability on the floodplain, but not at the mining site. Differences in metapopulation dynamics and relative abundance between the 2 sites can be attributed to differences in hydrology and habitat quality. Although rice rats were present at the mining site in much lower numbers than at the floodplain site, these less-natural wetland complexes might serve as valuable refuges for species occurring in increasingly fragmented landscapes. For my second objective, I collected hair samples from 6 species of small mammals (n = 416) occurring at these wetland complexes. I analyzed C and N stable isotopes for 3 mammal taxa (Oryzomys palustris, Peromyscus spp,, Microtus ochragaster) to compare diet between species, sites, and, times. Food sources (vegetation and invertebrates) were collected at each site to form the isotopic baseline. Using stable isotope mixing models, I found no seasonal difference in diet composition, but signatures varied between sites. Oryzomys palustris at both wetland complexes incorporated primarily (70-80%) invertebrates in their diet, and used more C4 vegetation (30%) than C3 (0%). Isotope signatures of Peromyscus diets at the floodplain site were similar to that of Oryzomys, with ~80% invertebrates and >C4 vegetation than C3 vegetation (~20% and 0%, respectively). At the mining site, Peromyscus were at a much lower trophic level and consumed 70% vegetation with C3 plants making up a greater part of their diet than C4 vegetation (50% and 20%, respectively). Microtus was at a lower trophic position than the other 2 species at both sites. These isotope results point to reduced niche overlap between Oryzomys and Peromyscus at the mining site, perhaps due to lower habitat quality and limited suitable resources. Although small mammals had narrower diet breadths at the mining site, none of the species was at a higher trophic position at the mining site than at the floodplain site. At the floodplain site, the more dynamic hydrology might have given rise to higher biodiversity and consequently provided more resources to allow small mammals to use similar food items.
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Guimond, Julie K. "The effects of river connectivity on floodplain wetland ecology in Jasper National Park, Alberta, Canada." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ60435.pdf.
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Adam, Linda [Verfasser], Petra [Akademischer Betreuer] [Gutachter] Döll, and Andreas [Gutachter] Güntner. "Modeling water storage dynamics in large floodplains and wetlands / Linda Adam ; Gutachter: Petra Döll, Andreas Güntner ; Betreuer: Petra Döll." Frankfurt am Main : Universitätsbibliothek Johann Christian Senckenberg, 2017. http://d-nb.info/113755519X/34.
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Haque, Md Mominul. "Modeling Flood Extent of a Large Wetland in a Data-Scarce Region Using Hydrodynamic and Empirical Models." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/40109.
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Wetlands are dynamic ecosystems and important sources of natural resources that provide a large array of ecosystem services. Unfortunately, most wetlands are threatened by human and natural stressors, such as damming, irrigation, water abstraction, climate change and variability that compromise the sustainability of the whole system. The Inner Niger Delta (IND), Mali, West Africa, is one of the biggest floodplains in the world, has a vast natural resource that attracts many people to live in and around the delta. The IND is considered a hub of human activities that include agriculture, fishing, transport, and tourism and plays an important role in promoting sustainable development for food security, water management, and the environment. As for most wetlands in the world, the very existence of the IND is at stake with the ever-increasing number of dams and irrigation schemes that are built to feed the growing population in the region. Given the fragility of the system and the multiplicity of water uses in the IND, the current knowledge of the flood dynamics and its relation to ecosystem services and the productivity of economic activity is insufficient. There is no operational hydrodynamic model of the IND, and the Malian authorities rely on simplified models and empirical relations for water resources management in the area. This thesis contributes to a better water resources management of the IND by a) developing the first 2D hydrodynamic model based on a triangular adaptative mesh of the IND that performs well despite the poor quality of available topographic/bathymetric data b) developing an innovative way of accounting for the strong hysteresis phenomenon in the IND in the hydrodynamic modeling that allowed a better reproduction of the hydraulic connectivity between important lakes and the main river and c) developing the first non-stationary relationship between the water levels at a reference station and the flooded area in the IND.
The first part of the thesis deals with the challenge of developing a hydrodynamic model using only two low-resolution satellite-derived Digital Elevation Models: the Shuttle Radar Topography Mission (SRTM), which has a 30m horizontal resolution, and the Multi-Error-Removed Improved-Terrain (MERIT). Given the low vertical accuracy of global DEMs, another DEM was derived using the waterline method, by combining water extent map from satellite images and local water level information. Channel depths were approximated using the hydraulic geometric relationship methods, while the friction coefficient was derived from the global land-use class classification (GLCC) data. The river network was extracted from the water extent map corresponding to the lowest water level. Six different hydrodynamic models were created by varying the DEM and downstream boundary conditions. Each of the models was calibrated for discharge and water levels. Bayesian Model Averaging (BMA) was finally used to combine the outputs of all six hydrodynamic models into one robust simulation.
In the second part, the effect of hysteresis at the downstream boundary condition of the hydrodynamic model was examined. Existing hydrodynamic models of the IND use a static stage-discharge relationship as a downstream boundary condition during both the rise and recession of the flood, leading to potential inaccuracies in the simulation of the flood extent. This paper explores the improvement in the simulation of the flood and connectivity dynamics resulting from the use of a looped rating curve at the downstream boundary of a hydrodynamic model of the IND. The hysteresis effect is integrated into the rating curve using two methods, one based on dimensionless discharges and levels (DLRC) and the other based on the modified Jones formula (MJRC). Results show that the hysteresis effect is better represented using DLRC and that simulations using any of the modified rating curves improves the accuracy of floodplain extent simulations in the areas close to the downstream station, as well as the timing of the connectivity of the river system to one important lake in the IND. The improvement in water level simulation decreases steadily with distance from the downstream boundary of the modeled area.
