Project ECCOMAT Ticino

Research in the field of erosion prevention and slope stabilization, whether of natural or artificial origin, is continually advancing. Emerging techniques, aside from providing an answer from an engineering perspective, are focused on reducing environmental impacts and providing more sustainable solutions. This research project involves the application and monitoring of a bio-based, biodegradable geotextile intended for helping revegetation and erosion control on slopes facing a combination of unfavourable conditions. Importantly, this approach aims to avoid long-term environmental traces such as microplastics. The present research project aims to test the evolution of erosion and greening of slopes following the application of biodegradable erosion control mats ECCOMAT, which are an innovative product compared to the old product of Geobrugg AG TECMAT. The ECCOMAT geotextile was developed by the company Geobrugg AG and is produced with degradable bioplastics. The mechanical properties of this material and its degradation time have already been tested in the laboratory, in partnership with the TCKT (Trasfercenter für Kunststofftechnik GmbH), to guarantee an ideal period for the development of vegetation and the consequent protection from the progressive surface erosion of slopes. Therefore, it is now desired to proceed to test the product in the field under real weathering conditions depending on territory, climate, and soil properties. To analyse the behaviour of the mats (ECCOMAT vs. TECMAT) in the field, two large-scale 1:1 test areas were identified. These two study sites, located one in Maroggia Piazzo and one in Chiasso Penz, differ in slope exposure, steepness, and microclimatic conditions. Following the installation of the geotextile for both sites in spring 2022, a comprehensive seasonal monitoring initiative spanning two years was launched, by analysing the evolution of the following parameters over time: 1. Erosion is quantified by a geodetic survey on the ground combined with 3D scanning of the slope using a laser scanner (LS Riegl VZ-4000). 2. Greening or rate of revegetation is assessed using UAV multispectral imagery to determine the NDVI (Normalized Difference Vegetation Index) with a DJI P4 Multispectral drone. 3. Soil temperature and moisture (humidity) under the mat are monitored continuously throughout the project duration (1 acquisition every hour) using scientific data loggers. In addition, for each study site, the following analyses will be provided: 4. the physical-mechanical characteristics of the soil such as its grain size (according to USCS classification), its permeability, and its shear strength. All the parameters collected on the field were compiled to assess: • The rate of erosion and greening based on the characteristics of each study site: altitude, exposure, steepness, and soil characteristics. • Evolution of temperatures and humidities under the ECCOMAT depending on the climatic conditions, through a comparison with the MeteoSwiss meteorological station of Stabio (the nearest in the area). • Finally, the differences between the areas covered with ECCOMAT, TECMAT, and the “free mat areas” were highlighted.