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Flood Risk (flood + risk)
Terms modified by Flood Risk Selected AbstractsEvidence for Changing Flood Risk in New England Since the Late 20th Century,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 2 2009Mathias J. Collins Abstract:, Long-term flow records for watersheds with minimal human influence have shown trends in recent decades toward increasing streamflow at regional and national scales, especially for low flow quantiles like the annual minimum and annual median flows. Trends for high flow quantiles are less clear, despite recent research showing increased precipitation in the conterminous United States over the last century that has been brought about primarily by an increased frequency and intensity of events in the upper 10th percentile of the daily precipitation distribution , particularly in the Northeast. This study investigates trends in 28 long-term annual flood series for New England watersheds with dominantly natural streamflow. The flood series are an average of 75 years in length and are continuous through 2006. Twenty-five series show upward trends via the nonparametric Mann-Kendall test, 40% (10) of which are statistically significant (p < 0.1). Moreover, an average standardized departures series for 23 of the study gages indicates that increasing flood magnitudes in New England occurred as a step change around 1970. The timing of this is broadly synchronous with a phase change in the low frequency variability of the North Atlantic Oscillation, a prominent upper atmospheric circulation pattern that is known to effect climate variability along the United States east coast. Identifiable hydroclimatic shifts should be considered when the affected flow records are used for flood frequency analyses. Special treatment of the flood series can improve the analyses and provide better estimates of flood magnitudes and frequencies under the prevailing hydroclimatic condition. [source] An environment for prosperity and quality living accommodating growth in the Thames ValleyCORPORATE SOCIAL RESPONSIBILITY AND ENVIRONMENTAL MANAGEMENT, Issue 1 2004Hugh Howes The Thames Valley is seen as the powerhouse of the British economy, and one of the best performing regions in Europe. This economic base offers opportunities for expansion with the potential for it to become the knowledge capital of Europe. Business interests view the area as a highly desirable location, not only because of its markets, skills and proximity to the City and Heathrow but also because of its high quality environment. Companies, however, complain of skills shortages, traffic congestion, lack of suitable premises and housing that is affordable to the workforce. Much of the Thames Valley is either Green Belt or Areas of Outstanding Natural Beauty. Furthermore, the availability of future water supplies, the maintenance of the quality of water in the rivers and managing flood risk are also likely to act as constraints on development in the future. How economic growth is to be achieved with minimal additional development and without detriment to the environment is the central question that is likely to dominate planning in the this region over the next few years. Is it possible to achieve more with existing resources? Copyright © 2004 John Wiley & Sons, Ltd and ERP Environment. [source] ,It'll never happen to me': understanding public awareness of local flood riskDISASTERS, Issue 2 2008Kate Burningham Following the severe flood events of 1998 and 2000, the United Kingdom's Environment Agency prioritised the need to increase public flood risk awareness. Drawing on data collected during research undertaken for the Environment Agency, this paper contributes to understanding of one aspect of flood awareness: people's recognition that their property is in an area that is potentially at risk of flooding. Quantitative analyses indicate that class is the most influential factor in predicting flood risk awareness, followed by flood experience and length of time in residence. There are also significant area differences. Our qualitative work explores how those defined as ,at risk' account for their lack of awareness or concern about their risk status. We conclude that the problem is often not simply a lack of awareness, but rather, assessments of local risk based on experience that underestimate the impact of rare or extreme events. We underline the importance of engaging with local perspectives on risk and making local people part of ,awareness-raising' processes. [source] Global evidence that deforestation amplifies flood risk and severity in the developing worldGLOBAL CHANGE BIOLOGY, Issue 11 2007COREY J. A. BRADSHAW Abstract With the wide acceptance of forest-protection policies in the developing world comes a requirement for clear demonstrations of how deforestation may erode human well-being and economies. For centuries, it has been believed that forests provide protection against flooding. However, such claims have given rise to a heated polemic, and broad-scale quantitative evidence of the possible role of forests in flood protection has not been forthcoming. Using data collected from 1990 to 2000 from 56 developing countries, we show using generalized linear and mixed-effects models contrasted with information-theoretic measures of parsimony that flood frequency is negatively correlated with the amount of remaining natural forest and positively correlated with natural forest area loss (after controlling for rainfall, slope and degraded landscape area). The most parsimonious models accounted for over 65% of the variation in flood frequency, of which nearly 14% was due to forest cover variables alone. During the decade investigated, nearly 100 000 people were killed and 320 million people were displaced by floods, with total reported economic damages exceeding US$1151 billion. Extracted measures of flood severity (flood duration, people killed and displaced, and total damage) showed some weaker, albeit detectable correlations to natural forest cover and loss. Based on an arbitrary decrease in natural forest area of 10%, the model-averaged prediction of flood frequency increased between 4% and 28% among the countries modeled. Using the same hypothetical decline in natural forest area resulted in a 4,8% increase in total flood duration. These correlations suggest that global-scale patterns in mean