The third part of the thesis deals with the development of an improved relation between inundation extent and water levels in the IND. Accurate knowledge of the flooded extent considered crucial for the proper management of natural resources in the IND. Several authors have developed empirical relationships between water levels at key stations in the IND and the flooded extent in an attempt to provide simple tools to link hydraulic parameters to the performance socio-economic activities in the IND. However, simulations from a hydrodynamic model of the IND showed that the relationship between water levels and the inundation extents varies greatly from year to year, and cannot be adequately captured by static formulas. First, it is demonstrated in this paper that if the maximum water level area is known in advance, accurate relationships between water levels and inundation extents can be derived. In the second part of the paper, stepwise regression is used to develop a function that can forecast maximum water levels at Akka using observed streamflow and precipitation upstream of the Delta. The combination of the two results allows a realtime estimation of the inundated area in the IND using observed water levels, precipitation, and streamflow.
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Pazol, Jordan Samuel. "Effects of Floodplain Reconnection on Storm Response of Restored River Ecosystems." Ohio University Honors Tutorial College / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1618926160551753.
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Arias, Mauricio Eduardo. "Impacts of Hydrological Alterations in the Mekong Basin to the Tonle Sap Ecosystem." Thesis, University of Canterbury. Civil and Natural Resources Engineering, 2013. http://hdl.handle.net/10092/8913.
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The Tonle Sap is the largest and most important natural wetland in Southeast Asia. It covers an area of more than 15,000 km2 with a unique mosaic of natural and agricultural floodplain habitats that coexist with the largest fishery in the Mekong Basin. Accelerating hydropower development and climate change, however, are altering the Mekong’s hydrology, which could negatively affect downstream ecosystems.
The Tonle Sap is facing a two-fold problem. First, the link between its hydrology and ecosystem properties is not well understood. Second, potential ecological changes caused by future hydrological disruptions related to hydropower and climate change are unknown. Thus, the main objective of this thesis was to quantify how alterations to the Mekong hydrology could affect the Tonle Sap ecosystem. The following studies were performed to addressed the objective: (1) an assessment of landscape patterns using geographical information and remote sensing tools; (2) an assessment of habitat patterns based on field surveys of water, vegetation, and soils; (3) ecosystem function modelling to simulate net primary production (NPP) as a function of water quantity, sediments, and habitat type; and (4) fauna habitat modelling linking the results from the assessment of landscape patterns to fauna species.
The assessment of landscape patterns revealed a distinct relationship between inundation and vegetation. Habitats in the Tonle Sap were divided into five groups based on annual flood duration, as well as physiognomic factors and human activity: (1) open water, (2) gallery forest, (3) seasonally flooded habitats, (4) transitional habitats, and (5) rainfed habitats. Large habitat shifts could occur as a result of hydropower development scenarios by the 2030s; areas optimal for gallery forest could decrease by 82% from baseline conditions, whereas areas of rainfed habitats could increase by 10-13 % (813-1061 km2).
The assessment of habitat patterns demonstrated that despite the complexity and intense human use of this ecosystem, the flood-pulse is the underlying driver of habitat characteristics by (1) determining inundation depth and duration; (2) creating the main soils gradient; (3) limiting the area cleared for agriculture; (4) influencing vegetation structure and water quality; and (5) shaping the composition of plant species.
The ecosystem function model was used to estimate a reduction of 9-39% in annual NPP caused by different scenarios of hydropower development and/or climate change during 2032-2042. Cumulative impacts from hydropower would disrupt NPP to a greater extent than climate change.
The fauna habitat model revealed that species richness was greatest in the gallery forests and seasonally flooded habitats. Animals that permanently reside in or that rely on these habitats to complete essential life-history stages would be the most affected by future changes.
This thesis provides the first quantitative formulation that directly links fundamental components of the Tonle Sap ecosystem to its flood-pulse hydrology. It also provides a comprehensive assessment of the impacts of expected hydrological alterations. Hydropower is expected to bring more abrupt and distinct ecological alterations than climate change in future decades. Relative aerial changes to the gallery forests are expected to be greater than in other habitats. A decline of the Tonle Sap’s ecosystem services will occur if appropriate measures are not implemented. These measures include mitigating hydropower alterations, conserving natural habitats in areas that are likely to remain hydrologically undisturbed, restoring natural habitats in projected areas for optimal growth, and optimizing agricultural practices in the floodplain. Research findings from this thesis focused on the Tonle Sap, but given the fundamental commonalities between this system and other large floodplains, the information presented is highly informative to other large flood-pulse driven systems around the globe.
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Munyati, Christopher. "Wetland change assessment on the Kafue Flats, Zambia : a remote sensing approach." Thesis, University of Stirling, 1997. http://hdl.handle.net/1893/21424.
Full textAbstract:
The Kafue Flats floodplain wetland system in southern Zambia is under increasing climate and human pressures. Firstly, drought episodes appear more prevalent in recent years in the region and secondly, two dams were built on the lower and upper ends of the wetland in 1972 and 1978, respectively, across the Kafue River which flows through the wetland. The study uses multi-temporal remote sensing to assess change in extent and vigour of green vegetation, and extent of water bodies and dry land cover on the Kafue Flats. The change detection's management value is assessed. Four normalised, co-registered digital Landsat images from 24 September 1984, 3 September 1988, 12 September 1991 and 20 September 1994 were used. The main change detection method used was comparison of classifications, supplemented by Normalised Difference Vegetation Index (NDVI) and Principal Component Analysis (PCA) change detection. Ancillary land use and environmental data were used in interpreting the change in the context of cause and effect. The results indicate inconsistent trends in the changes of most land cover classes, as a result of manipulation of the wetland by man through annual variations in the timing and magnitude of regulated flows into the wetland, as well as burning. However, the results also show spatial reduction in the wetland's dry season dense green reed-grass vegetation in upstream sections which are not affected by the water backing-up above of the lower dam. Sparse green vegetation is replacing the dense green vegetation in these upstream areas. It is inferred that this dry season degradation of the wetland threatens bird species which may use the reeds for dry season nesting. It is proposed that ground surveying and monitoring work at the micro-habitat level is necessary to ascertain the implications of the losses. It is concluded that, in spite of difficulties, multi-temporal remote sensing has a potential role in wetland change assessment on the Kafue Flats at the community level, but that it needs to be supplemented by targeted, micro-habitat level ground surveys.
