Values and floodplain management: Case studies from the Red River Basin,Canada

Where floods are prevalent, decisions on how to mitigate vulnerability are made within a social-cultural context that includes values (and related customs, norms, beliefs, technology) of local people, which have evolved through interactions with the physical environment. Consequently, the success of floodplain management and flood mitigation activities is determined, at least in part, by the nature of values that impact the decision-making process. This paper explores this contention by considering the community values context surrounding flood risk management in two small Canadian communities in the Red River Basin.

Using a qualitative methodology that includes semi-structured interviews with residents, community values are identified and accounted for in the context of flood vulnerability. Values discussions are organized around seven broad categories: community identity and community attributes; community economic development; technical and nonstructural approaches; civic engagement; flood legacy; personal rights and liberties; and shared values. Challenges posed by key identified values and their policy implications are considered. Some values are found to act as constraints if sustainable floodplain management practices are to be realized.     

The consequences and policy implications of urban encroachment into flood-risk areas: the case of Ibadan

Urban encroachment on floodplains has exacerbated flood disasters owing to the reduction in the floodplain’s capacity to mitigate flooding, thereby bringing more settlements and people at flood risk. This study examined the consequences and policy implications of urban encroachment into Ibadan’s flood-risk areas. The survey-based study relied on primary and secondary data, with multistage sampling procedures selecting 15% of the flood-affected buildings in 2011, from which a structured questionnaire was administered to 402 households. The study revealed that the institutional arrangements with respect to responsibilities, regulations and control of urban floodplains were fragmented and non-participatory. At least 62% of all the affected buildings encroached into the statutory setbacks to rivers. Household property lost/damaged included domestic goods (75%), domestic animals and pets (60%), working instruments/machines (31%), the source of domestic water (34%) and vehicles (29%). Strong direct correlations were found between the urban and peri-urban communities in (1) the number of damaged/lost property and (2) the number of households that suffered health-related challenges. The paper recommends that the overall co-ordination of flood management activities be entrusted to an institution that can assume responsibility for legal, technical, administrative and financial matters related to urban planning and flood-risk management.     

Flood insurance and floodplain management: the US experience

Abstract

With over six million buildings located within the boundaries of the 100-yr floodplain, flood losses across the United States are widespread (88% of US counties experienced at least one flood disaster during the second half of the twentieth century). To deal with this problem, the federal government provides flood insurance through the National Flood Insurance Program, which was initiated by Congress in 1968 and amended significantly in 1969, 1973, and 1994. This article describes the US approach to flood insurance and notes a number of problems that have limited its effectiveness. Flood hazard identification is incomplete, and methods used are flawed. Mitigation has failed to contain increasing exposure to property damage in floods and coastal storms, and it has failed to markedly reduce exposure to loss of older buildings located in flood hazard areas. Market penetration of flood insurance is low, in spite of mandatory purchase requirements for new construction and the availability of subsidized insurance rates for older buildings located in flood-hazard areas. These problems, although serious, can be remedied through a variety of actions taken by governments at the federal, state, and local level.     

The spatial and temporal variability of residential real estate values in response to flooding

A relationship between residential property values and the incidence of flooding is represented, using a case study of two Californian communities that were flooded following a levee break. Analysis of the real estate market before and after the flood shows that the flood was capitalized into housing values, whereby both list and selling prices dropped immediately and have recently begun to recover. However, recovery of the market is not uniform throughout the floodplain. Houses that suffered eighteen inches of water recovered to near pre-flood values in less than one year. In contrast, houses that had approximately ten feet of water in them have not recovered to the same extent, indicating that capitalization and recovery do not occur evenly. These findings suggest that policies and programs should address these spatial and temporal differences in recovery, which are expected to vary with different flood frequencies and magnitudes.     

The effects of flooding upon buildings in developing countries

The genera] effects of flooding on buildings and structural materials in developing countries are comprehensively reviewed. The aim of the paper is to stimulate further field based research as to how and what type of building improvements can be introduced, given the prevailing economic and cultural constraints of many communities, and to examine the appropriateness of floodproofing measures in developing countries where there are often few floodplain management or large scale flood prevention schemes. Proposals are suggested as to the method and type of information which is required for detailed studies prior to developing new and more effective building designs.     

Interactions between scientific uncertainty and flood management decisions: Two case studies in Colorado

Flood management policies in the United States rely on scientific information about the frequency and intensity of extreme precipitation and runoff. Yet, the available information is inherently uncertain because of the complexity of meteorological and hydrological processes. In mountainous areas, flood risk can vary greatly even within short distances depending on local climate, topography, soil characteristics, and land use. This paper describes two Colorado cases in which policy makers were presented with conflicting scientific estimates: revision of the Fort Collins floodplain map and modification of the Cherry Creek Dam. The case studies demonstrate that uncertainty can have substantial impacts on regulatory processes, public safety, and costs. The analysis considers the differing perspectives of various participants in the flood management processes, illustrating the interplay between uncertainties attributable to scientific issues and values issues. It suggests that attempts to provide a single “best” estimate do not necessarily meet the decision needs of all stakeholders. Conclusions indicate a need to improve communication about uncertainty when scientific estimates areprovided to decision makers. Furthermore, in highly controversial decisions, it may be necessary to reframe the discussion to consider the values issues raised by scientific uncertainty.     

