The water footprint of city naturalisation. Evaluation of the water balance of city gardens

摘要

The new paradigm regarding the role of urban infrastructures related to the urban water cycle in cities is based on three strategies: improving water use efficiency, avoiding water contamination and restoring natural water streams. Achieving an improved water balance in cities is an ambitious objective that involves the naturalisation of cities and, in the specific case of consolidated areas, the multiplication of green spaces by developing green areas scattered by public roads. The water in and out the city gardens is modelled for the first time by including the water necessities of the plants. This work presents a methodology to assess new urbanistic projects by means of adapting the calculation of the water footprint developed by Hoekstra and Chapagain. The latter is most commonly applied to the agricultural sector, and it is adapted for the evaluation of a street project in Seville, Spain. The estimation of the water balance of an urban system in the presence of greenery, with a biophysical perspective and a spatiotemporal scale based on the incorporation of local data and water consumption in the urban sector, until now has been scarcely explored. The model developed helps to differentiate urbanisation projects, both to identify those alternatives that are best suited to each urban environment and to define specific objectives, and subsequently to predict the resilience of solutions using the local scenarios.