STONEWALLS4LIFE - using Dry-Stone Walls as a Multi-purpose Climate Change Adaptation tool: preliminary results in terms of geological and geomorphological quantitative analysis.

Due to its rugged morphology and a general lack of flat areas suitable for cultivation, Liguria region is widely characterized by slope terracing, carried out by its inhabitants for centuries. Slope terraces are usually retained by dry-stone walls; secondly, by retaining walls made of stones bounded by lime mortar or by grassy edges, in this case characterized by the absence of retaining structures.

The widespread abandonment of rural areas that occurred in the second half of the last century resulted in a diffuse lack of dry-stone walls maintenance, which is a fundamental activity in order to keep the function of dry-stone structures. Such aspect, together with an increasing occurrence of extreme hydro-meteorological events over the last years, accelerates the dry-stone walls decay and collapse, as well as the instability of single terraces and consequently of the whole terraced slope.

This is the case in which the Cinque Terre National Park (eastern Liguria, north-western Italy) is involved, a narrow strip of land close to the seaside and characterized by small valleys and terraced slopes showing high steepness values. This anthropogenic landscape represents a high-value peculiarity attracting more than three million tourists every year.

The main objective of the project is to demonstrate how an ancient technology, drystone walling, can be effectively used to improve the resilience of the territory to climate change by adopting a socially and technically innovative approach. Stonewalls4life started in the second half of 2019 involving many subjects, both public bodies and privates, in a multidisciplinary workgroup.

More into details, it will be demonstrated on a specific site measuring 6 hectares (Manarola, Cinque Terre) the climate change adaptation effectiveness of the approach by restoring abandoned drystone terraces, making them more resilient with innovative techniques; at the same time, three additional sites were identified in order to test the approach under different circumstances (two within the same territory, one in Catalonia – Parc del Garraf – with dissimilar conditions). Furthermore, from a scientific point of view, the project will allow to carry out a quantitative and objective assessment of the dry-stone walls effectiveness against extreme rainfall events, through the installation of several multiparameter stations that will record in continuous a set of geo-hydrological parameters associated to walls.

An extensive and detailed geological and geomorphological survey activity along with GIS analysis and bibliographical research has been carried out in order to create a geological-structural model of the aforementioned site and to identify its geomorphological features. Moreover, an accurate mapping and analysis of dry-stone walls has been performed employing an innovative approach developed in the frame of the project and based on field-surveyed and remotely-sensed data.

The outcomes represent a solid base for the implementation of the future phases of the project, in particular to understand the relationship among the geological, geomorphological and anthropic features of the area with the terraced-slopes stability in order to develop an accurate management plan concerning the dry-stone walls recovery activity.