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<p> To provide a logical framework for the comparison of various methods of kinematic flood routing a general method of kinematic flood routing is developed.</p> <p> After presenting the general framework, the properties of the numerical model are investigated by: l. Algebraic examination of the finite difference scheme. 2.Numerical experiments using a high speed digital computer. 3. Comparison of the kinematic flood routing results with results of simulations using the complete one dimensional dynamic representation.</p> <p> Particular facets of the numerical kinematic model that were studied included: 1. The stability of the numeric schematizations. 2. The degree of approximation with the finite difference system. 3. The applicability of kinematic methods to unsteady flow systems. 4. Methods of extending the kinematic solutions to predict attenuation as well as translation of the flood wave through the channel systems. </p> <p> The results indicate that kinematic flood routing methods differ primarily in the point about which the finite difference equation is formulated, hereafter termed the nucleus, and that the general framework is capable of emulating such methods as the Muskinghum Method, other non-linear kinematic methods and reservoir routing. By varying the location of the nucleus the stability and degree of approximation is significantly altered. This results in the outflow hydrograph being sensitive to the location of the nucleus and the size of the finite difference steps.</p> <p> To facilitate further research and application of the methods outlined in the thesis, a computer program was developed to enable kinematic flood routing to be performed in a natural channel with arbitrary geometry. Furthermore, the data is compatible with a program that is capable of performing a flood routing analysis using a numerical solution of the complete Saint-Venant equations. Documentation of the computer program for kinematic analysis is included with this thesis.</p> / Thesis / Master of Engineering (MEngr)

River stage or flow rates are required for the design and evaluation of hydraulic structures. Most river reaches are ungauged and a methodology is needed to estimate the stages, or rates of flow, at specific locations in streams where no measurements are available. Flood routing techniques are utilised to estimate the stages, or rates of flow, in order to predict flood wave propagation along river reaches. Models can be developed for gauged catchments and their parameters related to physical characteristics such as slope, reach width, reach length so that the approach can be applied to ungauged catchments in the region. The objective of this study is to assess Muskingum-based methods for flow routing ill ungauged river reaches, both with and without lateral inflows. Using observed data, the model parameters were calibrated to assess performance of the Muskingum flood routing procedures and the Muskingum-Cunge method was then assessed using catchment derived parameters for use in ungauged river reaches. The Muskingum parameters were derived from empirically estimated variables and variables estimated from assumed river cross-sections within the selected river reaches used. Three sub-catchments in the Thukela catchment in KwaZulu-Natal, South Africa were selected for analyses, with river lengths of 4, 21 and 54 km. The slopes of the river reaches and reach lengths were derived from a digital elevation model. Manning roughness coefficients were estimated from field observations. Flow variables such as velocity, hydraulic radius, wetted perimeters, flow depth and top flow width were determined from empirical equations and cross-sections of the selected rivers. Lateral inflows to long river reaches were estimated from the Saint-Venant equation. Observed events were extracted for each sub-catchment to assess the Muskingum-Cunge parameter estimation method and Three-parameter Muskingum method. The extracted events were further analysed using empirically estimated flow variables. The performances of the methods were evaluated by comparing both graphically and statistically the simulated and observed hydrographs. Sensitivity analyses were undertaken using three selected events and a 50% variation in selected input variables was used to identify sensitive variablesThe performance of the calibrated Muskingum-Cunge flood routing method using observed hydrographs displayed acceptable results. Therefore, the Muskingum-Cunge flood routing method was applied in ungauged catchments, with variables estimated empirically. The results obtained shows that the computed outflow hydrographs generated using the Muskingum-Cunge method, with the empirically estimated variables and variables estimated from cross-sections of the selected rivers resulted in reasonably accurate computed outflow hydrographs with respect to peak discharge, timing of peak flow and volume. From this study, it is concluded that the Muskingum-Cunge method can be applied to route floods in ungauged catchments in the Thukela catchment and it is postulated that the method can be used to route floods in other ungauged rivers in South Africa. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2005.

CASCADE 2001 is a multi-basin flood routing program used in areas of flat terrain. CASCADE was used for different situational elements including the Florida Keys, Broward County, and Pensacola. The goal for this screening tool was to create flood inundation watershed mapping for the Florida Division of Emergency Management (FDEM). After showing the risks of flooding that could occur in Florida, the thought of how useful CASCADE can be in other environmental conditions. The Rocky Mountains were selected to show the effect of flood inundation that can be mirrored in an opposite condition from prior experimentation. We chose to test this program in an area with mountainous terrain like the region of Grand Lake, Colorado. Rainfall, in collaboration with groundwater tables, ground soil storage and topography have the most effect on the CASCADE modeling program. Effects that were not used in the Florida models but added for Grand Lake included snowmelt. Snowmelt in the Rocky Mountains affects the flow of the Colorado River causing excess discharge that flows throughout the valleys and into Shadow Mountain Lake. WINSRM was a recommended model that could be used to simulate snowmelt during different months of Colorado’s spring season. The effects of snowmelt and rainfall flooding can be compared in relation to each other. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2021. / FAU Electronic Theses and Dissertations Collection

