This thesis is concerned with the study of flood plains and the flood hazard in England and Wales. Flood plains form an important resource which is only successfully utilised by the reduction of the flood hazard. The extent of the flood hazard in a study area, the problem of assessing flood damage, and the perception of the flood hazard and adjustment to it, are all investigated in order to suggest ways in which floods may be reduced. The flood hazard is a widespread phenomenon affecting most parts of the study area of this dissertation which consists of the Severn, Wye and Usk catchments, and a group of catchments in Glamorgan. Most major settlements extend into flood risk areas, and require flood alleviation programmes. Flood damage assessment is found to be a major problem which adversely affects our ability to optimise flood plain resource use. The assessment of potential flood damages based directly upon actual damage data is found to be impracticable. Instead, standard flood damage information, based upon actual flood damage data, is developed for residences. This allows the computation of potential residential flood damage. The important problem of flood hazard adjustment is considered in a study of the preconditions of flood hazard perception and individual and community adjustment at study sites. The adjustment process is found to be conditioned by flood experience, spatial variations in the hazard, access to information and adjustment evaluation, whilst personality traits do not appear to be directly important. At the community level, unconventional combinations of adjustment are found to be of value, although low levels of public awareness of flood risk pose a serious problem. Flood hazard reduction can be improved in this country by explicit management of flood plains, by improved economic analyses, and by the application of behavioural principles.

Flooding is an increasing problem in metropolitan Seoul and the management of floods and floodplains is a neglected priority for urban planning. The causes of flooding are triggered by heavy rain, or tropical storms, especially under conditions where soils are already saturated. Rivers overflow into surrounding built-up areas, bringing death and injury to people as well as considerable damage to buildings. Among the residents of Seoul, flooding is most often attributed to failure of the pumping system that is the city’s chief line of defense against inundation. However, other analysts believe that a major reduction in the amount of green open spaces is contributing to increased flood risks. The impacts of these events encompass tragic loss of life, damage to built and natural environments, and massive disruption to the lives of affected populations in the short term. In the longer term, the recovery and post-recovery phases can also cause distress, disruption, health problems, and financial hardship lasting many years. This professional report tries to focus the impact of flood on environment along Han River and Seoul, Korea’s flood prone area. Furthermore, this report prepares maps and its output that can be used during flood emergency in inundated areas. Arc GIS 10 software is used to analyze impact of flood in Seoul, Korea. / text

Flash flooding, as a result of excessive rainfall in a short period, is considered as one of the worst environmental hazards in arid regions. Areas located in the western provinces of Saudi Arabia have experienced catastrophic floods. Geomorphologic evaluation of hydrographic basins provides necessary information to define basins with flood hazard potential in arid regions, especially where long-term field observations are scarce and limited. Six large basins (from North to South: Yanbu, Rabigh, Khulais, El-Qunfza, Baish and Jizan) were selected for this study because they have large surface areas and they encompass high capacity dams at their downstream areas. Geographic Information System (GIS) and remote sensing techniques were applied to conduct detailed morphometric analysis of these basins. The six basins were further divided into 203 sub-basins based on their drainage density. The morphometric parameters of the six basins and their associated 203 sub-basins were calculated to estimate the degree of flood hazard by combining normalized values of these parameters. Thus, potential flood hazard maps were produced from the estimated hazard degree. Furthermore, peak runoff discharge of the six basins and sub-basins were estimated using the Snyder Unit Hydrograph and three empirical models (Nouh’s model, Farquharson’s model and Al-Subai’s model) developed for Saudi Arabia. Additionally, recommendations for flood mitigation plans and water management schemes along these basins were further discussed.

Jamaica, the third largest island in the Caribbean, has been affected significantly by flooding and flood-related damage. Hence assessing the probability of flooding and susceptibility of a place to flood hazard has become a vital part of planning and development. In addition to heavy rainfall from tropical storms and Atlantic hurricanes, several terrestrial factors play significant roles in flooding, including local geology, geomorphology, hydrology and land-use. In this study, a GIS-based multi-criteria statistical methodology was developed to quantify hazard potential and to map flood characteristics. Fourteen factors potentially responsible for flooding were identified and used as initial input in a hybrid model that combined principal component analysis with logistic regression and frequency distribution analysis. Of these factors, seven explained 65 % of the variation in the data: elevation, slope angle, slope aspect, flow accumulation, a topographic wetness index, proximity to a stream network, and hydro-stratigraphic units. These were used to prepare the island’s first map of flood hazard potential. Hazard potential was classified from very low to very high, nearly one-fifth (19.4 %) of the island was included within high or very high flood hazard zones. Further analysis revealed that areas prone to flooding are often low-lying and flat, or have shallow north- or northwest-facing slopes, are in close proximity to the stream network, and are situated on underlying impermeable lithology. The multi-criteria hybrid approach developed could classify 86.8 % of flood events correctly and produced a satisfactory validation result based on the receiver operating characteristic curve. The statistical method can be easily repeated and refined upon the availability of additional or higher quality data such as a high resolution digital elevation model. Additionally, the approach used in this study can be adopted to evaluate flood hazard in countries with similar characteristics, landscapes and climatic conditions, such as other Caribbean or Pacific Small Island Developing States.

