Integrated Flood Risk Management Research Articles

Coupled modelling of subsurface water flux for an integrated flood risk management

Abstract. Flood events cause significant damage not only on the surface but also underground. Infiltration of surface water into soil, flooding through the urban sewer system and, in consequence, rising groundwater are the main causes of subsurface damage. The modelling of flooding events is an important part of flood risk assessment. The processes of subsurface discharge of infiltrated water necessitate coupled modelling tools of both, surface and subsurface water fluxes. Therefore, codes for surface flooding, for discharge in the sewerage system and for groundwater flow were coupled with each other. A coupling software was used to amalgamate the individual programs in terms of mapping between the different model geometries, time synchronization and data exchange. The coupling of the models was realized on two scales in the Saxon capital of Dresden (Germany). As a result of the coupled modelling it could be shown that surface flooding dominates processes of any flood event. Compared to flood simulations without coupled modelling no substantial changes of the surface inundation area could be determined. Regarding sewerage, the comparison between the influx of groundwater into sewerage and the loading due to infiltration by flood water showed infiltration of surface flood water to be the main reason for sewerage overloading. Concurrent rainfalls can intensify the problem. The infiltration of the sewerage system by rising groundwater contributes only marginally to the loading of the sewerage and the distribution of water by sewerage has only local impacts on groundwater rise. However, the localization of risk areas due to rising groundwater requires the consideration of all components of the subsurface water fluxes. The coupled modelling has shown that high groundwater levels are the result of a multi-causal process that occurs before and during the flood event.

Exploring the challenges of integrated coastal zone management and reflecting on contributions to ‘integration’ from geographical thought

Integrated coastal zone management (ICZM) is a challenging process, defined by stakeholder engagement and underpinned by knowledge on the integrated behaviour of coastal systems. While significant advancements in ICZM have been made, a range of difficult and important questions about ‘integration’ remain to be explored. This paper discusses opportunities for addressing such challenges of integration through the application of geographical thinking to understanding and managing coastal environments. It focuses on geographical traditions on systems thinking, the process‐based nature of geographic research and geographical contributions to conceptualising place and our relationships to it. Using UK‐based case studies the paper explores integration challenges from three different coastal contexts and management perspectives, examining: adaptation through managed realignment in a local community, integrated flood risk management in London and the Thames Estuary and enhancing the ‘socially just’ nature of coastal management. The case‐study discussion highlights the importance of ‘geographical thought’ to improving the integrative basis of strategies for managing complex coastal environments. This paper argues that ‘thinking geographically’ is one logical vehicle for increasing our understanding of, and providing solutions to, barriers which limit progress towards greater ‘integration’ in coastal management. Geography is dynamic, plural and based on the recognition that reality is contested and as such geographical ideas could add considerably to emerging cross‐disciplinary knowledge on the interactions and interdependencies of behaviours within coastal systems.

Flood risk management in Central Viet Nam: challenges and potentials

This article explores the impacts of floods on the economy, environment, and society and tries to clarify the rural community’s coping mechanism to flood disasters in Central Viet Nam. It focuses on the social aspects of flood risk perception that shapes the responses to floods. The research findings revealed that flooding is an essential element for a coastal population, whose livelihood depend on productive functions of cyclical floods. The findings also revealed that floods, causing losses and damages, often inhibited economic development. The surveyed communities appeared to have evolved coping mechanisms to reduce the negative impacts of the floods, yet these coping mechanisms are under pressure due to environmental degradation. Integrated flood risk management is considered as a suitable paradigm for coping with flood disasters.

Application of scenario technique in flood risk management

It is now commonly accepted that the management of flood risks has to be fulfilled within an integrated framework. About two decades ago flood risk was managed from a limited perspective predominantly by means of structural measures aimed at flood control. In contrast integrated flood risk management incorporates the complete management cycle consisting of the phases prevention, protection and preparedness. In theory it is a well described concept. In the stage of implementation, however, there is often a lack of support although a consistent policy framework exists. Consequently, the degree of implementation must be rated as inadequate in many cases. In particular this refers to the elements which focus on preparedness and prevention. The study to which this paper refers emphasises the means and potentials of scenario technique to foster the implementation of potentially appropriate measures and new societal arrangements when applied in the framework of integrated flood risk management. A literature review is carried out to reveal the state-of-the-art and the specific problem framework within which scenario technique is generally being applied. Subsequently, it is demonstrated that scenario technique is transferable to a policy making process in flood risk management that is integrated, sustainable and interactive. The study concludes with a recommendation for three applications in which the implementation of measures of flood damage prevention and preparedness is supported by scenario technique.