forest trends across countries are meaningful with respect to flood dynamics. Unabated loss of forests may increase or exacerbate the number of flood-related disasters, negatively impact millions of poor people, and inflict trillions of dollars in damage in disadvantaged economies over the coming decades. This first global-scale empirical demonstration that forests are correlated with flood risk and severity in developing countries reinforces the imperative for large-scale forest protection to protect human welfare, and suggests that reforestation may help to reduce the frequency and severity of flood-related catastrophes. [source] Floodplain agricultural systems: functionality, heritage and conservationJOURNAL OF FLOOD RISK MANAGEMENT, Issue 3 2010H.F. Cook Abstract Floodplain infrastructural features reduce flood risk and have the potential to enhance habitat, biodiversity, water quality and provide societal benefits. Man-made water management systems common in southern England are both flood tolerant and form part of the functional floodplain. Historic floodplain features should be incorporated into agri-environmental policy, as climate change and increasing climate variability makes flood detention areas ever more desirable. Of major importance are floodplain meadows, grazing marshes, water meadows and riparian vegetation, and there is a trend to restore river channels to more natural conditions. This paper describes the operation of historic floodplain water management systems and considers the features associated with canals and mills. The major themes in achieving conservation and restoration goals are presented, and it is demonstrated that a refinement of policies on the ground is required. [source] Assessing poverty, risk and vulnerability: a study on flooded households in rural BangladeshJOURNAL OF FLOOD RISK MANAGEMENT, Issue 1 2010M.I. Rayhan Abstract Flood is a common catastrophe in Bangladesh. This study aimed to examine the poverty, risk and vulnerability for flood hazards. A cross-sectional household survey was carried out after 2 weeks of the flood in four districts in the year 2005. In total, 600 rural households were interviewed through a three-stage stratified random sampling. A utilitarian approach was used to assess flood vulnerability and its components. A set of households' characteristics and shock (flood) variables were used as explanatory variables. The results showed that poverty and idiosyncratic flood risks are positively correlated and highly significant. Households with higher educated members, headed by a male and owners of a dwelling place have been found to be less vulnerable to idiosyncratic flood risk. Possession of arable land and a small family size can reduce poverty and the aggregate flood risk. [source] Managing flood risk, reliability and vulnerabilityJOURNAL OF FLOOD RISK MANAGEMENT, Issue 4 2009S.P. Simonovic Special Issue Associate Editor [source] Flood risk management and planning policy in a time of policy transition: the case of the Wapshott Road Planning Inquiry, Surrey, EnglandJOURNAL OF FLOOD RISK MANAGEMENT, Issue 3 2009S. Tunstall Abstract This paper focuses on an English case study example of decision making on development and flood risk. It was carried out through qualitative document analysis and 13 in-depth interviews with flood risk professionals and others in the Lower Thames Valley. It illustrates the recent shift in policy in England from flood defence to a flood risk management approach with an increased emphasis on spatial planning and development control. It shows that decision makers take time to come to terms with new government policy. Despite the more prescriptive government guidance on development and flood risk in Planning Policy Guidance 25 and later documents, there remains scope for disagreements, for example, over what constitutes ,safe' development in flood risk areas. Other sustainability objectives can still weigh heavily against flood risk in local decision making. The potential contributions of modelling, and new visualisation techniques in the flood risk management and planning context are considered. [source] Qualitative analysis of future flood risk in the Taihu Basin, ChinaJOURNAL OF FLOOD RISK MANAGEMENT, Issue 2 2009G.L. Harvey Abstract This paper presents the results of a qualitative analysis of future flood risk in the Taihu Basin, China, performed using an adaptation of the UK Foresight Future Flooding approach. Drivers of increased flood risk were identified and ranked according to their importance in contributing to future flooding by experts and stakeholders working within an inclusive, participatory framework. Management responses to increasing flood risk were also identified and assessed in terms, first, of their potential to reduce flood risks and, second, their sustainability. This analysis provides the foundation for quantitative flood risk modelling to be performed in the next phase of the project. It has also added value to flood risk management in the Taihu Basin by bringing stakeholders together to develop a shared understanding of the flooding system and the relative importance of multiple flood risk drivers and responses. Together, the qualitative and quantitative analyses will provide a comprehensive vision of possible future flood risk to inform policy development and decision making. [source] Flood risk analysis for determining optimal flood protection levels in urban river managementJOURNAL OF FLOOD RISK MANAGEMENT, Issue 3 2008Masaru Morita Abstract The objective of the paper is to present a specific risk-analysis method for the assessment of optimal flood protection levels in urban flood risk management using intensity,duration,frequency relationships. Risk herein is understood as the product of flood damage potential and its occurrence probability. The risk analysis is based on a geographic information system-based flood damage prediction model to calculate flood damage for design storms with different return periods. Estimation of the monetary damages for these design storms and their return periods is the prerequisite for quantifying flood risk based on an annual risk density curve. The risk-analysis method is applied to determine optimal flood protection levels for the Kanda River basin in Tokyo, Japan. It shows how two cost curves can be used: risk cost reduction curves and capital cost curves. [source] Exploring the interactions between flood defence maintenance works and river habitats: the use of River Habitat Survey dataAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 6 2009Gemma L. Harvey Abstract 1.More extensive physical management of rivers in response to increasing flood risk, and action to improve the ecological quality of rivers represent two major, and potentially conflicting, challenges. 