Since at least one millennium, terraced systems are the dominant feature of the Ligurian landscape. They witness the capacity to adapt and develop cropping systems on morphological environments usually inhospitable to agricultural activities. The territory of Chiavari and Lavagna, in the Ligurian Levante sector, overlooks the suggestive Gulf of Tigullio. On one hand, Lavagna still shows a prevalent rural dimension and survived the edification process during the Sixties; on the other hand, Chiavari has drastically changed during the strong urbanization process occurred since the second half of the XX century.
Vernazza, one of the famous ‘Cinque terre’, based its economy especially on viticulture activities, setting up terraces on any possible strip of land, even in almost inaccessible areas. Terraced systems reached the maximum expansion at the end of the XIX century. However, during the XX century, the Phylloxera affected all the wine varietals and forced many farmers to migrate elsewhere. Hence, a demographic decline started in the area: such important demographic decay drove to drastic reduction of terraces maintenance and, therefore, the increase of the hydrogeological risk which made the Ligurian territory much more susceptible to structural instability and to important erosion processes. And with the menace of climate change terraces – well maintained however – can mitigate the extremes of weather conditions (severe droughts and heavy rains).
Abandonment of terraced slope areas often implies potential danger of different magnitude, according to several geomorphological, climatic and construction factors: from the fall of pieces of dry-stone walls, to important land movement which can involve entire, and sometime very wide, sectors of the slope areas. The risk can have a wide range of variability, according to the different degree of land use and urbanization.
By evaluation of the slope stability, is it possible to develop a parameterization and risk assessment related to the abandonment or insufficient use of terraced systems? How to develop preventative risk measures in wide areas such as several terraced spaces?
Which actions can be taken to minimize the hydrogeological risk in abandoned areas? What is the risk perception from the population in proximity of terraced system without maintenance and agricultural activities?
The thematic session Environmental and hydrogeological risk, organized in a territory tragically and continuously involved by flood events and slope instability, will collect studies, good practices and suggestions to mitigate the risk, in order to develop strategies and guidelines to secure the degraded slopes in terraced system.