Rozprawy doktorskie: „Floods”

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Thieken, Annegret Henriette. "Floods, flood losses and flood risk management in Germany". Thesis, Universität Potsdam, 2009. http://opus.kobv.de/ubp/volltexte/2009/2916/.

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Die vorliegende Habilitation beschäftigt sich mit verschiedenen Aspekten des Hochwasserrisikos in Deutschland. In zwölf Artikeln werden neue wissenschaftliche Erkenntnisse über Hochwassergefahren, über Faktoren, die Hochwasserschäden beeinflussen, sowie über effektive private Vorsorgemaßnahmen präsentiert. So wird die jahreszeitliche Verteilung von Hochwasser in ganz Deutschland gezeigt. Weiterhin werden mögliche Auswirkungen des Klimawandels auf Abflussverhältnisse und Häufigkeiten von Hochwasserereignissen am Beispiel des Rhein-Einzugsgebietes abgeschätzt. Ferner wird am Niederrhein simuliert, welche Auswirkungen Deichbrüche haben können. Hochwasserschäden stehen im zweiten Teil der Arbeit im Fokus: Nach dem August-Hochwasser 2002 wurden ca. 1700 Privathaushalte telefonisch befragt. Damit konnten die Einflüsse verschiedener Faktoren, wie der Überflutungsdauer oder der Verunreinigung des Hochwassers mit Öl, auf die Höhe von finanziellen Schäden quantifiziert werden. Daraus ist zum einen ein neues Modell entstanden, mit dem Hochwasserschäden großräumig berechnet werden können. Zum anderen konnten Hinweise für die Verbesserung der privaten Vorsorge abgeleitet werden. Beispielsweise zeigte sich, dass versicherte Haushalte schneller und besser entschädigt werden als Nicht-Versicherte. Ebenfalls wurde deutlich, dass verschiedene Bevölkerungsgruppen, wie Mieter und Hauseigentümer, unterschiedliche Möglichkeiten haben, Vorsorge zu betreiben. Dies ist zukünftig in der Risikokommunikation zu berücksichtigen. In den Jahren 2005 und 2006 waren Elbe und Donau wiederum von Hochwasser betroffen. Eine erneute Befragung von Privathaushalten und Behörden ermöglichte, die Verbesserung des Hochwasserrisikomanagement und der Vorsorge am Beispiel der Stadt Dresden zu untersuchen. Viele Methoden und Erkenntnisse dieser Arbeit sind in der wasserwirtschaftlichen Praxis anwendbar und tragen somit zur Verbesserung der Hochwasserrisikoanalyse und des Risikomanagements in Deutschland bei.
This thesis deals with different aspects of flood risk in Germany. In twelve papers new scientific findings about flood hazards, factors that influence flood losses as well as effective private precautionary measures are presented. The seasonal distribution of flooding is shown for the whole of Germany. Furthermore, possible impacts of climate change on discharge and flood frequencies are estimated for the catchment of the river Rhine. Moreover, it is simulated at reaches of the Lower Rhine, which effects may result from levee breaches. Flood losses are the focus of the second part of the thesis: After the flood in August 2002 approximately 1700 households were interviewed by telephone. By this, it was possible to quantify the influence of different factors such as flood duration or the contamination of the flood water with oil on the extent of financial flood damage. On this basis, a new model was derived, by which flood losses can be calculated on a large scale. On the other hand, it was possible to derive recommendations for the improvement of private precaution. For example, the analysis revealed that insured households were compensated more quickly and to a better degree than uninsured. It became also clear that different groups like tenants and homeowners have different capabilities of performing precaution. This is to be considered in future risk communication. In 2005 and 2006, the rivers Elbe and Danube were again affected by flooding. A renewed pool among households and public authorities enabled us to investigate the improvement of flood risk management and the precaution in the City of Dresden. Several methods and finding of this thesis are applicable for water resources management issues and contribute to an improvement of flood risk analysis and management in Germany.

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Bagwell, Anne Marina. "A synoptically guided approach to determining suburbanization's impacts on the hydrology of the Red and White Clay Creeks, Pennsylvania and Delaware /". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 169 p, 2008. http://proquest.umi.com/pqdweb?did=1459905411&sid=7&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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Cook, Brian Robert. "Knowledges, controversies and floods : national-scale flood management in Bangladesh". Thesis, Durham University, 2010. http://etheses.dur.ac.uk/371/.

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This research explores the views, beliefs and knowledges of experts responsible for flood management in Bangladesh. As one of the most disaster-prone nations on Earth, and in response to the neglect of power-holding experts within the existing literature, this project analyses the differences between academic accounts of flooding, labelled the ‘prevailing understanding’, and the local expertise of those responsible for management. Relative to the entrenched narrative, local experts are surveyed and an alternate interpretation is constructed using their knowledge. This combination of textual and perception-based analyses accounts for the complex interrelations between competing forms of knowing. It is on this juxtaposition that the research contributes to new knowledge. The thesis is based on research conducted in Bangladesh between November 2007 and March 2008. To accomplish its objectives, using prominent debates as entry points, academic and government sources are used to account for the lineage of the prevailing understanding. On the basis of this narrative, qualitative interviews with 54 experts explore the construction of flood management knowledge and its relationship with decision making. The experts describe and justify understandings of flood management that are contextual, adaptive and indefinite, challenging many of the assumptions associated with the prevailing understanding. The findings inform several findings: that individuals close to the poverty line are uniquely vulnerable; that disasters merge with management to produce second-generation events; and that a hybrid socio-physical context is both a product and a producer of flood management knowledge. Overall, despite the already complex issue of flooding, managers in Bangladesh consider increasingly issues as diverse as poverty, environmental sustainability and economic and human development. Given the scope of the controversy surrounding flood management, the findings show how analyses of competing knowledges, assumptions and framings can aid the interrogation of prevailing knowledge to generate original findings

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Bauer, Donald R. "Floods to Floodwalls in Newport, Kentucky: 1884-1951". Xavier University / OhioLINK, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=xavier1274982457.

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O'Hara, M. "Floods, flood damage and flood risk assessment in tropical environments : A Jamaican case study". Thesis, University of Exeter, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.232974.

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O'Mara, Kaitlyn M. "The Effects of Floods on Estuarine Fisheries and Food Webs". Thesis, Griffith University, 2020. http://hdl.handle.net/10072/391521.

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Floods are extreme events that can rapidly alter water and habitat quality in receiving estuaries. Because floods are unpredictable, they are more difficult to study, so have received less research attention than freshwater flow studies, resulting in a paucity of information on their ecological effects in the coastal zone. Previous studies have shown correlations between high flow periods and increased fisheries catches, which suggests that floods stimulate productivity in receiving waters. However, there have been no studies providing direct links between floods and increased productivity responses in fisheries species. In addition, the long-term effects of deposited flood sediment on food webs in estuaries are poorly understood. Floodwaters can carry high loads of fine sediment, which settles at the most offshore portion of the estuary delta, known as a prodelta. Nutrients, trace elements and other substances are also exported from the catchment dissolved in floodwater or attached to fine sediment particles and are deposited in estuaries. However, the processes of nutrient release from suspended sediments and settled sediments, and uptake of nutrients and trace elements into the food web in receiving estuaries are not well understood. Therefore, this thesis used laboratory experiments (Chapter 2 & 3) to study these processes with the aim of gaining a better understanding of the mechanisms underpinning measured ecological flood responses using field studies (Chapter 4 & 5). This study used catchment soils formed from three distinct rock types (granite, basalt and sandstone) from the Brisbane River (Queensland, Australia) catchment in a flood simulation experiment to quantify the rates of nutrient release during flooding (Chapter 2). In the laboratory, the fine fraction (<63 µm) of the soils was tumbled in freshwater for three days and left to settle in seawater for four weeks, and filtered water samples were taken throughout. A thin layer of the fine soils was also added to incubated sediment cores collected from central Moreton Bay, Queensland, Australia, to measure the influx or efflux of dissolved nutrients from sediments. Basalt soils, in particular, were relatively nutrient-rich and released substantial quantities of organic and inorganic dissolved nutrients, particularly phosphate. However, when soils were added to estuarine sediment cores and incubated, there was a net influx of phosphate from the overlying water. All soils continually released ammonium in both experiments, indicating that catchment soils may be an important source of ammonium to fuel productivity within the coastal zone. Catchments can also contribute trace elements to estuaries and coastal areas. Sources of trace element (cadmium (Cd), manganese (Mn) and zinc (Zn)) accumulation in estuarine fisheries species occupying different trophic levels were determined using radioisotope experiments (Chapter 3). Clams, prawns and fish common to estuaries on the East Australian coastline were exposed to a combination of Cd, Mn and Zn in three sources: dissolved in seawater, attached to suspended sediment particles, and diet. The study showed that clams accumulated all three elements from seawater, while prawns and fish showed negligible uptake. This indicates that clams may be an important link between dissolved and bioavailable elements for higher trophic level species, since the clams bioconcentrated these elements from seawater. The suspended sediment exposures had similar outcomes, with accumulation by clams, with negligible uptake by prawns and fish. Clams may therefore be particularly sensitive to accumulation of contaminants during floods, which may be exacerbated by their sessile nature. Biokinetic modelling using moderate environmental metal concentrations showed that diet was the main source of Cd and Zn accumulation in clams, whereas seawater was likely to be the main source for clam Mn accumulation. Diet was found to be the main source of Cd, Mn and Zn accumulation in prawns and fish, which is supported by previous studies. In the diet exposures, there was also a considerable difference in assimilation efficiencies between prawns and fish. The results of this study suggest that the contribution of diet to trace element accumulation at higher tropic levels may be larger than previously thought, and diet should therefore be considered in trace element studies involving high trophic level species. To identify short-term responses to a flood, multiple condition indices were determined for brown tiger prawns collected before and after a large cyclone-driven flood from several sites in central Moreton Bay (Chapter 4). Prawns collected from sites closest to the Brisbane River and Moreton Island showed no consistent change in condition over time. However, prawns collected from the most southern sites closest to the Logan River, which was the most severely flooded river system during the storm, responded positively to the flood with increased condition measured in terms of length-weight relationships, carbon-nitrogen ratios and muscle lipid content. Peak condition was measured on the first post-flood sampling occasion (i.e. day 11), and prawns collected 53 d after the flood were found to be in a similar condition to those before the flood. This peak in prawn condition coincided with an increase in benthic algal biomass that occurred simultaneously, measured as chlorophyll-a concentrations. Unlike previous studies, which found negative flood condition responses in fish in urban estuaries, the results from this study show that floods in South East Queensland can increase food web productivity in Moreton Bay. Water conditions in estuaries following floods usually return to normal within a couple of months, therefore long-term flood effects are likely to be caused by catchment sediment that is deposited on the estuary prodelta. To assess catchment influences on energy flow to fish and prawns living on flood prodeltas, common fish and prawn species were analyzed for stable isotope and trace element composition (Chapter 5). Fish and prawns were collected from a prodelta in an urbanized catchment (Moreton Bay) and three non-urbanized catchments (Gulf of Carpentaria). Links between diet and trace element composition were found. Differences in trace element composition were greatest between fish and prawns, which was reflected in correlations of trace elements with nitrogen isotopes. Differences within fish and prawn groups were also found, which were correlated to carbon isotopes and reflected benthic versus pelagic diets of different species. These correlations also highlight the importance of diet in trace element accumulation, and show that trace elements can be useful in food web studies. Variations in diet between locations were measured for some species, particularly catfish, suggesting that material exported from the catchment during floods influences food webs through availability of quality prey in estuary prodeltas. Catfish in Moreton Bay were found to be feeding at a high trophic level, suggesting that the urbanization of the Brisbane River catchment does not negatively affect the quality of food available in the Brisbane River prodelta. Overall, the results of this thesis showed that floods, and the sediments they transport to estuaries, can be beneficial for fisheries and food webs in receiving estuaries. In addition, trace element accumulation is linked to diet, and stable isotopes and trace elements can be combined to study catchment influences on estuarine food webs. An effective and transferrable methodology for mapping catchment influences and evaluating food quality in important fisheries habitats was identified. Floods facilitate a seaward transport of water, sediment and substances from catchments that are taken up into food webs in the coastal zone. Flood frequency and intensity is expected to increase with a changing climate and the work presented here fills important knowledge gaps on ecological responses to floods. While organisms have responded to and recovered from flood events throughout history, changes to sediment and water volumes through land clearing and damming of rivers may affect the quality of food, and therefore fisheries productivity, in the coastal zone. This study therefore has important implications for management of land use, erosion and water resource allocation within catchments.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environment and Sc
Science, Environment, Engineering and Technology
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Medley, Erica. "Ancient Cataclysmic Floods in the Pacific Northwest: Ancestors to the Missoula Floods". PDXScholar, 2012. https://pdxscholar.library.pdx.edu/open_access_etds/581.