2.Improved understanding of the interactions between flood defence works and habitat structure must be achieved in order to satisfy both of these demands in the context of flood risk management and habitat improvement. 3.This paper examines the ,extensive' and ,intensive' use of data derived from a standardized method of assessing habitat character to explore the effects of flood risk maintenance works on river habitat quality. 4.Analysis of the UK River Habitat Survey (RHS) data set reveals some broad trends towards reduced habitat heterogeneity associated with recent flood defence works such as dredging and weed-cutting. 5.These observations correspond with published localized experimental work and suggest that the RHS database can be a useful resource for identifying relationships at relatively broad scales. 6.Applying the RHS methodology at finer spatial scales for sites experiencing continuing maintenance reveals contrasting results and highlights some key methodological issues; these include the availability and selection of high quality benchmark conditions, the legacy of past management, lag times associated with maintenance and recovery, and recording of marginal habitat features. 7.Small modifications to the RHS method could enable calculation of more detailed habitat indices while maintaining comparability with the national dataset. 8.If the issues identified in this paper can be addressed or accounted for, RHS could be an important tool for assessing the relationship between flood defence management and new statutory obligations for ecological improvement. Copyright © 2009 John Wiley & Sons, Ltd. [source] Flood prone risk and amenity values: a spatial hedonic analysisAUSTRALIAN JOURNAL OF AGRICULTURAL & RESOURCE ECONOMICS, Issue 4 2010Oshadhi Samarasinghe This study examines the impact of flood-hazard zone location on residential property prices. The study utilises data from over 2000 private residential property sales occurred during 2006 in North Shore City, New Zealand. A spatial autoregressive hedonic model is developed to provide efficient estimates of the marginal effect of flood prone risks on property prices. Results suggest that the sale price of a residential property within a flood prone area is lower than an equivalent property outside the flood prone area. The flood plain location discount is reduced by the release of public information regarding flood risk. [source] Compartmentalisation: flood consequence reduction by splitting up large polder areasJOURNAL OF FLOOD RISK MANAGEMENT, Issue 1 2010F. Klijn Abstract River and coastal floodplains are often protected by vast systems of connected embankments. In the Netherlands, about 55% of the country is protected in this way, by some 3600 km of primary defences. The protection level is probably the highest in the world, and annual mean flood risks are low. Nevertheless, the consequences of a major flood event might be unacceptable. This is a reason to consider whether and how the consequences of floods could be reduced in a cost-effective manner. Splitting up large polder areas into smaller portions, the so-called compartmentalisation, would reduce the area subject to flooding, and thus the economic damage, the number of people exposed and the fatality risk. We carried out a policy analysis for the national authorities in order to establish whether, where and under which conditions a further compartmentalisation of the country would be desirable. This paper gives some results, discusses our experiences in four case studies and finally focuses on the fundamental questions of assessment and the trade-off between better flood protection and the benefit/cost ratio of reducing consequences. [source] Assessing poverty, risk and vulnerability: a study on flooded households in rural BangladeshJOURNAL OF FLOOD RISK MANAGEMENT, Issue 1 2010M.I. Rayhan Abstract Flood is a common catastrophe in Bangladesh. This study aimed to examine the poverty, risk and vulnerability for flood hazards. A cross-sectional household survey was carried out after 2 weeks of the flood in four districts in the year 2005. In total, 600 rural households were interviewed through a three-stage stratified random sampling. A utilitarian approach was used to assess flood vulnerability and its components. A set of households' characteristics and shock (flood) variables were used as explanatory variables. The results showed that poverty and idiosyncratic flood risks are positively correlated and highly significant. Households with higher educated members, headed by a male and owners of a dwelling place have been found to be less vulnerable to idiosyncratic flood risk. Possession of arable land and a small family size can reduce poverty and the aggregate flood risk. [source] Qualitative analysis of future flood risk in the Taihu Basin, ChinaJOURNAL OF FLOOD RISK MANAGEMENT, Issue 2 2009G.L. Harvey Abstract This paper presents the results of a qualitative analysis of future flood risk in the Taihu Basin, China, performed using an adaptation of the UK Foresight Future Flooding approach. Drivers of increased flood risk were identified and ranked according to their importance in contributing to future flooding by experts and stakeholders working within an inclusive, participatory framework. Management responses to increasing flood risk were also identified and assessed in terms, first, of their potential to reduce flood risks and, second, their sustainability. This analysis provides the foundation for quantitative flood risk modelling to be performed in the next phase of the project. It has also added value to flood risk management in the Taihu Basin by bringing stakeholders together to develop a shared understanding of the flooding system and the relative importance of multiple flood risk drivers and responses. Together, the qualitative and quantitative analyses will provide a comprehensive vision of possible future flood risk to inform policy development and decision making. [source] | |||||||||||||