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Collings, Sandy Lyn. "Economic consequences of ecological change: restoration options for the Mfolozi floodplain and implications for Lake St. Lucia, South Africa." Thesis, Rhodes University, 2010. http://hdl.handle.net/10962/d1006950.
Full textAbstract:
Lake St Lucia in northern KwaZulu-Natal, South Africa, experiences severe ecological stress during dry periods largely as a result of diminishing freshwater supplies and conditions of hypersalinity. Possible intervention involves diverting the Mfolozi River to the St Lucia Lake system. However, due to high sediment loading, water from the Mfolozi river requires considerable filtration before a link can be established. A suggested option considered in this study is to restore the existing sugarcane farmlands on the Mfolozi Floodplain (~20 800 ha) to previous wetland conditions to reinstate a sediment removal function amongst other benefits. Proposed restoration will have a direct impact on the industries currently supported by the iSimangaliso Wetland Park and the Mfolozi Floodplain (tourism, sugar, conservation). to understand a measure of such impacts, ecosystem services for both Lake St Lucia and the Mfolozi Floodplain were analysed (flood alleviation, water provision, water purification, sediment regulation, tourism, fisheries, vegetation for harvest, existence, cultural and research). Annual economic values for each ecosystem service were determined by means of valuation methods that included benefit transfer and replacement cost. Results showed a current annual minimum value of the Mfolozi Floodplain and Lake St Lucia as greater than R21 million and R1.1 billion respectively. Partial restoration of the floodplain (~6 000 ha) is expected to increase the sum of all ecosystem services values by approximately 26% for the Mfolozi Floodplain and by 23% for the St Lucia System. Full restoration (~20 800 ha) increases the total ecosystem services value by 88% and 50% for the Mfolozi Floodplain and St Lucia System respectively. Results showed that economic values for existence, fisheries, tourism and water provision increase by the greatest percentage for the St Lucia System under both restoration scenarios. Partial and full restoration of the floodplain will result in the greatest increases in economic value for the services existence, tourism, fisheries and the harvesting of vegetation on the Mfolozi Floodplain.
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Manyanga, Munyaradze. "Resilient Landscapes: socio-environmental dynamics in the Shashi-Limpopo Basin, southern Zimbabwe c. AD 800 to the present." Doctoral thesis, Uppsala University, Archaeology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7205.
Full textAbstract:
The general perception today is that the Shashi-Limpopo Basin in southern Africa is hot and dry and not conducive to human habitation. Today there is no doubt that the Shashi-Limpopo Basin has been home to many communities throughout the pre-historical period. A study of the changing ecological conditions in the Mateke Hills and the Shashi-Limpopo Valley as well as historical and present day land-usage offers an alternative explanation of how prehistoric communities could have interacted with this changing landscape. The archaeological record, historical sources and recent land-use patterns show that settlement location has always been orientated towards the rivers and circumscribed environments. The mosaic of floodplains, wetlands, drylands and circumscribed zones provided the ideal ecological setting for the development of socio-political complexity in southern Africa. The resilience of these semi arid savanna regions together with human innovation and local knowledge ensured that societies continued to derive subsistence even in the face of seasonal variability in rainfall and even climate change.
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Higgins, Andrew. "Consequences of Sulfate reduction in Floodplain Wetlands." Master's thesis, 2016. http://hdl.handle.net/1885/110695.
Full textAbstract:
This research project has been a laboratory based experimental
study on the cycling of sulfur in acid sulfate soils and
underlying sediments of floodplain wetlands. Of particular focus
was the effect that the reductive transformations of sulfur can
have on nitrogen and phosphorus cycling. The objectives of this
study were to quantify the rates at which sulfidic material
forms, the controls on these rates, and to analyse the nutrient
pulse from the sediments under a low redox potential.
In-vitro experiments simulating inundation were conducted on
sediments collected from three wetlands of the Lower River
Murray. Two were salt disposal basins and another was a
freshwater wetland. Experimental data collected indicates that
significant amounts of nitrogen and phosphorus will be released
from the sediments when inundated and anoxia is induced. The
pulse of nutrients from the sediments related to the geochemistry
of the sediments, as well as the hydrological regime. Partial
drying and oxidation of sulfidic material results in the
formation of poorly crystalline iron (oxyhydr)oxide minerals,
which sorb phosphorus, with reductive dissolution following
inundation liberating sorbed phosphorus. The high calcium
concentrations in the salt disposal basins can potentially
occlude the phosphorus through the formation of apatite minerals.
The result is that phosphorus is limiting primary production in
salt disposal basins and nitrogen is limiting in the freshwater
systems.
The pulse of nitrogen and phosphorus has the potential to
increase algal growth. Consequently, the increased algal growth
and subsequent availability of energy sources for microbial
metabolism could increase the rate of sulfide production. This
research will enable land and catchment managers to better manage
sediment and water quality in the Murray-Darling Basin.
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Bjornsson, Kjartan Tumi. "Regional scale modelling of the lower River Murray wetlands: a model for the assessment of nutrient retention of floodplain wetlands pre- and post-management." 2008. http://hdl.handle.net/2440/47936.
