Integrated techniques for slope erosion modelling and badland monitoring in key sites of Central Italy

The growing interest in studying badland dynamics reflects the need to increase knowledge of geomorphologic processes and dynamics in subhumid badland areas, particularly because of their importance in generating extremes of water and sediment production. Field studies of soil erosion are expensive, time-consuming and data needs to be collected over many years. Though providing detailed understanding of the erosion processes, field studies have limitations because of the complexity of interactions and the difficulty of generalising from the results. Cost-efficient methods of estimating erosion over whole catchments are required as ways of predicting erosion after disturbance or following various erosion management strategies. Thus, the indirect estimation and the prevision of erosion rates is still one of the main research topics of the scientific community in the field of geomorphology and is far from solved. This Ph.D. research project is aimed at defining an integrated methodology of denudation intensity estimation and prevision, for areas greatly affected by badlands, and it is based on both quantitative geomorphic analysis and multivariate statistical investigations, in order to deepen the relationships between the main denudation effects and the potential causal factors favoring geomorphologic instability in badlands areas. The research have allowed to propose a statically based method for water erosion hazard assessment, conceived as a spatially distributed prevision of calanchi badlands, and associated erosion rate, occurrence. Direct measures of erosion intensity in badlands were used to validate the water erosion estimates and previsions. As the research project is focused mainly on methodological objectives, well-known study areas of Tyrrhenian side of central Italy, included within the Tevere and Ombrone River Basins, have been selected, in order to compare the results gradually achieved with the earlier available data. Erosion rate estimations were performed refining some empirical equations (“Tu Denudation index”), that estimate the suspended sediment yield (SSY) as a function of morphometric parameters related to drainage network and relief (Ciccacci et al., 1981, 1986). Tu denudation index was confirmed to be a good estimator of the suspended sediment yield (SSY) for catchments characterized by the prevalence of sedimentary and weakly coherent outcropping lithologies. The improvement of the regression relations contributed to better estimate sedimentary output for catchment widely affected by badland areas. In these basins, in fact, SSY is strongly correlated to the areal ratio affected by badlands to the total catchment area. Thus, using the not-projected drainage density parameter (D3d), instead of the traditional drainage density parameter (D), even if not improving the SSY estimation for large basins, was considered to better reflect the conditions predisposing erosions than D for smaller catchments, where large calanchi badlands and related high slope gradients are present. The dominant role of drainage density in estimating erosion rate for badland areas was confirmed by the attempt of zoning the estimated erosion rates using the Tu Grid Analysis. This attempt proved to be very efficient in estimating the erosion rate due to runoff within badland areas, as confirmed by the comparison between the estimated and the measured erosion rates. This result seems to increase the prospective of using Tu grid analysis when prolonged denudation monitoring is not possible. Moreover, even where punctual erosion rates are measured by pin monitoring, the estimated erosion rate map represents a validated continuous representation of water erosion rate for larger areas. Geomorphological susceptibility evaluation was performed applying a multivariate statistical method based on conditional analysis (Bayesian interpretation of probability) integrated by a proposal of a new method for most influential causal factors selection. The procedure provided satisfactory results for the unbiased prediction of landslide and water erosion susceptibility for the Upper Orcia Valley. The method is conceptually simple but, at the same time, effective in evaluating the conditional probability of hazardous events given a certain combination of causal factors: the proposed factor selection procedure has proved to be a useful tool for the unbiased detection of the factors really discriminant for instability landforms in the study area, and can be very helpful when analyzing new areas. Moreover the use of vector datasets allow to create vector easy-to-read susceptibility maps, in which the fragmentation generally characterizing raster outputs is avoided. These characteristics make this susceptibility method easy to be understood and each resulting map easy to be read, thus suitable for policy makers in planning land management strategies. The association of the estimated erosion rate for calanchi badland