Sion is a crossing city, an intermodal center, connected to different territorial scales and able to link different streams and life styles. The aspect that makes Sion a very special place is that its capacity to be a catalyzer is concentrated in the close landscape of a Swiss Alps valley. The mountains surrounds the city as a bowl, projecting it in a world apart. The visitor’s look is led towards the sky and the time seems to float gently in a soap bubble. The only accidental point is placed along the railway line, where the prospective completely changes and shows the complexity of this urban reality.

SWISS. The swiss orografy is so imposing that it constitutes the most important code to understand the urbanisation process of this territory. Swiss urban structures are constituded of conglomerations which have developed in the flat areas taking a form which is exactly the negative of the mountain’s shape. Those conglomerations follow the stream of the rivers, whose flows corroded the mountains’ body creating linear infiltrations. Sion, in particular, is placed in a thin valley, being the only urban surface in its canton, the Valais. This valley is an isolated canal, with a continuous non omogenic urban character. It connects the big conglomeration of the north part of Switaerland with the metropolitan area in the south, belonging to the vision of a policentric country, constituted by different networks, intergrated and divided by rural and natural areas From this point of view, the valley really appears like a thin chain which connects big scale systems. It is able to canalize dense streams and to put itself in connection with big dynamic urban processes. On the other side it has no possibilities to drag its development through transversal connections running the risk of being not able to get nourishment from those main streams. Policentric Switzerland, constituted by different networks, intergrated and divided by rural and natural areas. It certainly has the potential of being a linear model of metropolitan area. The future of Sion is deeply influenced by the role that this area will obtain in the national dimension. That’s why the project departs considering the valley as a programmatic area where Sion’s project is coherently inserted.

VALLEY. The structure of the valley follows its shape faithfully.It works like a tube which canalises linear and continuous infrastucturing systems. The river, the highway and the railway pass through the valley. These infrastructures flow constantly in the deepest and flat area of the section, modifying the territory with different strategies. The system of the river is functionally connected to the agricolture. This activity designs the surface of the valley through the constructions of irrigation canals and terracing systems. This texture almost covers all the valley’s free surface deforming itself in relation to the orography. The highway infrastructures the territory in a capillar way connecting little urban centers into a net and reaching also the ones placed in the high part of the valley The railway is certainly the most interesting among these infrastructures. On one side its stiffness doesn’t allow a capillarity into the territory, on the other side it is able to activate a urban development in the areas between the railway field and the old cities structures, re-enforcing the weight of the centers and stimulating a transport oriented urban development.

To work on the station district of Sion means to activate the potential of a metropolitan area which flows into the valley. This we will call the “Flowing City”.

THE FLOWING CITY IS SUSTAINABLE. It is based on a transport oriented strategy and it works with the concentration of density. It is aimed at reducing the costs of transport and the costs of infrastructuring the dwelled territory. It also means to preserve natural resources which constitute a factor balance in the city development. In the last 50 years the railway transport doubled, while the airway system became 5 time bigger. Developing the railway system means to increase the exchange possibilities promoting the use of soft mobility.

THE FLOWING CITY IS NOMAD. It is the city of mobile users, based on the possibility of mouvement into the conglomeration system, connecting the valley to the national and international channels. The flow of temporary users is able to double the population during the working hours. This temporary population uses the structures of each city overcrowding them without the possibility for the nomad population to be active in the Administration and development of the Flowing City.

The project of the Flowing City has to be supported by the creation of new spaces and new Institutions able to intergrate the the traditional city with the new one.

The infrastructure is an active social space of the Flowing City. The marginal spaces along the railway are spaces of potential development. The Flowing City has to be recognizable, linked to the territory and able to offer services and spaces related to the differnt times of use overlapping.

1. The Flowing City occupies the ground between the railway and the stable city building up a threshold of virgin soil which constitute the foundation of the new city. This soil is dragged and follows the direction of the railway in order to receive a sistem of new connections and take form by it. It draws an ideal limit between the stable and the mobile city offering a possible base of new interactions. 2.On this soil new connecting paths find place in order to link the functions in the Flowing City and in order to connect the Flowing City to the stable city creating the possibility to move with different speeds. The railway is not a limit anymore, it becomes a possibility of linking. 3.Insertion of buildings able to host the functions of the Flowing City’s program. Those buildings are points of densification and reception of the different flows running on the Flowing City’s ground. They have to be recognizable as land marks and contain a mixed functional program

RECEPTION PROGRAM. The program of the Flowing City departs from the specification of the different categories of mobile users. We divide this population in city users and commuters. The city user is characterized by a regular daily flow and they use the Flowing City in order to work in it or to be connected to other destinations. They need a set of services characterized by a speed consumption. On the other side the commuters population has a more unforeseeable frequency and can be attracted into the Flowing City from one day to a period of 6 months. They are attracted by working opportunities or by cultural interests. They are residents of the Flowing City. The services offered for this kind of users promote the specific potential of the local territory and constitute a gate to the re-launching of the economy of the stable city.

The project for Sion can be thought as the first application of the Flowing City, the one which could promote a developing of this parallel system also for the other cities of the valley. The concepts of ground, streams and catalyzers get a specific formal approach connected to the suggestions offered by the site. The site offers an excellent opportunity to build a new layout space able to characterize and activate the station district, thinking to a relevant intervention which can satisfy the future development needs of Sion. The whole space of the station square is invaded by the railway line, and the limit between infrastructuring space and infrustructured space disappears showing the station district as a gate to another dimension. The ground is capable of being deformed, it swells and become multilayered , creating a connective underground space and a soft surface. These two spaces are connected through holes which mark the position of the buildings. The ground is crossed by the connective streams. Each crossing system is characterized by a different speed in addition to the different speeds of the railways. The bridging system permits to pass to step over the railway area and to integrate the south part of the city into the project. This stream brings to the existent underground gateways connecting every level of the area. The cycling lanes allow to cross the area in a fast way and are connected to the exchange points. The spiral system is a walking lane whose main aim is to lead to the entrance of the buildings. The last system is a second walking path system wich takes along for a a walk without a clear destination and offers the possibility to stop or stay. The buildings floats on the ground and are hugged by the different lanes. The buildings are bubbles able to capture the flows from the underground and from the surface projecting them up. These “floating bubbles” are landmarks which contains and comunicate the main vocation of the building. Every bubble is connected to the underground, contains the main representative function on the top , a interfacing function at the surface level and a mix of functions in the middle section. This part contains living, commercial and cultural activities, mixing them toghether in relation to different times of use.

Every bubble catalyze different uses and different times of use. They are a meeting point for the stable population, city users and commuters. The auditorium, the public green house, the public square and the wellbeing center are integrated with producing, consuming and living spaces. Every floor is a mixed layer which proposes a particular lifestyle. The residential offer is based on a research on the sharing possibility of different kinds of living space. Depending on the time of residence the proportion between individual space and shared space changes in a sensitive way. The shorter the residence time is, the more the program provides big shared spaces. Every floor is the result of spaces which have different sharing levels and offer the possibility of new metropolitan dynamics. The mobile users have a different perception and conception of spatial use and are more inclined to share also essential services, building new categories of relations and going over the conception of generic space related to the spaces of mobility.