美国洪泛平原管理的新方向

根据美国联邦跨机构洪泛平原管理审查委员会对密西酉比河１９９３年特大洪水的调查分析以及对美国现行洪泛平原管理方式、水土资源规划的原则与准则等的评价，简要介绍现有管理方式存在的问题与发展方向，为我国从事洪泛区规划与管理提供参考信息．     

Institutional challenges to robustness of delta and floodplain agricultural systems

The farming of natural coastal deltas and floodplains was in many parts of the world the cradle of civilization. Through history the transformation of risky floodplain systems into socially controlled environments was the result of an intricate interplay between ecology, demography, religion, social organization and technology of the time. After the harnessing of most large tropical rivers, there are in our time few natural deltas and floodplains left to study in the warm regions of the world. One such floodplain is the Rufiji coastal delta and floodplain in Tanzania. Here an artificial irrigation culture has not been developed, but a robust risk-minimizing system based on rice, maize, cotton and peas has evolved for delta and floodplain agriculture. Through the Arab, German and British colonization, attempts were made to ‘modernize’ this agricultural system, resulting in new crops and varieties being incorporated into the system in a way that made it even more robust. This study explains the genesis of this as a socio-ecological system, that is, an interaction of resource systems, resource units, governance and users. It analyses some fundamental challenges to this agricultural system during the last 100 years: the removal of the floodplain population to ‘safe ujamaa villages’, the recurring large infrastructure development initiatives and the modern institutional challenges such as individualized tenure, urban food market expansion, coastal and marine conservation, and the recent development of ‘land-grabbing’ practices.     

北京水灾及其社会影响

北京在历史上曾发生多次重大水灾,给人民生命财产、城市建设及社会安定带来了巨大影响。形成水灾的主要因素是永定河决口泛溢和区域雨涝。现从大量的历史文献中列举几个实例,来看水灾的严重程度及其影响后果。     

美国防洪政策演变

回顾了近３００年来美国防洪战略转移的历史进程。美国陆军工程兵团曾根据国家防洪与发展航运的需要,实施“堤防万能”的防洪政策,然而,１９２７年的大洪水冲毁了“堤防万能”的神话,迫使国会通过１９２８年的防洪法,进行水库、行洪区、分洪区与堤防协调防洪。随着联邦洪水及其它灾害救济费用的不断攀升,促使美国颁布１９６８年的洪水保险法与１９７３年的洪水灾害防御法,实行洪水风险区划与土地利用规划,以减轻洪水灾害。１     

行蓄洪区可持续发展战略探讨

人水共处是我国行蓄洪区无可回避的现实,实现行蓄洪区可持续发展是关系到防洪安全建设和区内人民生活和经济发展的重要课题。本文在分析我国行蓄洪区现状及所问题的基础上,提出了行蓄洪区可持续发展的基本模式,进一步从实施洪水保险,鼓励移民、产业结构高速等方面搪塞了保障行蓄洪区可持续发展的政策。     

Contextual influences on national level flood risk communication

With high profile flooding events and increasing risk and probable damages of flooding in the future flood risk management (FRM) in England and Wales has undergone substantial changes over the last decade. The contextual influences on flood risk communication in the areas of flood forecasting, warning and response, spatial planning and development control and flood insurance at a national level are investigated in this paper. Research is based on qualitative interviews with 21 representatives of key organisations and activities at a national level of FRM. Drawing on communication theory the research highlights the key contextual features at play: the characteristics of communication flow through organisations, the importance of policy as a communication tool informed and constrained by flood events, organisational agendas, communication approaches and the development of knowledge and technology. The paper describes the influence of clear policy guidance on activities in certain government FRM communication initiatives and the commercial imperative driving the insurance industry activities.     

Contextual influences on national level flood risk communication

With high profile flooding events and increasing risk and probable damages of flooding in the future flood risk management (FRM) in England and Wales has undergone substantial changes over the last decade. The contextual influences on flood risk communication in the areas of flood forecasting, warning and response, spatial planning and development control and flood insurance at a national level are investigated in this paper. Research is based on qualitative interviews with 21 representatives of key organisations and activities at a national level of FRM. Drawing on communication theory the research highlights the key contextual features at play: the characteristics of communication flow through organisations, the importance of policy as a communication tool informed and constrained by flood events, organisational agendas, communication approaches and the development of knowledge and technology. The paper describes the influence of clear policy guidance on activities in certain government FRM communication initiatives and the commercial imperative driving the insurance industry activities.     