areas to the surveyed landforms allowed to use the susceptibility method to evaluate the water erosion hazard, since the temporal information about the erosion processes was related to the spatial data. This procedure is proposed when direct erosion rate measures are not available. Different techniques of direct monitoring of erosion rates and processes have been performed, with the aim of identifying the main geomorphic processes acting in the study areas and quantifying their intensity. In particular, direct measurements (erosion pin monitoring, geomorphologic survey, DGPS survey and digital photogrammetric analysis) were used to validate the results obtained after indirect erosion rate estimations and susceptibility and hazard assessment models application. Even though, interesting remarks have been concluded on the applicability of various methods of erosion monitoring. The size of the study area, the time available, and the quality of the data required are perhaps the most critical issues to be considered when looking for the most appropriate technique. As well-known, the traditional erosion pin method generally allows to carry out very accurate punctual measures, whose error is measurable in few millimeters. So, it can be used to quantify very detailed temporal variations (monthly or after-event ground level changes). On the other hand, DGPS survey can be proper when a single hillslope of less than few hectares is being monitored, as the time and effort required would be acceptable. For larger areas or wider time interval, high resolution photogrammetric analysis could be more appropriate. However, all these methods are affected by many error sources, that limit their use to very specific time and spatial ranges. Finally, some new contributions to the knowledge of the physical factors influencing the initiation and the development of different water erosion landforms in the studied badland areas have been achieved. Comparison of pluviometric data and measured ground level variations for Bargiano site (Tevere River Basin) has highlighted that clay removal by water erosion is generally due to intense rainfall event preceded by quite long dry periods, while accumulation (due to gully banks collapsing) is favoured by intense rainfall after a certain number of rainy days (frequent in spring). Moreover, in inter-rill position, where almost the lonely water erosion acts, intense events are significantly more effective than long events. Considering the distribution of calanchi and biancane landforms of Upper Orcia Valley (Ombrone River Basin) among the different classes of the main topographic and physiographic factors, it is a matter of fact that calanchi badlands develop on steeper slopes and where higher values of amplitude of relief occur, due to the morphoevolutionary processes. Moreover, observations on present embryonic biancane of Lucciolabella site confirm the leading role played by reticular systems of joints in the dissection of original, gently-dipping surfaces. Actually, a resolute difference on dispersivity level of the biancana parent material samples of La Piaggia subcatchment was not found with respect to calanchi badlands samples of the same subcatchment. On the other hand, a significant influence of clay properties was observed on the different erosion rates measured during decadal monitoring investigations by means of erosion pins in the study areas. Calanchi badlands show lower erosion rates due to surface runoff. The major facility of biancane clays to be entrained at very low stream powers is reflected in their major dispersivity, while, in badlands, the morphoevolution and sediment removal is predominantly caused by widespread mudsliding from the rill and gully heads, as also confirmed by the mean positive variations of ground level recorded at some calanchi monitoring stations. This observation can be also related to the higher sand content in calanchi badlands, which may favour the infiltration processes to the detriment of runoff. Finally, as already observed by several authors, the agricultural exploitation of these lands lead to a decrease of exchangeable cations concentration (and, thus, clay dispersivity), even if the permanent inhibition of chemical dispersion due to increase of soil stability hypothesized by Phillips (1998) cannot be completely agreed. Decadal monitoring and observation in the study areas and in other sites of central Italy have outlined that badlands initiation is even enhanced by agricultural manipulation: grazing and farming are among the most important triggers for accelerated water erosion, and tillage erosion has been recognized as an increasing factor of water erosion. The performed investigations have allowed to carry out some new remarks about both the applied and proposed methodologies and the studied areas and related processes. In particular, results from this research have contributed to improve some methods useful to deepen the knowledge of processes and denudation intensity acting in badland areas of Mediterranean drainage basins

