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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Určení záplavového území a hydrotechnické posouzení vodního toku Říčanský potok / Determination of floodplains and hydrotechnical assessment of Říčanský water flow

Bezděková, Veronika January 2016 (has links)
This thesis deals with determining the flood lines and hydrotechnical assessment of the Říčanský water flow and objects that interfere with the flow profile. Hydrotechnical assessment preceding hydrological study of catchment. The basis for this work was digital model relief Czech Republic, which obtained from Airborne Laser Scanning. This method is considered to be of the most accurate methods for altimetry data obtained, but the near-infrared laser beam used in this method cannot penetrate water masses. The result of this problem is error as the extracted cross sections lose a significant portion of their flow area. These errors can be removed to recess the channel using specialized software Crosolver tool. For hydrotechnical assessment is used hydrodynamic model in HEC-RAS. On the basis of results are determined the flood line for N-years flows (5-years flow, 20-years flow and 100-years flow). The final part of this work deals evaluation of hydrotechnical assessment Říčanský water flow, object and floodplains.
52

Modelování povodňových průtoků a záplavových čar na vodním toku Želivka / Modelling of flood event runoff and flood lines in Želivka river

Mudra, Jiří January 2016 (has links)
Nowadays, the issue of floods and flood protection is very reflected theme which is dedicated to the thesis. The first part deals with the gathering and the processing of relevant information, the emphasis is on the development of basic questions about flooding and flood protection because of importance for understanding its. The next part of thesis provides a description of the catchment Želivka which involves the interest area which is bounded swells water reservoir Švihov at 41.6182 Km and dykes of water reservoirs Sedlice at 63.8893 Km. The next, the thesis also discusses the modeling of steady flow of flood flows and modeling flood lines in the area of interest. For the simulation are used ArcGIS 10.2 with overlaid of GeoRAS, HEC-RAS 4.1.0 and the description of creating a model for the assembly are used the digital elevation model fifth-generation, transverse profiles of stream, longitudinal profile of stream and roughness of stream and inundation and geometry of objects on the stream. The outcome of this work are maps of inundation in selected sections on the stream, in particular in areas with existing buildings.
53

Modelagem hidrológica e hidráulica a partir de dados TRMM aplicada a análise de risco em áreas inundáveis: estudo de caso no município de Atalaia / Hydrological and hydraculic modeling based on TRMM data applied to risk analysis in flooded areas: a case study in Atalaia city

