Use of computer models of flood inundation to facilitate communication in flood risk management

It is now widely recognised that good communication between multi-disciplinary stakeholders is central to effective flood risk management. Recent developments in Geographical Information Systems, increased availability of accurate digital terrain models from remotely sensed data sources and improved graphical computer interfaces have made the outputs from computer models of flood inundation easily accessible to the stakeholder community. As a consequence, predictions from such models are now being used routinely as a means of communication between engineers and other stakeholders in flood risk management. This paper provides a review of the modelling methods most appropriate for flood risk communication. These are one-dimensional models which are suitable for simulating flood risk at a catchment or sub-catchment scale and appropriate for communicating the impact of strategic flood management decisions and two-dimensional models which can be applied across a range of scales but, are now being regularly applied at the relatively small scale, less than 10 km², where they have the potential to inform and communicate disaster management decisions. The role of such models in communicating between modellers and non-modellers by providing a means for immediate visualisation of “the future” is discussed and illustrated by application to two case studies.     

Models of best practice in flood risk communication and management

Risk communication plays an increasingly central role in flood risk management, but there is a variety of conflicting advice about what does – and should – get transmitted, why, how, and to whom. The aim of this paper is to elucidate the underlying normative and conceptual models on which those competing assessments of ‘good’ risk communication depend. To that end, the paper identifies four broad models, or approaches, to risk communication: a risk message model of information transfer; a risk instrument model of behavioural change; a risk dialogue model of participatory deliberation; and a risk government model of self-regulation and normalization. These models differ in their theoretical and disciplinary origins and associated philosophical and political commitments, and consequently they define the basic purpose, practice, and future prospects of flood risk communication in quite different ways. Unless these different models of ‘good’ risk communication are acknowledged and understood, efforts to identify best practice for flood risk management are likely to produce inconsistent, if not contradictory, recommendations.     

Community strategies to improve flood risk communication in the Red River Basin, Manitoba, Canada

More than a decade after the 1997 Red River Flood, vulnerability to future flooding exists due to a lack of risk communication. This study identifies risk communication gaps and discusses the creation of strategies to enhance information-sharing, bottom-up activity and partnership development. The objectives were achieved using mixed methods, including interviews, a floodplain-wide survey, and a decision-makers' risk management workshop. The results highlight a number of external pressures exerted by regional floodplain policies and procedures that restrict risk communication and affect social vulnerability in the rural floodplain. The failures of a top-down approach to floodplain management have impacted on communities' abilities to address floodplain risks, have amplified local risks, and have decreased community cooperation in floodplain management initiatives since the 1997 'Flood of the Century'. Recommended policies promote the establishment of community standards to compensate for gaps in risk communication and the development of partnerships between floodplain communities.     

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.     

长江荆江分蓄洪区历史演变、前景和风险管理

依据社会经济统计数据、水文资料、遥感影像信息和实地调查资料，分析了荆江分蓄洪区在历史演变过程中形成的分洪与发展的矛盾及其在未来长江流域防洪体系中的重要作用，指出其风险管理的必要性。运用基于GIS栅格数据的二维水动力洪水动态演进模型，对荆江分蓄洪区1954年的分洪过程进行了模拟和验证，模拟了不同分洪规划方案下的洪水淹没范围，水深和水位，并结合现阶段社会经济发展情况，定量估算了农户和农业的分洪可能损失。在分洪损失评估基础上提出了荆江分蓄洪区引导人口合理发展、促进土地有效利用、开展防洪教育、实施洪水保险和确保安全运用预案等减轻洪水损失提高运用机率的洪水风险管理初步方案。     

Ensemble predictions and perceptions of risk, uncertainty, and error in flood forecasting

