Mapping Flood Risks with Future Flow and Precipitation

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The United Nations Office for Disaster Risk Reduction estimates that flooding affects 100 million people and results in $14 billion of economic damage every year (average values 1980-2008). Annual economic costs in England are estimated at £1.1 billion, rising to £27 billion by 2080 (National Audit Office, 2011; Office of Science and Technology, 2004). It is widely accepted that flood risk is of major concern globally, and that its management in an uncertain climate is becoming increasingly important. In the UK, mapping of fluvial and pluvial flood extent for the current climatic conditions has been undertaken by the Environment Agency and some local authorities. Within industry, there also exists baseline mapping of areas vulnerable to flooding for risk management purposes. However, with the predicted changes in river flows and precipitation, the frequency and magnitude of future flood events are expected to change accordingly, resulting in uncertainty of future flood risks. Furthermore, given increasing urbanization and land cover changes in the UK, it is likely that the overall exposure to flooding, from various sources, will increase. The decision making of many stakeholders in both private and public sectors relies on a better understanding of future flood risks. However, there are currently limited decision-making or what-if scenario tools for planning and asset management in relation to future flood risks. This project will develop a prototype mapping service for future flood risks at a test site, focusing on flooding from both the river and intense rainfall. A recently published dataset of projected flow time series will be used to generate future flood risks from the river. A sensitivity-based approach will be used to estimate potential impact of intensified rainfall on surface water flooding. Visualisation and communication tools will be produced to understand end user needs. This project will also evaluate the usability of remotely sensed data for flood risk management, in particular flood modelling. Remote sensing data including, e.g. RADAR, aerial photos and satellite images will be collected for previous events. Data will be used to evaluate their capacity for providing input data for flood modelling and model evaluation. The mapping service is expected to benefit a wide range of stakeholders, including, e.g. (re)insurance industry, utility companies and Local Planning Authorities.