Multitemporal dendrogeomorphological analysis of slope instability in Upper Orcia Valley (Southern Tuscany, Italy)

The Upper Orcia Valley (Southern Tuscany, Italy) is a key site for the comprehension of denudation processes typically acting in Mediterranean badlands (calanchi) areas, thanks to the availability of long-lasting erosion monitoring datasets and the rapidity of erosion processes development. These features make the area suitable as an open air laboratory for the study of badlands dynamic and changes in geoheritage due to erosion (i.e. active geomorphosites). Decadal multitemporal investigations on the erosion rates and the geomorphological dynamics of the study area allowed to highlight a decrease in the average water erosion rates during the last 60 years. More in detail, a reduction of bare land and, consequently, of erosion processes effectiveness and a contemporary increasing frequency of mass wasting events were recorded. These trends can be partly related to the land cover changes occurred in the study area from the 1950s onwards, which consist of the significant increase of reforestation practices and important other forms of human impacts on slopes, mainly land levelling for agricultural exploitation. In order to better identify the most significant phases of geomorphological instability occurred in this area during the last decades, an integrated approach based on multitemporal geomorphological mapping and dendrogeomorphology analysis on specimen of Pinus nigra Arn. was used. In detail, trees colonizing a denudation slope located in the surrounding of the Radicofani town (Tuscany, Italy) and characterized by calanchi and shallow mass movements deposits, were analyzed for the 1985-2012 time period. The analysis of the growth anomaly indexes and of compression wood allowed to determine a spatio-temporal differentiation along the slope and respect to an undisturbed reference site. The negative anomaly index results to be more pronounced in the trees located on the investigated slope with respect to the ones sampled in a non-disturbed area. Compression wood characterizes trees on slope sectors mainly affected by runoff and/or mass movements with a different persistence. Erosion rates were finally calculated through dendrogeomorphological analysis on tree roots exposure (0.31-3 cm/y runoff prevailing; 5.86-27.5 cm/y, mass movements prevailing). Dendrogeomorphological results are in accordance with those obtained in the investigated areas with multitemporal photogrammetric and geomorphologic analyses

Contribution for an urban geomorphoheritage assessment method. Proposal from three geomorphosites in Rome (Italy)

Urban geomorphology has important implications in spatial planning of human activities, and it also has a geotouristic potential due to the relationship between cultural and geomorphological heritage. Despite the introduction of the term Anthropocene to describe the deep influence that human activities have had in recent times on Earth evolution, urban geomorphological heritage studies are relatively rare and limited and urban geotourism development is recent. The analysis of the complex urban landscape often need the integration of multidisciplinary data. This study aims to propose the first urban geomorphoheritage assessment method, which originates after long-lasting previous geomorphological and geotouristic studies on Rome city centre, it depict rare examples of the geomorphological mapping of a metropolis and, at the same time, of an inventory of urban geomorphosites. The proposal is applied to geomorphosites in the Esquilino neighbourhood of Rome, whose analysis confirm the need for an ad hoc method for assessing urban geomorphosites, as already highlighted in the most recent literature on the topic. The urban geomorphoheritage assessment method is based on: (i) the urban geomorphological analysis by means of multitemporal and multidisciplinary data; (ii) the geomorphosite inventory; and (iii) the geomorphoheritage assessment and enhancement. One challenge is to assess invisible geomorphosites that are widespread in urban context. To this aim, we reworked the attributes describing the Value of a site for Geotourism in order to build up a specific methodology for the analysis of the urban geomorphological heritage

Geomorphological classification of urban landscapes. The case study of Rome (Italy)

The results of a long-lasting geomorphological survey carried out in Rome are summarized. A method aimed at integrating survey data, historical maps, aerial photographs and archaeological and geomorphological literature produced a geomorphological map of the present-day historical centre. The geomorphology of Rome is related to the paleogeographical conditions prior to the founding of the City; they allow us to recognize the stages of landscape evolution of the ancient Caput Mundi (Capital of the World). The study area has been affected by continuous man-made changes to the drainage network and to the topographic surface over the last 3000 years. It has forced the authors to develop innovative solutions to undertake effective analysis of the urban environment and the legend of the geomorphological map in this peculiar context. The resulting map is useful for urban planning and archaeological research

