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Geographic placement: San Fruttuoso (red rectangle ), in Portofi no Park in Liguria Region, northwestern Italy (A), San Fruttuoso bay (B). Photo by: A. Girani.
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Man-made terraces represent both a cultural and environmental asset. This important human modification has determined changes in the original balance of geomorphological and geo-hydrological factors, representing a human interference with the geomorphic system. The abandonment of lands, according to altered socioeconomic condi- tions and climate ch...
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Citations
... The San Fruttuoso basin is considered highly significant for the modeling of a flow as the source area, based on historical and scientific documentation [32][33][34][35], is represented by dry stone wall terraces, similar to the ones described above in Liguria and that look to be related to many shallow landslides in the Mediterranean area. ...
... The high slope gradient in the whole catchment minimizes debris and soil accumulation along the slopes so, considering the ancient anthropogenic modification of the area, we considered man-made debris and soil accumulation within stone wall terraces as a possible source. In fact, starting from the first Abbey complex settlement in the 10th Century, stone walled terraces were constructed mainly for olive orchard plantations [34]. Many historical terraces are still present in the area (Fig. 36.2). ...
... They are man-made landforms [49] and after more than 100 years, no sign of scarps or erosion cuts were left after their washing away. Besides, due to the high slope gradient, terraces in the study area have been often constructed by putting stone walls directly on the bedrock and bringing soil and sediments to constitute the terraces [34,50]. Then, the collapse would have left the original rocky surface only. ...
In mountainous areas during intese rain events shallow landslides are often triggered adding their effect and enhancing the damaging consequences of flash flood. Many coastal area of the Mediterranean are exposed to such events, as recently largely happened in Italy, France, Spain and Greek. Large portions of the coastline mountainous territories have been settled and modified since ancient times with agricultural terraces, in order to practice the subsitence cultivation. This kind of anthropogenic modification of the slopes may be considered as an artificial immobilization of debris cover along steep slopes and, particularly after their abandonment, they can turn into sources of shallow landslides. Then terraces from belonging to soil and water conservation measures may represent a source of hazard if not properly mainteined. Considering the intense rain event that hit the Portofino promontory in 1915 causing strong damage to the Medieval monk Abbey in the iconic small San Fruttuoso village in northern Italy, a numerical modeling has been applied basing on historical testifying and the available evidences. A possible terraced area has been highlighted as a source area for the debris/mud flow that hit the Abbey and the model has been applied to assess its effect. This reconstruction allows to test the modeling technique in order to furtherly assess possible risk scenario even in other areas and in the framework of the H2020 RECONECT project, where recovering ancient terraces is considered in the framework of the Nature Based Solutions to riduce geo-hydrological risk.
... To ensure the drainage of excess water, the stone material is usually laid without a binder [6]. The hard work to make the land cultivable has thus given rise to a real "stepped land" of exploitation for agriculture in areas where spaces are limited and the slopes would not allow subsistence production [7][8][9]. ...
... In Liguria, since the 1950s, agricultural practices in mountainous landscapes have been significatively reduced causing terraces to become unstable and triggering landslides during flood events [9,21]. In 2011, a devastating flash flood hit the famous landscape of Cinque Terre after a violent storm, triggering hundreds of shallow landslides in small and steep catchments. ...
... Among the anthropic landforms, dry-wall slope terracing is a very common farming technique that dates back to ancient times [9]. Terracing has severely modified the geomorphological, vegetation and anthropic landscape at a slope scale. ...