Full textAbstract:
Most of the lower River Murray and its floodplain wetlands are impacted upon by degradation caused by river regulation. Increasingly the restoration of these ecosystems and the river water quality has become a high priority for federal and state governments and associated departments and agencies. Public concern is adding to the pressures on these departments and agencies to restore these ecosystems and to sustainably maintain the river water quality. The long term monitoring of floodplain wetlands has been limited, compounding the difficulties faced by managers and decision makers on assessing the potential outcome of restoration options. The role of this project in the broad scheme of restoration/rehabilitation is to contribute to the construction of a model capable of increasing managers and decision makers understanding, and build consensus of potential outcomes of management option. This model was to use available data. The developed model, based on WETMOD developed by Cetin (2001), simulates wetland internal nutrient processes, phytoplankton, zooplankton and macrophyte biomass as well as the interaction (nutrient and phytoplankton exchange) between wetlands and the river. The model further simulates the potential impact management options have on the wetlands, and their nutrient retention capacity, and therefore their impact on the river nutrient load. Due to the limitation of data, wetlands were considered in categories for which data was available. Of these two had sufficient data to develop, calibrate and validate the model. Management scenarios for these two wetlands were developed. These scenarios included, the impact of returning a degraded wetland in a turbid state to a rehabilitated clear state, and the impact the removal of nutrient from irrigation drainage inflows has on wetland nutrient retention, and consequent input to the river. Scenarios of the cumulative impact of the management of multiple wetlands were developed based on using these two wetlands, for which adequate data was available, as “exemplar” wetlands, i.e. data from these wetlands were substituted for other similar wetlands (those identified as belonging to the same category). The model scenarios of these multiple wetlands provide some insight into the potential response management may have on individual wetlands, the cumulative impact on river nutrient load and how wetland morphology may relate to management considerations. The model is restricted by data availability and consequently the outputs. Further, some limitations identified during the development of the model need to be addressed before it can be applied for management purposes. However, the model and methods provide a guide by which monitoring efforts can assist in developing future modelling assessments and gain a greater insight not only at the monitoring site but also on a landscape scale.http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1320131
Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2008
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Powell, Susan Jennifer. "Analysis and modelling of the flood pulse and vegetation productivity response in floodplain wetlands." Phd thesis, 2011. http://hdl.handle.net/1885/8713.
Full textAbstract:
This thesis aims to develop a conceptual understanding of the flooding patterns and vegetation response of large floodplain wetlands and to develop an inundation and vegetation response model for water management. Applicable to a range of floodplain wetland systems, the conceptual node-network approach was developed in relation to the Gwydir wetlands, NSW, Australia. The Gwydir floodplains and wetlands occur in a dryland setting and are reliant on flows from the upstream catchment that has substantial water resource development. The Gwydir wetlands include a range of ecological values and are listed under international agreements for the protection of wetlands and migratory waterbirds.
The challenge of understanding flooding patterns in the Gwydir wetlands are common to other floodplain systems where shallow inundation, rapid vegetation growth and canopy cover may preclude the assessment of open water flooding from conventional remote sensing techniques. To characterise the flooding patterns a multi-temporal decision tree approach was developed. Based on classification of flooding as open water or from the subsequent high vigour vegetation response, the method uses remotely sensed vegetation indices to map a range of flood events. The results are summarised into homogenous patches with respect to flood frequency and connectivity. Using the patch analysis and assessment of connectivity between the patches and channels, the floodplain wetlands were conceptualised using a node-network model of the 17 patches.
Patches were categorised according to vegetation associations and the resulting landscape units used to develop models of vegetation productivity response measured as the fraction of photosynthetically active radiation (fPAR). Phenological attributes such as greenup, maturity, senescence and dormancy were extracted from the time series fPAR to characterise landscape units, and the fPAR response to inflow and soil moisture was modelled. Multiple linear regression models show significant relationship with inflows for many of the wetland landscape units.
The node-network and fPAR models are combined to develop the Inundation and Vegetation Response Model (IVRM) that provides a means of distributing river inflow and climate variables across the landscape and linking these to vegetation productivity response. Sensitivity testing is undertaken for uncertain parameters and further research needs identified. The model is applied to predicting inundation and vegetation response outcomes from predevelopment, current development and future climate change (2030) scenarios. Results suggested that in the most frequently flooded patch, inundation could have occurred over 99% of the time under the predevelopment scenario, compared to less than 63% of the time under a ‘dry’ prediction of future climate change.
This thesis integrates hydrological and ecological understanding, remote sensing analysis, statistical methods, and good modelling practice to develop the IVRM. The assessment framework takes a holistic view of an ecosystem, and explores how a wetting regime influences structure and function. The landscape scale approach uses the lateral, temporal and vertical connectivity, critical to the floodplain wetland functioning, to inform the development the model. The spatial and temporal scales are specific to the geomorphology, hydrology and ecology of the case study catchment, but the principles and methods can be applied to floodplain wetland systems in general.
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Garden, Suzanne. "Wetland geomorphology and floodplain dynamics on the hydrologically variable Mfolozi River, KwaZulu-Natal, South Africa." Thesis, 2008. http://hdl.handle.net/10413/1068.