Under the auspices of the World Meteorological Organization, there are a number of international initiatives to promote the development and use of so-called ensemble prediction systems (EPS) for flood forecasting. The campaign to apply these meteorological techniques to flood forecasting raises important questions about how the probabilistic information these systems provide can be used for what in operational terms is typically a binary decision of whether or not to issue a flood warning. To explore these issues, we report on the results of a series of focus group discussions conducted with operational flood forecasters from across Europe on behalf of the European Flood Alert System. Working in small groups to simulate operational conditions, forecasters engaged in a series of carefully designed forecasting exercises using various different combinations of actual data from real events. Focus group data was supplemented by a follow-up questionnaire survey exploring how flood forecasters understand risk, uncertainty, and error. Results suggest that flood forecasters may not instinctively use ensemble predictions in the way that promoters of EPS perhaps think they should. The paper concludes by exploring the implications of these divergent ‘epistemic cultures’ for efforts to apply ensemble prediction techniques developed in the context of weather forecasting to the rather different one of flood forecasting.     

Ensemble predictions and perceptions of risk,uncertainty, and error in flood forecasting

Under the auspices of the World Meteorological Organization, there are a number of international initiatives to promote the development and use of so-called ensemble prediction systems (EPS) for flood forecasting. The campaign to apply these meteorological techniques to flood forecasting raises important questions about how the probabilistic information these systems provide can be used for what in operational terms is typically a binary decision of whether or not to issue a flood warning. To explore these issues, we report on the results of a series of focus group discussions conducted with operational flood forecasters from across Europe on behalf of the European Flood Alert System. Working in small groups to simulate operational conditions, forecasters engaged in a series of carefully designed forecasting exercises using various different combinations of actual data from real events. Focus group data was supplemented by a follow-up questionnaire survey exploring how flood forecasters understand risk, uncertainty, and error. Results suggest that flood forecasters may not instinctively use ensemble predictions in the way that promoters of EPS perhaps think they should. The paper concludes by exploring the implications of these divergent ‘epistemic cultures’ for efforts to apply ensemble prediction techniques developed in the context of weather forecasting to the rather different one of flood forecasting.     

Internal communication a prerequisite for risk governance: hazard zone planning in South Tyrol,Italy

Mountain risk management is currently facing a scientifically driven, normative paradigm change towards risk governance, where communication and participation take on key roles. On the local level, hazard zone planning is a risk management tool to balance land-use developments and hazard processes, such as debris flows, avalanches, rock fall, mass movements or flooding. In this contribution, communication among stakeholders professionally involved in hazard zone planning (internal communication) is analysed by participant observation. Here, the quality of internal communication is seen both as an indicator and as a prerequisite for transition processes from risk management to risk governance. This case study of communication in hazard zone planning in the Autonomous Province of South Tyrol points out pitfalls and challenges in an advanced, spatial planning scheme. Based on the concept of social learning, it is argued that the transition towards governance of mountain risks requires fundamental changes in the underlying normative models, objectives, organizational understandings, structures and qualifications of the administrative bodies. Proposals for change are provided.     

Influence of road characteristics on flood fatalities in Australia

ABSTRACT

An analysis of published flood fatalities in Australia occurring between 1960 and 2015 revealed that 49% of 229 flood fatalities were vehicle related. After reviewing previous work on vehicle-related flood fatalities, this study examines attributes of roadways that may have influenced driver decisions to enter floodwaters and the survivability of people in vehicles that did so and concludes by discussing policy implications. Characteristics most frequently present were small upstream catchment length that may influence the rate of rise of floodwaters; the absence of roadside barricades; deep flooding immediately adjacent to the roadway; the absence of lighting; dipping road grades that lead floodwaters to increase once a vehicle enters them; the lack of curb and guttering and the inability of motorists to easily turn around. Each of these factors were observed in at least 50% of the cases studied and provide a risk-based means of assessing other sites vulnerable to flooding but where fatalities have not been observed to date.     