Terraced landscapes are widely applied in many mountainous regions around the world
as a result of the necessity to practice subsistence agriculture. Hence, they can be regarded as one of the most diffused anthropogenic modifications of the Earth’s surface. Different techniques have been used for their implementation leading to the artificial immobilization of debris and soil along the slopes whose surface is interrupted by a sequence of sub-horizontal and sub-vertical areas often using stone walls. In some areas of the world, such interventions are thousands of years old and their resistance to the degradation caused by the morphogenetic system can be attributed to the
permeability of the stone walls as well as to their regular maintenance. In some other areas, the lack of maintenance has been the main cause for degradation processes ending with their collapse. The effects of climate change manifested through higher intensities and higher frequencies of rainfall are likely to accelerate the degradation process further by causing terraces to act as a source of debris or hyperconcentrated flow. This will in turn increase the severity of geo-hydrological hazards. The measures concerning reduction of geo-hydrological hazards are sought through identification of
abandoned terraces and assessment of the potential for their sudden collapse. The present paper describes a framework for identification of abandoned terraces and estimation of the potential volume of shallow landslides that can be generated. The research conducted aims to advance the existing hazard assessment practices by combining numerical modeling with processing of high-resolution LiDAR data. A new algorithm is developed to support localization of terraces. The catchment scale
approach applied to eight smaller catchments enables estimation of the total volume of soil and debris trapped along the slopes. It also generated some important quantitative data which will be used in the future risk assessment work. The work has been carried out within the EU-funded H2020 project RECONECT.
... Land cover essentially consists of mixed and coniferous forest, transitional woodland shrubs and Mediterranean scrub, although agricultural areas such as vineyards and olive groves standing over abandoned or in use dry stone terraced systems have an important role (Paliaga et al., 2016;Faccini et al., 2018). On the top of the Promontory, eluvial ad colluvial deposits occur, while scree deposits are dominant laying over steep slopes and cliffs (Rellini et al., 2017;Rellini et al., 2019). ...
Hydrogeological mapping is a key tool for groundwater resource management. Generally, hydrogeological maps focus mainly on porous or karst aquifer at large scale. In a fractured-rock aquifer, the groundwater flow path is not immediately deductible due to the intrinsic complexity of fracture systems. Then, it is of crucial importance collecting a complete dataset describing the site of interest: fault and strata patterns, geomorphological features, occurrence of springs. Here we present the hydrogeological map at 1:10,000 scale of the fractured rock aquifer of Conglomerate of Portofino (Italy). The graphical information contained in this map is based on the authors’ field survey and the revision of papers written for academic purposes and technical reports. The aim of the research is to achieve a useful tool for land planning, conservation of groundwater resource and geo-hydrological risk reduction in the unique area of the Natural Park of Portofino.
... These can take the form of deliberately constructed features with extensive sub-horizontal benches cut into hillsides and bounded by dry-stone walls . Terraces are commonly recognized as a crucial component of the agricultural landscape for their cultural value and their importance in food production in high-slope environments (Paliaga et al., 2016). Additionally, terraces represent the most obvious, widespread and profound anthropogenic alteration of the soil-slope system (effectively anthropogenic catenae) to the earth's surface (Tarolli et al., 2019). ...
... The bedrock is Portofino Conglomerates (Faccini et al., 2018) which contains pebbles that are primarily calcareous/limestone and secondarily sandstone, ophiolites, gneiss and cherts, while the matrix is calcareous sandstone with quartz and clay elements. Two NW-SE and NE-SW oriented faults systems affect the bedrock, causing fractures that can dislocate rocky blocks exceeding 10 m (Paliaga et al., 2016). Furthermore, the geology creates conditions for a remarkable subterranean water circulation with small springs occurring across the terraces. ...
... Later documents describe the land use and agricultural practices from the mid-13th Century that were developed by the Order of Saint Benedict. To make cultivation possible, the original steep slope profile was modified with dry-stone terraces that required constant maintenance activity, which was performed until the middle of the 20th Century (Paliaga et al., 2016). The progressive abandonment of agricultural practices has caused a high threat of erosion and gravity-induced processes (rockslides) which accompany terrace collapse. ...