Brito, Tainara Ramos da Rocha Lins de 28 March 2017 (has links)
This work consisted in the analysis of the off-line coupling of hydrological and hydraulic models from observed rainfall data and in the TRMM satellite precipitation intensity estimates in the Paraíba do Meio watershed (AL/PE), with the final objective the mapping of flooded areas and risk analysis of Atalaia-AL city, when considering the flood event occurred in 2010. The main computational programs used were: HEC-HMS in hydrological modeling and HEC-RAS in hydraulic modeling, in addition to their respective extensions integrated with ArcMap in the preprocessing stage, HEC-GeoHMS and HEC-GeoRAS. The results showed that the rainfall intensity data estimated by the TRMM satellite presented a good correlation with the rainfall data series, presenting values of 0.90 ("TRMM" x Postos) and 0.94 ("TRMM + Postos" x Postos). The hydrological model presented a good representation in relation to flood events in the Paraíba do Meio watershed, from data the flood occurred in 2000 and the flood of 2010. The validation of the model presented satisfactory results in the Atalaia post (39870000) in relation to the corrected satellite series ("TRMM + Postos"), evidencing with a Nash Sutcliffe coefficient - COE of 0.91. The hydraulic modeling was calibrated based on the Manning coefficient (n) adjustment for the banks and bottom of the channel, based on the ENGEMAP field markings and the peak flow recorded during the 2010 event by the fluviometric Atalaia post (39870000), already the model validation was done from the calibrated Manning coefficient (n) and the hydrograph generated in the hydrological simulation based on the corrected satellite series TRMM ("TRMM + Postos"). Thus, the mapping of the flooded areas made based on the 2010 flood data allowed a Risk Analysis in Atalaia city, based on the threat and vulnerability of the resident population in the riverine region to the occurrence of floods. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Este trabalho consistiu na análise do acoplamento “off-line” de modelos hidrológico e hidráulico a partir de dados de precipitação observada e nas estimativas de intensidade de precipitação do satélite TRMM em relação à bacia hidrográfica do rio Paraíba do Meio (AL/PE), tendo como objetivo final o mapeamento das áreas inundáveis e análise de risco do município de Atalaia-AL, ao considerar o evento de cheia ocorrido em 2010. Os principais programas computacionais empregados foram: o HEC-HMS na modelagem hidrológica e o HEC-RAS na modelagem hidráulica, além de suas respectivas extensões integradas ao ArcMap na etapa do pré-processamento, HEC-GeoHMS e HEC-GeoRAS. Os resultados mostraram que as intensidades pluviométricas estimadas pelo satélite TRMM apresentaram boa correlação com a série de dados dos pluviômetros, com valores de 0,90 (“TRMM” x Postos) e de 0,94 (“TRMM+Postos” x Postos). O modelo hidrológico demonstrou uma boa representatividade em relação a eventos de cheia na bacia, a partir de dados da cheia ocorrida em 2000 e da cheia de 2010. A validação do modelo hidrológico demonstrou resultados satisfatórios no posto Atalaia (39870000) para a série corrigida do satélite (“TRMM+Postos”), exibindo um coeficiente de eficiência de Nash Sutcliffe – COE – de 0,91. A modelagem hidráulica teve sua calibração baseada no ajuste do coeficiente de Manning (n) para as margens e fundo do canal, com base nas marcas de cheia levantadas em campo pela ENGEMAP e pela vazão de pico registrada no posto Atalaia (39870000) durante o evento de 2010, já a validação do modelo partiu do coeficiente de Manning (n) calibrado e do hidrograma gerado na simulação hidrológica a partir da série corrigida do satélite TRMM (“TRMM+Postos”). Por fim, o mapeamento das áreas inundadas, permitiu uma Análise de Risco no município de Atalaia baseada na análise da vulnerabilidade social e das ameaças às quais a população residente às margens do rio está exposta diante da ocorrência de eventos de inundação.
54

Using HAZUS-MH flood model as a floodplain management tool: Evaluation of river engineering effects on flood losses for the Middle Mississippi River

Carlson, Megan L. 01 December 2010 (has links)
By combining FEMA's HAZUS-MH (Hazards U.S. Multi-Hazard) flood-loss estimation software and the HEC-RAS hydraulic modeling package, this study was able to quantify potential beneficial and adverse impacts of flood-control and navigational structures along the Middle Mississippi River (MMR; between Mississippi-Missouri River confluence and Thebes, IL). The goal of this investigation was to assess changes in water-surface elevations and associated flood losses to: 1) quantify the potential exposure of flooding under different flood-control configurations along the Middle Mississippi River (MMR), and 2) assess the relative contributions of various engineered structures and flood-loss strategies to potential flood losses. Assessment of the impact of engineering structures was accomplished by modeling five scenarios for the 100- and 500- year floods: 1) current MMR levee configuration (levee protecting for ≤50-year flood); 2) removal of all flood-control structures on the MMR; 3) increasing the height of levees and floodwalls in metropolitan St. Louis to protect urban areas to the 500-year flood level while simultaneously removing all agricultural levees downstream; 4A) a less engineered MMR channel and floodplain with fewer flood control and navigation structures, simulating conditions from 65 years ago (1942-1947) with 1940's levees; and 4B) a less engineered MMR channel and floodplain with fewer flood control and navigation structures, simulating conditions from 65 years ago (1942-1947) with current levee configuration. Comparison of scenarios 2 and 3 relative to scenario 1 allows for quantitative assessment of the flood-control structures on stages and flood losses. Results from scenario 2 revealed that removing all levees along the MMR reduces the average stages from 2.2 m (100-year) to 2.5 m (500-year, but also increased economic and social impacts relative to scenario 1. Scenario 3 revealed that removing agricultural levees downstream of St. Louis on the MMR decreased stages by 1.4 m (100- and 500-year); however, flood losses for the 100-year flood were increased. Flood losses for the 500-year flood were decreased relative to scenario 1. These results suggest that agricultural levees along the MMR protect against medium size floods (50- or 100-year flood) but cause more damage than they prevent during large floods such as the 500-year flood. Comparison of scenarios 4A and 4B relative to scenario 1 allows for a quantitative assessment of river engineering structures and modern buildings constructed over the last 65 years. In scenarios 4A and 4B, a less engineered river decreased stages by 1.2 m (for the 100-year flood) relative to scenario 1. In scenario 4A, the 1940's levees expose modern buildings in the floodplain to flooding, causing economic building losses to increase; however, in scenario 4B, current levee configuration protects modern buildings in the floodplain from flooding causing, economic building losses to decrease. If the current flood-control structures were not built, it is likely that the land in the floodplain for scenarios 4A and 4B would not be developed and the land used would be more flood-tolerant. Sensitivity analyses were run to assess the impact of using the default HAZUS-MH national-level data; this was done by comparing results produced by using aggregate analysis (coarse data) versus results using UDF analysis (detailed data). The aggregate analysis estimated 51% fewer buildings damaged than the UDF analysis. Conversely, the aggregate analysis increased the economic building losses by 51% relative to the UDF analysis. Although collecting local data for a study is not always feasible, the large differences documented here need to be considered when discussing HAZUS-MH results. Overall, this project shows implications for historic and future flood-control and navigational structure projects on the MMR and other rivers. It also emphasizes the importance of studying the impact future engineering structures will have on water-surface elevations and flood losses before implementing them.
55