Book Reviews

Book Reviews

Improvements on Flood Alleviation in Germany: Lessons Learned from the Elbe Flood in August 2002

The increase in damage due to natural disasters is directly related to the number of people who live and work in hazardous areas and continuously accumulate assets. Therefore, land use planning authorities have to manage effectively the establishment and development of settlements in flood-prone areas in order to avoid the further increase of vulnerable assets. Germany faced major destruction during the flood in August 2002 in the Elbe and Danube catchments, and many changes have been suggested in the existing German water and planning regulations. This article presents some findings of a "Lessons Learned" study that was carried out in the aftermath of the flood and discusses the following topics: 1) the establishment of comprehensive hazard maps and flood protection concepts, 2) the harmonization of regulations of flood protection at the federal level, 3) the communication of the flood hazard and awareness strategies, and 4) how damage potential can be minimized through measures of area precaution such as resettlement and risk-adapted land use. Although attempts towards a coordinated and harmonized creation of flood hazard maps and concepts have been made, there is still no uniform strategy at all planning levels and for all states (Laender) of the Federal Republic of Germany. The development and communication of possible mitigation strategies for "unthinkable extreme events" beyond the common safety level of a 100-year flood are needed. In order to establish a sustainable and integrated flood risk management, interdisciplinary and catchment-based approaches are needed.

Flood-risk mapping: contributions towards an enhanced assessment of extreme events and associated risks

Abstract. Currently, a shift from classical flood protection as engineering task towards integrated flood risk management concepts can be observed. In this context, a more consequent consideration of extreme events which exceed the design event of flood protection structures and failure scenarios such as dike breaches have to be investigated. Therefore, this study aims to enhance existing methods for hazard and risk assessment for extreme events and is divided into three parts. In the first part, a regionalization approach for flood peak discharges was further developed and substantiated, especially regarding recurrence intervals of 200 to 10 000 years and a large number of small ungauged catchments. Model comparisons show that more confidence in such flood estimates for ungauged areas and very long recurrence intervals may be given as implied by statistical analysis alone. The hydraulic simulation in the second part is oriented towards hazard mapping and risk analyses covering the whole spectrum of relevant flood events. As the hydrodynamic simulation is directly coupled with a GIS, the results can be easily processed as local inundation depths for spatial risk analyses. For this, a new GIS-based software tool was developed, being presented in the third part, which enables estimations of the direct flood damage to single buildings or areas based on different established stage-damage functions. Furthermore, a new multifactorial approach for damage estimation is presented, aiming at the improvement of damage estimation on local scale by considering factors like building quality, contamination and precautionary measures. The methods and results from this study form the base for comprehensive risk analyses and flood management strategies.

An analysis of the current practice of policies on river flood risk management in different countries

The Netherlands Centre for River Studies (NCR) organised a special session on River Flood Risk Management in Different Parts of the World, during the 3rd International Symposium of Flood Defence (ISDF3) on 25 and 26 May 2005 in Nijmegen, the Netherlands. Lectures were given on the past and present policy approach in Bangladesh, the USA, Germany, England and Wales, and the Netherlands. Also, an introduction was given on UNESCO's initiative to promote integrated flood risk management worldwide by capacity building and training in developing countries. This paper summarises the common issues and differences between the approaches in the various parts of the world, and attempts to provide a synthesis of the discussions, held after the respective presentations. Copyright © 2006 John Wiley & Sons, Ltd.

Integrated Flood Risk Management in England and Wales

The flooding system includes the physical process of flooding, the inhabitants of floodplains, their infrastructures and ecosystems, and the people and organizations in the public and private sector that influence or are subject to flooding and its impacts. Flooding systems are continuously changing because of natural and socioeconomic processes, as well as activities that are intended to reduce flood risk. Flood risk management is the process of data and information gathering, risk assessment, appraisal of options, and making, implementing, and reviewing decisions to reduce, control, accept, or redistribute risks of flooding. Integrated flood risk management explicitly recognizes the interrelationships between all risk management measures, and their analysis, costs, and effectiveness, within changing social, economic, and environmental contexts. It can be helped by improving access to data and models, sharing and communicating risk analyses, involving a wider range of stakeholders, and coordinating risk management actions. Flood risk management in England and Wales is rapidly changing. This paper explains these changes in terms of their contribution to integrated flood risk management and describes further developments that are required to enable the difficult task of integrated flood risk management to be realized in practice.

Evaluation Method of Integrated Flood Risk Management

It is difficult that the risk control such as the structure constructions only mitigate the catastrophic flood disaster. So, we have to carry out the integrated flood risk management including the non-construction measures as the land use regulation and the risk finance as flood disaster insurance. In this paper, we structured the model that integrate the location equilibrium model and the runoff-inundation model for evaluating the integrated flood risk management. And it was shown through the simple simulations that this model is able to comprehensively evaluate the integrated flood risk management, especially, the disaster insurance systems, the land use regulations and the flood controls.