Relationships between geo-hydrological processes induced by heavy rainfall and land-use: the case of 25 October 2011 in the Vernazza catchment (Cinque Terre, NW Italy)

On 25 October 2011, heavy rainfall affected an area of ca. 1000 km2 between eastern Liguria and northern Tuscany (northwest Italy). The event caused floods, hundreds of shallow landslides, four casualties and severe structural and economic damage in Monterosso and Vernazza villages. The distribution of geo-hydrological processes triggered by rainfall in relation to land-use was analyzed in the Vernazza catchment. Both, an inventory map of geo-hydrological processes and a land-use map were prepared through air photo-analysis and field surveys; a derivative map combining these two outputs provides insight into the relationships between geo-hydrological processes and land-use. The density of shallow landslides (n/km2) and the frequency of erosional processes (%) are higher in terraced areas compared to other land-use classes. The study highlights the high vulnerability of agricultural terraces which, over the centuries, have been a fundamental tool for the prevention and control of erosional processes and slope instability

THE SOILS OF PORTOFINO PROMONTORY (NW ITALY): DISTRIBUTION, GENESIS AND PALAEOENVIRONMENTAL IMPLICATIONS.

The coverage of detailed soil maps is commonly limited in Italy, and the available regional soil inventories are obviously not adequate for local land planning strategies. The aim of this research is to map soil units using a Geographical Information System (GIS) approach in the Portofino regional park. Soil micromorphology has been selected as support to the laboratory routine analyses for studying some representative benchmark profiles in order to explain their genesis and to assess their palaeoclimatic significance. The spatial distribution and variability of the most extensive soil types were analysed using a GIS approach and are presented in a 1:10,000-scale soil map with a descriptive legend. We identified six RSGs: Cambisol, Regosol, Leptosol, Luvisol, Acrisol, and Umbrisol. This GIS database was then used to produce three derived maps: soil erodibility factor, spatial distribution of soil organic carbon (SOC) and soil hydrological groups. Deep and highly weathered soils were identified on an ancient erosional surface. These soils are relict palaeosols, products of longer pedogenesis, and are no longer affected by active processes. Polygenetic development of these palaeosols was underlined by micromorphological studies showing relict features reflect climate conditions typical of past interglacial periods which were warmer and more humid than today

Matsucoccus bast scale in Pinus pinaster forests: a comparison of two systems by means of emergy analysis

The bast scale (Matsucoccus feytaudi) is responsible for the destruction of most of the Pinus pinaster forests in the Mediterranean area, causing resination, defoliation and subsequent death of the trees. This study was carried out in Cinque Terre National Park (Italy), in which pinewood are partially affected by the bast scale M. feytaudi. A whole system evaluation is here proposed aiming at the assessment of the impacts, both on the environmental and economic side, arising from the P. pinaster losses in a certain territory. To this aim we compared a pinewood without visible damages from bast scale with a clearly damaged pinewood by means of emergy analysis. Bast scale reduced the arboreal composition of the stand favouring understorey species sprouting, which benefitted of increasing sunlight level caused by affected tree crowns reduction or trees fall. As a consequence of the changed forest\u2019s condition the system suffered an ecosystem services provision loss equal to 2250 EmV ha \uc01 year \uc01 that, if extended to the entire surface of the Cinque Terre National Park lead to a total loss of a million of Euro per year

Assessment of flash floods in a small Mediterranean catchment using terrain analysis and remotely sensed data: A case study in the Torrente Teiro, Liguria, Italy

Mediterranean catchments are particularly sensitive to temperature oscillations, rainfall intensity and human activities. Especially intensive precipitation events, changing land-use and thin soil layer trigger surface runoff generation and hence, soil erosion, sediment transport, flooding and related damages. In this study, we propose a methodology using remotely sensed data, terrain analysis and stochastic modeling to characterize the soil hydrological and physical components of the Teiro catchment. Particularly, we focus on the triggering land-cover and soil information that can be derived with multispectral remote sensing techniques. To study the hydrological dynamics of the Teiro catchment we applied the Soil Conservation Service Curve Number method implemented in a GIS system for different precipitation events related to various return periods. The input data was calculated based on multispectral indices describing the heterogeneity of soils and vegetation. The discharges obtained show reasonable values that have been validated with mapped flooded areas of the 4th October 2011 flood event. This event corresponds roughly to a 10 years return period. However, it is striking that a 50 years return period event was calculated to yield the double amount of discharge and thus, implies a major hazard for the local populatio