Improved techno-economic evaluation of Blue Green Solutions for managing flood risk to infrastructure

与气候变化有关的极端天气事件日益频繁，导致地表水(洪水)泛滥的风险增加，对关键城市基础设施的完整性和功能构成极大威胁。2013/14年度冬季，英格兰南部发生了12场重大冬季风暴，导致5000多户家庭、企业和基础设施被淹。以可持续城市排水系统(SUDS)为形式的绿色基础设施已被提议作为一项可能对城市环境中的洪水风险产生重大影响的潜在措施。然而，尽管有多功能的好处，但SODS往往没有达到洪水风险管理(FRM)成本效益评估的可行性标准。环境局强调了有关大规模肥皂剂改装计划的成本和效益方面的一些知识差距，特别是消除有关对创新解决方案进行经济评估的不确定性的数据。科学界和工程顾问也认识到，通过向城镇提供一系列基本服务和支持城市适应气候变化，利用植被加强城市水管理的重要性。气候-KIC资助的蓝绿色梦想(BGD)项目聚集了著名的合作伙伴，开发工具来评估城市供水系统(蓝色)和植被(绿色)区域之间的相互作用，从而最大限度地发挥所谓的蓝色绿色解决方案(包括肥皂水)的多功能效益。在这项研究的基础上，该项目将通过提高对蓝色绿色解决方案提供成本效益洪水风险管理服务的能力的了解和理解，将绿色基础设施干预措施作为资产进行分配。这将通过汇集三个BGD项目合作伙伴的专业知识来实现，这三个合作伙伴是伦敦帝国理工学院、Deltares和AECOM，得到了EA Water London团队的支持。巴内特伦敦区的Decoy Brook分集水区将被用作案例研究：a)利用适应支持工具绘制用于基础设施保护的蓝绿色解决方案图；b)通过量化创新的蓝绿色解决方案的多功能效益来改进肥皂泡的成本效益评估；以及c)根据洪水风险管理评估，制作一个先进的工具，用于对拟议的肥皂水改造计划进行全面的成本效益分析。这将使EA能够透明和客观地根据广泛的好处评估Blue Green Solutions。此外，它将为AECOM提供一个利用SUDS/Blue Green解决方案来保护基础设施的强大商业案例，以解决与此类分析结果相关的不确定性水平的降低问题。该项目的成果将被用来向大伦敦管理局提供证据，说明如何制定泛伦敦办法来提供可持续的排水系统。此外，更准确和可靠的肥皂水估值并显示每磅投资的全部回报，将使EA的肥皂水改造项目能够在平等的基础上竞争洪水和海岸侵蚀风险管理补助金的援助资金。

The increased frequency of extreme weather events associated with climate change results in the increased risk of surface water (pluvial) flooding, posing a great threat to the integrity and function of critical urban infrastructure. During the winter of 2013/14 twelve major winter storms occurred resulting in more than 5,000 homes, businesses and infrastructure being flooded in southern England. Green infrastructure, in the form of Sustainable Urban Drainage Systems (SUDS), has been proposed as a potential measure that is likely to have a significant effect on flood risk in urban environments. However, despite their multifunctional benefits, SUDS often fail the feasibility criteria of Flood Risk Management (FRM) cost-benefit assessment. The Environment Agency (EA) highlighted a number of knowledge gaps concerning the cost and benefits of large-scale SUDS retrofitting schemes, in particular the data to remove uncertainties concerning the economic appraisal of innovative solutions. The scientific community and engineering consultants have also recognised the importance of utilising vegetation to enhance urban water management by delivering a range of essential services to towns and cities and supporting urban adaptation to climate change. The Climate-KIC funded Blue Green Dream (BGD) project gathered eminent partners to develop tools for assessing the interactions between urban water (blue) systems and vegetated (green) areas and hence maximise the multifunctional benefits of so-called Blue Green Solutions (including SUDS). Building on that research, this project will assign green infrastructure interventions as assets by progressing knowledge and understanding of the ability of Blue Green Solutions to provide cost-beneficial Flood Risk Management services. This will be achieved by brining together the expertise from three BGD project partners - Imperial College London, Deltares and AECOM, supported by the EA Water London Team. The Decoy Brook sub-catchment in London Borough of Barnet will be used as a case study for: a) mapping of Blue Green Solutions for infrastructure protection using the Adaptation Support Tool; b) improving the cost-benefit assessment of SUDS by quantifying multifunctional benefits of innovative Blue Green Solutions; and c) producing an advanced tool for full cost-benefit analysis of the proposed SUDS retrofitting scheme in compliance with the Flood Risk Management assessment. This will enable the EA to transparently and objectively assess Blue Green Solutions against the broad range of benefits. In addition, it will provide AECOM an example of a robust business case for utilising SUDS/Blue Green Solutions to protect infrastructure that addresses the reduction in the levels of uncertainty associated with the results from such analyses. Outputs from this project will be used to provide evidence to the Greater London Authority on the development of a pan London approach to delivering sustainable drainage systems. In addition, more accurate and robust valuing of SUDS and demonstrating the full return on each pound invested will enable EA's SUDS retrofit projects to compete on an equal footing for Flood and Coastal Erosion Risk Management Grant in Aid funding.