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Abstract. When floods hit inhabited areas, great losses are usually registered in terms of both impacts on people (i.e., fatalities and injuries) and economic impacts on urban areas, commercial and productive sites, infrastructures, and agriculture. To properly assess these, several parameters are needed, among which flood depth is one of the most important as it governs the models used to compute damages in economic terms. This paper presents a simple yet effective semiautomatic approach for deriving very precise inundation depth. First, precise flood extent is derived employing a change detection approach based on the normalized difference flood index computed from high-resolution synthetic aperture radar imagery. Second, by means of a high-resolution lidar digital elevation model, water surface elevation is estimated through a statistical analysis of terrain elevation along the boundary lines of the identified flooded areas. Experimental results and quality assessment are given for the flood that occurred in the Veneto region, northeastern Italy, in 2010. In particular, the method proved fast and robust and, compared to hydrodynamic models, it requires sensibly less input information.

Urbanization is a fundamental force of change and in Europe has underpinned the flourishing of civilization for millennia. However, the 21st-century is also witnessing the impact of other societal challenges, including climate change adaptation, and mitigation, as well as the need to secure the efficient utilisation of finite resources. These societal challenges are impacting not only the social fabric of urban life, and the economy of cities, but also the civil quality of urban environments throughout Europe. It is clear that if properly governed cities can become a major part of the solutions to the growing threat of these urban challenges, and so can become economically vital, culturally vibrant, and healthy environments delivering first-class quality of life for hundreds of millions of city dwellers throughout Europe. Nonetheless, the challenge of urban governance is immense, and must address the complex and interconnected reality of urban systems to secure a proper balance between the socio-economic and environmental dynamics of urban areas. The key to effective governance of cities is the generation of the necessary intelligence to inform decision-making by city administrations and politicians, to guide urban policy making and implementation, and to inform and engage all citizens in the delivery of sustainable urban development. The DECUMANUS project underpins this understanding that the delivery of more sustainable cities requires the application of enhanced intelligence in urban management, to produce an effective basis for assessment of urban complexity and decision-making. The enhanced services proposed by DECUMANUS offer the potential to provide urban planners with the tools and intelligence that allow city managers to deploy geo-spatial products in the development and implementation of their climate change strategies, and more generally in meeting the diverse challenges of sustainable urban development. The services are based on related state-of-the-art Earth Observation techniques, methodologies and products. The paper analyses the impact of the developed DECUMANUS services on urban governance and provides an overview of the services identified by the project city users as most relevant and useful for supporting the sustainable governance of the city.