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Ancient Cataclysmic Floods were the Ice Age Floods that left erosional and depositional features and preceded the Missoula Floods (15-18,000 ka) in the Pacific Northwest of the United States (Allen et al., 2009). All previously studied ancient sites were visited (14) and new sites (11) were found; four Missoula Flood quarries were also visited; a total of 29 sites were studied in this thesis. The use of calcrete paleosols to provide relative age dates for flood deposits was analyzed in this thesis. Missoula Flood gravel pits were sampled in order to examine the degree of calcrete development in flood deposits of known ages. All of the Missoula Flood deposits tested contain Stage 1 calcrete soil development. Calcrete paleosols at sites with evidence for older floods were all analyzed. Eight sites have paleosols with Stage II development (3-12% CaCO3): Rulo Outcrop, Potholes Coulee, Leslie Road, Benge, E. Callaway Road, Collier Coulee, Palouse, and Connell. Five sites have paleosols with Stage II+ development (12-17% CaCO3): Brown Road, Leslie Road, Benge, Reese Coulee, and Connell. Fourteen sites have paleosols with Stage III development (17-35% CaCO3): The Dalles, Rulo Outcrop, Winans Road 1, Poplar Heights, Yakima Bluffs, Canal Outcrop, Othello Canal, Reese Coulee, Potholes Coulee, E. Callaway Road, Frenchmen Coulee, Macall, Ritzville, and East Connell. One site has a paleosol with Stage III+ development (35-50% CaCO3): Othello Canal. Ancient Cataclysmic flooding initiated in the Early Pleistocene, at least 1.5 Ma. Sixteen field sites show evidence for Early Pleistocene flooding, preserved in all six provinces: Othello Channels, Columbia River Gorge, Cheney-Palouse Scabland, Quincy Basin, Pasco Basin, and the Walla Walla Valley. There are 26 field sites with evidence for Middle Pleistocene flooding, present in all regions except Othello Channels. Eleven of those 26 sites also show evidence for Early Pleistocene floods. Evidence for Early and Middle Pleistocene floods is present over a wide distribution of elevations from 117 to 524 meters.

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Guinea, Barrientos Héctor Estuardo. "Institutional Aspects of Integrated Flood Management in Guatemala". Doctoral thesis, Uppsala universitet, Institutionen för geovetenskaper, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-234303.

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Floods are a recurrent natural disaster in Guatemala. Heavy and prolonged rainfall often results in floods that affect people’s life and property. Several institutions and policy instruments at local, national or transnational level address flood management. The purpose of this study is to provide useful insights of the institutional aspects of integrated flood management at local, national and transboundary level in Guatemala. Papers I and II, explore institutions at local level, paper III at national level, while paper IV addresses flood management institutions at transboundary level. This research found that for the local and national level, there are several institutions concerned with flood management. In contrast, at transboundary level, and especially for international rivers, flood management institutions are largely absent. At local level, the Local Councils for Development (COCODEs, the acronym in Spanish) are responsible for flood prevention and preparation. While some municipalities are active in flood prevention, response and recovery activities, their limited economic and technical resources restrict their scope of action. Local stakeholders such as COCODEs, farmers groups and other actors are largely neglected in the decision making process. The National Coordinator for Risk Reduction to Disasters (CONRED, Coordinadora Nacional para Reducción de Desastres), the Secretariat for Planning and Programming of the Presidency (SEGEPLAN, Secretaría de Planificación y Programación de la Presidencia), the Guatemalan Ministry of Infrastructure and other national institutions are in charge of planning and implementing flood management strategies, leaving public involvement of local actors mainly to public consultation. At the Central American level, the Coordination Centre for Natural Disasters Prevention in Central America (CEPREDENAC, Centro de Coordinación para la Prevención de Desastres Naturales en América Central), an institution part of the Central American Integration System (SICA by Spanish acronym), shall promote transboundary cooperation regarding disaster management, including flood management. However, transboundary flood management faces several challenges: territorial disputes and sovereignty issues over international rivers are significant obstacles to the implementation of integrated flood management programs.

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West, Tracy L. "Flood mitigation and response comparing the Great Midwest Floods of 1993 and 2008". Thesis, Monterey, California. Naval Postgraduate School, 2010. http://hdl.handle.net/10945/4962.

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Approved for public release; distribution is unlimited
Floods are the nation's greatest natural disaster. According to the U.S. Geological Survey, floods cause an average of $6 billion of property damage, claim 140 lives, and prompt more Presidential disaster declarations per year than any other hazard. The Federal Emergency Management Agency (FEMA) is the lead for federal response to natural disasters. FEMA was the lead agency in 1993 when floods caused an estimated $1 8 billion in damage in the Midwest. The scope and damages of this historic disaster led FEMA to change its approach to floodplain management, flood protection, flood mitigation, disaster response, and recovery. FEMA and federal emergency response further evolved following the terrorist attacks on September 11, 2001 and Hurricane Katrina in 2005. The latest changes resulted in a national response framework for all levels of government to prepare and respond to all natural and manmade hazards. In 2008, the Midwest experienced its second "500-year flood" in fifteen years. This thesis examines whether changes to national disaster response and investments in flood mitigation over the last fifteen years have improved preparation, protection, and response capabilities at the federal, state, and local levels.

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Evatt, Geoffey William. "Jokulhlaups and sub-glacial floods". Thesis, University of Oxford, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.496870.

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Michelson, Katelyn Rachel. "Examining the Spatial Characteristics of Pluvial Flooding Through Citizen Science in Portland, Oregon". PDXScholar, 2018. https://pdxscholar.library.pdx.edu/open_access_etds/4548.

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Pluvial flooding is caused by rainfall events that overwhelm drainage systems and do not allow excess water to be absorbed by soils or water infrastructure. This type of flooding occurs frequently in urban systems and leads to public inconveniences and infrastructure deterioration, which could cost more than fluvial flooding over time. Increased rainfall intensity, which is projected to increase with climate change, could result in increased pluvial flooding. This study aims to examine the vulnerability of pluvial flooding in Portland, OR (2010-2017) by incorporating an interdisciplinary framework that examines the physical and socioeconomic vulnerability of flooding through citizen-reported flooding data. We use a spatially dense network of 5-minute interval rainfall measurement to examine 3-day storm events associated with flooding reports to correlate storm size with the frequency of reports. Additionally, we use a Topographic Wetness Index (TWI) to identify the hotspots of pluvial flooding over space and characterize the sociodemographic and building characteristics of hotspots by performing a spatial analysis using census tract and tax lot level data. We investigate how individual neighborhood characteristics (i.e. ethnicity, education, gender, age, income) and building characteristics (i.e. building type, building age) contribute to reported flooding. This research seeks to identify where pluvial flooding occurs across the city, and how flood management planning can better address flood vulnerability through the biophysical and socioeconomic characteristics that exists amongst communities in Portland.

