This master's thesis consists of three main parts. The first section describes some types of fish crossings and basic information of their design. There is also marginally described program HEC-RAS. The second part is about the Zuberská weir and Osek stage. I review here fish ladders according to the original drawings in the HEC-RAS and suggest possible options to address these passable fish crossings for the fish crew. The last section is devoted to Mikulenkov weir where the fish crossing has been completely removed. Here I propose a new fish ramp according to modern knowledge and applicable standards. I also review the proposed fish ramp in the HEC-RAS program in order to verify the hydraulic characteristics.

This thesis deals with revitalization of the selected part of river Drevnice. Main scopes of the work are proposals of fish passages through migration barriers. The work is conceived on four levels. The first of them is dealing with the general characteristics of selected segment and with description of objects on watercourse. The second level is dealing with revitalization, where the basic information about migration and efficiency of fishes are described. In this chapter basic distribution of fish ladders is included. In third part, which is the most comprehensive, I design a boulder fish ramp and bypass channel. The last chapter contains drawings documentation of watercourse Drevnice and my own proposed revitalization elements.

This study solves revitalizing proposal of selected section of river Kuřimka in km 0,212 to 0,312 in the cadastral Kníničky. Work is focused on assessing the current state, capacity assessment and subsequent design of revitalization using extension space for sedimentation. Calculations of flow capacity were performed using HEC-RAS 5.0.0. The assessment was made based on my own errand, remeasurement and photographic documentation. The work also includes a proposal of riparian vegetation and drawings.

The diploma thesis is focused on the use of software based on an open-source license to determine scale and extent of the flood risk of municipality with the possibility of use for municipality spatial planning activities. The diploma thesis is divided into the theoretical and practical part. Theoretical part deals with issues related to flood wave, flood types, hydrologic and hydraulic modeling, land use documents, land use planning documents and flood control measures of non-technical and technical character with local purpose. In the practical part an analysis of the Lešany u Prostějova territory was carried out for the identification of critical sites from the point of view of the flash floods. The critical sites, also called the critical points, were further analyzed for determination of the scale and extent of the flood risk. At the end of the practical part the used analyses and models for municipal self-government are evaluated. Also, an idealized design of flood control measures and measures for water retention in the landscape are presented. All outputs are presented as maps and included in the annex of the diploma thesis.

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Satellite derived data has become an essential input in hydraulic modelling. Digital ElevationModels (DEMs) derived from different sources through remote sensing techniques have become a powerful tool for poorly gauged regions. This paper analyses the capabilities of DEMS derived from Shuttle Radar Topography Mission (SRTM) and a Light Detection and Ranging (LiDAR) and compares their accuracy against each other in a 1D hydraulic model. The study tests two different methods for inferring the river bathymetry under the water surface level for the SRTM derived DEM in order to enhance its performance, the study further analyze the reliability of remotely sensed altimetry data derived from different satellite missions (TOPEX and ENVISAT) and its suitability to complement spaceborne topographic data in hydraulic modelling.

Urbanization increases runoff during storm events due to a reduction in vegetation and an increase in impervious surfaces, which limits the land's capacity to absorb and slow down water. This increase in runoff contributes to channel erosion. While extensive research exists on the hydrologic benefits of various types of stormwater control measures (SCMs), the relationship between urbanization, widespread SCM implementation, and channel stability in headwater streams remains less explored. Additionally, the impact of climate change (CC) on SCMs, with its growing focus due to improved global and regional CC models and data, is a critical area of study. However, most existing studies rely on simplified design storm analyses and unit-area runoff models, and there is a lack of comprehensive research evaluating the long-term, continuous hydrologic response of SCMs under future CC scenarios. This study presents an in-depth evaluation of the effectiveness of SCMs in maintaining channel stability in urbanized headwater streams, with a particular focus on the challenges posed by urbanization and CC. Conducted in a small catchment in Montgomery County, Maryland, USA, the study employs a sequential hierarchical modeling approach integrating the Storm Water Management Model (SWMM) with the Hydrologic Engineering Center's River Analysis System (HEC-RAS). First, the impact of a stormwater management system design following Maryland's Unified Stormwater Sizing Criteria (USSC) on channel stability was investigated. Simulation over 16 years (2004-2020) demonstrated that the majority of storm events were short in duration, with the greatest peak flows resulting from storm events with durations less than 24 hours. However, results indicated that despite the use of multiple SCMs, channel changes, including both degradation and aggradation up to 1.2 m, are likely over a period of 16 years. Study results indicate SCMs should be designed using continuous simulation models to simulate pre- and post-development sediment transport. Secondly, the impact of SCMs and CC on flow regime and channel stability was examined, challenging the previous simplified analyses. The findings highlight that future CC scenarios, characterized by decreased total rainfall but increased intensity, will likely shift watershed hydrology towards a flashier regime, exacerbating channel erosion. To address these shortcomings, a multicriteria design approach for SCMs is required, considering local sediment transport capacity and the complexities of urban catchments under changing climatic conditions. Lastly, evaluation of the impact of proposed stormwater regulations on channel stability using a novel three-step methodology revealed that SCM design goals focused on maintaining pre-development sediment transport or excess shear stress could reduce channel disturbance. Overall, this study illustrates the need for more nuanced and holistic approaches to stormwater management to ensure channel stability, especially in the face of the challenges posed by climatic changes. / Doctor of Philosophy / As cities grow, with more buildings and roads replacing green spaces, managing stormwater becomes a crucial challenge. Without enough soil and plants to absorb it, stormwater rushes over these hard surfaces, contributing to stream erosion. This urban scenario sets the stage for my research, which investigated effective ways to handle stormwater in cities to protect small, local streams. The focus of this study was to understand the performance of stormwater control measures (SCMs), which are engineered structures designed to manage this excessive runoff in urban environments. The key question is: Are SCMs effective, especially as we face the impacts of climate change? This research was conducted in a small watershed in Montgomery County, Maryland, using computer simulations to replicate water flow and stream conditions over a 16-year period. The findings reveal that, despite using SCMs, streams can still experience significant changes. This is especially true during intense, short-duration storms that can rapidly increase stream flow and cause channel erosion. With climate change, these problems may increase. Future weather patterns could lead to less frequent but more intense rainstorms. This study suggests that our approach to designing SCMs needs to be more sophisticated, taking into account not only the amount of water running into streams, but also the amount of coarse sediment moving during floods. In summary, this research highlights the need for comprehensive strategies in urban water management to ensure the stability and health of urban streams amidst the challenges of increasing urban development and climatic changes.