How structural mitigation shapes risk perception and affects decision‐making

This paper reviews the relationships between risk perception and structural measures in an Australian context in three respects: (i) opinions about authorities’ ability to mitigate flood risks; (ii) the role of flood experience in shaping views on risk; and (iii) perspectives on the ways in which structural measures shape decision‐making pertaining to protective action. The main finding of this analysis is that the study participants do not suffer from the ‘levee paradox'. Most take precautionary steps to guard against residual flood risk. Such actions, however, do not mean that there is a lack of trust in structural measures to reduce significant flood risk. The majority of the respondents agreed about the necessity of engineering structures to mitigate inherent flood risk. This support, though, does not extend to their management. Losses during major flooding in southeast Queensland, Australia, in 2010–11 were attributed primarily by residents to operational decisions concerning dam water releases.     

Urban flooding in Australia: Policy development and implementation

This paper presents a review of Australian urban riverine flooding. By world standards the Australian flood problem is relatively small, though there are pockets of development subject to regular severe inundation. In the past, government response to flooding was ad hoc and characterized by structural adjustments. The 1970s and 1980s, however, have seen a major shift in approach. The new approach emphasizes resource management rather than construction, and consists of the announcement of policies, enactment of enabling legislation, and the introduction of procedures to help ensure that the widest range of flood damage reduction measures are considered. The changes are evident at both the federal and state levels of government.
Though problems remain, particularly at the local government level, where ultimate responsibility for policy implementation generally rests, the authors feel there are good grounds for optimism. Some suggestions for future policy are offered and the importance of public safety is stressed.     

Disaster risk, climate change and international development: scope for, and challenges to, integration

Reducing losses to weather-related disasters, meeting the Millennium Development Goals and wider human development objectives, and implementing a successful response to climate change are aims that can only be accomplished if they are undertaken in an integrated manner. Currently, policy responses to address each of these independently may be redundant or, at worst, conflicting. We believe that this conflict can be attributed primarily to a lack of interaction and institutional overlap among the three communities of practice. Differences in language, method and political relevance may also contribute to the intellectual divide. Thus, this paper seeks to review the theoretical and policy linkages among disaster risk reduction, climate change and development. It finds that not only does action within one realm affect capacity for action in the others, but also that there is much that can be learnt and shared between realms in order to ensure a move towards a path of integrated and more sustainable development.     

基于GIS和OREMS的洪灾避难系统

面对突发的灾害,人类采取避难转移的方式来减少生命和财产的损失。大范围的人口转移是一个十分复杂的过程,必须有合理的计划和有效地利用现有的交通设施。提出了基于GIS和OREMS的洪灾避难系统来模拟洪灾的避难转移过程。根据洪灾危险区的统计资料,应用基于GIS的风暴潮洪灾风险系统分析洪灾淹没范围、避难区域的人口分布、路网结构,使用OREMS避难交通模型模拟避难过程。以长兴岛为例进行洪灾避难交通模拟,得到避难耗费时间,路网拥堵路段,并且在分析模拟结果的基础上对避难计划进行优化。     

近十几年来中国铁路水害的时空统计特征

利用收集的２０００多个铁路水害的记录，计算分析了我国铁路水害的一些统计规律，它们可以总结为：１．我国铁路水害的月特征是：从整体上看绝大部分都发生于６－８月，由北到南又有些差异；２．我国铁路水害月平均断道次数服从正态分布规律；３．铁路水害频发地区集中的成都、郑州、哈尔滨、沈阳等铁路局，其中成都、郑州两局水害占全路的一半。     

Household adjustment to flood risk: a survey of coastal residents in Texas and Florida,United States

Individual households have increasingly borne responsibility for reducing the adverse impacts of flooding on their property. Little observational research has been conducted, however, at the household level to examine the major factors contributing to the selection of a particular household adjustment. This study addresses the issue by evaluating statistically the factors influencing the adoption of various household flood hazard adjustments. The results indicate that respondents with higher‐value homes or longer housing tenure are more likely to adopt structural and expensive techniques. In addition, the information source and the Community Rating System (CRS) score for the jurisdiction where the household is located have a significant bearing on household adjustment. In contrast, proximity to risk zones and risk perception yield somewhat mixed results or behave counter to assumptions in the literature. The study findings provide insights that will be of value to governments and decision‐makers interested in encouraging homeowners to take protective action given increasing flood risk.     

The performance of the sydney flood warning system, august 1986

During August 1986 Sydney experienced its worst flooding for decades. Some 2,500 properties were flooded and transport was severely disrupted in much of the metropolitan area. The flood provided an opportunity to examine the operation of a warning system in a major Australian city. Pre-existing research into flood warnings was expanded to take advantage of the opportunity.
The warning system is examined in terms of: its impact on flood losses; consumer satisfaction; and inefficiences or breakdowns within the system. Much of the flooded area was not covered by a formal warning system. For the area that was covered, performance could be improved. Problems were experienced with the data collection and transmission network. Warning dissemination was inadequate, and the majority of those surveyed claimed that they did not receive warnings. The actions of householders reduced the flood damage substantially, but this does not appear to be the result of official warnings. Key recommendations concern improving the reliability of the flood detection network and information management.