Sustainable Management of Urban Watercourses: The Vila Nova de Gaia Historic Center Case Study P. J. Ramísio *, D. Arezes** * CTAC, Department of Civil Engineering, University of Minho, Azurém, Guimarães, Portugal (E-mail: pramisio@civil.uminho.pt) ** CTAC, Department of Civil Engineering, University of Minho, Azurém, Guimarães, Portugal (E-mail: ldaarezes@gmail.com) Abstract: Watercourses in the urban environment play a relevant role, promoting sustainability conditions and improving the life quality of the regions. In this context, the management of this resource has face up serious challenges over the years. Climate change associated with an increasing imperviousness of soils in urban centers are added problems, increasing peak flows and their impacts. The study of new methodologies to mitigate these problems are, therefore, an urgent need. This article aims to present the case study of the Vila Nova de Gaia Historic Center, a UNESCO World Heritage Site, where water streams have, historically, been the support on urban activities. As a result, structural and non-structural measures are proposal, which is believed to have direct and positive impacts in promoting a more efficient management of these watercourses – mitigating their negative effects, namely floods – and enhancing the sustainable development of the region. Keywords: sustainable development; urban watercourses; watercourses management The urban growth observed in the last decades (UNDESA, 2014), the increased imperviousness of the soils in the big urban centers, and the changes of the meteorological patterns – with great precipitation intensities in short periods of time – has been giving rise to situations in which the urban drainage systems do not respond to the objective for which they were designed (Howden et al., 2007), leading to the need of requalification operations that guarantee the sustainability and efficiency of the entire grid (Meehl, et al., 2007). On the other hand, a significant part of the urbanized space is near watercourses, and due to the specific characteristics of these urban basins – generally of small dimensions and with low concentration times – the effect of the urban growth has direct impact on water quality (Jha, Bloch & Lamond, 2012). Therefore, an integrated and sustainable water management in the urban environment is crucial, resulting in economic and financial advantages for the municipalities and contributing greatly to the improvement of the cities livability as well as to mitigate the floods negative effects. Hydrological phenomena can not be avoided but their effects can be reduced, depending on the magnitude of the flow conditions – water height, flow rates and velocity - and the frequency with which they occur. The main problem is that there are no hydrometric data that allow for significative statistical analysis and the definition of return periods for short period floods. Hydrological and hydraulic models can solve, in part, this problem (Lee et al., 2012). Thus, the main goal of this work was to characterize, analyze and present an integrated solution for a real case study affected by this type of problems. The project includes three watercourses – Horto, Serpa Pinto and Santa Marinha –, located in the historic center of the city of Vila Nova de Gaia, Porto, Portugal, an area considered a World Heritage by UNESCO. This zone has a high population density – associated to a high tourist presence –, with impervious soils and accentuated topographic slopes. Reports of floods are frequent. At the same time, the economic impact of the Porto Wine industry and tourism are very important for the development of the region.