Bio-engineering interventions to maintain the settlement of the Valtellina historical slope steps

An historical system of hill characterize the slope of the ‘Retico dell’ Adda prelaucale’ in Italy. This area is situated in the Alps and it extends, hydrographically, for the most part to the left from the bottom of the valley to a variable height, depending on the placing of the sites, with a height difference of between 300 and 500 m, and a width-difference that goes from a couple of hundred metres to between 800 and 1000 m. Aware of the great environmental and socioeconomic valence the italian Authority laid down the 102/90 Law. With this law the basis for the planning of the operations finalized in the maintenance in efficiency of the system of hill terraces has been settled. Since then the regional and local authorities carry out the activities prewied in the Valtellina Reassessment Plan. The Valtellina area in question is chararacterized by the presence of man-made terraced pieces of land from different periods, some extremely old, supported by more or less dry-walls and served by a rural road network that links the various communities. On these terraces rural communities dedicated to agricultural activity, in particular the cultivation of vines, have settled. These activities have gradually reduced even in the areas considered to be of better agricultural quality as a consequence of the progressive abandonment of the land by the local population. This has caused the abrupt loss of an incalcuable countryside heritage and the worsening of conditions for hydrological stability on the slopes overlooking the communities and the bottom of the valley.