区域水灾恢复力及水灾风险管理研究——以湖南省洞庭湖区为例

近年来灾害恢复力研究在领域的拓展和定义的延伸等方面取得了较大的进步。灾害恢复力作为系统的一个有价值的属性，与风险、脆弱性和适应性一起成为当前灾害综合管理和减灾研究的重要内容。但目前灾害恢复力研究仍停留在理论和概念层面，鲜有深入的实际操作性强的工作开展。为进一步理解水灾恢复力的内涵和实质，为区域恢复力建设提供切实可行的方案，作者在原有对灾害恢复力研究进展进行综述的基础上，开展了以湖南省洞庭湖区为例的洪水高风险区水灾恢复力理论和实践的研究，提出了由自然维、经济维、组织维、社会维组成的四维区域水灾恢复力概念模型，然后细致分析了区域水灾恢复力利益主体的相互关系，提供了初步的区域水灾恢复力评估模型。最后在定性分析的基础上，对洞庭湖区区域水灾风险管理进行了探讨，提出了相应的管理对策和建议，旨在为政府的防灾减灾决策提供科学依据。     

Risk communication and risk perception: lessons from the 2011 floods in Brisbane,Australia

Risk communication and risk perception are critical factors in disaster management. Governments at all levels play a part in communicating risk, whereas the perception of risk entails active roles by community participants, including potential and actual victims of disasters. This paper discusses these matters in relation to the floods in Brisbane, Australia, in 2011. The findings are based on interviews with representatives of households whose dwellings or business premises were fully or partially inundated by the waters. The research shows how important it is to recognise the problems of institutional fragmentation in terms of communication and the active engagement of recipients in understanding and interpreting flood risk information (especially for slow‐onset riverine flooding, such as that suffered by Brisbane). Locally targeted information on risk is of vital importance in avoiding the misinterpretation of warning information in relation to environmental cues and in promoting adequate responses. The paper concludes with some recommendations.     

Taking stock of community-based flood risk management in Malawi: different stakeholders,different perspectives

Current flood risk strategies in Malawi are characterized by community-based flood risk management (CB-FRM), even though studies explicitly documenting evidence of successful CB-FRM remain limited. This paper investigates the realities and challenges of CB-FRM as seen through a lens of different stakeholders. In order to capture the experiences of CB-FRM, a predominantly qualitative research framework was developed. In 2016, 11 focus group discussions with stakeholder groups (local communities, local government and non-governmental organisations) were held. Additionally, informal discussions, field visits, a short survey and an extensive desk study were undertaken. The findings were analysed according to the major themes that emerged related to the realities and challenges of specific stakeholder groups. Although response and relief still remain prominent components of CB-FRM in Malawi, a number of mitigation and preparedness activities is observed. However, a lack of in-country resources, relief-oriented aid approaches and an ‘aid dependency’ syndrome represent obstacles. Different stakeholder groups share similar challenges in terms of financing, participation, decentralised governance and project management. Lack of project sustainability and localised ownership also emerged as major challenges. The identified challenges shed light on the frontiers and directions in which improvements are needed, thus offering a valuable contribution to the existing knowledgebase.     

中国水灾风险综合管理--平衡大都市区水灾致灾强度与脆弱性

中国大都市区主要分布在大江大河的中下游地区,由于区域土地利用格局的巨大变化,特别是较多的水域和湿地因城市化而被占据,因此,一方面大都市区面临严重的洪水危险,另一方面为了使大都市区尽可能减轻洪水灾害,而加强了防洪能力的建设.然而,近50年的减灾实践证明,洪水灾害却在波动中趋于上升,即大都市区对洪水的脆弱性在增大.在对中国大都市区洪水灾害的区域分析基础上,以广东省为例,构造了综合水灾致灾因子和承灾体为一体的风险评估模型体系,以此提出了平衡大都市区水灾致灾强度与脆弱性的基本土地利用模式,和"政府-企业(社区)-保险公司"相结合的企业风险管理模式.     