Estudo de indicadores de risco de inundação no município do Cabo de Santo Agostinho

BATISTA, Larissa Ferreira David Romão 06 July 2015 (has links)
Submitted by Isaac Francisco de Souza Dias (isaac.souzadias@ufpe.br) on 2015-10-22T17:32:21Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) VersãoBiblio_LarissaBatista_Diss_UFPE_PPGEC_GRH_2015.pdf: 3785832 bytes, checksum: 935efbfbfe308f7ca28092c3a1c2ca54 (MD5) / Made available in DSpace on 2015-10-22T17:32:21Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) VersãoBiblio_LarissaBatista_Diss_UFPE_PPGEC_GRH_2015.pdf: 3785832 bytes, checksum: 935efbfbfe308f7ca28092c3a1c2ca54 (MD5) Previous issue date: 2015-07-06 / CAPES / Mudanças no meio ambiente causadas por ações antrópicas e dinâmicas naturais são evidentes com o aumento do número de eventos extremos, dentre os quais se destacam as inundações por sua abrangência, recorrência e potencial de destruição. A gestão de desastres e as consequentes políticas de mitigação de danos passam pela compreensão do comportamento e interações entre os componentes do risco chamados indicadores. Para tal, foi estabelecida e aplicada metodologia de classificação de indicadores de risco no município do Cabo de Santo Agostinho, Pernambuco, Brasil. Inserida na bacia do rio Pirapama, a cidade do Cabo constitui área em plena expansão com grande relevância econômica para o Estado. Esta pesquisa faz parte do convênio Ministério das Cidades / GEGEP – UFPE - Projeto “Elaboração de cartas geotécnicas de aptidão à urbanização frente aos desastres naturais nos Municípios de Camaragibe; Abreu e Lima; Cabo de Santo Agostinho; Jaboatão dos Guararapes, localizados na Região Metropolitana do Recife, Estado de Pernambuco”. Foram simulados eventos extremos com o uso dos modelos HEC-HMS e HEC-RAS. O modelo hidrológico (HEC-HMS) foi calibrado possibilitando aquisição de hidrogramas para áreas sem dados de vazão observados. O modelo hidrodinâmico (HEC-RAS) simulou eventos em regime permanente para os picos de vazão detectados nos anos de 2000 e 2010, e com auxílio da ferramenta de geoprocessamento, foi possível gerar mapas de profundidade, velocidade e exposição. Foi selecionada uma área na sede do município para estimativa dos danos resultantes das cheias. Foram utilizadas curvas cota-dano desenvolvidas para a cidade de Itajubá/MG. Foi observada a influência fundamental da profundidade para os cenários pós-enchentes, a contribuição determinante da exposição para a origem dos prejuízos e a atuação dos danos diretos para a quantificação da vulnerabilidade, uma vez que são elementos acessíveis. O dano por m2 chegou a R$ 80,29 e se refere apenas à área construída com uso residencial selecionada para a análise.
56

Can morphologic restoration of hydropower outlet channels create hydraulically suitable spawning and larvae habitats for grayling? : Modelling the effects of environmental measures with HEC-RAS.