High-resolution topographic (HRT) techniques allow the mapping and characterization of geomorphological features with wide-ranging perspectives at multiple scales. We can exploit geomorphometric information in the study of the most extensive and common landforms that humans have ever produced: agricultural terraces. We can only develop an understanding of these historical landform through in-depth knowledge of their origin, evolution and current state in the landscape. These factors can ultimately assist in the future preservation of such landforms in a world increasingly affected by anthropogenic activities. From HRT surveys, it is possible to produce high-resolution Digital Terrain Models (DTMs) from which important geomorphometric parameters such as topographic curvature, to identify terrace edges can be extracted, even if abandoned or covered by uncontrolled vegetation. By using riser bases as well as terrace edges (riser tops) and through the computation of minimum curvature, it is possible to obtain environmentally useful information on these agricultural systems such as terrace soil thickness and volumes. The quantification of terrace volumes can provide new benchmarks for soil erosion models, new perspectives to stakeholders for terrace management in terms of natural hazard and offer a measure of the effect of these agricultural systems on soil organic carbon sequestration. This paper presents the realization and testing of an innovative and rapid methodological workflow to estimate the anthropogenic reworked and moved soil of terrace systems in different landscapes. We start with remote terrace mapping at large scale and then utilize more detailed HRT surveys to extract geomorphological features, from which the original theoretical slope-surface of terrace systems were derived. These last elements were compared with sub-surface information obtained from the excavations across the study sites that confirm the reliability of the methodology used. The results of this work have produced accurate DTMs of Difference (DoD) for three terrace sites in central Europe in Italy and Belgium. Differences between actual and theoretical terraces from DTM and excavation evidence have been used to estimate the soil volumes and masses used to remould slopes. The utilization of terrace and lynchet volumetric data, enriched by geomorphometric analysis through indices such as sediment conductivity provides a unique and efficient methodology for the greater understanding of these globally important landforms, in a period of increasing land pressure.
... The promotion of touristic activities would be beneficial if specifically tied to terraces and agriculture, because if the tourism sector were to become more lucrative than agriculture, it is likely that people would abandon their farms and terraces. One further option that has been suggested by some researchers [82,83] and has been successfully The literature suggests a variety of options for the conservation or requalification of terraced landscapes. There is a first distinction here, as most studies suggest strategies both for abandoned and cultivated terraces, while other studies suggest that the efforts should be focused on cultivated terraces and renaturalizing abandoned ones [78,79]. ...
... The promotion of touristic activities would be beneficial if specifically tied to terraces and agriculture, because if the tourism sector were to become more lucrative than agriculture, it is likely that people would abandon their farms and terraces. One further option that has been suggested by some researchers [82,83] and has been successfully applied in Italy [84] and outside of the Mediterranean area [85] entails the possibility of renting terraces to hobby farmers and city dwellers. ...
... Even though there were not many factual examples of local involvement, all of these projects were successful and resulted either in the restoration or in the preservation of a terraced landscape. [15,45,48,49,78,82,87,[93][94][95][96] Slovenia [83] Malta [97][98][99] Greece [100,101] Israel [102] Palestine [46] Tunisia [103] Morocco [104] B ...
Coupled human–environment systems and traditional agricultural landscapes can be a key element in the conservation of biodiversity, ecological functionality, and cultural heritage. Terraced landscapes are a relevant example of traditional landscapes within the Mediterranean area, but they are now threatened due to the abandonment of agricultural activities. In order to identify factors that can affect the conservation strategies needed to maintain terraced landscapes in the Mediterranean area, we performed a literature review on studies about terraces and their management, soil erosion and vegetation dynamics after abandonment, etc. We collated a total of 285 scientific papers reporting 293 case studies in 19 countries. The majority of these studies analyze dry stone terraces and their influence on soil erosion and water runoff, either in cultivated or abandoned terrace systems. Only a minority of papers suggest maintenance or conservation strategies or involve farmers, exploring their decision-making. The conservation of terraced landscapes is in the hands of local farmers, and thus they should be actively involved in decision-making to find the most suitable strategies for assuring the continuity in farming and preserve cultural landscapes in the Mediterranean area.
