Risk analysis provides a rational basis for flood management decision-making at a national scale, as well as regionally and locally. National-scale flood risk assessment can provide consistent information to support the development of flood management policy, allocation of resources and monitoring of the performance of flood mitigation activities. However, national-scale risk assessment presents particular challenges in terms of data acquisition and manipulation, numerical computation and presentation of results. A methodology that addresses these difficulties through appropriate approximations has been developed and applied in England and Wales. The methodology represents the processes of fluvial and coastal flooding over linear flood defence systems in sufficient detail to test alternative policy options for investment in flood management. Flood outlines and depths are generated, in the absence of a consistent national topographic and water level data set, using a rapid parametric inundation routine. Potential economic and social impacts of flooding are assessed using national databases of flood-plain properties and demography. A case study of the river Parrett catchment and adjoining sea defences in Bridgwater Bay in England demonstrates the application of the method and presentation of results in a geographical information system.

10.1680/maen.156.3.235.37976

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Citations (203)

A quantitative multi-hazard risk assessment framework for compound flooding considering hazard inter-dependencies and interactions

Journal of Hydrology (2022)

Xiaodong Ming Qiuhua Liang Richard Dawson Xilin Xia Jingming Hou

Multi-hazard risk assessment may provide comprehensive analysis of the impact of multiple hazards but still needs to resolve major challenges in three aspects: (1) proper consideration of hazard inter-dependency, (2) physically based modelling of hazard interactions, and (3) fully quantitative risk assessment to show the probability of loss. Compound flooding is a typical multi-hazard problem that involves the concurrence of multiple hazard drivers, e.g. heavy rainfall, extreme river flow, and storm surge. These hazard drivers may result from the same weather system and are thus statistically inter-dependent, physically overlayed and interacted in the same region. This paper aims to address the mentioned challenges and develop an integrated assessment framework to quantify compound flood risk. The framework is constructed based on the three typical components in disaster risk assessment, i.e. hazard, vulnerability and exposure analysis. In hazard analysis, joint probability and return period distributions of the three hazard drivers of compound flooding are estimated using Copula functions with hazard dependency analysis, which are then used to generate random multi-hazard events to drive a 2D high-performance hydrodynamic model to produce probabilistic inundation maps and frequency-inundation curves. Vulnerability and exposure analysis provides damage functions of the elements at risk, which are used to quantify multi-hazard risk with the frequency-inundation curves. The framework is applied in the Greater London and its downstream Thames estuary to demonstrate its capability to analyse hazard interactions and inter-dependencies to produce fully quantitative risk assessment results such as risk curves quantifying the probability of loss and risk maps illustrating the annual expected loss of residential buildings.

Vulnerability

Return period

10.1016/j.jhydrol.2022.127477

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Citations (59)

An agent-based model for risk-based flood incident management

Natural Hazards (2011)

Richard Dawson Roger Peppé Miao Wang

Natural hazard

Storm Surge

Vulnerability

Coastal flood

Incident management

10.1007/s11069-011-9745-4

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Citations (308)

Performance-based management of flood defence systems

Proceedings of the Institution of Civil Engineers - Water Management (2004)

Richard Dawson Jim W. Hall J. P. Davis

Performance-based asset management is a process of managing an infrastructure system in order to optimise its behaviour when evaluated against specified objectives. It enables prioritisation of investment in flood defence infrastructure construction, inspection and maintenance. It is risk-based, in that costs of alternative interventions in the flood defence system are weighed against their benefit in terms of flood risk reduction. It also has to take account of the multiple objectives for flood management, including economic efficiency, the environment and safety. A new approach to representing the performance of a flood defence system has been developed by the authors. The flood defence system is represented hierarchically providing an overview of system performance as well as more detailed insights into the performance of specific assets. Performance is measured by a set of performance indicators held in a database. These performance indicators are projected through value functions reflecting organisational objectives and regulatory standards and are merged to generate a figure of merit for the system and each subsystem. The figure of merit forms the basis for asset management decisions. Uncertainty in the available evidence is represented and propagated through the hierarchy, providing a commentary on sources and implications of uncertainty. A case study for the flood defence system surrounding a town demonstrates how the methodology provides insights into system performance and can be used to explore different asset management decisions.

Performance indicator

Flood risk management

10.1680/wama.157.1.35.36784

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Citations (6)

Level and distribution of DDT in surface soils from Tianjin, China

Chemosphere (2003)

Zitong Gong Shu Tao Fu‐Liu Xu Richard Dawson W.X. Liu

10.1016/j.chemosphere.2003.10.021

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Citations (138)