Future changes in climate and land use are likely to affect catchment hydrological responses and consequently influence the amount of runoff reaching roads. Blockages and damage to under-dimensioned infrastructure can be extremely costly for the regions affected. This study aims to produce scientifically well-founded suggestions on adaptation of road drainage systems to climate changes resulting in more frequent floods. This thesis demonstrates the need to integrate aspects of climate change and land use impacts into the planning and practice of road construction and maintenance in Sweden. Tools such as hydrological models are needed to assess impacts on discharge dynamics. Identifying a ‘best’ practically performing hydrological model is often difficult due to the potential influence of modeller subjectivity on calibration procedure, parameter selection, etc. Hydrological models may need to be selected on a case-by-case basis and have their performance evaluated on an application-by-application basis. The work presented here began by examining current practice for road drainage systems in Sweden. Various hydrological models were then used to calculate the runoff from a catchment adjacent to a road and estimate changes in peak discharge and total runoff resulting from simulated land use measures. Overall, the results indicate that the specific effect of land use measures on catchment discharge depend on their spatial distribution and on the size and timing of storm events. Scenarios comprising a changing climate up to 2050 or to 2100 and forest clear-cutting were used to determine whether the current design of road drainage construction is sufficient for future conditions. Based on the findings, the approach developed can be used for similar studies, e.g. by the Swedish Transport Administration in dimensioning future road drainage structures to provide safe and robust infrastructure. Furthermore, a statistical method was developed for estimating and mapping flood hazard probability along roads using road and catchment characteristics. The method allows flood hazards to be estimated and provides insight into the relative roles of landscape characteristics in determining road-related flood hazards. Overall, this method provides an efficient way to estimate flooding hazards and to inform the planning of future roadways and the maintenance of existing roadways. / <p>QC 20140130</p>

Este trabalho teve objetivo estabelecer o zoneamento das áreas de risco a inundação da área urbana do município de Porto Xavier/RS, localizado na margem esquerda do rio Uruguai, na região noroeste do estado do Rio Grande do Sul. Para atingir este objetivo foi organizado um inventário sobre as inundações ocorridas entre os anos de 1980 a 2010; identificou-se a porção da área urbana suscetível à inundação determinando o grau de perigo e os diferentes graus de vulnerabilidade através das características das ocupações; e, a partir da correlação entre o grau de perigo e vulnerabilidade, foi determinado o grau de risco das áreas afetadas. Os procedimentos metodológicos envolvem quatro etapas: fundamentação teórica e levantamento de dados; análise das condições naturais e sociais do desastre; elaboração dos mapas base do perigo e da vulnerabilidade e; análise dos resultados, zoneamento e elaboração do mapa de risco. Os materiais utilizados foram carta topográfica, imagens de satélite, GPS, dados hidrológicos e documentos. Os resultados possibilitaram estimar dois graus de perigo, um relacionado as inundações recorrentes que definiram as áreas de alto perigo, outro relacionado a inundação extraordinária de 1983, que delimitou a área de baixo perigo. A vulnerabilidade foi estabelecia em três graus a partir do padrão construtivo das residências e infraestrutura pública. Por fim, foi possível estabelecer três graus de risco a partir da correlação dos dados. Os resultados deste trabalho podem vir a auxiliar outros trabalhos de pesquisa e permitir propostas de planejamento e ordenamento da infraestrutura urbana de Porto Xavier. / This work has the objective to establish the zoning of flood risk areas to the urban area of Porto Xavier / RS, located on the left bank of the Uruguay River, in the northwestern region of the state of Rio Grande do Sul. To achieve this goal was an organized inventory of flooding between the years 1980 to 2010, identified the portion of the urban area susceptible to flooding by determining the degree of hazard and the different degrees of vulnerability through the characteristics of occupations; finally from the correlation between the degree of hazard and vulnerability, we determined the degree of risk of the affected areas. The methodological procedures involve four steps: theoretical basis and data collection, analysis of natural and social conditions of the disaster, preparation of base maps of danger and vulnerability and, analysis of results, preparation of zoning and risk map. The materials used were topographic maps, satellite imagery, GPS, hydrological data and documents. It was possible to estimate two degrees of danger, a related recurrent floods that defined areas of high danger, another related the extraordinary flood of 1983, which delimited the area of low hazard. The vulnerability has been established in three degrees from the constructive pattern of homes and public infrastructure. Finally, it was possible to establish three degrees of risk from the correlation of the data. The results of this study may well help other research papers and proposals to allow the planning and management of urban infrastructure of Porto Xavier/RS.