The Mississippi River (MR) has been engineered with the development of the levee system, dams for flood control measures, jetties, revetments and dredging of the navigation channel. These alterations have reduced the replenishment of the sediment to the Louisiana Coastal area. To aid in the restoration planning, 1-D numerical models have been calibrated and validated to predict the river response to various changes such as channel modifications, varied flow conditions and hurricane situations. This study utilized the HEC-RAS 4.1 and the CHARIMA (Dr. Forrest Holly, University of Iowa). The models were calibrated for hydrodynamics and sediment using Tarbert Landing discharges (HEC-RAS), Belle Chasse sand concentrations (CHARIMA), and Gulf of Mexico (GOM) stages. The models showed that a large percentage of the river flow is lost over the East Bank downstream of Bohemia which reduces the sand transport capacity of the river. This reach is subject to flow reversals during hurricanes.

Orientador: César Gustavo da Rocha Lima / Resumo: O Brasil, frente aos acidentes ocorridos em Mariana – MG (2015) e em Brumadinho – MG (2019), tem vivenciado inúmeras discussões no que tange à assuntos regulatórios e à confiabilidade das barragens construídas no país. Neste trabalho, inicialmente, fez-se um breve comparativo entre a legislação brasileira e alguns normativos internacionais (China, Portugal, Estados Unidos e África do Sul) sobre segurança de barragens, observando-se a existência de diferentes aspectos abordados entre eles. A Política Nacional de Segurança de Barragens se demonstrou uma das regulamentações menos rígidas entre as analisadas quanto a pré-requisitos técnicos para sua aplicação, deixando grande parte das barragens de pequeno porte dispensadas do cumprimento de algumas obrigações. Além disto, a legislação federal brasileira foi implementada há menos de uma década, o que implica, atualmente, em uma dificuldade muito grande do empreendedor, dos órgãos fiscalizadores e do governo federal a se adaptarem a possuir esta cultura de segurança de barragens. Diante da interface destas construções com o meio ambiente, faz-se necessário um monitoramento constante das estruturas por uma equipe multidisciplinar e um programa de segurança consistente que vise garantir a integridade do meio ambiente nas áreas de influência das barragens, bem como resguardar o bem-estar e a vida da população situada a jusante. O uso de funções matemáticas e softwares para o mapeamento das áreas sujeitas aos riscos impostos pelas bar... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Brazil, faced with the accidents that occurred in Mariana - MG (2015) and in Brumadinho - MG (2019), has experienced numerous discussions regarding regulatory issues and the reliability of the dams built in the country. In this work, it was made a brief comparison between Brazilian legislation and some international regulations (China, Portugal, United States and South Africa) on dam safety, observing the existence of different aspects addressed among them. The National Dams Safety Policy demonstrated one of the less rigid regulations among those analyzed regarding technical prerequisites for their application, leaving most of the small dams exempted from compliance with certain obligations. In addition, Brazilian federal legislation was implemented less than a decade ago, which currently implies a great difficulty for the entrepreneur, the inspection agencies and the federal government to adapt to having this dam safety culture. In view of the interface of these constructions with the environment, it is necessary a constant monitoring of the structures by a multidisciplinary team and a consistent safety program that aims to guarantee the integrity of the environment in the areas of influence of the dams, as well as to protect the well-being and the life of the downstream population. The use of mathematical functions and softwares for the mapping of the areas subject to the risks imposed by the dams is a great advance in the safety aspect of these structures. In this context,... (Complete abstract click electronic access below) / Mestre