Orientador: Jefferson Nascimento de Oliveira / Resumo: O estudo do comportamento de corpos hídricos propicia a obtenção de informações relevantes à bacia hidrográfica e ao meio pertencente a ela, resultando em diversos benefícios, não só do ponto de vista econômico, onde através de operação otimizada de reservatórios de água pode-se obter um maior aproveitamento para geração de energia hidrelétrica, abastecimento, irrigação ou outros fins, mas também subsidia o planejamento e a tomada de decisões com a relação à mitigação de riscos hidrodinâmicos, como o mapeamento de zonas potencialmente inundáveis e a detecção de áreas sujeitas a maiores riscos relacionados às inundações. Neste trabalho foi desenvolvido um modelo operacional simplificado para propagação de vazões, baseado no modelo Muskingum-Cunge-Todini, e realizado comparações dos resultados com o modelo hidrodinâmico completo HEC-RAS. Os modelos foram aplicados em trechos do rio Tocantins, entre os municípios de Peixe –TO e Bom Jesus do Tocantins–TO. Os resultados obtidos apresentaram similaridade entre o HEC-RAS e o modelo desenvolvido. / Abstract: The study of the behavior of water bodies supports relevant information to the hydrographic basin and to the means belonging to it, resulting in several benefits. Not only from the economic point of view, where, through an optimized operation of water reservoirs, can be obtained greater use for hydroelectric power generation, water supply, irrigation, or other purposes, but subsidizes planning and decision-making about hydrodynamic risk mitigation, such as mapping potentially floodable areas and the detection of areas subjected to higher risks of floods. In this work a simplified operating model for flow propagation was developed, based on the Muskingum-Cunge-Todini model, and comparisons of the results with the complete hydrodynamic model HEC-RAS were performed. The models were applied in stretches of the Tocantins river, between the municipalities of Peixe – and Bom Jesus do Tocantins-TO. The results obtained showed similarity between HEC-RAS and the developed model. / Mestre

In case of exceptional floods induced by the failure of a dam, huge amounts of sediments may be eroded. This results in large-scale modifications of the valley morphology and may drastically increase the resulting damages. The objective of the research is to advance the understanding of sediment transport under dam-break flows. For such highly erosive and transient floods, it is crucial to account explicitly for sediment inertia, and therefore traditional “clear-water” modelling approaches are largely inappropriate. The present approach relies on a two-layer idealisation of the flow behaviour. Separating a clear-water flow region from the underlying sediment bed, the transported sediments are confined in a flow layer of finite thickness, endowed with its proper inertia, density and velocity. The thesis also pinpoints granular dilatancy as an essential mechanism of interaction between the layers. When passing from a solid-like to a fluid-like behaviour as they are entrained by the flow, the eroded sediment grains dilate along the vertical, and this generates vertical exchanges of mass and momentum that should be accounted for. The thesis proceeds first with experimental investigations. Laboratory dam-break waves are reproduced in a dedicated flume, exploring different bed configurations and sediment densities. Imaging observations are used to support the proposed phenomenological description of the flow. Within a shallow-water framework, theoretical and numerical endeavours are then developed to investigate the implications on the flow dynamics of the two essential contributions of the proposed description, i.e. the two-layer flow behaviour, and the effects of granular dilatancy.

Water levels up- and downstream of dams are strongly affected by water levels in the reservoir as well as the discharge of the dam. To ensure that no harm comes to buildings, bridges or agricultural land it is important to ensure that the water level in the reservoir is adjusted to handle large floods. This report studies within what range the water level in the reservoir of the Yayangshan dam, located in Lixian River, can vary without causing any flooding downstream the dam or at the Old and New Babian Bridge located upstream the dam. By calculation of the designed flood, flood routing- and backwater computation, initial water level ranges in the reservoir have been set for the pre-flood, main flood and latter flood season for damages to be avoided. Due to the far distance between the dam site and the bridges, backwater effects had no influence on the limitations of the initial water level in the reservoir.