Decision‐making and evacuation planning for flood risk management in the Netherlands

A traditional view of decision‐making for evacuation planning is that, given an uncertain threat, there is a deterministic way of defining the best decision. In other words, there is a linear relation between threat, decision, and execution consequences. Alternatives and the impact of uncertainties are not taken into account. This study considers the ‘top strategic decision‐making’ for mass evacuation owing to flooding in the Netherlands. It reveals that the top strategic decision‐making process itself is probabilistic because of the decision‐makers involved and their crisis managers (as advisers). The paper concludes that deterministic planning is not sufficient, and it recommends probabilistic planning that considers uncertainties in the decision‐making process itself as well as other uncertainties, such as forecasts, citizens responses, and the capacity of infrastructure. This results in less optimistic, but more realistic, strategies and a need to pay attention to alternative strategies.     

The Tlokwe City Council Dolomite Management Desk: a communication and relationship management perspective

Two-way communication and strong relationships between government and affected communities are necessary to enhance the latter's resilience to disaster risks. The Tlokwe City Council (TCC) in the North-West province, South Africa, is facing a dolomite and sinkhole disaster risk that threatens the safety of several residential areas, including informal settlements. A dolomite disaster risk reduction (DRR) management system such as the TCC Dolomite Management Desk (DMD) can be used to facilitate two-way communication and strong relationships between government and the affected communities. Semi-structured interviews with two different groups of people were conducted and the responses evaluated to determine in what way DRR communication via the Tlokwe DMD served to establish strong relationships between the TCC and the affected community. It was found that the two groups of interviewees had contradictory views on the risk communication and quality of relationships as facilitated by the Tlokwe DMD. These views illuminated the predicament of communicating about the dolomite and sinkhole risk. The Tlokwe DMD is unique in South Africa and its ability to enable communication and strong government–community relationships needs to be developed further. Recommendations are made in this regard.     

Risk communication in emergency response to a simulated extreme flood

Risk communication in flood incident management can be improved through developing hydrometeorological and engineering models used as tools for communicating risk between scientists and emergency management professionals. A range of such models and tools was evaluated by participating flood emergency managers during a 4-day, real-time simulation of an extreme event in the Thamesmead area in the Thames estuary close to London, England. Emergency managers have different communication needs and value new tools differently, but the indications are that a range of new tools could be beneficial in flood incident management. Provided they are communicated large model uncertainties are not necessarily unwelcome among flood emergency managers. Even so they are cautious about sharing the ownership of weather and flood modelling uncertainties.     

Risk communication in emergency response to a simulated extreme flood

Risk communication in flood incident management can be improved through developing hydrometeorological and engineering models used as tools for communicating risk between scientists and emergency management professionals. A range of such models and tools was evaluated by participating flood emergency managers during a 4-day, real-time simulation of an extreme event in the Thamesmead area in the Thames estuary close to London, England. Emergency managers have different communication needs and value new tools differently, but the indications are that a range of new tools could be beneficial in flood incident management. Provided they are communicated large model uncertainties are not necessarily unwelcome among flood emergency managers. Even so they are cautious about sharing the ownership of weather and flood modelling uncertainties.     

Perceptions of risk characteristics of earthquakes compared to other hazards and their impact on risk tolerance

People tolerate different levels of risk owing to a variety of hazards. Previous research shows that the psychometric properties of hazards predict people's tolerance of them. However, this work has not taken into account events such as earthquakes. The present study tested how earthquakes score vis‐à‐vis risk properties and risk tolerance as compared to five other familiar hazards. Participants from Wellington, New Zealand (N=139) rated these six hazards using measures of risk characteristics and risk tolerance. Participants demonstrated different levels of risk tolerance for the different hazards and viewed earthquakes as having similar risk features to nuclear power. They also preferred different risk mitigation strategies for earthquakes (more government funding) to the other five hazards (stronger legislation). In addition, earthquake risk tolerance was predicted by different risk characteristics than the other five hazards. These findings will help risk communicators in identifying which risk characteristics to target to influence citizens' risk tolerance.