O início da construção de estruturas para reserva de água no mundo é conhecido há milhares de anos, e, desde então, as barragens são consideradas alternativas viáveis não apenas para reserva de água para consumo, mas também para as finalidades de geração de energia hidrelétrica, contenção de rejeitos, entre outras. Entretanto, mesmo com os contínuos avanços nas técnicas construtivas e na fiscalização da segurança destas estruturas, a possibilidade de rompimento de barragens é uma realidade constante. Nesta perspectiva, o presente texto objetiva analisar os aspectos hidráulicos de metodologias simplificadas para estimativa de parâmetros de inundação proveniente do rompimento de barragens, a saber, as vazões e respectivas profundidades atingidas no vale a jusante, em um evento de rompimento hipotético. Para tal, analisaram-se os resultados de três metodologias simplificadas existentes, aplicadas em três barragens estudo de caso, com características estruturais e geometria do vale a jusante distintas. Os resultados das metodologias simplificadas foram comparados com os estudos de Dam Break das três barragens estudo de caso, obtidos com o uso do software HEC-RAS unidimensional e cedidos por empreendedores. O presente texto também sugere uma nova equação empírica para previsão da vazão máxima resultante do rompimento de barragens por galgamento, e propõe uma nova metodologia simplificada para análise preliminar de rompimento de barragens, com base nos métodos analisados e nas respectivas conclusões obtidas. Os resultados indicam que o uso de metodologias simplificadas na análise preliminar de rompimento de barragens é uma alternativa viável em vales cuja declividade do talvegue é acentuada e cujas características geométricas são aproximadamente constantes. Identificou-se que pequenas alterações no coeficiente de rugosidade do terreno e na declividade da linha de energia refletiram em diferenças nos resultados de profundidades e larguras máximas de 20%, em média. A proposta de nova equação empírica para previsão de vazão máxima na seção da barragem baseou-se na análise de 39 casos reais envolvendo ruptura de barragens por galgamento e resultou em um coeficiente de determinação (R²) de 0,79. Quando comparada com as principais equações semelhantes indicadas na bibliografia, a equação proposta obteve vazões máximas próximas ou superiores às dos demais pesquisadores analisados sempre que a altura da barragem foi inferior a 30 m. Evidencia-se a importância na estimativa cautelosa da vazão máxima na seção da barragem, uma vez que essa reflete em diferenças significativas nas vazões e respectivas profundidades alcançadas ao longo do vale a jusante da estrutura. Nos casos analisados, diferentes vazões máximas na seção da barragem refletiram em distinções de até 50%, em média, nas profundidades e larguras máximas a jusante. A nova metodologia proposta para definição de características de inundação provenientes do rompimento de barragens pode contribuir em estudos preliminares para tal, especialmente aos empreendedores que possuem número expressivo de barragens. Nesses casos, a metodologia poderá nortear a prioridade a ser dada em estudos detalhados de Dam Break. / For thousands of years, water reservoir structures have been built worldwide. Since then, dams have been considered viable alternatives not only for reserving water for consumption but also for the purposes of hydroelectric power generation and sediment retention, among others. Despite the continuous advances in the construction techniques and in the safety inspection of these structures, the possibility of breaking of dams remains a constant reality. Hence, this paper aims to analyze the hydraulic aspects of simplified methodologies for estimating flood parameters on dam ruptures, namely, the flows and respective depths reached in the downstream valley in a hypothetical breach event. Results of three existing simplified methodologies were studied applied in three dams with different structural characteristics and downstream valley geometry. The results of simplified methodologies were compared with dam break studies of three study case dams, obtained with one-dimensional HEC-RAS and provided by entrepreneurs. The present paper suggests also a new empirical equation for predicting the maximum flow resulting from the overtopping dam failure and proposes a new simplified methodology for preliminary analysis of dam rupture, based on the analyzed methods and respective obtained conclusions. The results indicate that the use of simplified methodologies in the preliminary dam break analysis is a viable alternative in valleys with high thalweg declivities and close to constant geometric characteristics. It was identified that small changes in the coefficient of rough terrain and in the energy line slope reflected in differences in the results of depths and maximum widths of 20%, on average. The proposed new empirical equation for maximum flow prediction in the dam section was based on the analysis of 39 actual cases involving overtopping dam failure and resulted in a coefficient of determination (R²) of 0.79. When compared to similar main equations indicated in the bibliography, the proposed equation obtained maximum flows near or higher than those of other researchers analyzed whenever the height of the dam did not exceed 30 m. The importance of a cautious estimation of the maximum flow rate in the dam section is to be highlighted, since it results in significant variations of flow and respective depths along the valley and downstream of the structure. Different maximum flows were found in the dam section, which reflected in distinctions of up to 50%, in average, in the maximum depths and widths downstream. The new proposed methodology for defining dam break characteristics caused by dam rupture may contribute to preliminary studies, especially to entrepreneurs who own a significant number of dams. In these cases, the methodology may guide the priority to be given in detailed studies of dam break.