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Dietz, Brian C. "Some new approaches to measuring willingness to pay : a case study of flood risk reduction in Roanoke, Virginia /". Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-12232009-020407/.

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Khan, Imran. "Towards Sustainable Flood Management in upper Sindh, Pakistan : A case study of District Sukkur". Thesis, Mittuniversitetet, Avdelningen för ekoteknik och hållbart byggande, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-19553.

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Flooding is the most devastating natural hazard in Pakistan and the recent flooding has demonstrated its severeness. Floods are common all over the country, though the province of Sindh experience the most damages. River Indus flows on a ridge here and once the surplus water during flood events leave the main channel does not return back. Therefore it is very important to adapt to this disaster. This study aims at identifying ways to address the problem of floods in upper Sindh for which Sukkur district was chosen. Questionnaire survey and interviews were conducted in three talukas of the district in the aftermath of recent floods (2010, 2011 and 2012) to provide a baseline study for Sustainable Flood Disaster Management Plan for the upper Sindh region. Recommendations were put to reduce the flood losses for the future floods.

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Deutsch, Mathias. "Untersuchungen zu Hochwasserschutzmassnahmen an der Unstrut (1500-1900)". Göttingen : Goltze, 2007. http://catalog.hathitrust.org/api/volumes/oclc/175651941.html.

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Gul, Marium. "Mitigating floods : reconstructing Lives : rehabilitating Thatta". Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/65548.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Architecture, 2011.
Page 87 blank. Cataloged from PDF version of thesis.
Includes bibliographical references (p. 82-86).
Pakistan was struck by floods in July 2010, the effects of which left 20.36 million people affected and 1.9 million homes damaged or destroyed'. In the province of Sindh in Pakistan, most of the affected population of the historic city of Thatta took refuge by fleeing to Makli Hill, a necropolis with mausoleums dating as far back as 1352A.D. The capital of three successive dynasties Thatta is famed for its cultural heritage and Makli Hill. Some four hundred thousand flood victims camped out on the hill most lacking any form of shelter. This thesis develops a framework for refugee camps and resettlement strategies that respond to and integrate the migratory trends of deltaic communities in the case of a flood event in an area with great cultural heritage. Taking into account different scenarios of flood disasters and recovery it aims to present an incremental, sustainable and transitional shelter program that local populations residing in flood prone areas of the Indus deltaic region of Thatta District can adopt in order to mitigate the effect of floods and hence reduce risk and vulnerability. The case of the Indus delta is particularly interesting because it requires a combined design strategy for the local phenomena of natural hazards and the global issue of climate change. The geographical importance of the site has been analyzed with respect to surrounding communities and primarily areas of relatively higher elevation, heterogeneous soil and water resources, and concentrated cultural heritage. The urban development of Makli Hill because of its geographic location and topographical characteristics is a highly likely and viable one as can be concluded from the transformation of Makli Hill to a site of refuge when floods affected the region. The thesis concludes with the proposal of the developmental growth of villages through small scale local productive landscapes so that communities can be partially self-sufficient and sustainable especially in times of flooding. The project is conceptualized in Thatta as a model approach that is transitional in nature and may be adapted by low-income communities residing in vulnerable locations in other deltaic/coastal regions in Pakistan, and wherever there is a conjunction of natural hazards, cultural heritage, and safe building opportunities worldwide.
by Marium Gul.
S.M.

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Haddad, Khaled. "Design flood estimation for ungauged catchments in Victoria : ordinary and generalised least squares methods compared". Thesis, View thesis, 2008. http://handle.uws.edu.au:8081/1959.7/30369.

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Design flood estimation in small to medium sized ungauged catchments is frequently required in hydrologic analysis and design and is of notable economic significance. For this task Australian Rainfall and Runoff (ARR) 1987, the National Guideline for Design Flow Estimation, recommends the Probabilistic Rational Method (PRM) for general use in South- East Australia. However, there have been recent developments that indicated significant potential to provide more meaningful and accurate design flood estimation in small to medium sized ungauged catchments. These include the L moments based index flood method and a range of quantile regression techniques. This thesis focuses on the quantile regression techniques and compares two methods: ordinary least squares (OLS) and generalised least squares (GLS) based regression techniques. It also makes comparison with the currently recommended Probabilistic Rational Method. The OLS model is used by hydrologists to estimate the parameters of regional hydrological models. However, more recent studies have indicated that the parameter estimates are usually unstable and that the OLS procedure often violates the assumption of homoskedasticity. The GLS based regression procedure accounts for the varying sampling error, correlation between concurrent flows, correlations between the residuals and the fitted quantiles and model error in the regional model, thus one would expect more accurate flood quantile estimation by this method. This thesis uses data from 133 catchments in the state of Victoria to develop prediction equations involving readily obtainable catchment characteristics data. The GLS regression procedure is explored further by carrying out a 4-stage generalised least squares analysis where the development of the prediction equations is based on relating hydrological statistics such as mean flows, standard deviations, skewness and flow quantiles to catchment characteristics. This study also presents the validation of the two techniques by carrying out a split-sample validation on a set of independent test catchments. The PRM is also tested by deriving an updated PRM technique with the new data set and carrying out a split sample validation on the test catchments. The results show that GLS based regression provides more accurate design flood estimates than the OLS regression procedure and the PRM. Based on the average variance of prediction, standard error of estimate, traditional statistics and new statistics, rankings and the median relative error values, the GLS method provided more accurate flood frequency estimates especially for the smaller catchments in the range of 1-300 km2. The predictive ability of the GLS model is also evident in the regression coefficient values when comparing with the OLS method. However, the performance of the PRM method, particularly for the larger catchments appears to be satisfactory as well.

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Kamwi, Innocent Silibelo. "Fitting extreme value distributions to the Zambezi river flood water levels recorded at Katima Mulilo in Namibia". Thesis, University of the Western Cape, 2005. http://etd.uwc.ac.za/index.php?module=etd&amp.

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The aim of this research project was to estimate parameters for the distribution of annual maximum flood levels for the Zambezi River at Katima Mulilo. The estimation of parameters was done by using the maximum likelihood method. The study aimed to explore data of the Zambezi's annual maximum flood heights at Katima Mulilo by means of fitting the Gumbel, Weibull and the generalized extreme value distributions and evaluated their goodness of fit.

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Marks, Daniel. "An Urban Political Ecology of the 2011 Bangkok Floods". Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/15749.

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This thesis challenges the dominant approach to examining flooding through a case study of the 2011 Bangkok floods. The alternative approach developed here views floods not only as outcomes of biophysical processes but also as products of political decisions, economic interests, and power relations. This approach illustrates how vulnerability to floods, which is a combination of exposure to floods and capacity to cope with them, and the extent to which floods are a disaster, are uneven at multiple scales across geographical and social landscapes. Using a mixture of quantitative and qualitative methods, the thesis investigates how state actors and socioeconomic processes affect the production of vulnerability to flooding. The study addresses theoretical and empirical gaps in earlier studies through its multi-temporal and multi-scalar approach to a major disaster. Little research in Southeast Asia, and thus in Thailand, analyses disasters from an in-depth urban political ecology (UPE) perspective before, during, and after the event. This thesis argues that floods in Bangkok are the result of human-nature interactions over time, particularly over the last half-century. While the Chao Phraya River Basin received heavy rainfall in 2011, a number of human activities interacted with that rainfall to create the floods. Bangkok’s dense urbanisation heightened resident's collective exposure while the pattern of urbanisation caused vulnerability to floods to become more imbalanced both spatially and socioeconomically. The historical development of the water system of the basin reflected primarily the interests of elites, which further heightened the collective vulnerability to flooding of those living in Bangkok. During the floods, both politicians and bureaucrats made decisions on how dams and water gates were managed to protect the interests of farmers. These varied decisions caused more water to flow downstream. Fragmentation and conflicting interests among state actors, patronage incentives, and technical weaknesses enervated the state’s response. Once the water reached Bangkok, state actors undertook various actions, such as closing water gates, erecting temporary dykes, and diverting water, which created new inequalities in terms of those who were exposed. Reflecting Bangkok’s socioeconomic and political inequalities, communities in the peri-urban fringes, particularly slum communities, were heavily inundated. These communities experienced the highest flood levels and for the longest duration, whereas the inner city of Bangkok was protected and remained dry. During the floods, many local leaders and residents collectively challenged these injustices by various forms of protest, somewhat reshaping the spatiality of the floods and reducing their vulnerability. Subsequent to the floods, for the most part, state agencies have not addressed underlying drivers of vulnerability to floods. Due to unchanging power geometries, state responses merely reproduced the proposed solutions and associated economic and environmental injustices of the past, while also creating new patterns of uneven exposure. Overall, placing the role of the state as central in it analysis, the UPE analysis made in this thesis provides a nuanced understanding of how state actors together with unequal socioeconomic processes have mostly reinforced each other and have created uneven and unjust vulnerabilities to flooding across several spatial and temporal scales.

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Storck, Pascal. "Trees, snow, and flooding : an investigation of forest canopy effects on snow accumulation and melt at the plot and watershed scales in the Pacific Northwest /". Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/10103.

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Haddad, Khaled. "Design flood estimation for ungauged catchments in Victoria ordinary & generalised least squares methods compared /". View thesis, 2008. http://handle.uws.edu.au:8081/1959.7/30369.

