Adaptable urban drainage: Addressing change in intensity, occurrence and uncertainty of stormwater (AUDACIOUS)

Local drainage systems are crucial to everyone. These comprise building drainage systems and the drainage networks around buildings, locally in streets and in small ditches and watercourses. Problems arise both due to the inflows to the system, which in future will be less certain, and increasing downstream hydraulic and regulatory constraints on outflows. In addition, key stakeholders often find it difficult to engage due to the complex institutional structure of flood risk management in England and Wales. The major drivers identified for future increases in flood risks relate to rainfall, environmental legislation, urbanization and urban planning. In a recent UK government study it was identified that traditional solutions to managing urban drainage related flood risk changes are likely to be too costly and that alternatives need to be found. The development of an analytical approach to local urban drainage that takes account of potential future changes, such as climate and urban form, is described that will allow alternative adaptable solutions to be evaluated. The approach has been applied to several case studies. The effectiveness of these processes in the light of changing future risks is reviewed and a proposed framework and guide for adapting urban drainage systems to climate change presented.