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

与气候变化相关的极端天气事件频率的增加导致地表水（雨洪）洪水的风险增加，对关键城市基础设施的完整性和功能构成了巨大威胁。2013/14年冬季，英格兰南部发生了12场大型冬季风暴，导致5000多所房屋、企业和基础设施被洪水淹没。绿色基础设施，以可持续城市排水系统（SUDS）的形式，已经被提议作为一种潜在的措施，可能对城市环境中的洪水风险产生重大影响。然而，尽管SUDS具有多功能效益，但往往无法达到洪水风险管理（FRM）成本效益评估的可行性标准。环境署（EA）强调了关于大规模sud改造计划的成本和效益方面的一些知识差距，特别是消除对创新解决办法的经济评价方面的不确定性的数据。科学界和工程顾问也认识到利用植被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来加强城市水管理的重要性。气候kic资助的蓝绿色梦想（BGD）项目聚集了杰出的合作伙伴，开发工具来评估城市水（蓝色）系统和植被（绿色）区域之间的相互作用，从而最大限度地发挥所谓的蓝绿色解决方案（包括SUDS）的多功能效益。在该研究的基础上，本项目将通过提高对蓝绿解决方案提供具有成本效益的洪水风险管理服务能力的认识和理解，将绿色基础设施干预措施作为资产分配。这将通过汇集三个BGD项目合作伙伴的专业知识来实现-伦敦帝国理工学院，Deltares和AECOM，并由EA Water London团队提供支持。伦敦巴尼特自治市的诱饵溪子集水区将作为一个案例研究：a)使用适应支持工具绘制基础设施保护的蓝绿色解决方案；b)通过量化创新蓝绿解决方案的多功能效益，改善系统的成本效益评估；及c)根据“洪水风险管理”评估，编制先进的工具，对拟议的系统安装计划进行全面的成本效益分析。这将使EA能够根据广泛的利益范围透明和客观地评估蓝绿解决方案。此外，它将为AECOM提供一个强大的商业案例，利用SUDS/蓝绿色解决方案来保护基础设施，从而减少与此类分析结果相关的不确定性水平。这个项目的产出将被用来为大伦敦当局提供证据，以制定一个泛伦敦的方法来提供可持续的排水系统。此外，更准确、更稳健的SUDS估值，以及每一英镑投资的全部回报，将使EA的SUDS改造项目能够与洪水和海岸侵蚀风险管理基金在援助资金中竞争。

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.