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Thesis (M.Eng. (Hons.)) -- University of Western Sydney, 2008.
A thesis submitted towards the degree of Master of Engineering (Honours) in the University of Western Sydney, College of Health and Science, School of Engineering. Includes bibliographical references.

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Rathburn, Sara L. "Pleistocene glacial outburst flooding along the Big Lost River, east-central Idaho". Thesis, The University of Arizona, 1989. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_etd_hy0127_sip1_w.pdf&type=application/pdf.

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Orchard, Kenneth Lynn. "Paleoflood hydrology of the San Juan River, southeastern Utah, USA". Thesis, The University of Arizona, 2001. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_etd_hy0025_m_sip1_w.pdf&type=application/pdf.

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Collins, Adrian Loric. "The use of composite fingerprints for tracing the source of suspended sediment in river basins". Thesis, University of Exeter, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307312.

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Vafeidis, Anthanasios. "Regional estimation of post-fire erosion using remote sensing and GIS : an example from Greece". Thesis, King's College London (University of London), 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248186.

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Hofer, Thomas. "Floods in Bangladesh : a highland-lowland interactions ? /". Berne : University of Berne Institute of Geography, 1998. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.

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Díaz, Loaiza Manuel Andrés. "Drought and flash floods risk assessment methodology". Doctoral thesis, Universitat Politècnica de Catalunya, 2015. http://hdl.handle.net/10803/325143.

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Floods and Drought are some of the most catastrophic natural disasters for humanity, averaging 1 to 5 billion dollar of annually damage for flood events and 6 to 8 billion dollars respectively for drought events. To avoid this phenomena risk management science has grown in the last years and allows us to assess the risk and the possible benefits if some specific measures are implemented (e.g. mitigation / adaptation measures). A methodology for Non-Structural Measures (NSM) implementation in risk assessment has been developed for flood event management. Likewise, an uncertainty analysis has been done in order to identify the variation of the possible results in the risk assessment. An analysis has been done based on the Expected Annual Damage (EAD) to determine the optimal return period of design of a structural measure. A new indicator has been proposed based on this analysis: The Optimal Expected Annual Damage indicator (OEAD). In the present document the results of pluvial flood risk assessment are described. These results include structural and non-structural measures based on a developed methodology for Arenys de Munt basin, which belongs to the region of Catalonia in Spain. To include non-structural measures in risk assessment, mitigation coefficients where built in the methodology, and are described in the methodology. Also, steps for the optimization of their possible implementation are defined. This research shows that potential economic losses are decreasing with the construction of structural measures from approximately 6.6 M€ to 3 M€ (box culvert of €14Million), and in combination with the implementation of non-structural measures this could even decrease to 0.7 M€ if the non-structural measures are implemented (for 500 year return period event). Related potential casualties results decrease from approx. 11 casualties to 8 and even as low as 2 casualties respectively if non-structural measures are implemented (for 500 year return period). This, demonstrate that non-structural measures are a way to follow in the flood risk mitigation. For drought events, a new methodology has been developed in order to relate quantitative potential economic losses for rainfed crops with "Meteorological Drought". In the same, a method for the hazard (through the Palmer index) and vulnerability assessment was developed. The susceptibility of a particular crop due to a drought event was linked with a classification of the phenological stages according two seasons: the sowing and harvesting season. The case study was focus on the Llobregat basin, in which both, hydrometeorological and crop statistics data series were available. Results illustrate that the Llobregat basin has suffered at least 2 important periods of drought (2000/2001 and 2005/2006) during the length of the considered 16 year crop production record statistics. These periods of drought caused potential economic losses of approximately 40.13 M€ and 55.84 M€ in the geopolitical subdivision called "Comarcas" of the Llobregat basin. The related methodology, demonstrates coherence in the detection of "important" drought events, and in the quantification of individual potential losses per crop type, which shows that crops, like olives (classified in category woody crop type) are more resistant to drought than vegetables (tomato, lettuce chard etc.). Finally, in addition to the presented methodology the potential losses of crop efficiency curves are proposed, as indicators for agricultural drought risk assessment.
Les inundacions i les sequeres són alguns dels desastres més catastròfics per a la humanitat, promitjant anualment al voltant d'1 a 5 x 10³ milions de dòlars i 6 a 8 x 10³ milions de dòlars en pèrdues econòmiques respectivament. Per combatre aquests fenòmens, la ciència de la "gestió del riscs" ha anat desenvolupant al llarg dels últims anys, permetent-nos quantificar el risc i els possibles beneficis en el cas que algunes mesures siguin implementades (tals com mesures de mitigació/adaptació etc.). En el present document es presenta una metodologia per a la quantificació del risc considerant la implementació de mesures no-estructurals (NSM). Així mateix, es va desenvolupar una anàlisi d'incertesa per identificar les fonts de variància sobre els resultats en el càlcul del risc. Amb l'indicador EAD (Expected Annual Damage), es va realitzar una anàlisi per determinar el període de tornada òptima en el disseny de mesures estructurals, com a resultat del mateix, es proposa un nou indicador: l "Optimal Expected Annual Damage" (OEAD). En el present document s'exposen els resultats per a la quantificació del risc pluvial. Aquests resultats inclouen mesures estructurals i no-estructurals d'acord amb la metodologia desenvolupada per a la conca d'Arenys de Munt a Catalunya-Espanya. Per incloure en el càlcul del risc a les mesures no-estructurals, es van desenvolupar coeficients de mitigació els quals són explicats dins de la metodologia. Igualment, es defineixen els passos a seguir per a l'optimització en la implementació d'aquestes mesures. En aquesta investigació, s'il·lustra que les pèrdues potencials econòmiques disminueixen si una mesura estructural és implementada (canalització per Box Culvert de 14 M€), des de 6.6 M€ a 3 M€ (T=500 anys), i si s'implementen mesures no-estructurals en combinació amb la mesura estructural, les pèrdues potencials poden disminuir-se fins a 0.7 M€ per al període de tornada de 500 anys. Sobre les pèrdues potencials de vides humanes, la mitigació obtinguda segueix el mateix comportament que les pèrdues potencials econòmiques, disminuint des d'11 possibles víctimes a 8 amb la mesura estructural i a 2 en combinació amb la mesura no estructural. Pel fenomen de la sequera, es va desenvolupar una metodologia per relacionar la "Sequera Meteorològica" amb les pèrdues potencials econòmiques en cultius de secà. En la mateixa, es proposa un mètode per a la quantificació de la perillositat (mitjançant els índexs de Palmer) i la vulnerabilitat. La susceptibilitat d'un cultiu de secà a un esdeveniment de sequera (vulnerabilitat) es va relacionar fent una classificació d'acord a dos estats fenològics: l'època de sembra i de recol·lecció. El cas d'estudi es va enfocar a la conca del riu Llobregat-Espanya, de la qual es va disposar d'informació hidrometeorològica i de les estadístiques de producció de diferents tipus de cultius de secà. De l'anàlisi realitzada sobre la conca, es va observar que al llarg dels 16 anys d'estadístiques en els cultius, van ocórrer dos períodes importants de sequera (2000/2001 i 2005/2006). Aquests períodes de sequera van deixar respectivament pèrdues potencials econòmiques d'aproximadament 40.13 M€ i 55.84 M€ per a les comarques associades a la conca del riu Llobregat. La metodologia desenvolupada, demostra eficàcia en la detecció d'esdeveniments importants de sequera, així mateix, il·lustra una coherència en la quantificació de les pèrdues individuals en els tipus de cultiu, en les que cultius com l'oliva (classificat com a cultiu llenyós), demostra més resistència a la sequera respecte a altres cultius com l'enciam, tomàquets etc.. Finalment, com a complement a la metodologia desenvolupada, es proposa a les corbes de pèrdua d'eficiència de cultiu, com a indicadors per a la gestió del risc de sequeres en cultius de secà.

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Melone, Anthony Michael. "Extreme floods in the Pacific coastal region". Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/27143.

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The research program developed hydrograph procedures for estimation of extreme rain-on-snow floods on ungauged watersheds in the Pacific coastal region. A multi-disciplinary investigation was undertaken encompassing the areas of hydrometeorology, snow hydrology and hydrologic modelling. Study components include assessment of flood producing mechanisms in the coastal region; analysis of regional rainfall characteristics for input to a hydrograph model; examination of the role of a snowpack during extreme events; and application of a hydrograph model. Based on an assessment of atmospheric processes which affect climate, examination of historical flood data, and analysis of flood frequency, it is shown that the area bounded by the crests of the coastal mountains forms a hydrologic region with similar flood characteristics. Extreme floods in the coastal region are rainfall-induced, either as runoff from rainfall-only or as a combination of rain and snowmelt. Recorded storm rainfall along the coast was examined to determine whether regional characteristics could be identified from available data even though the magnitude of rainfall varies between stations. Multi-storm intensity data available from Atmospheric Environment Service and rainfall intensities occurring within single storms that were identified as part of this study were analyzed. Results show that ratios of shorter duration intensities to the 24-hour rainfall are in a relatively narrow range in the coastal region for both multi and single storm intenstity data, and this range set limits on the hourly intensities that need to be considered as input rainfall data to a hydrograph model. With regard to basin response to extreme rain-on-snow, available literature suggests that for a ripe snowpack, development of an internal drainage network within the snowpack is the dominant routing mechanism for liquid water. Consequences of this conclusion on hydrograph procedures are that a watershed undergoes a transition from snow-controlled to more terrain-controlled water movement and basin storage characteristics approach conditions which would occur on the same basin without a snowcover. Lag and route hydrograph techniques were investigated to assess whether this method can be applied to rain-on-snow floods. Results from analysis of two rain-on-snow floods suggest this procedure can be applied when the following methodology is adopted: 1) estimate travel time through the basin from channelized and overland flow considerations; 2) select a storage coefficient which simulates basin response; 3) take water inputs as the sum of snowmelt and rainfall; and 4) consider there are no losses to groundwater. The combination of results from each study component provides a methodology for estimating input rainfall data and for undertaking hydrograph analysis for extreme rain-on-snow floods in the mountainous Pacific coastal region.
Applied Science, Faculty of
Civil Engineering, Department of
Graduate

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Sun, Hongyong. "Investigation of flood probability and regionalization". Ohio : Ohio University, 1992. http://www.ohiolink.edu/etd/view.cgi?ohiou1173275342.