Este trabalho teve objetivo estabelecer o zoneamento das áreas de risco a inundação da área urbana do município de Porto Xavier/RS, localizado na margem esquerda do rio Uruguai, na região noroeste do estado do Rio Grande do Sul. Para atingir este objetivo foi organizado um inventário sobre as inundações ocorridas entre os anos de 1980 a 2010; identificou-se a porção da área urbana suscetível à inundação determinando o grau de perigo e os diferentes graus de vulnerabilidade através das características das ocupações; e, a partir da correlação entre o grau de perigo e vulnerabilidade, foi determinado o grau de risco das áreas afetadas. Os procedimentos metodológicos envolvem quatro etapas: fundamentação teórica e levantamento de dados; análise das condições naturais e sociais do desastre; elaboração dos mapas base do perigo e da vulnerabilidade e; análise dos resultados, zoneamento e elaboração do mapa de risco. Os materiais utilizados foram carta topográfica, imagens de satélite, GPS, dados hidrológicos e documentos. Os resultados possibilitaram estimar dois graus de perigo, um relacionado as inundações recorrentes que definiram as áreas de alto perigo, outro relacionado a inundação extraordinária de 1983, que delimitou a área de baixo perigo. A vulnerabilidade foi estabelecia em três graus a partir do padrão construtivo das residências e infraestrutura pública. Por fim, foi possível estabelecer três graus de risco a partir da correlação dos dados. Os resultados deste trabalho podem vir a auxiliar outros trabalhos de pesquisa e permitir propostas de planejamento e ordenamento da infraestrutura urbana de Porto Xavier. / This work has the objective to establish the zoning of flood risk areas to the urban area of Porto Xavier / RS, located on the left bank of the Uruguay River, in the northwestern region of the state of Rio Grande do Sul. To achieve this goal was an organized inventory of flooding between the years 1980 to 2010, identified the portion of the urban area susceptible to flooding by determining the degree of hazard and the different degrees of vulnerability through the characteristics of occupations; finally from the correlation between the degree of hazard and vulnerability, we determined the degree of risk of the affected areas. The methodological procedures involve four steps: theoretical basis and data collection, analysis of natural and social conditions of the disaster, preparation of base maps of danger and vulnerability and, analysis of results, preparation of zoning and risk map. The materials used were topographic maps, satellite imagery, GPS, hydrological data and documents. It was possible to estimate two degrees of danger, a related recurrent floods that defined areas of high danger, another related the extraordinary flood of 1983, which delimited the area of low hazard. The vulnerability has been established in three degrees from the constructive pattern of homes and public infrastructure. Finally, it was possible to establish three degrees of risk from the correlation of the data. The results of this study may well help other research papers and proposals to allow the planning and management of urban infrastructure of Porto Xavier/RS.

