The study concerns the River Ripoll space, a major tributary of the Besos in the metropolitan area of Barcelona. It defines the main features of the river "blueprint" a strategic area for the great Barcelona. Along the river confront two different rationalities: that of natural dynamic, systemic, complex and fundamentally unitary and urban rationality as complex but fragmented and diverse, often contradictory.
The study is divided into parts that each conclude with a scenario: first, the river as an ecological object, made with the " reasons of the river " scenario, in extrêmisant opportunities to return to large areas of expansion water. The second part (the river as an object of rationalization, expression of a hydraulic safety research, energy production and related industrial production) and the third (the river as political and social object) articulated two scenarios that ask "reasons of the city." In a scenario of " introverted river " that extrêmise current trends and leaving the Ripoll in the current position of marginality in relation to cities nearby. The inland area is privatized and inaccessible because of vegetable gardens, industrial tapes, major infrastructure that fragment . What future for this type of relationship with the river, also motivated by social and productive reasons?
On the other side the last scenario explores the consequences of extending the urban area to the river: it is to overcome the barrier, to invent a new public space for activities related to habitat and at the metropolitan level.
The three scenarios are not projects, or better they are special forms of project that question the possibilities that can talk about the future clarifying the different logics that define the arena possible. They do not build free or simplified contradictions, but they require to make explicit the points of conflict and so they require to go deeper into the possibilities of coexistence of different viewpoints.