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Gaume, Eric. "Eĺéments d'analyse sur les crues éclair". Paris, ENGREF, 2002. https://pastel.archives-ouvertes.fr/pastel-00002654.

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Les crues éclair (i. E. Crues soudaines provoquées par des événements pluvieux orageux) constituent sans aucun doute le risque naturel le plus destructeur en France. Malgré la menace qu'elles représentent et les nombreuses questions qu'elles suscitent, elles n'ont pas fait l'objet par le passé d'études systématiques. Dans la première partie de ce document, une méthodologie d'analyse hydrologique post-événementielle a été mise au point et testée sur cinq études de cas. Les premiers résultats obtenus sont encourageants et relativement inattendus : a) les bassins versants réagissent avec retard aux épisodes de pluies intenses, b) les volumes d'eau de pluie retenus sur les bassins et ne participant pas à la crue sont importants (de 150 à 200 millimètres dans les études de cas traitées), c) le type d'occupation des sols ne semble pas jouer un rôle déterminant sur la réponse des bassins versants. La seconde partie de la thèse est consacrée à l'analyse théorique des lois de probabilité des débits de pointes de crues. Les possibilités offertes par l'approche qualifiée de semi-déterministe, consistant à coupler un modèle mathématique de genèse aléatoire de séries pluviographiques et un modèle ``pluie-débit'' sont explorées. Il apparaît que, compte tenu des propriétés de la relation pluie-débit, les distributions des débits pointes de crues (DDPC) n'appartiennent probablement à aucun des trois types de lois des valeurs extrêmes. Elles sont asymptotiquement contrôlées par la distribution des intensités moyennes maximales des événements pluvieux, mesurées sur une durée caractéristique du bassin versant
Flash floods (i. E. Floods produced by severe thunderstorms of limited areal extent) are certainly the most destructive natural hazard in France. They also give rise to numerous questions but no systematic studies have been conducted in the past on such events. In the first part of this document, a post flood investigation methodology is proposed and tested on five case studies. The first results obtained are hopeful and reveal some original aspects of the rainfall-runoff relationship during flash floods : 1) the watershed response to the intense storm bursts is late and relatively sudden, 2) a large amount of rainwater (150 to 200 millimeters in the present case studies) is retained on the catchments and does not contribute to the flood flow, 3) no significant effects of the land use type could be identified. The second part of the document, is devoted to the theoretical analysis of the flood peak distributions. The potential of the so called derived distribution methods consisting in coupling a stochastic rainfall simulator and a mathematical ``rainfall-runoff'' model is assessed. It appears that, due to the properties of the ``rainfall-runoff'' process, flood peak distributions (FPD) belong most probably to none of the three extreme value distibution types. The asymptotic behaviour of the FPD is controlled by the maximum rainfall intensities measured over a duration characteristic of the studied watershed

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Khondaker, Mohammad S. "Perception of and response to floods in Bangladesh". Thesis, University of Manchester, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277489.

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Walfish, Michael Howard. "Defending networked resources against floods of unwelcome requests". Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/43054.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, February 2008.
Includes bibliographical references (p. 172-189).
The Internet is afflicted by "unwelcome requests'" defined broadly as spurious claims on scarce resources. For example, the CPU and other resources at a server are targets of denial-of-service (DOS) attacks. Another example is spam (i.e., unsolicited bulk email); here, the resource is human attention. Absent any defense, a very small number of attackers can claim a very large fraction of the scarce resources. Traditional responses identify "bad" requests based on content (for example, spam filters analyze email text and embedded URLs). We argue that such approaches are inherently gameable because motivated attackers can make "bad" requests look "good". Instead, defenses should aim to allocate resources proportionally (so if lo% of the requesters are "bad", they should be limited to lo% of the scarce resources). To meet this goal, we present the design, implementation, analysis, and experimental evaluation of two systems. The first, speak-up, defends servers against application-level denial-of-service by encouraging all clients to automatically send more traffic. The "good" clients can thereby compete equally with the "bad" ones. Experiments with an implementation of speak-up indicate that it allocates a server's resources in rough proportion to clients' upload bandwidths, which is the intended result. The second system, DQE, controls spam with per-sender email quotas. Under DQE, senders attach stamps to emails. Receivers communicate with a well-known, untrusted enforcer to verify that stamps are fresh and to cancel stamps to prevent reuse. The enforcer is distributed over multiple hosts and is designed to tolerate arbitrary faults in these hosts, resist various attacks, and handle hundreds of billions of messages daily (two or three million stamp checks per second). Our experimental results suggest that our implementation can meet these goals with only a few thousand PCs.
(cont) The enforcer occupies a novel design point: a set of hosts implement a simple storage abstraction but avoid neighbor maintenance, replica maintenance, and mutual trust. One connection between these systems is that DQE needs a DoS defense-and can use speak-up. We reflect on this connection, on why we apply speak-up to DoS and DQE to spam, and, more generally, on what problems call for which solutions.
by Michael Walfish.
Ph.D.

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Walter, Fabian. "Seismic activity on Gornergletscher during Gornersee outburst floods /". Zürich : Versuchsanstalt für Wasserbau, Hydrologie und Glaziologie, ETH Zürich, 2009. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000263370.

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Amponsah, William. "Stream power and geomorphic effects of flash floods". Doctoral thesis, Università degli studi di Padova, 2017. http://hdl.handle.net/11577/3426210.

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As one of the most devastating natural hazards, flash floods are responsible for major and abrupt geomorphic effects in the fluvial system as well as significant loss of life and socio-economic damages. Flash floods are characterized by strong spatio-temporal rainfall variability and therefore show variations in discharge and energy expenditure: associated geomorphic effects depend on geological controls on channel geometry and sediment characteristics, as well as on variations in flood intensity. Geomorphic effects usually take the form of erosional and depositional modification of the pre-flood channel. The central question of this thesis is to evaluate why flash floods of similar magnitudes and intensities sometimes produce dissimilar geomorphic results. The use of peak instantaneous hydraulic flow parameters such as discharge, velocity, shear stress, and stream power to quantify geomorphic changes has commonly been non-deterministic. This thesis aims at investigating how factors such as channel geometry, substrate, and flood magnitude and duration can interact and influence geomorphic effectiveness of high magnitude floods. A combined analysis of data from post-flood surveys and hydrological modelling permitted a comprehensive hydro-geomorphic investigation of seven major flash flood that occurred between 2007 and 2014 in different hydro-climatic regions in central and southern Europe. High peak discharge coupled with long flow duration ensured significant geomorphic impacts in Mediterranean basins. Values of stream power are generally consistent with observed geomorphic changes in the studied cross sections. However, bedrock channels show the highest values of energy expenditure but no visible erosion, whereas major erosion has been observed in alluvial channels. The trends in semi-alluvial channels urge the recognition of local or event-specific conditions that increase the resistance of channel bed and banks to erosion. Short flow duration caused major sedimentological effects but limited channel widening in most semi-alluvial channels. Eight rivers that were highly affected by three of the studied flash floods were selected for detailed analysis and modelling of the contiguous downstream variability in stream power. Power functions adequately interpreted the systematic downstream increase in peak discharge, whereas contrary to the usual exponential function, a quadratic function better interpreted the high downstream variability in channel gradient. The performance of the resulting empirical models for cross-sectional stream power and unit stream power were essentially influenced by channel gradient. The availability of high-resolution pre- and post-flood satellite images allowed assessment of channel changes along seven of these channels. Statistical analysis indicated that hydraulic forces alone are not adequate to interpret the rate of channel widening, which is primarily influenced by the degree of channel confinement. Together with lateral confinement, unit stream power better predicted channel widening in steep channels, whereas cumulative energy expenditure was relatively better for moderate channel reaches. The use of different erosion-resistance thresholds to quantify the geomorphological changes of riverbeds supports the conclusion that the determination of these changes is much more difficult than to determine the hydraulic variables involved.
Le piene improvvise (flash flood) sono fra i processi naturali più devastanti e sono responsabili di rilevanti e subitanei effetti morfologici, nonché della perdita di vite umane e di gravi danni economici. Le piene improvvise sono caratterizzate dalla forte variabilità spazio-temporale delle precipitazioni innescanti, cui consegue una forte variabilità delle portate e della potenza della corrente. Gli effetti geomorfologici delle piene improvvise dipendono sia dal controllo che l’assetto geologico esercita sulla geometria del canale e sulle caratteristiche del sedimento, sia dall’intensità della piena. Gli effetti geomorfologici delle piene improvvise si manifestano attraverso processi sia erosivi che deposizionali che determinano variazioni nell’assetto del canale rispetto alle condizioni antecedenti l’evento. La questione centrale di questa tesi è valutare perché piene improvvise di simile intensità producano talvolta effetti morfologici nettamente differenti. L’uso dei valori istantanei massimi di variabili di tipo idraulico, quali la portata, la velocità, lo sforzo tangenziale e la potenza della corrente, si è spesso rivelato non conclusivo nel quantificare i cambiamenti morfologici. Questa tesi mira a studiare come fattori quali la geometria del canale, il substrato, l’intensità e la durata dell’evento possano interagire e influenzare l’azione morfologia delle piene improvvise. Un’analisi combinata, basata rilievi post-evento e sulla modellazione idrologica, ha consentito di caratterizzare sette importanti eventi di piena improvvisa verificatisi fra il 2007 e il 2014 in diverse regioni dell’Europa centrale e meridionale. Nei bacini mediterranei gli elevati valori delle portate di picco, uniti alla durata relativamente lunga degli eventi, hanno determinato le condizioni favorevoli a significativi impatti geomorfologici. I valori della potenza della corrente sono generalmente coerenti con i cambiamenti morfologici osservati. Inoltre, i canali in roccia mostrano i valori di dispendio energetico più elevati ma senza erosioni apprezzabili, mente ingenti fenomeni di erosione sono stati osservati in canali alluvionali. Gli andamenti dei processi geomorfologici nei canali semi alluvionali richiedono il riconoscimento di situazioni locali che aumentano la resistenza del letto del canale e delle sponde all’erosione, o di condizioni specifiche di un particolare evento. Piene di breve durata causano talvolta abbondante trasporto solido, peraltro non associato a significativi allargamenti del canale nella maggior parte degli alvei semi-alluvionali. Otto corsi d’acqua, individuati fra quelli maggiormente interessati da tre delle piene studiate sono stati scelti per ulteriori analisi e per la modellazione della variazione longitudinale dei valori della potenza della corrente. Funzioni di potenza interpretano adeguatamente l’aumento verso valle delle portate di picco, mentre funzioni quadratiche si sono dimostrate più soddisfacenti delle relazioni esponenziali comunemente utilizzate per rappresentare la variazione longitudinale della pendenza dell’alveo. Le prestazioni dei modelli empirici per la variazione longitudinale della potenza della corrente per unità di larghezza dell’alveo (unit stream power) evidenziano il fondamentale controllo esercitato dalla pendenza dell’alveo. La disponibilità di immagini satellitari ad elevata risoluzione riprese prima e dopo gli eventi oggetto di studio ha permesso di valutare le modifiche del canale lungo sette di questi canali. Analisi statistiche hanno indicato che le sole variabili idrauliche non sono sufficienti per interpretare il tasso di allargamento del canale, che è principalmente influenzato dal grado di confinamento del canale stesso. Insieme al confinamento laterale, la potenza della corrente per unità di larghezza dell’alveo appare un valido predittore dell’allargamento in alvei ad elevata pendenza, mentre l’energia complessiva della corrente calcolata per l’intero evento fornisce prestazioni migliori nell’interpretare la variabilità dell’allargamento dell’alveo in canali a pendenza moderata. L'uso di differenti soglie di resistenza all’erosione per quantificare i cambiamenti geomorfologici degli alvei supporta la conclusione che la determinazione di tali cambiamenti è molto più difficile della determinazione delle variabili idrauliche coinvolte.