Este trabalho teve objetivo estabelecer o zoneamento das áreas de risco a inundação da área urbana do município de Porto Xavier/RS, localizado na margem esquerda do rio Uruguai, na região noroeste do estado do Rio Grande do Sul. Para atingir este objetivo foi organizado um inventário sobre as inundações ocorridas entre os anos de 1980 a 2010; identificou-se a porção da área urbana suscetível à inundação determinando o grau de perigo e os diferentes graus de vulnerabilidade através das características das ocupações; e, a partir da correlação entre o grau de perigo e vulnerabilidade, foi determinado o grau de risco das áreas afetadas. Os procedimentos metodológicos envolvem quatro etapas: fundamentação teórica e levantamento de dados; análise das condições naturais e sociais do desastre; elaboração dos mapas base do perigo e da vulnerabilidade e; análise dos resultados, zoneamento e elaboração do mapa de risco. Os materiais utilizados foram carta topográfica, imagens de satélite, GPS, dados hidrológicos e documentos. Os resultados possibilitaram estimar dois graus de perigo, um relacionado as inundações recorrentes que definiram as áreas de alto perigo, outro relacionado a inundação extraordinária de 1983, que delimitou a área de baixo perigo. A vulnerabilidade foi estabelecia em três graus a partir do padrão construtivo das residências e infraestrutura pública. Por fim, foi possível estabelecer três graus de risco a partir da correlação dos dados. Os resultados deste trabalho podem vir a auxiliar outros trabalhos de pesquisa e permitir propostas de planejamento e ordenamento da infraestrutura urbana de Porto Xavier. / This work has the objective to establish the zoning of flood risk areas to the urban area of Porto Xavier / RS, located on the left bank of the Uruguay River, in the northwestern region of the state of Rio Grande do Sul. To achieve this goal was an organized inventory of flooding between the years 1980 to 2010, identified the portion of the urban area susceptible to flooding by determining the degree of hazard and the different degrees of vulnerability through the characteristics of occupations; finally from the correlation between the degree of hazard and vulnerability, we determined the degree of risk of the affected areas. The methodological procedures involve four steps: theoretical basis and data collection, analysis of natural and social conditions of the disaster, preparation of base maps of danger and vulnerability and, analysis of results, preparation of zoning and risk map. The materials used were topographic maps, satellite imagery, GPS, hydrological data and documents. It was possible to estimate two degrees of danger, a related recurrent floods that defined areas of high danger, another related the extraordinary flood of 1983, which delimited the area of low hazard. The vulnerability has been established in three degrees from the constructive pattern of homes and public infrastructure. Finally, it was possible to establish three degrees of risk from the correlation of the data. The results of this study may well help other research papers and proposals to allow the planning and management of urban infrastructure of Porto Xavier/RS.

This thesis deals with flood maps and their use in the context of property insurance. There are flood maps presented in comparison with similar projects of the European Union, the flood hazard maps and flood risk maps. There is also assessed the impact of flood maps on Flood Prevention Strategy in the Czech Republic. This thesis analyzes the offers insurance companies in the property insurance according to 4 risk flood zones. Finally, it evaluates the importance of flood maps not only from the perspective of insurance companies, but also from the perspective of others (people, companies etc.).

The primary motivation of this study is to estimate the current and future flood hazard throughout the Sacramento-San Joaquin Delta in the context of sea-level rise. I also analyzed the effects of storm surge and river flow on extreme events to better understand how these events originate and vary spatially and in time. To address this goal, I combined digital water level records (primarily 1983-present) with archival data collected by the California Department of Water Resources (1929-1983) to reevaluate flood hazard in the Delta and investigate the possible sensitivity of the region different sea-level rise projections. Available archival records from 8 stations were digitized and quality assured, producing a length of record that approximately doubles previously available data. The records were then analyzed using the Generalized Extreme Value (GEV) and Generalized Pareto distributions (GPD). Additionally, the contribution of storm surge and river flow to water level events at each station was assessed using a regression approach. Finally, the impact of future sea-level rise on the 1-, 10-, 100-, and 500-year return period water level was assessed through 2150, using recently published sea-level rise projections. Results show that the total water level (tides + storm surge + river flow) during the 100-year event increases by roughly 0.5m between San Francisco and interior Delta stations such as Rio Vista and Venice Island. For present-day sea-levels, the 100y event increased from 2.59 meters at San Francisco to 3.08 meters at Rio Vista (river-km 100from the Golden Gate), using the GPD approach (relative to NAVD-88). Further upstream, river influence becomes an increasingly important component of high-water events. At Walnut Grove (river-km 123), more than 80% of high-water events were forced by river flow, as estimated by the Net Delta Outflow Index (on average). The water level caused by river flow was significantly higher than coastal surge, and the 100y event was estimated to be 4.71 meters (NAVD-88). Confidence intervals and uncertainty in the flood hazard increases as stations become more influenced by river flow, likely because river flow is more variable from year-to-year than the combination of coastal tides and storm surge. The largest high-water events measured in the Delta typically receive a larger contribution from river flow than smaller high-water events. Interestingly, GEV and GPD results are consistent with an earlier assessment of flood hazard in the Delta from the 1970s. Results show that future flood hazard is likely to be significantly influenced by sea-level rise, particularly in the western Delta region which is more coastally influenced. Under the assumption that sea-level rise will linearly add to existing flood hazard, I find that the 100-year event could reach 4.09 meters at San Francisco and 6.21 meters at Walnut Grove by the end of the century, under the “Intermediate-High” sea-level rise scenario. Based on available flood datums, the first flood stage datum may get exceeded once every 10 years by 2150, under the Intermediate scenario. However, since much of the interior Delta is subsiding, individual locations may reach actionable hazard levels earlier. More analysis with sea-level rise, changing precipitation patterns, and vertical land motion should be done to increase the accuracy of projected flood hazards.