Full textAbstract:
Wetlands in southern Africa can be considered a rarity, forming despite a regional negative water balance and a continental background of wide scale incision. These particular characteristics lead to southern African wetlands generally forming on drainage lines, where incision has been momentarily paused and water is locally abundant. The exact evolutionary history of valley bottom and floodplain wetlands is varied. However, their development follows four main themes; 1) those that evolve due to resistant lithologies outcropping on a drainage line and acting as local base levels, 2) those that occur on the coast, with current sea level preventing drainage line incision, 3) those that arise from a particular relationship with a trunk or tributary channel that blocks a drainage line with sediment, and finally, 4) those that occur in a region of dramatic loss of confinement, resulting in the formation of a wetland alluvial fan. Despite varied histories, all wetlands share a common thread, developing along a continuum from small and steep unchanneled valley bottom wetlands to large and flat floodplain wetlands. Incision in valley-bottom wetlands is controlled by a geomorphic slope threshold, whereby for a given wetland size, a particular slope may be considered stable. Wetlands exceeding the particular slope for their size are most likely already incised, or are vulnerable to incision in the near future. This thesis examines the general evolution of drainage line wetlands, followed by a detailed study of a large coastal floodplain, the Mfolozi River Floodplain, located on KwaZulu-Natal’s northern coastal plain. The Mfolozi Floodplain is one of South Africa’s largest at 19 000ha and is located just south of the world heritage site of Lake St. Lucia, with the St. Lucia and Mfolozi River mouths occasionally joining at the coast. Although once a mosaic of Cyperus papyrus and Phragmites australis permanent and seasonal wetland, approximately 60% of the floodplain has been reclaimed since the 1920’s for large-scale sugar cane cultivation. A smaller percentage is used for subsistence farming, while the remaining lower portion falls in the Greater St. Lucia Wetlands Park (which was renamed iSimangeliso Park in November 2007). The formation of the large coastal valley in which the Mfolozi Floodplain now sits was created during a period of incision during the last glacial maximum 18 000 BP when sea level was 120m below the current level. The lowered sea level resulted in regional river rejuvenation and valley down cutting. The Mfolozi River valley became deeply incised resulting in the formation of incised meanders upstream of the Lebombo Mountains. Below the mountains, less resistant lithologies of the Maputaland and Zululand Groups allowed the development of a wide coastal valley. Following the last glacial maximum, sea level rose, reaching its present level approximately 6000 BP. As sea level rose, coastal valleys were drowned and began to infill with sediments. Above the floodplain, the Mfolozi River follows a meandering course in an incised confined valley. Upon passing through the Lebombo Mountains, the valley widens considerably from 915 m to over 6 km in just 1.15 km. This rapid change from confinement to a broad floodplain setting results in a reduction of carrying capacity of the Mfolozi River, creating a node of large-scale deposition at the floodplain head in the form of an alluvial fan. Deposition in this region causes a local oversteepening of the valley’s longitudinal profile, with a gradient of 0.1%. Contrastingly, the mid- floodplain is almost flat, with a decrease in elevation of just 1 m over almost 6 km (0.02%). The lower floodplain, where gradient is completely controlled by sea level, has a steeper gradient of 0.05%. The reason for the rather drastic slope break in the mid floodplain is currently unknown, although it may be related to faulting in the underlying Tertiary aged Zululand Group, which is currently concealed by Quaternary deposits. In addition, tributary drainage lines that once flowed into the Mfolozi River have been blocked by long-term sediment accumulation on the floodplain. As a result, these drainage lines have become drowned and provide local conditions for the formation and accumulation of peat. Besides geological setting, hydrology is commonly recognized as being the other most important factor in valley evolution. Flow in the Mfolozi River has been characterized as highly variable relative to the rest of the globe. The Black Mfolozi has the lowest Coefficient of Variation (CV) at 61%, followed by the White Mfolozi at 69% and the Mfolozi River at 79%. In addition, catchment precipitation was shown to be variable, especially when compared to global values. As a result of variable rainfall and discharge, the Mfolozi River shows hysteresis in sediment concentration on an annual scale, and there is an indication that hysteresis may also occur on a longer time scale during wet and dry rainfall cycles. This however, needs to be confirmed with a longerterm data set. Variable discharge and sediment transport leads to different floodplain processes and dynamics than would be expected for a river of regular flow. Since flow is generally very low in the Mfolozi River, and is characterised by a series of extremely large outlier flood events, the persistence of flood features is likely to be large. In addition, it is likely that extreme flood events are the primary drivers of floodplain evolution and dynamics in such variable settings. The Mfolozi Floodplain wetland study throws light on floodplain process rates, and the forces behind floodplain dynamics in such hydrologically variable settings.Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2008.
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Creeper, Nathan Leonard. "Inland acid sulfate soils in the floodplain wetlands of the Murray- Darling Basin: regional occurrence using rapid methods and the impacts of reflooding on water quality." Thesis, 2015. http://hdl.handle.net/2440/119793.