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Smyth, Kenneth Jeffrey. "Debris torrent mechanisms". Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26739.

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The phenomenon of the debris torrent is explored by examining the mechanisms of initiation, particularly those of rainfall and deforestation. The types of precipitation likely to contribute to instability are identified and data collection is reviewed. Debris torrents have characteristics unlike that of ordinary stream flow, and are capable of transporting massive quantities and sizes of material. Models to explain this transport capability are compared and contrasted. A theoretical analysis of the flow regime is carried out which is argued to be consistent with the observed turbulent nature of a debris torrent. This analysis is extended to the calculation of superelevation in bends and shows that current attempts to estimate velocities from super-elevation data may be very conservative. Further application of the turbulent stress analysis is used to estimate the angle of spread of the debris torrent in the deposition zone, and this analysis may be useful in zoning the downstream area to safeguard construction.
Applied Science, Faculty of
Civil Engineering, Department of
Graduate

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Ghorpade, Yashodhan. "Essays on household behaviour at the intersection of conflict and natural disasters : the 2010 floods in Pakistan". Thesis, University of Sussex, 2016. http://sro.sussex.ac.uk/id/eprint/61367/.

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This thesis examines household behaviour at the intersection of natural disasters and conflict. I structure this research around four distinct analytical chapters that use empirical microeconomic analysis to study household-level decisions and outcomes in the year following the 2010 floods in Pakistan. I first examine how does conflict affect household access to cash transfer programmes, and what mechanisms explain such effects. Using IV estimation to overcome endogeneity of conflict exposure and cash transfer receipts, I find that conflict reduces household and community level access to two large cash transfer programmes in Pakistan. The effects are driven by the likely presence of armed rebel groups who possibly resent state-led efforts to win legitimacy through social protection programmes. Next, I examine the effect of conflict on household access to remittances. I use IV estimation to overcome the endogeneity of conflict and remittance receipts and find that conflict exposure reduces household remittance receipts. This effect is driven by security threats associated with armed group presence, which threatens the operations of informal money transfer agents. Further, I find evidence for conflict negatively affecting investment-focused remittances as the effects of conflict are strongest among households more likely to use remittances for investment, than for consumption. These findings are in contrast to the macro literature that tend to view conflict as a factor that affects altruistic motives of remittances but has not examined investment motives in detail. In my third analytical chapter I examine the unintended effects of household aid receipts on violence through a mechanism that has not been studied in much detail: civilian militarisation through the purchase of guns. Using propensity score matching to overcome selection bias, I find that overall, flood relief cash transfers did not lead to any increases in household gun ownership. However recipients who own large tracts of land and live in conflict-affected areas were 8.3% more likely to acquire a gun, compared to a matched group of non-recipient households. The effects are driven by households that lived in displacement camps, which may have enhanced security concerns and the need for guns. This suggests that for groups that have low material but high security needs, exogenous increases in cash, through cash transfers, can increase the likelihood of acquiring guns for use, or for signalling, as a safety good. Finally, I examine the under-studied role of uncertainty of disasters in affecting post-disaster short-term migration decisions. I find that while flooding exposure increases the propensity to migrate, a higher level of uncertainty, represented by more anomalous floods (compared to recurring floods), decreases migration. I also develop a measure of flooding anomaly, based on the likely past exposure to floods at the community level, using satellite data on long term precipitation levels, and distance to the nearest rivers. My research examines important, but hitherto under-studied and challenging relationships that play out in complex emergencies, where many households simultaneously face flooding and violent conflict shocks. The findings are relevant for economic theory, empirical analysis and for policy.

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Zamora-Reyes, Diana. "Relevance of Flood Heterogeneity to Flood Frequency in Arizona". Thesis, The University of Arizona, 2014. http://hdl.handle.net/10150/347093.

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In the United States, the flood frequency analysis guidelines described in Bulletin 17B are followed to provide reliable flood discharge magnitude estimates for urban floodplain planning and flood insurance studies. The statistical analysis in Bulletin 17B has various assumptions, including that floods are generated by the same type of atmospheric mechanism (flood homogeneity). However, these assumptions should be carefully assessed before proceeding since they might not always be valid and could increase the potential for flood risk. This study focuses on flood frequency analysis from the perspective of flood heterogeneity, the hydrometeorological genesis of each flood event, in Arizona. This was done by analyzing the occurrence and magnitude of individual flood events, which were classified by their flood-producing atmospheric mechanism. Flood frequency curves were derived for each mechanism and combined using a new approach involving the Partial Duration Series peaks. The combined frequency curves were then compared to curves derived from the standard Bulletin 17B method. Results showed that in southern Arizona, the dominant flooding mechanism is characterized by brief, intense, and localized convective precipitation in the summer. However, the dominant flood-producing mechanism in the central Arizona topographic transition zone and at higher elevations is characterized by prolonged and widespread precipitation from synoptic activity in the winter. Tropical cyclone-enhanced precipitation is also an important, but infrequent, flood-producing mechanism throughout the state. Overall, the dominant mechanism does not necessarily produce the largest floods. In such cases flood heterogeneity can have a strong influence on the discharge estimates for the most extreme upper tail probabilities calculated from the flood frequency analysis. Thus, the most frequent floods may impose very little risk of flooding while uncommon floods can impose a much larger one. These results suggest that the flood homogeneity assumption is not valid in many Arizona watersheds. To produce the most accurate discharge estimates possible, it is critical that both analysts and flood managers become aware of the potential repercussions if these details are overlooked.

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37

Rossman, Edwin J. (Edwin John). "Individual Resources, Social Environment, and Flood Victimization". Thesis, University of North Texas, 1990. https://digital.library.unt.edu/ark:/67531/metadc330855/.

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The study is a contextual analysis of flood victimization. Victimization is defined as the social, psychological, and physiological aftermath experienced by victims of a disaster. Disaster researchers concentrate on the victims' characteristics to explain the varying degrees of their victimization, providing only ambiguous results. Theorists such as Kreps, Wildavsky, and Douglas contend that the outcomes of disasters are contingent upon social structure. This analysis treats victimization as one such outcome. The condition and behavior of individuals can be explained by the presence of disaster and the conditions of social organization. A model explains victimization based on individual's attributes (individual resources), his social environment, and the disaster characteristics. This study uses the 1984 Mingo Creek Flood Victims Survey data to test the model. The data contain information measuring victimization. The survey data are linked with 1980 Census tract data. The tract data provide indicators of the social networks. This tract information, the contextual variables, taps the social conditions, including poverty, unemployment, geographic mobility, and family patterns. This study uses factor analysis to identify the dimensions of victimization. Regression tests the relationship between the contextual variables, the individual resource variables, the disaster characteristic variables, and victimization. The results of the analysis show that victimization is multidimensional with different types of variables being significant predictors for each dimension of victimization, one variable indicating the intensity of the disaster, the dollar value of damage victims experienced, is found to be a significant predictor of the psychological, physiological, and social disruption aspects of victimization. Variables measuring the family and unemployment patterns in the victims' census tract are significant predictors of the psychological and social disruption aspect of victimization. The findings provide general support for the proposed model of victimization. However, victimization is multidimensional with each dimension having a unique set of predictors. Based on the findings, this study suggests that future research focus on measurement and conceptualization of the characteristics of disasters and the victims' social environment.

