Transforming the relationships between geoscientists and urban decision-makers: European Cost Sub-Urban Action (TU1206)

The European COST Sub-Urban Action (TU1206) has had the fundamental aim of closing the knowledge gap between subsurface experts and potential users of subsurface knowledge - urban decision- makers, practitioners and researchers. The Action assembled a network involving >30 countries, 23 actively participating cities, researchers, practitioners and urban decision-makers, and brought together the fragmented research and good practice across Europe in sustainable urban sub-surface use. Development of national exemplars has been encouraged, and good practice identified to inspire others, using a lighthouse-follower approach to cascade knowledge and good practice across Europe and further afield. Experts from both sides of the knowledge gap were brought together to assess and synthesise the state-of-the-art in lighthouse cities with respect to urban sub-surface knowledge, understanding, and use of that knowledge. This was achieved in 19 City Studies, with findings encapsulated in an over-view report "Out of Sight - Out of Mind". Expert sub-groups then identified good practice in subsurface data and knowledge locally, nationally, and Europe-wide. These are highlighted in the synthesis report "Opening up the subsurface for the cities of tomorrow", and expanded on in seven topic review reports. These also identified key gaps in knowledge, and its use. A new concept, GEOCIM is proposed for City Quarter to Conurbation scales, combining subsurface and above-ground models. These enable: a.) holistic urban planning; b.) identifying subsurface opportunities; and c.) saving costs by reducing uncertainty in ground conditions. Finally, the Action's reports and outputs were integrated within an online toolbox, and will be further outlined in the Final Report of the Action, to be made available on the Action's website. The Sub-Urban Toolbox promotes and disseminates the good practice, and decision-support tools: a.) to help better inform and empower city decision- and policy-makers about the sub-surface and the vital importance of its early-stage consideration; and b.) accelerate uptake amongst sub-surface experts of sub-surface modelling workflows. Users with different backgrounds and needs, require different access to, and appropriate translations of, the Sub-Urban Toolbox. Therefore different entry points are provided for sub-surface technical experts, and urban planners, and decision- and policy-makers. As the critical mass of city decision- and policy-makers that is better aware of the sub-surface and its sustainable use expands, the potential for higher level policy consideration of the subsurface grows, and a wider range of impacts will become achievable.