Mapping Flood Risks with Future Flow and Precipitation

联合国减少灾害风险办公室估计，洪水每年影响1亿人，造成140亿美元的经济损失（1980年至2008年的平均值）。英国每年的经济成本估计为11亿英镑，到2080年将上升到270亿英镑（国家审计署，2011；科学技术办公室，2004）。人们普遍认为，洪水风险是全球关注的主要问题，在不确定的气候下对其进行管理正变得越来越重要。在英国，环境署和一些地方当局已经着手绘制当前气候条件下的河流和洪积洪水范围图。在工业内部，也存在易受洪水影响地区的基线地图，用于风险管理。然而，随着预测的河流流量和降水的变化，预计未来洪水事件的频率和规模也会发生相应的变化，从而导致未来洪水风险的不确定性。此外，考虑到英国日益增长的城市化和土地覆盖变化，各种来源的洪水的总体暴露可能会增加。私营和公共部门的许多利益相关者的决策依赖于对未来洪水风险的更好理解。然而，目前与未来洪水风险有关的规划和资产管理的决策或假设情景工具有限。该项目将在一个试验场为未来的洪水风险开发一个原型地图服务，重点关注河流和强降雨引发的洪水。最近发布的预测流量时间序列数据集将用于预测未来河流的洪水风险。将采用一种基于敏感性的方法来估计强降雨对地表水洪水的潜在影响。将生产可视化和通信工具，以了解最终用户的需求。该项目还将评估遥感数据在洪水风险管理，特别是洪水建模方面的可用性。将为以前的活动收集遥感数据，例如雷达、航空照片和卫星图像。数据将用于评估它们为洪水模型和模型评估提供输入数据的能力。该地图服务预计将使广泛的利益相关者受益，包括（再）保险业、公用事业公司和地方规划当局。

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.