Ahonen, Jani January 2018 (has links)
The aim of this study was to model if hydraulically suitable habitats for juvenile and spawning grayling could be created by morphological restoration alone in the Bjurfors Övre hydropower outlet channel in the Ume River Basin. The study was done by 2D modelling with HEC-RAS using hourly water flow and level data collected during the period 20160521-20161029. Suitable water depth and velocity values for larvae and spawning grayling were collected from literature. Environmental measures for the Bjurfors Övre outlet channel were designed based on the morphology in outlet channels with documented reproducing grayling populations and large habitat diversities. The outlet channel at present morphology and after morphological modifications were modelled at different flow scenarios (0-369m3/s) and areas of suitable water velocities and depths before and after proposed measures were compared. Results show that suitable velocity areas would increase with a factor of between 1,03-1,81 and the suitable depth areas with a factor of 2,34-19,09 and that suitable depths may be the major limiting factor in current conditions. Results also show that zero-flow events at Bjurfors Övre hydropower plant create unsuitable velocities for larvae and spawning grayling and that the frequency and duration of such events could be more limiting than the mere occurrence of such events. The study indicates that the morphological restoration in hydropeaking outlet channels could improve the availability of habitats with suitability water depth and velocity not only for larvae and spawning grayling, but for other lotic organisms. The study also showed that HEC-RAS modelling is a potential resource effective way to assess to what extent certain proposed environmental measures may create suitable water depths and velocities in hydropeaking outlet channels.
57

Simulering av hydrauliska effekter av biotopvårdande åtgärder i Vitsåns avrinningsområde / Simulation of hydraulic effects from biotope promotion measures within the catchment area of Vitsån

Johansson, Felix January 2021 (has links)
En stor del av Sportfiskarnas arbete handlar om att återställa den ursprungliga morfologin i vattendrag efter påverkan av främst jordbruk. Sådana återställningar kan exempelvis göras genom att återföra rensat material i form av block och sten till vattendragen samt att rätade sträckor återmeandras. Syftet med sådana åtgärder är ofta att hålla kvar vattnet i landskapet och uppnå jämnare flöden i vattendragen, för att vårda eller bevara den naturliga biotopen. Inom det biotopvårdande arbetet utgörs en del av arbetet av att uppskatta de hydrauliska effekterna av aktuella åtgärder i vattendraget. I många scenarion tillämpas Mannings formel för att beräkna och uppskatta dessa effekter.   Det här projektet som utförs inom ramen för sportfiskarnas projekt Hydrologisk restaurering av Södertörns avrinningsområden, utreder vanliga biotopvårdande åtgärder och dess hydrauliska effekter genom upprättandet av hydrauliska flödesmodeller i HEC-RAS. De simulerade effekterna jämförs med beräknat resultat utifrån Mannings formel för att utreda värdet av upprättande av modell relativt de konventionella beräkningarna. Metodiken utgjordes av en mindre initial litteraturstudie följt av inmätningar av bottennivå och vattennivå i de aktuella flödessträckorna varpå flödesmodeller för respektive objekt upprättades. Flödessträckan i Hågaån utgjorde objektet för jämförelse mellan modell och konventionella beräkningar. Återmeandring visade sig vara den mest lämpade åtgärden för att erhålla en sänkt hastighet och ett ökat djup över en längre sträcka. Utplacering av sten i vattendraget kunde konstateras ha lokalt avgränsade effekter i form av ett mer turbulent flödestillstånd. Även ett ökat djup samt minskad hastighet kunde i varierande omfattning erhållas i sektioner med utplacerade stenar. De hydrauliska effekterna av den upprättade våtmarken speglas av en lokalt sänkt hastighet och minskat djup. Mannings formel visade sig generera mycket liknande resultat som modellen för åtgärden utplacering av sten. För återmeandring erhölls lite större skillnad i resultatet som troligtvis beror på felaktigheter i den geometriska beskrivningen av fårans tvärsnitt. Intressanta uppslag för fortsatta studier inom området är att jämföra resultat med inmätningar i fält efter utförd åtgärd samt att jämföra metoderna för fler olika objekt och scenarion. / A significant part of the work process at Sportfiskarna consists of restoring the original morphology of waterways after, mainly the influence of agriculture. Such restorations can be made, for example, by restructuring straightened waterways and it may also include replacing material, like blocks of stone, that has been removed from the waterways in the past. The purpose of such measures is often to retain the water in the landscape and achieve more moderate flow variations in the waterways to preserve and promote the natural biotope. This work includes estimating the hydraulic effects of intended measures in the waterways. In many scenarios, Manning’s formula is applied to calculate and estimate these effects.  This study is performed within the context of the ongoing project, Hydrological restoration of the catchment areas at Södertörn, run by Sportfiskarna. Common measures and their hydraulic effects are investigated through the establishment of hydraulic flow models in HEC-RAS. The simulated effects are compared with calculated results from using Manning’s formula to investigate the value of establishing a model compared to the conventional calculations. A minor initial literature study was performed followed by measurements of bottom- and water level in the investigated flow sections whereupon flow models for each object were established. Hågaån was chosen as the object for comparison between model and conventional calculations. Restructuring straightened waterways proved to be the most suitable measure to obtain a reduced speed and an increased depth over a longer distance. Replacing blocks of stone in the waterways could be observed to have locally delimited effects in the form of a more turbulent flow condition. Increased depth and reduced speed could also be obtained in the sections with replaced stones. The hydraulic effects of the established wetland are displayed in a locally reduced speed and reduced depth. Manning’s formula proved to generate very similar results as the model for the replacement of stones measure. For restructuring straightened waterways, a slightly larger difference was obtained in the result which is probably due to inaccuracies in the geometric description of the cross section in the waterway. Suggestions for further studies are to compare results with measurements in the field after the measure has been performed and also to compare the methods for several different objects and scenarios.
58