Incremental damage assessment is a tool used to assess the justification for expensive modifications of inadequate dams. The input data to incremental damage assessment are the output from the breach analysis and flood routing. For this reason, flood routing should be conducted carefully. Distorted results from the flood routing technique or unstable modeling of the problem will distort the results of an incremental damage assessment, because an error in the estimated incremental stage will cause a certain error in the estimated incremental damages. The objectives of this study were (1) to perform a comprehensive survey of the available dam break flood-routing techniques, (2) to evaluate the performance of commonly used flood-routing techniques for predicting failure and no-failure stage, incremental stage, average velocities, and travel times, and (3) to develop a set of recommendations upon which future applications of dam break models can be based. Flood-routing techniques that are evaluated cover dynamic routing as contained in DAMBRK, and kinematic, Muskingum-Cunge, and normal depth storage routing as contained in the Hydrological Engineering Center (HEC 1). These techniques were evaluated against the more accurate two-dimensional flood-routing technique contained in the diffusion hydrodynamic model (DHM). Results and errors from different techniques for different downstream conditions were calculated and conclusions were drawn. The effect of the errors on the incremental stage and the errors in the incremental stage were estimated. Overall, the performance of one-dimensional techniques in predicting peak stages, and assessing a two-feet criterion showed that DAMBRK did best, and normal depth storage and outflow did worst. This overall ranking matches the degree of simplification in representing the true flood-routing situation. However, in some circumstances DAMBRK performed worst, and normal depth storage and outflow outperformed either the Muskingum-Cunge or kinematic techniques. Thus, it is important to understand the specific performance characteristics of all the methods when selecting one for a flood-routing application.

Thesis (Ph.D.)--University of Melbourne, School of Anthropology,Geography and Environmental Studies and the Dept. of Civil and Environmental Engineering, 2006. / Typescript. Includes bibliographical references.

Esse trabalho identificou, testou e aprimorou modelos de propagação de vazão simplificados a fim de verificar as vantagens e desvantagens dos modelos. As soluções apresentadas por esses modelos foram testadas com um modelo hidrodinâmico completo, considerado nesse trabalho como resultados ideias. Os modelos hidrodinâmicos simplificados testados foram: Um modelo não linear de Onda Cinemática, o modelo Muskingum-Cunge linear, duas versões do modelo Muskingum-Cunge não linar, o modelo Muskingum-Cunge modificado por Todini e o modelo IPHS1. O modelo hidrodinâmico completo utilizado nesse trabalho foi o modelo HEC-RAS. Desenvolveu-se ainda uma metodologia para representar o efeito da planície de inundação. Essa metodologia foi implementada nos modelos hidrodinâmicos simplificados. Para avaliar o comportamento dos diferentes modelos de propagação disponíveis foram criados testes numéricos em que foram aplicados os diferentes modelos, com variação de características dos hidrogramas sintético de entrada, das características do leito do rio e da planície de inundação, e dos critérios de discretização temporal e espacial. A avaliação dos resultados foi feita através dos erros de conservação de volume, de vazão de pico e de tempo de ocorrência da vazão de pico. Além disso, também foram considerados, em alguns testes, os critérios de aplicabilidade de Ponce para onda cinemática e difusão além da formulação do Δx ideal proposto por Fread. Os resultados mostram que o modelo Muskingum-Cunge Todini, modificado para representar o efeito da planície de inundação, é muito promissor. Esse modelo apresentou resultados que se aproximaram muito dos resultados obtidos pelo HEC-RAS, enquanto os outros modelos hidrodinâmicos simplificados apresentaram resultados piores. Com relação aos critérios de aplicabilidade, recomenda-se o uso de um Δx três vezes menor do que o valor sugerido por Fread. Além disso, pode-se concluir que os modelos simplificados podem ser utilizados fora dos limites de aplicabilidade sugeridos por Ponce. / This work has identified, tested and improved simplified flood routing models to verify the advantages and disadvantages presented. The solutions provided by these models were tested by using a full hydrodynamic model considered in this work as an ideal result. The simplified hydrodynamic models used were: A variable parameter kinematics wave model, the Muskingum-Cunge flood routing model, the variable parameter Muskingum-Cunge flood routing model (three and four points scheme) the Muskingum-Cunge modified by Todini (MCT) and the model IPHS1. The full hydrodynamic model used was HEC-RAS. It was also proposed a procedure to represent the effect of the floodplain rivers. To evaluate the behavior of different flood routing models numerical tests were created and were applied to then. The characteristics of synthetic inflow hydrographs, the characteristics of riverbed and floodplain, and the criteria for temporal and spatial discretization were perturbed. The evaluation of the results was made through the errors of conservation of volume, peak flow and time of occurrence of peak flow. Moreover, it was also considered, in some tests, applicability criteria recommended by some authors for different models, such as models of kinematic flood wave and diffusive flood wave. The results show that the Muskingum Cunge Todini, modified to represent the effect of the floodplain flow is very promising. Finally, it is also shown that this model closely approaches the full Saint Venant equation solution (HEC-RAS). The others models were worse than HEC-RAS and MCT. About applicability criteria, it recommends the use of the Δx three times smaller than the value suggested by Fread. Moreover, the simplified hydrodynamic models can be used outside limits of applicability suggested by Ponce about kinematic and diffusive wave.