Geomorphology of the historic centre of the Urbs (Rome, Italy)

Based on long-lasting multidisciplinary and multitemporal investigations, in 2016 the first geomorphological map of the central area of Rome was presented. It introduced innovative solutions for cartographic restitution of urban landforms. Under this work, the urban geomorphological analysis delved deeper, because the study focused on the smaller area of the Urbs, the ancient city centre that has been modified by human activities over millennia. The main goal of the new study was to verify if the 1:5000 scale survey could allow to improve the legend symbols, in order to better represent landforms from natural and anthropogenic processes in urban environment. Since the map scale was doubled compared with the previous and consequently the map area available was four times bigger, we were able to provide much more details. Moreover, results better highlighted the applicative significance of urban geomorphological maps as complementary tool for the assessment of natural hazards and risks

Cathodal transcranial direct current stimulation improves focal hand dystonia in musicians: A two-case study

Focal hand dystonia (FHD) in musicians is a movement disorder causing abnormal movements and irregularities in playing. Since weak electrical currents applied to the brain induce persistent excitability changes in humans, cathodal tDCS was proposed as a possible non-invasive approach for modulating cortical excitability in patients with FHD. However, the optimal targets and modalities have still to be determined. In this pilot study, we delivered cathodal (2 mA), anodal (2 mA) and sham tDCS over the motor areas bilaterally for 20 min daily for five consecutive days in two musicians with FHD. After cathodal tDCS, both patients reported a sensation of general wellness and improved symptoms of FHD. In conclusion, our pilot results suggest that cathodal tDCS delivered bilaterally over motor-premotor (M-PM) cortex for 5 consecutive days may be effective in improving symptoms in FHD

AUTOMATED SEMANTIC AND SYNTACTIC BIM DATA VALIDATION USING VISUAL PROGRAMMING LANGUAGE

Building Information Modeling (BIM) is part of a digitalization process that, in recent years, has been revolutionizing the way buildings and infrastructures are designed, built, and maintained. Compared to traditional processes, BIM enhances the production and the management of data related to buildings and infrastructures throughout their life cycle. It is founded on a three-dimensional graphical model based on the specificity of project goals following the “level of information need” defined in BIM procurement documents. In this framework, an automated process for checking information within a BIM model plays a role of fundamental importance. Although this increases the model’s reliability, on the other hand, it decreases the time of working. Therefore, this research aims to develop a working methodology based on Visual Programming Language (VPL) for an automated BIM Data Validation process. This workflow aims to meet the growing need of owners to centralize data relating to their real estate assets to always have the appropriate one at the operational level. This methodology has been tested in different case studies to evaluate the strengths and weaknesses of using a standardization protocol in a large portfolio and complex buildings. This allows the huge amount of data from BIM models to be checked and summary reports to be produced, sharing with the various stakeholders involved in the knowledge process

Landslide susceptibility assessment in the Upper Orcia Valley (Southern Tuscany, Italy) through conditional analysis: a contribution to the unbiased selection of causal factors

Abstract. In this work the conditional multivariate analysis was applied to evaluate landslide susceptibility in the Upper Orcia River Basin (Tuscany, Italy), where widespread denudation processes and agricultural practices have a mutual impact. We introduced an unbiased procedure for causal factor selection based on some intuitive statistical indices. This procedure is aimed at detecting among different potential factors the most discriminant ones in a given study area. Moreover, this step avoids generating too small and statistically insignificant spatial units by intersecting the factor maps. Finally, a validation procedure was applied based on the partition of the landslide inventory from multi-temporal aerial photo interpretation. Although encompassing some sources of uncertainties, the applied susceptibility assessment method provided a satisfactory and unbiased prediction for the Upper Orcia Valley. The results confirmed the efficiency of the selection procedure, as an unbiased step of the landslide susceptibility evaluation. Furthermore, we achieved the purpose of presenting a conceptually simple but, at the same time, effective statistical procedure for susceptibility analysis to be used as well by decision makers in land management