Návrh protipovodňové ochrany na vybrané části toku / Design of flood protection on selected location of the river

Filípková, Monika January 2019 (has links)
The master’s thesis deals with the hydraulic analysis of the water flow capacity for the flood flow on the river Litava in the river kilometres 11,550 – 18,315 using the HEC-RAS 5.0.5 specifically 1D-2D numerical model. On the basic of flood areas, depths and speeds the results were evaluated and subsequently was created own proposal flood protection.
59

Návrh revitalizace části Knínického potoka / Project of revitalization part of Kninicky brook

Vyplel, Adam January 2020 (has links)
The diploma thesis is focused on the proposal of systematic revitalization of the selected section of the Knínický brook in the cadastral area of Veverské Knínice. It is a straight, very deep channel due to technical adjustments in the past. The HEC-RAS program verifies the capacity of the channel for the Q100 flow. In this way, it was found that the channel has very high capacity so a new route with Q1 flow capacity was designed. Due to the height conditions, the design also included three boulder chutes. Subsequently, the vegetation accompaniment and bank stands were suitably supplemented.
60

ANALYZING THE STREAMFLOW FOR FUTURE FLOODING AND RISK ASSESSMENT UNDER CMIP6 CLIMATE PROJECTION

Pokhrel, Indira 01 December 2020 (has links)
Hydrological extremes associated with climate change are becoming an increasing concern all over the world. Frequent flooding, one of the extremes, needs to be analyzed while considering climate change to mitigate flood risk. This study forecasted streamflow and evaluated the risk of flooding in the Neuse River, North Carolina considering future climatic scenarios, and comparing them with an existing Federal Emergency Management Agency (FEMA) flood insurance study (FIS) report. The cumulative distribution function transformation (CDF-t) method was adopted for bias correction to reduce the uncertainty present in the Coupled Model Intercomparison Project Phase 6 (CMIP6) streamflow data. To calculate 100-year and 500-year flood discharges, the Generalized Extreme Value (GEV) (L-Moment) was utilized on bias-corrected multimodel ensemble data with different climate projections. The delta change method was applied for the quantification of flows, utilizing the future 100-year peak flow and FEMA 100-year peak flows. Out of all projections, shared socio-economic pathways (SSP)5-8.5 exhibited the maximum design streamflow, which was routed through a hydraulic model, the Hydrological Engineering Center’s River Analysis System (HEC-RAS), to generate flood inundation and risk maps. The result indicates an increase in flood inundation extent compared to the existing study, depicting a higher flood hazard and risk in the future. This study highlights the importance of forecasting future flood risk and utilizing the projected climate data to obtain essential information to determine effective strategic plans for future floodplain management.

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