Full textAbstract:
A full appreciation of the extent and significance of acid sulfate soils (ASS) in Australia's inland environments has only recently been realised, in contrast to ASS in Australia’s modern-day coastal zones, which have been well studied over the last four decades. Investigations into the inland ASS systems of the Murray-Darling Basin (MDB), Australia's largest river system, did not occur with any intensity prior to 2006. A number of key knowledge gaps exist concerning the occurrence, properties and behaviour of inland ASS systems in the MDB. These knowledge gaps, combined with the ecological and economic significance of the MDB, and the potential for environmental and infrastructure degradation through ASS acidification, provided the incentive for this research project. The main objective was to advance the understanding of inland ASS in the MDB. This was achieved by answering two key research questions: What is the prevalence and distribution of ASS with hypersulfidic and sulfuric materials in the floodplain wetlands of the MDB? What are the dominant geochemical pathways taken following freshwater reflooding of inland ASS containing sulfuric materials and the timescales of impact? The first research question was answered through a regional assessment of ASS in the MDB and represents the most extensive estimate of the basin-wide occurrence of inland ASS in the floodplain wetlands of the MDB thus far. As part of a government funded initiative, regional environmental officers collected approximately 7200 wetland soil samples, which were then submitted for soil incubation tests. The large number of samples requiring analysis, and the need for the rapid and robust classification of hypersulfidic materials led to the development of a simplified incubation method (see Chapter 2). This method was found to offer significant improvements over existing incubation methods. Firstly, the use of chip-trays as incubation vessels was found to offer many advantages in terms of transport, storage and analysis of soil samples compared with soil-slabs. Secondly, the conditional extension of the incubation period resulted in the accurate classification of slowly acidifying hypersulfidic materials whist maintaining a minimal test length. Following its development, the simplified incubation method was used to assess the acidification potential of ca. 2500 profiles in over 1000 wetlands located throughout the MDB (see Chapter 3). The results of pH measurements made before and following soil incubation were used to estimate the prevalence and distribution of sulfuric and hypersulfidic ASS materials across the MDB. A total of 238 floodplain wetlands, representing 23% of the total wetlands assessed, were found to contain soils that severely acidified (pH < 4) when oxidised. The number of these soils, the majority of which are likely to be hypersulfidic ASS materials, indicates that inland ASS are prevalent in the floodplain wetlands of the MDB. As a result, the potential existence of inland ASS should be a key consideration for wetland management plans in any floodplain wetland located in the MDB. The distribution of ASS materials in the MDB was investigated by dividing it into 13 geographical regions, whose boundaries roughly followed hydrological catchment boundaries. The distribution of acidification hazard was non-uniform throughout the MDB. The geographical regions with the greatest acidification hazard were in the southern MDB, downstream of the Murray-Darling confluence, and in catchments on the southern side of the Murray River channel in Victoria. The non-uniform distribution of ASS throughout the MDB has implications for the successful management of inland ASS in the MDB, whereby regions presenting the greatest acidification should receive much greater attention. Overall, the development of the simplified incubation method and the extensive broad-scale assessment of ASS in the MDB provided policy makers with a valuable screening tool, helping them to identify priority wetlands and regions that required more detailed IASS investigations. The second research question was answered through two focused field studies, which applied in situ sampling and monitoring techniques to investigate the geochemical behaviour of severely acidified inland ASS materials following reflooding by freshwater. The reflooding of severely acidified inland ASS by freshwater has been suggested as a viable remediation method. However, this hypothesis is based on observations made in coastal ASS systems following reflooding by sea water and had not yet been extensively documented in freshwater systems at the commencement of this research project. In the first study, equilibrium dialysis membrane samplers were used to investigate in situ changes to soil acidity and abundance of metals and metalloids following the first 24 months of restored subaqueous conditions (see Chapter 4) In the second study, mesocosms were installed in situ to simulate reflooding and the key geochemical pathways were documented through continuous in situ redox monitoring and the use of in situ soil solution samplers (see Chapter 5). In both studies, the strongly buffered low pH conditions of the oxidised sulfuric materials and the limited supply of external alkalinity in freshwater systems meant that soil acidity persisted for more than 24 months following reflooding. The persisting low pH conditions, along with insufficiently reducing redox conditions, and competitive exclusion by iron(III)-reducing bacteria were suspected to inhibit sulfate reduction. Following the eventual removal of the above limitations it is hypothesised that the lack of readily available soil organic carbon will further inhibit sulfate reduction. Under continued absence of net in situ alkalinity production, via the formation of reduced inorganic iron and sulfur species, observed trajectories indicate that neutralisation of soil acidity may take several years. Small increases in soil pH confined to within 10 cm of the soil-water interface were observed after 24 months of subaqueous conditions. Substantial decreases in the concentrations of some metals and metalloids were observed to coincide with the small increases in soil pH, most likely owing to lower solubility and sorption as a consequence of the increase in pH. In the acidic porewaters, aluminium activity was consistent with a control by a solid phase aluminium species with stoichiometry Al:OH:SO4 (e.g. jurbanite). In the same acidic porewaters, iron and sulfate activity were regulated by the dissolution of natrojarosite. Following the establishment of reducing conditions, the reductive dissolution of accumulated natrojarosite and schwertmannite phases was responsible for large increases in total dissolved iron. The differing physical properties and chemical characteristics, such as stored acidity and contaminant concentrations, of dominantly clayey soils and dominantly sandy soils, led to contrasting impacts on the transport of solutes following reflooding (diffusive versus advective flow, respectively) and timescales of recovery. A number of key geochemical processes influencing the porewater concentrations of acidity, iron, aluminium, and metals and metalloids following reflooding by freshwater were observed in these severely acidified inland ASS systems. These physical and geochemical processes were summarised in two conceptual hydrogeochemical process models, which were used to distil complex information and convey it in a format readily understandable to a non-ASS specialist audience.Thesis (Ph.D.) (Research by Publication) -- University of Adelaide, School of Biological Sciences, 2015.
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Silva, Thiago Sanna Freire. "Spatial and temporal variability of macrophyte growth and productivity in the Amazon floodplain." Thesis, 2009. http://hdl.handle.net/1828/1754.
Full textAbstract:
The main objective of the present thesis was to investigate the spatial and temporal variability of macrophyte growth and productivity in the Amazon floodplain, and the possible effects of this variability on the carbon budget of the floodplain.
In Chapter 3, two methods for estimating macrophyte biomass were compared in terms of accuracy and applicability to the Amazon floodplain conditions. Phenotypic variation was large enough to preclude indirect (phenometric) modelling of biomass, while direct sub-sampling was able to account for this variation. Sub-sampling also allowed reduction on the biomass sampling effort, presenting the best trade-off between accuracy and coverage for macrophyte biomass measurements in the Amazon floodplain.