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38

Mohammed, Abdel-Fattah Sayed Soliman. "Integrated Hydro-geomorphological Approach to Flash Flood Risk Assessment and Mitigation Strategies in Wadi Systems". Kyoto University, 2017. http://hdl.handle.net/2433/227604.

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WAI, THWE AUNG. "DEVELOPMENT OF FUNDAMENTAL THEORY ON UNSTEADY OPEN CHANNEL FLOWS". Kyoto University, 2019. http://hdl.handle.net/2433/244536.

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40

Pandey, Ganesh Raj. "Regional estimation of floods and rainfalls for ungauged sites". Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=40219.

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This research deals with the estimation of rainfalls and floods for locations at which the corresponding data are unavailable (ungauged sites). The overall study can be divided into three different parts. The first part explores the validity of the distributional similarity of the rainfall time series aggregated at different time scales. Based on the theory of multiplicative cascade process, a scale independent mathematical model has been proposed to describe the probability distributions of rainfall time series aggregated at different time scales. It has been demonstrated that the multifractal formalism can be used to estimate the probability distribution of rainfalls for a wide range of space and time scales.
The second part of the research deals with the estimation of floods at an ungauged site using regional physiographic and climatic variables. To this end, a detailed study was carried out to determine the best technique for estimating the parameters of the commonly used power-form flood regionalization model, and to identify the minimum number of physiographic and hydrometeorological variables which should be included in the model. The study was further elaborated by applying the linear and nonlinear covariance structural models. Results of a numerical example using hydrologic data from Quebec and Ontario have indicated the superior performance of the nonlinear optimization method. Further, it was found that the significant variables which should be considered in the estimation of floods, are the area of the basin, the basin slope and the total precipitation five days before the flood for Quebec, and the area of the basin, the area of forests, lakes, and marses and the slope of the main channel for Ontario.
The third part of the study proposed a new method of flood estimation based on the scaling of the statistical moments of the regional flood series with the basin area. Analysis of the physiographic and hydrologic data from Quebec and Ontario showed that the non-central moments of order from one to six are scaling with the basin area. This empirical evidence was used in defining the hydrologically similar basins (i.e., homogeneous flood regions), and in selecting a suitable regional distribution function for the estimation of flood quantiles. It was observed that the grouping of homogeneous basins as proposed in this study formed well-defined geographical regions with distinct climatic characteristics. Further, it was recommended that the selection of regional probability distribution and the corresponding parameter estimation method should be made such that the scaling properties of the flood series were preserved. The improved estimates of the statistical moments and flood quantiles for unguaged sites have indicated the superiority of the proposed approach as compared to those values given by existing methods.

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41

Thomas, Sara. "Experimental design and scale-up methods for micellar floods". Thesis, University of Birmingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420520.

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42

Roberts, Matthew James. "Controls on supraglacial outlet development during glacial outburst floods". Thesis, Staffordshire University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.392999.

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This project arose from the need to evaluate existing knowledge of intraglacial floodwater routing and supraglacial outlet development during glacial outburst floods (jökulhlaups). The overall aim of this thesis is to produce a refined model of the controls on supraglacial outlet development during jökulhlaups. The following hitherto unknown findings constitute a significant advance in our understanding of jökulhlaups hydrodynamics. (i) Transient increases in basal water pressure, can induce the temporary, time-transgressive formation of linked cavity drainage across large zones of the glacier bed. Linked cavity drainage facilitates hydraulic jacking and associated down-glacier transfer of potential energy in the form of a basal flood wave; consequently, supraglacial jökulhlaup outbursts form in response to transient hydraulic conditions imposed at the front of a basal flood wave. (ii) The gradient of excess basal water pressure over glaciostatic pressure governs the propensity for englacial floodwater routing. Rapid, steady increases in basal hydraulic pressure enable retro-feeding of pre-flood intraglacial drainage circuits. Conversely, rapid, unsteady increase in basal hydraulic pressure, which exceed glaciostatic pressure and fracture toughness at regular intervals through the glacier profile, facilitate intrusive hydrofracturing from glacier bed to ice surface. (iii) Retro-feeding of englacial drainage produces supraglacial outlets that have a plan and profile morphology dictated mainly by the shape of near-surface drainage structures. Where hydrofractures reach the glacier surface, their strike and planimetric length is an important control on outlet morphology. (iv) The depth beneath the glacier surface at which single hydrofractures transform into complex fracture networks is fundamental in determining the plan and profile morphology of fracture outlets. (v) A qualitative inverse-relationship exists between the magnitude of near-surface floodwater pressure and the extent to which pre-existing glaciological structures control floodwater routing and outlet morphology. (vi) Once basal water pressure exceeds the weight of a water column extending vertically from glacier bed to ice surface, the prime control on outlet evolution is the rapidity of water-pressure-increase during the period of supraglacial discharge. Comparatively rapid rates of increase in supraglacial discharge are associated with sudden changes in outlet morphology, and vice versa for lower rates of discharge increase.

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43

Albright, Lydia T. "Hydraulic Modeling of Floods in an Open Conduit Cave". Ohio University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1596647829960682.

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44

Krauch, Amy Lynn. "Hazards assessment of St. Charles County - earthquakes and floods". Diss., Rolla, Mo. : Missouri University of Science and Technology, 2008. http://scholarsmine.mst.edu/thesis/pdf/Krauch_09007dcc805e91c0.pdf.

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Thesis (M.S.)--Missouri University of Science and Technology, 2008.
Vita. The entire thesis text is included in file. Appendixes B and C are on files. Title from title screen of thesis/dissertation PDF file (viewed January 21, 2009) Includes bibliographical references (p. 152-159) and appendixes.

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45

Maia, Diego Corrêa [UNESP]. "Impactos pluviais na área urbana de Ribeirão Preto - SP". Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/104327.

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Made available in DSpace on 2014-06-11T19:33:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-10-10Bitstream added on 2014-06-13T19:23:01Z : No. of bitstreams: 1 maia_dc_dr_rcla.pdf: 6898164 bytes, checksum: 733e22021409aa6674ba5fca9fc353d6 (MD5)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Nos últimos 15 anos as enchentes e a densidade demográfica de Ribeirão Preto aumentaram consideravelmente. As inundações em Ribeirão Preto são presentes na área urbana desde o início do século XX. As notícias de jornal veiculadas pela Folha Nordeste - SP e Folha Ribeirão, na ausência de dados climáticos e históricos sobre as enchentes, demonstraram ser uma fonte valiosa na análise dos impactos pluviais na área urbana de Ribeirão Preto. A análise das matérias demonstrou que as enchentes são veiculadas quando existe um grande prejuízo à população, como alagamento de casas e lojas, desaparecimento de pessoas, falta de transporte, queda de árvores e de energia elétrica etc. Em 2002 houve uma grande enchente, deixando Ribeirão Preto embaixo d'água, sob estado de calamidade pública. Em 17 anos de análise dos episódios de inundação na área urbana de Ribeirão Preto, conforme noticiado pelos jornais, mostram 45 ocorrências, ou seja, em média cerca de 3 inundações/ano, o que revela grande frequência do fenômeno. Os índices mostram que praticamente todo ano, entre os meses de outubro a março, têm-se enchentes na área urbana, com saldo de grandes prejuízos à população. De 1990 a 2006 existe uma tendência de aumento nas inundações na área urbana Ribeirão Preto, sendo que, na década de 90, do século XX, ocorreram 20 inundações e, nos 6 primeiros anos do século XXI, presenciou-se 24 inundações, ou seja, um aumento de 20%. Das 43 inundações ocorridas, foram descobertos 26 pontos de inundação, com destaque para duas regiões: a Vila Virgínia e a baixada, região comercial que se situa o mercado municipal, a rodoviária e o camelódromo. Com relação ao período diário da incidência das inundações, elas ocorrem, predominantemente, após o meio-dia. Em todas as enchentes ocorridas no período da análise, a circulação...
In the last 15 years, the floods and the demographic density in Ribeirão Preto municipality have considerably increased. Inundations in Ribeirão Preto municipality are present in the urban area since the beginning of the 20th century. Articles presented in Folha Nordeste-SP and Folha Ribeirão newspapers, in the absence of climatic and historical data about the floods, seemed to be a valuable source in the analysis of the pluvial impacts in Ribeirão Preto urban area. The analysis of the newspaper articles demonstrated that floods are presented in the media when there is a great damage to the population, such as houses inundations, people disappearance, lack of transportation, tree and electricity fall, etc. In 2002 there was a great flood in the city, leaving Ribeirão Preto under water and in public calamity state. The analysis of flood episodes in the Ribeirão Preto urban area, in 17 years, according to the articles presented by the newspapers, showed 45 occurrences, in other words, an average of 3 floods/year, which reveals a great frequency of this phenomenon. The indices show that almost during all the year, between October and March, there are floods in the urban are, with great damage to the population. From 1990 to 2006 there is an increasing tendency in the floods occurrence in Ribeirão Preto urban area, since that in the 90s decade of the 20th century, there were 20 inundations and in the first six years of the 21st century, there were 24 floods, in other words, an increase of 20%. From the 43 flood occurrences, 26 inundation sites were discovered, highlighting two regions: Virginia Village and a low area where it is situated the municipal market, the bus station and an informal commercial center (camelódromo). In relation to the daily period of flood incidence, they occur, mainly, after noon. In all the floods that occurred... (Complete abstract click electronic access below)

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46

Cloud, Kimberly C. "Changes and trends in streamflow during floods and droughts in the urbanizing Christina River Basin". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 131 p, 2007. http://proquest.umi.com/pqdweb?did=1397904211&sid=9&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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47

Maia, Diego Corrêa. "Impactos pluviais na área urbana de Ribeirão Preto - SP /". Rio Claro : [s.n.], 2007. http://hdl.handle.net/11449/104327.

