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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.
71

An investigation of town relocation as a part of flood control planning

Deines, Vernon P January 1962 (has links)
No description available.
72

Šetření závislostí vybraných parametrů protipovodňových opatření ve vybraných obcích v Ústeckém kraji v povodí Ohře a Labe. / Investigation of the dependence of selected parameters of flood control measures in selected municipalities in the Ústí nad Labem region in Ohře and Elbe river basin.

PALÁNOVÁ, Jana January 2019 (has links)
This thesis discusses the relationship between the population endangered by floods and the funds allocated to flood control measures in the Ústí nad Labem Region in the drainage basin of the Ohře and Elbe rivers, the general characteristics of flood control issues in the Czech Republic and particularly in the Ústí nad Labem Region, as well as other parameters that impact flood issues. In order to achieve its objectives, this dissertation utilised data collection and general theoretical and data file processing methods. A significant step was the application of two-dimensional statistical analyses, specifically regressive and correlation analyses. Another selected method was SWOT analysis. Solving the described research problems was associated with the process of verifying the following hypotheses: Hypothesis H1: The statistical dependence between the number of endangered inhabitants and the amount of funds for flood protection is based on linear regression. This hypothesis was confirmed, and the benefit of the confirmation of the hypothesis is also the determination of the significant role of the number of endangered inhabitants in ascertaining the amount of funds for flood control measures. Hypothesis H2: The statistical dependence between the number of the endangered inhabitants and the amount of funds for flood control measures is based on a strong positive correlation. This hypothesis was partially confirmed. A positive correlation was proved, though only a weak one rather than the expected strong correlation. This result indicates the necessity of not ignoring the examination of all parameters that affect approaches to the protection of the population in the municipalities. The verification of hypotheses H1 and H2 and the performance of a SWOT analysis made it possible to make other partial conclusions as well. Although the dissertation discussed floods at the Q100 limit, floods that correspond to level Q10 were proved to occur most frequently in the Ústí nad Labem Region. It is also for this reason that many flood control measures in the municipalities in this region are based on this finding. The flood control measures implemented at levels Q20-Q100 seem to be adequate.
73

Análise de sistemas complexos de drenagem urbana. / Urban drainage complex systems analysis.

Ros, Deise Assenci 11 April 2012 (has links)
Este tese objetiva analisar sistemas complexos de drenagem urbana visando definir uma técnica de dimensionamento de obras de reservação. Nesta pesquisa, sistemas complexos de drenagem urbana são aqueles compostos por diversos reservatórios de detenção, distribuídos numa rede de canais formada por vários trechos. Este tipo de sistema é típico em megacidades. O dimensionamento das obras de reservação em redes complexas possui uma série de condicionantes, ou seja, ele é função de diversas variáveis, muitas delas de caráter aleatório. A principal delas é a chuva de projeto. Esta tese desenvolve uma técnica conjunta de simulação e de cenarização de chuvas com defasagem no tempo e no espaço para tratar a questão da variabilidade da precipitação de projeto. Do ponto de vista hidráulico, existem outras condicionantes para dimensionamento, dependendo do tipo de reservação adotada. Basicamente existem dois tipos de reservatórios para controle de cheias em cidades, os reservatórios on-line e os reservatórios off-line, cada um apresenta características próprias de desempenho que devem ser consideradas quando o sistema é dimensionado. Esta tese apresenta uma técnica de dimensionamento iterativa que permite compor um conjunto de reservatórios (on-line ou off-line) que atendem ao grau de proteção requerido para uma bacia urbana. Os métodos foram avaliados em bacias hipotéticas típicas de grandes cidades. Desse modo, uma série de variáveis foi contemplada, na tentativa de generalizar o método proposto. Os resultados mostraram a importância da cenarização da chuva de projeto. É praticamente inviável trabalhar hoje com as premissas clássicas para definir a chuva de projeto, a cenarização permite avaliar o desempenho do sistema segundo diferentes condições hidrológicas. Finalmente, ressalta-se que esta tese apresenta um enfoque novo de dimensionamento e que certamente irá requerer novas investigações e aperfeiçoamentos. Ela procura trazer à discussão a implementação de novos paradigmas para desenvolvimento de projetos no campo da drenagem urbana em grandes cidades. / This thesis aims to analyze urban drainage complex systems in order to define a technique for the design of detention ponds structures. In this study, Urban Drainage Complex Systems are those composed of several detention ponds, distributed in a network of channels formed by various reaches. This type of system is typical in megacities. The design of the reservation structures in complex networks has a number of constraints, in other words, it is a function of several variables, many of them are randomness. The main one is the design rainfall. This thesis develops a joint technical of simulation and the design rainfall scenario generation delayed in time and space to deal with the variability of design precipitation. From the hydrological point of view, there are other constraints for scaling, depending on the type of reservation adopted. There are basically two types of detention ponds for flood control in cities, on-line detention and off-line detention, each performance has its own characteristics that must be considered when the system is designed. This thesis presents an iterative design technique for composing a set of detention ponds (on-line or off-line) that satisfy the degree of protection required for an urban watershed. The methods were evaluated in hypothetical basins typical of large cities. Thus, a series of variables was included in an attempt to generalize the proposed method. The results showed the importance of design rainfall scenario generation. It is practically impossible to work today with the classical assumptions to define the design rainfall; the scenario generation allows evaluating system performance under different hydrological conditions. Finally, we emphasize that this thesis presents a new approach to sizing and it certainly will require further research and improvements. It seeks to bring the discussion to implementation of new paradigms for development projects in the field of urban drainage in large cities.
74