In Chapter 4, annual net primary production (NPP) of macrophytes was estimated for a large lake on the eastern Amazon floodplain, and the uncertainty associated with these measures was assessed, offering a comparison of previous estimates of macrophyte productivity in the Amazon region. Annual net primary production was estimated at 2400 – 3500 g m-2 yr-1, with above water production between 650 – 1100 g m-2 yr-1, and below water production between 1700 and 2600 g m-2 yr-1. Echinochloa polystachya (Poaceae) and Paspalum fasciculatum (Poaceae) were the most productive species, followed by Paspalum repens (Poaceae), Hymenachne amplexicaulis (Poaceae), and Oryza perennis (Poaceae). The four main sources of uncertainty in the estimates were macrophyte taxa, location, sampling design, and lack of measurements of dead material loss.
Chapter 5 presented a new object oriented method for combining radar and optical image time series to characterize seasonal evolution of macrophyte cover for an eastern Amazon floodplain lake. Macrophyte cover varied between 104 and 198 km2 (10% and 20% of total floodplain area, respectively) and exhibited significant changes both seasonally and inter-annually. Two distinct growth strategies were observed: short-lived communities that thrived during low water periods and year-long communities able to survive flooding year-round. Although the majority of the macrophyte carbon fixation derived from the latter, about 17% of macrophyte NPP was attributed to the short-lived communities, which depend directly on the flood levels for a given year. The increased frequency of droughts predicted for the Amazon system could potentially result in an increase on the macrophyte-derived carbon input to the Amazon floodplain.
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Matthews, Kimberly Yandora. "Functional assessment for a proposed floodplain stormwater treatment wetland." 2002. http://www.lib.ncsu.edu/theses/available/etd-12302002-083117/unrestricted/etd.pdf.
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Ligtermoet, Emma. "People, place and practice on the margins in a changing climate: Sustaining freshwater customary harvesting in coastal floodplain country of the Alligator Rivers Region, Northern Territory of Australia." Phd thesis, 2018. http://hdl.handle.net/1885/164233.
Full textAbstract:
Human-environment interactions will be profoundly affected by
anthropogenic climate change. Coastal communities, dependent on
freshwater ecosystems for their livelihoods and cultural
practices, are likely to be seriously impacted by rising sea
level. For communities already subject to marginalising forces of
remoteness, poverty or the legacies of colonisation, climate
change impacts will likely compound existing stressors. The
freshwater floodplains of the Alligator Rivers Region in the
Northern Territory, spanning Kakadu National Park and part of
West Arnhem Land, represent such a place. This area is at risk
from sea level rise, particularly saltwater intrusion, while also
home to Aboriginal Australians continuing to practice customary
or subsistence harvesting based on freshwater resources.
In seeking to support sustainable adaptation to climate change in
this context, this thesis examines Indigenous people’s
experiences, in living memory, of responding to past and
persisting social-ecological change. A place-based, contextual
framing approach was used to examine vulnerability and adaptive
capacity. Through semi-structured interviews, trips on country,
cultural resource mapping and archival work, contemporary
patterns of freshwater resource use and Aboriginal people’s
perceptions of changes to their freshwater hunting, fishing and
gathering activities (collectively termed ‘harvesting’) were
examined. Qualitative models were used to conceptualise factors
influencing an individual’s ability to engage in freshwater
customary harvesting and the determinants shaping adaptive
capacity for customary harvesting.
The social-ecological drivers of change in freshwater harvesting
practices raised by respondents included: existing threats from
introduced animals and plants, altered floodplain fire regimes
and the ‘bust then boom’ in saltwater crocodile population
following recovery from commercial hunting. These all had
implications for sustaining customary harvesting practices
including restricting access and the transmission of knowledge.
Impacts driven by the introduced cane toad, invasive para grass
and saltwater crocodile population change, represent examples of
solastalgia, particularly for women’s harvesting practices. In
addition to environmental conditions, determinants of adaptive
capacity of customary harvesting included; mobility on country-
particularly supported through on country livelihoods and
outstations, social networks facilitating access and knowledge
sharing, health and well-being and inter-generational knowledge
transmission. Past experience of saltwater intrusion facilitated
by feral water buffalo in Kakadu was examined through the lens of
social learning, as a historical analogue for future sea level
rise. These experiences were shown to influence contemporary
perceptions of risk and adaptive preferences for future sea level
rise. Customary harvesting was also found to offer unique
opportunities to improve remote Indigenous development outcomes
across diverse sectors.
To build adaptive capacity supporting freshwater customary
harvesting practices in this context it will be essential to;
understand historical trajectories of social-ecological change,
recognise the potential for diversity within groups- including a
gendered analysis of adaptive capacity, address existing
social-ecological stressors and foster knowledge collaborations
for supporting knowledge transmission, the co-production of
knowledge and sustaining social networks. Facilitating a social
learning environment will be particularly crucial in supporting
local autonomy, leadership and experimental learning, and is
particularly beneficial in jointly managed protected area
contexts. Most importantly, incorporating local Indigenous
knowledge, values, perceptions of change and risk into
locally-developed adaptation strategies will be essential in
developing more culturally relevant and thus sustainable,
adaptation pathways.
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"Sedimentation and chemical processes on the Lower Mkuze floodplain : implications for wetland structure and function." Thesis, 2008. http://hdl.handle.net/10413/430.
Full textAbstract:
The Mkuze Wetland System, situated in northern KwaZulu-Natal, is South Africa’s largest freshwater wetland area. The system plays a vital role in the functioning of the local landscape and has been identified as an important site for the retention of a number of solutes. The mechanisms through which this retention occurs were investigated through analysis of sediment, groundwater and porewater samples collected from the lower floodplain. Sample analysis was achieved through the use of several techniques, including Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES), X-ray Diffraction (XRD), X-ray Fluorescence (XRF), electron microscopy and sequential extraction.Thesis (Ph.D)-University of KwaZulu-Natal, Westville, 2008.
