Green and Grey Drainage Infrastructure: Costs and Benefits of Reducing Surface Water Flood Risk

在英国，洪水已被确定为国家目前面临的最大挑战之一，地表水和河流洪水被认为是主要的贡献者（RGS，2016）。当渗透率和/或能力被超过时，会发生地表水泛滥，导致地表水径流在特定区域聚集，当这导致土地或财产受损时，特别令人担忧。城市排水基础设施定期建设，以防止和减轻这种积累的水，从而减少洪水风险，但昂贵的（无论是在资金和资源方面），以发展和维护这些。可持续城市排水系统（SuDS）被认为是一种替代方案，模仿自然生态系统，从而降低建设和维护成本（Brown，Keath & Wong，2009）。然而，与“灰色”系统相比，这些系统的有效性如何，尚未得到充分分析和理解，也没有对其大规模实施进行评估。因此，拟议的研究将着眼于解决这些挑战，并为需要进一步投资排水基础设施的地区提供明智的见解。为此，它将解决以下概述的研究目标，形成当前洪水风险，基础设施发展和排水有效性的全面画面，然后可以根据投资建议。排水基础设施的有针对性的改进最终可以降低英国地表水洪水造成的风险，并降低洪水事件期间的损失成本。

In the UK, flooding has been identified as one of the biggest challenges the nation currently faces, with surface water and fluvial flooding considered the dominant contributors to this (RGS, 2016). Surface water flooding occurs when infiltration rates and/or capacity are exceeded, leading to surface water runoff that collects in a given area, and is of particular concern when this results in damage to land or property. Urban drainage infrastructure is regularly constructed to prevent and alleviate this build-up of water, and thus reduce flood risk, but is expensive (both in terms of money and resources) to develop and maintain these. Sustainable urban drainage systems (SuDS) are considered an alternative to this, mimicking natural ecosystems and so reducing both construction and maintenance costs (Brown, Keath & Wong, 2009). How effective these systems are compared to their 'grey' counterpart, however, has not yet been fully analysed and understood, nor has their large-scale implementation been assessed.The proposed study, therefore, will look to address these challenges and offer an informed insight into regions requiring further investment in drainage infrastructure. To do so, it will address the research aims outlined below, forming a comprehensive picture of current flood risks, infrastructure developments and drainage effectivities, on which investment recommendations can then be based. Well-targeted improvements in drainage infrastructure could ultimately reduce the risk posed by surface water flooding in the UK, and decrease the cost of damages during flood events.