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Orientador: Sandra Elisa Contri Pitton
Banca: Antonio Carlos Tavares
Banca: Anderson Luis Hebling Christofoletti
Banca: Deise Fabiana Ely
Banca: Francisco Arthur Silva Vecchia
Resumo: Nos últimos 15 anos as enchentes e a densidade demográfica de Ribeirão Preto aumentaram consideravelmente. As inundações em Ribeirão Preto são presentes na área urbana desde o início do século XX. As notícias de jornal veiculadas pela Folha Nordeste - SP e Folha Ribeirão, na ausência de dados climáticos e históricos sobre as enchentes, demonstraram ser uma fonte valiosa na análise dos impactos pluviais na área urbana de Ribeirão Preto. A análise das matérias demonstrou que as enchentes são veiculadas quando existe um grande prejuízo à população, como alagamento de casas e lojas, desaparecimento de pessoas, falta de transporte, queda de árvores e de energia elétrica etc. Em 2002 houve uma grande enchente, deixando Ribeirão Preto embaixo d'água, sob estado de calamidade pública. Em 17 anos de análise dos episódios de inundação na área urbana de Ribeirão Preto, conforme noticiado pelos jornais, mostram 45 ocorrências, ou seja, em média cerca de 3 inundações/ano, o que revela grande frequência do fenômeno. Os índices mostram que praticamente todo ano, entre os meses de outubro a março, têm-se enchentes na área urbana, com saldo de grandes prejuízos à população. De 1990 a 2006 existe uma tendência de aumento nas inundações na área urbana Ribeirão Preto, sendo que, na década de 90, do século XX, ocorreram 20 inundações e, nos 6 primeiros anos do século XXI, presenciou-se 24 inundações, ou seja, um aumento de 20%. Das 43 inundações ocorridas, foram descobertos 26 pontos de inundação, com destaque para duas regiões: a Vila Virgínia e a baixada, região comercial que se situa o mercado municipal, a rodoviária e o camelódromo. Com relação ao período diário da incidência das inundações, elas ocorrem, predominantemente, após o meio-dia. Em todas as enchentes ocorridas no período da análise, a circulação... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: In the last 15 years, the floods and the demographic density in Ribeirão Preto municipality have considerably increased. Inundations in Ribeirão Preto municipality are present in the urban area since the beginning of the 20th century. Articles presented in Folha Nordeste-SP and Folha Ribeirão newspapers, in the absence of climatic and historical data about the floods, seemed to be a valuable source in the analysis of the pluvial impacts in Ribeirão Preto urban area. The analysis of the newspaper articles demonstrated that floods are presented in the media when there is a great damage to the population, such as houses inundations, people disappearance, lack of transportation, tree and electricity fall, etc. In 2002 there was a great flood in the city, leaving Ribeirão Preto under water and in public calamity state. The analysis of flood episodes in the Ribeirão Preto urban area, in 17 years, according to the articles presented by the newspapers, showed 45 occurrences, in other words, an average of 3 floods/year, which reveals a great frequency of this phenomenon. The indices show that almost during all the year, between October and March, there are floods in the urban are, with great damage to the population. From 1990 to 2006 there is an increasing tendency in the floods occurrence in Ribeirão Preto urban area, since that in the 90s decade of the 20th century, there were 20 inundations and in the first six years of the 21st century, there were 24 floods, in other words, an increase of 20%. From the 43 flood occurrences, 26 inundation sites were discovered, highlighting two regions: Virginia Village and a low area where it is situated the municipal market, the bus station and an informal commercial center (camelódromo). In relation to the daily period of flood incidence, they occur, mainly, after noon. In all the floods that occurred... (Complete abstract click electronic access below)
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48

Wohl, Ellen Eva. "Northern Australian paleofloods as paleoclimatic indicators". Diss., The University of Arizona, 1988. http://hdl.handle.net/10150/184418.

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Paleoflood data are restrictive reflections of climatic conditions, representing one component of a region's climate; high rainfall intensity storms. In regions with a fairly simplistic, uniform hydroclimatological setting (floods above a given magnitude threshold are caused by predominantly one type of atmospheric circulation pattern), the temporal distribution of floods reflects that of the causal circulation pattern. Slackwater-deposit-based paleoflood reconstructions for three rivers in northern Australia cover an aggregate of 1200 years. Slackwater deposits (SWD) are fine-grained sediments which settle from suspension in low velocity areas during floods. These deposits approximate the flood's high water level, and allow reasonably accurate estimation of discharge. Radiocarbon dating of associated organics, and thermoluminescence (TL) dating of the 90-125 μm quartz fraction of the sediments, produce a paleoflood chronology. In this study, radiocarbon ages on SWD ranged from 1200 yr BP to modern, while TL ages on SWD and other fluvial sediments ranged from 2.6 to 60 ka. TL dating appears to have a large temporal range (1-100 ka) and a restricted spatial range (the lower reaches of a basin), while radiocarbon dating has a more restricted temporal range (0-35,000 yr BP) and a large spatial range (anywhere in the basin). The northern Australian paleoflood data formed clusters at 300-440 yr BP and 160 yr BP-present. This distribution is attributed to variations in the intensity of the El Nino/Southern Oscillation (ENSO) circulation (which prevents floods from occurring in northern Australia), and the anti-ENSO circulation (which is associated with large floods).

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House, Peter Kyle. "Reports on applied paleoflood hydrological investigations in western and central Arizona". Diss., The University of Arizona, 1996. http://hdl.handle.net/10150/191206.

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Interdisciplinary and unconventional research methods offer important insights into geomorphic, hydrologic and hydroclimatologic characteristics of large floods that are often difficult or impossible to resolve in the framework of conventional flood analysis. Four detailed studies of modern floods, historical floods, and paleofloods in western and central Arizona demonstrate the benefits of analyzing recent and historical extreme floods within the conceptual framework of paleoflood hydrology and flood hydroclimatology. Analysis of the hydroclimatological and paleohydrological context of extreme flooding in Arizona during the winter of 1993 provides a detailed analog to the likely climatic, meteorologic, and hydrologic conditions associated with the largest events in the regional paleoflood record. Investigation of the distribution of relict high-water evidence from extreme floods on the lower Verde River in 1993 improves the accuracy of the river's paleoflood record and reveals interesting hydrological phenomena of extreme floods in the Verde River Basin. A multidisciplinary study of the extraordinarily large Bronco Creek, Arizona, flood of August 1971, shows the original estimate to be significantly overestimated because of complex flow behavior of an extreme flood and the related dynamic morphological response of a high-gradient alluvial channel. The approach to this study is a template for similar analyses of extreme floods and extraordinary flood discharge estimates. A similar, more comprehensive application of paleoflood research methods is demonstrated by the compilation of a detailed regional chronology of flash-flooding in small desert drainage basins (7-70 km²) in western Arizona. The occurrences of large, recent and historical floods were documented with nearly annual resolution, and a 1200-year regional paleoflood record was compiled. Comparison of these records to conventional regional flood-frequency relations indicates that the regional equations are probably inaccurate because of data limitations. The study presents a viable approach to developing a quantitative assessment of regional flood frequency in areas with no conventional data on real floods. The results of each of these studies extend the spatial and temporal scope of the paleoflood and historical flood record of the lower Colorado River Basin and provide further support for the concept of a regional upper limit to flood peak magnitudes.

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Desilets, Sharon. "Flood Processes in Semi-arid Streams: Sediment Transport, Flood Routing, and Groundwater - Surface Water Interactions". Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/195652.

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Flooding in semi-arid streams is highly variable but distinguished from its humid counterpart in terms of forcing conditions, landscape response, flood severity, and stream-aquifer connectivity. These floods have the potential for great benefit in a water-limited environment, but also great devastation when powerful floods encounter human infrastructure. This dissertation employs an integrative approach to address several facets of flooding in semi-arid streams. In particular, information from field sampling during flood events combined with modeling are used to evaluate the processes of post-disturbance sediment transport, flood routing, transient bank storage, and stream disconnection. The major findings show: (1) Suspended sediment composition in floods following wildfire depends on the number, timing, and intensity of preceding storms and flood events, implicating overland flow hillslope processes as a dominant mass wasting mechanism (2) Isotopic chemographs for two representative intense convective storm events demonstrate that the flash flood bore develops from predominantly high elevation event water that overcomes, incorporates, and pushes baseflow to the front of the hydrograph peak (3) Isotope information combined with a plug-flow model can simulate this flood bore mixing process simultaneously in two separate canyons in the basin in order to calculate the timing and quantity of flow; this could be a useful tool for watersheds that are not extensively instrumented, or for calibrating a more complex or distributed model, (4) For a stream connected to an underlying aquifer, a circulation pattern develops at the onset of flooding that causes an upwelling of antecedent water into the unsaturated zone, challenging the assumptions of one dimensional, lateral flow and transport into the streambank, and (5) For small stream-aquifer disconnections, large increases in infiltration, large decreases in seepage, and a dominantly vertical profile for floodwater were observed. This implies that a stream that supports a wide riparian corridor may be in danger of vegetation die-offs with even shallow depletions of the groundwater table.

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