VA L L E M A G G I A SIMULATIONS The simulation tool played a fundamental role in the design process. Different models might generate various knowledge and be used for diverse purposes. First of all, through an abstract Excel model, it was possible to obtain basic knowledge about our design material, the mountain rivers landform and its features such as braiding configuration, water and sediments movement, islands and pools formations (page 37-38). Moreover different overall site specific conditions have been tested, in order to transfer the knowledge from general to particular. On one hand Caesar software provided the actual state of Maggia river flooding behaviour, then on the other, through a Grasshopper definition, potential overflow scenarios have been conceived (page 39). Finally in a very local scale some possible interventions to design within a dynamic natural process have been experimented. The alteration of the topography in terms of removal of hard borders, creations of channels, islands and pools is primary to let the river establish and consolidate its ecological value and riparian landscape. The combination Rhino, Python and Caesar softwares guaranteed the possibility to use the simulation tool in a more propositive and projective way (page 48). BRAIDING RIVER MODEL The intention behind this particular kind of simulation is to understand the general natural behaviour of the braided river landform. Which are the parameters that influence the conduct of the water? How does the braiding happen? Might different topography and slope conditions affect this process? Which is the role of sediment movement within this geomorphological course? What is the relevance of the time scale and in which way does it transform the landform? The Excel definition could give a generic but incisive answer to all of them. As a matter of fact the braiding formation is physically affected by the configuration of the land in terms topography, slope, width of the braidplain and the initial breadth of the several streams. The generated outputs might be easily compared and through an animation, more than a static paper, they can powerfully convey these kinds of information. On the contrary the limits of this model are relative to the impossibility to manipulate and use in a continuos loop the output results. In addition the data which could be input don’t allow explorations on site specific conditions and they remain at a rather general level. Another drawback is related to the time range: in this model the time factor is associated to the number of iterations run and not to a defined time scale. The different step outputs are then evaluated and temporalized through reasonable assumptions, comparing this model with the results developed by Caesar software.
Figure 83. Braidings of the Tagliamento river, Italy.
36 T H E R I PA R I A N L A N D-S H A P I N G M AC H I N E