Estudo das técnicas de controle de cheias em usinas hidroelétricas com aplicação de novas abordagens / The food control techniques in hydroelectric power plants

Castro, Marco Aurélio de Almeida 04 April 2003 (has links)
No sistema hidrotérmico de potência brasileiro predomina a utilização de fontes hidráulicas que correspondem à cerca de 92% da geração de energia. Assim, os reservatórios das usinas hidroelétricas assumem o importante papel de reguladores das vazões de muitos rios. O objetivo do controle de cheias é regular estas vazões evitando danos à própria usina, às regiões a jusante e às cidades ribeirinhas. As técnicas de controle de cheias em usinas hidroelétricas baseiam-se em alocação de volumes vazios nos reservatórios, os chamados volumes de espera, a fim de amortecer futuras cheias. Porém estas técnicas necessitam de profundos estudos e análises, pois a permanência destes volumes vazios prejudica a geração de energia. Neste trabalho faz-se o estudo de quatro metodologias para a alocação do volume de espera, algumas entre as mais utilizadas e outras inovadoras, as quais são: (i) Método da Curva Volume X Duração, o primeiro método aplicado no setor elétrico brasileiro; (ii) Método da Curva Volume X Duração por Janelas, que introduz o conceito de janelas aplicados ao método anterior; (iii) Método das Trajetórias Críticas, atualmente muito aplicado no setor elétrico brasileiro e que se baseia em um algoritmo recursivo; (iv) Método das Equações Diferencias Estocásticas, que modela a onda de cheia como um modelo de difusão de Markov. As metodologias são aplicadas a usinas hidroelétricas do Sistema Hidroelétrico Brasileiro e os resultados são comparados, considerando o impacto causado pela alocação dos volumes de espera à geração de energia. / In the Brazilian hydrothermal power system the use of hydropower corresponds to about 92% of the total energy generation. Hence the reservoirs of the hydroelectric power plants assume the important role of regulating the water flow of many rivers. The objective of flood control is to regulate the power plants releases preventing damages to the plants themselves, to downstream regions and to marginal cities. The food control techniques in hydroelectric power plants are based on the allocation of empty volumes in the reservoirs, in order to accommodate future water inflow peaks. As the maintenance of these empty volumes harms the energy generation, the techniques applied to their determination need careful studies and analyses. In this work four methodologies to specify the needed empty volumes are investigated: (i) Method of Curve Volume X Duration, the first method applied in the Brazilian Power System; (ii) Method of Curve Volume X Duration by Windows which applies the concept of time windows to the method (i); (iii) Method of the Critical Trajectories, currently very applied in the Brazilian Power System, which is based on a recursive algorithm; (iv) Method of the Stochastic Differentiate Equations which shapes the water inflows peaks as a Markov Diffusion Model. The methodologies are applied to hydroelectric plants of the Brazilian Hydroelectric System, determining different empty volumes. The impacts of these different empty volumes on the energy generation are evaluated throughout simulation studies.
75

Evaluating the Impact and Distribution of Stormwater Green Infrastructure on Watershed Outflow

Fahy, Benjamin 02 January 2019 (has links)
Green Stormwater Infrastructure (GSI) has become a popular method for flood mitigation as it can prevent runoff from entering streams during heavy precipitation. In this study, a recently developed neighborhood in Gresham, Oregon hosts a comparison of various GSI projects on runoff dynamics. The study site includes dispersed GSI (rain gardens, retention chambers, green streets) and centralized GSI (bioswales, detention ponds, detention pipes). For the 2017-2018 water year, hourly rainfall and observed discharge data is used to calibrate the EPA's Stormwater Management Model to simulate rainfall-runoff dynamics, achieving a Nash-Sutcliffe efficiency of 0.75 and Probability Bias statistic of 3.3%. A synthetic scenario analysis quantifies the impact of the study site GSI and compares dispersed and centralized arrangements. Each test was performed under four precipitation scenarios (of differing intensity and duration) for four metrics: runoff ratio, peak discharge, lag time, and flashiness. Design structure has significant impacts, reducing runoff ratio 10 to 20%, reducing peak discharge 26 to 68%, and reducing flashiness index 56 to 70%. There was a reverse impact on lag time, increasing it to 50 to 80%. Distributed GSI outperform centralized structures for all metrics, reducing runoff ratio 22 to 32%, reducing peak discharge 67 to 69%, increasing lag time 133 to 500%, and reducing flashiness index between 32 and 62%. This research serves as a basis for researchers and stormwater managers to understand potential impact of GSI on reducing runoff and downstream flooding in small urban watersheds with frequent rain.
76