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Nyarko, Benjamin Kofi [Verfasser]. "Floodplain wetland-river flow synergy in the White Volta River basin, Ghana / vorgelegt von Benjamin Kofi Nyarko." 2007. http://d-nb.info/986310441/34.
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Neal, Marian J. "The vegetation ecology of the lower Mkuze river floodplain, Northern KwaZulu-Natal : a landscape ecology perspective." Thesis, 2001. http://hdl.handle.net/10413/4685.
Full textAbstract:
The overall aim of this study was to develop an understanding of the vegetation ecology of
the lower Mkuze River floodplain from a landscape ecology perspective. The lower Mkuze
River floodplain and its associated wetlands are located east of the Lebombo Mountains
and north of Lake St. Lucia on the Maputaland Coastal Plain in northern KwaZulu-Natal.
This system is defined as a storage floodplain wetland and comprises a mosaic of different
wetland types. In addition it has a complex history of resource use and management.
Landscape ecology proved to be an ideal theoretical framework for this study because it
enables the examination of complex ecological processes and phenomena in an integrated
and holistic manner. It achieves this by explicitly recognizing the spatial heterogeneity,
dynamics and hierarchical organization of the landscape; concepts that proved useful in
developing an understanding of the ecological patterns and processes operating within the
lower Mkuze River floodplain.
The vegetation of the study area was classified, using multivariate techniques, into six
plant communities. The distribution of these plant communities was correlated with
underlying environmental gradients that summarized the interactions between hydrology,
substrate properties and topography within the floodplain system. Within the study area the
Phragmites mauritianus reed swamp community was found where there was slow moving
water, in semi- to permanently saturated soil. This was usually around the edges of pans or
in extensive stands in low-lying areas in the distal reaches of the floodplain. The Imperata
cylindrica hygrophilous grassland community was uncommon and was found in isolated
stands towards the edge of the region of seasonal flooding. The Echinochloa pyramidalis
backswamp community was the most extensive of all the plant communities identified.
This community was tolerant of flooding and was found in damp places such as seasonal
pans, backswamps and riverbanks as well as in standing water. The distribution of the
Ficus sycomorus riparian forest community was restricted to elevated levees adjacent to
the river channel that experienced inundation when floods were large enough to overtop
channel banks. The Cynodon dactylon floodplain community was generally found towards
the floodplain-terrestrial upland boundary in elevated areas with sandy well-drained soils.
The Acacia xanthophloea woodland community was distributed on the floodplain margin
in elevated areas on sandy soils, primarily fringing the linear pans draining towards the
Mkuze River from the north. The description of the plant community types and the
underlying environmental determinants of their distribution provided a useful foundation
for the examination of ecological processes and phenomena operating at spatially coarser
levels within the landscape hierarchy.
Plant communities were aggregated into functional types based on criteria such as
exposure to similar flooding and sedimentation regimes. The identification and mapping of
these functional types, using a Geographical Information System (GIS), enabled one to
identify a hydrogeomorphic continuum that described the interaction between floodplain
processes and vegetation distribution. Within the study area the proximal-seasonally
inundated functional type comprised plant community types found on channel levees and
within backswamp areas. These areas were functionally connected to the Mkuze River in
that they were exposed to seasonal flood events and associated sedimentation. The distal-permanently inundated functional type was typically found in the lower reaches of the
floodplain that were rarely exposed to hydrological and sedimentological inputs from the
Mkuze River. This functional type was permanently inundated and characterized by
standing water and/or permanently saturated soils that were generally associated with the
large floodplain pans. The distal-infrequently inundated functional type was typically
located in sandy areas along the southern distal reaches of the floodplain. These areas were
infrequently inundated by overbank floodwaters from the Mkuze River and were not
characterized by substantial clastic sedimentation. The distribution and interaction between
these functional types made it possible to develop process-based understanding of the
ecosystem patterns and processes operating within the lower Mkuze River floodplain.
Landscape ecology theory emphasises the importance of a temporal analysis of spatial
heterogeneity and the role of disturbance in ecosystem patterns and processes. Therefore a
temporal analysis of the landscape mosaic from 1937 to 1996 was undertaken, using a GIS,
in order to quantify landscape change over time. The landscape characteristics utilised to
examine this change were total category area, percentage contribution to the total
landscape area, number of patches, mean patch size, median patch size, patch size standard deviation and the mean perimeter-area ratio. These spatial statistics were calculated for
each year using PATCH ANALYST, an ArcView GIS extension and they were used to
illustrate the role of anthropogenic disturbance on the landscape mosaic at a variety of
levels within the landscape hierarchy. Anthropogenic disturbance was found to affect
landscape content and configuration and therefore had the potential to undermine the
underlying environmental determinants of landscape patterns and processes. Once the
underlying functional processes are undermined, irreversible ecosystem degradation is a
possible outcome.
The examination of the different levels within the landscape hierarchy and the dynamics of
ecosystem patterns and processes operating within the Mkuze River floodplain made it
possible to develop deeper insights into ecosystem patterns and processes than a
conventional vegetation ecology study that typically focuses primarily on plant community
classification. The use of landscape ecology as an overarching theory that guided the
research process and aided the interpretation of findings by explicitly recognising the
importance of examining spatial heterogeneity, hierarchical organisation and dynamics,
proved invaluable in developing process-based understanding of the lower Mkuze River
floodplain.Thesis (M.Sc.)-University of Natal, Durban, 2001.
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Wallace, Luke Joshua. "Sulfur storage and dynamics in an inland acid sulfate soil system of the lower Murray River floodlplains of South Australia." Phd thesis, 2009. http://hdl.handle.net/1885/148378.
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