Urban Flood Resilience in an Uncertain Future

Summary

The engineering core of this project couples an array of carefully selected, physics-based models to support investigation of how stormwater cascades through a city's drainage system, accounting for the dynamics of not just water, but also sediment, debris, natural solutes and contaminants carried by urban runoff. Based on the capability of this suite of models to simulate water flow, storage and quality within an urban system, we will investigate how the performance of grey systems (composed mainly of lined channels, pipes and detention tanks) can be improved by adding Blue-Green Infrastructure and Sustainable Drainage System (SuDS) to create treatment trains designed to manage both the quantity and quality of urban runoff. Models and design solutions will be developed and tested in the contexts of retro-fit (as part of urban renewal and uplift in Newcastle-upon-Tyne) and new build (as part of creation of a 'garden city' in Ebbsfleet, Kent). Our intent is to work out and demonstrate how resilience to floods and droughts can be achieved using integrated systems of Blue-Green and Grey assets, no matter how climate changes in future, assuring continuous, long term service delivery.

The work will adopt throughout a whole systems perspective that recognises interdependencies with other urban systems, including transport, energy and land-use. This will identify new opportunities for managing stormwater as a resource that will then be explored. This will add to the multi-functional benefits of using Blue-Green infrastructure to manage flood risk by increasing water security. Possibilities range from non-potable uses in homes or commercial buildings (based on rainwater harvesting) to irrigating green infrastructure (e.g. street trees), managing subsidence in clay soils, soil moisture enhancement and groundwater recharge. Wider benefits may extend to local energy generation using drainage infrastructure (i.e. micro-hydropower) and enhancement of urban watercourses and ecosystem services.

The models and protocols developed will form the basis for assessment of the potential for the optimised combinations of Blue, Green, Grey and smart infrastructure to deliver multiple-benefits in UK cities nationwide.

However, the goal of optimising urban flood and water management can only be achieved through a deep understanding citizen and community preferences with respect to managing flood risk. In short, engineering solutions must be better informed and explicitly accounted for in urban planning and development at all spatial scales. For this reason, our research will extend to investigation of the planning, development and organisational systems that govern urban flood risk management. This will be addressed using Participatory Action Research and Social Practice Theory to examine the attitudes and responses of citizens and communities to innovation in flood and water management, with the context of urban planning.

This aspect of the work is essential to underpin and enable implementation of the engineering analyses and solutions identified in the core research outlined above.

The mechanism for bringing together engineering, social and planning components of the project will be co-location research in Newcastle-upon-Tyne and Ebbsfleet, Kent. Team research in these case study cities will establish how barriers to innovation can be overcome despite uncertainties in future urban climates, land-use, development and political leadership. Critical engagement with planners, developers and land-owners throughout the project will feed back and inform the core engineering focus of the work, building on the current trend towards the development of urban infrastructure observatories to explore responses to the innovative changes needed to achieve urban flood resilience.