Design flood estimation for ungauged catchments in Victoria : ordinary and generalised least squares methods compared

Haddad, Khaled, University of Western Sydney, College of Health and Science, School of Engineering January 2008 (has links)
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. / Master of Engineering (Honours)
77

Reconstructing the levees : the politics of flooding in nineteenth-century Louisiana /

Poe, Cynthia R. January 1900 (has links)
Thesis (Ph.D.)--University of Wisconsin--Madison, 2006. / Includes bibliographical references (p. 265-291). Also available on the Internet.
78

Quantitative Flood Risk Assessment With Application In Turkey

Keskin, Fatih 01 September 2012 (has links) (PDF)
Floods can result in enormous causalities and huge economic losses in urban and rural regions. In recent years, while assessing the damage, risk analysis and assessment has become an important tool in addressing uncertainty in flood hazards. The lack of knowledge about the water extend, water depth, water velocity and potential damage in case of flood increase the vulnerability of the people to disasters in the flood region. Especially this information is valuable for city planners and decision makers. In case of new settlement area selection, correct decision can be taken by the help of this information. This type of information can be taken from hydraulic models as 1D or 2D. On the other hand, two dimensional (2D) hydraulic modeling becomes a need with increasing trends of very high speed computers and models instead of one dimensional (1D) ones. The ability of solving complex structures within few minutes enhances the use of 2D modeling with the integration of wave motion. In addressing the uncertainty, GIS becomes an important tool in risk assessment by integrating the flood depth, extend and vulnerability issues for definition of the quantitative risk. In this study, 1D and 2D hydraulic modeling is applied and combined with the quantitative vulnerability factors in Dalaman Plain-Turkey. Results show that the area is vulnerable to flood and high monetary damages can be seen in case a flood in the region.
79

出水による破壊機会の減少による河道内樹林化

辻本, 哲郎, TSUJIMOTO, Tetsuro, 村上, 陽子, MURAKAMI, Yoko, 安井, 辰弥, YASUI, Tatsuya 02 1900 (has links)
No description available.
80

Modeling Reallocation of Reservoir Storage Capacity Between Flood Control and Conservation Purposes

Kim, Tae Jin 2009 May 1900 (has links)
Interest in converting portions of the large volumes of flood control storage capacity in federal multiple-purpose reservoirs in Texas and elsewhere to water supply and other conservation purposes has been growing for some time. Evaluation of storage reallocations involving tradeoffs between flood control and conservation purposes in multiple-purpose, multiple-reservoir systems represents a new area for applying the Water Rights Analysis Package (WRAP) and Texas Water Availability Modeling (WAM) System. A system of 12 multiple-purpose reservoirs operated by the U.S. Army Corps of Engineers (USACE) and Brazos River Authority (BRA) was adopted as a case study in this research to develop and test expanded WRAP/WAM-based methods for analyzing modifications in reservoir storage allocations and related system operations. The research consisted of the following tasks: ? The Brazos River Basin WRAP input dataset from the Texas WAM System (Brazos WAM) has a 1940-1997 hydrologic period-of-analysis. The research included developing and applying methods to extend the period-of-analysis to 1900-2007 providing a better representation of river basin hydrology. The methodology developed could potentially be used to update the other river basin datasets in the statewide WAM System. ? The Brazos WAM has 3,830 control points, 670 reservoirs, and hundreds of water rights. The research included developing and applying methods to create a much easier-to-apply condensed dataset focused on the USACE/BRA reservoir system and associated water rights that have only 48 control points and 14 reservoirs. ? The WRAP/WAM System was developed based on a monthly computational time step. The research included applying developmental methodologies for converting a monthly model to a daily time step that includes disaggregation of monthly naturalized flows to daily flows, calibration of flow routing coefficients, and incorporation of forecasting in the simulation. ? The WRAP/WAM System is designed for assessing water supply reliabilities and stream flow and storage frequencies from the perspective of conservative purposes. The research added flood risk indices to the WRAP modeling system in order to address tradeoffs between flood control and conservation purposes. ? The WRAP/WAM-based simulation study performed with the modified WAM dataset developed in this research demonstrates the improvements in water supply capabilities and tradeoffs with flood control associated with various reservoir storage reallocation strategies and other modifications in reservoir system operations.

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