... The Rapallo plain is completely urbanized and adjacent slopes show cultivated terraces and overall natural and semi-natural areas resulting from the abandonment of agricultural terraces (Brandolini, 2017;Brandolini et al., 2018;Del Monte et al., 2015;Paliaga et al., 2016;Paliaga et al., 2020;Pepe et al., 2019b;Raso et al., 2019). ...
This paper describes the anthropogenic landforms of the alluvial-coastal plain of Rapallo (Eastern Liguria, NW Italy). Since the second half of the nineteenth-century Rapallo experienced a progressive urban sprawl that became particularly intense after the Second World War and severely modified the former landforms. The identification and mapping of morphological changes was performed through a multi-temporal comparison of historical and recent maps and aerial photographs, an analysis of geo-thematic maps and urban planning documents, an interpretation of stratigraphic data from boreholes, and a field survey activity. The main anthropogenic interventions that shaped the urban landscape of Rapallo were riverbed diversions and channelization, excavations, fillings, and embankments construction along the shoreline. These elements highlight the relevant extent of the human imprint on the pristine environment. Furthermore, the identified anthropogenic geomorphological features, combined with the local physiographic and climatic features, increased flood and sea storm hazards and risks.
... The classification of soil and water conservation measures is an important basis for soil erosion investigation, soil and water conservation planning, the extension of soil and water conservation measures, and benefit evaluation. According to the current situation of soil and water conservation work in the study area, all types of practical measures were not included in the evaluation system, but comprehensive indexes, such as forest and grass coverage [39,72] and the soil erosion rate, were calculated based on afforestation, recommendations, and terrace landscape [35][36][37]57,73]. The evaluation system avoids the overall benefit evaluation because of the particularities of engineering measures. ...
Soil erosion is the main threat to the stability of ecological environment and the harmonious development of society in Shendong Mining Area. The main causes of this threat include the strong interference of natural characteristics and land development. Scientific soil and water conservation measures can coordinate the contradictions among coal economic development, ecological protection, and residents’ prosperity. Based on particle swarm optimization and analytic hierarchy process, the benefit evaluation system of soil and water conservation measures in Shendong Mining Area is established. The weight ratio of three kinds of benefits in Shendong coal mine collapse area is: ecological benefit > social benefit > economic benefit. The conclusion shows that the implementation of the national policy and the effect of mining area management meet the expectation. Therefore, this study provides effective reference and reasonable suggestions for soil and water conservation in Shendong Mining Area. In terms of control measures, bioengineering measures, such as increased coverage of forest and grass as well as reasonable transformation of the landscape pattern of micro landform, can improve the degree of soil erosion control, optimize the land use structure, and improve the land use rate.
... The following ones have been considered: i) soil sealing; ii) culverting percentage of the hydrographical network; iii) density of infrastructures, which is responsible for the landscape fragmentation; iv) extension of agricultural areas, which is mostly linked to the presence of terraces due to the mountainous features of the area. The last aspect is related to geo-hydrological hazard as underlined by several authors (Tarolli et al., 2014;Paliaga et al., 2016) and represents an important anthropogenic landscape modification (Piana et al., 2019). ...
Anthropogenic modifications at catchments scale may be reconducted primarily at soil sealing and streams culverting, even if important consequences result from roads density and, more in general, infrastructures as they cause landscape fragmentation, and agricultural areas extension. Their most important outcomes in terms of hydrologic balance are the decreasing time of concentration and the increasing flood risk at catchment scale.
The research introduces a methodological approach to classify the degree of anthropogenic modifications at catchment scale: clustering techniques have been applied to 508 catchments in a high-risk flooding sector of the Mediterranean region. Then, flood data recorded in the study area in the 1900–2018 period have been compared to clustering classification, pointing out the relationships with soil sealing and hydrographical network culverting in the catchment.
The analysis has been performed considering fourteen subsets of 8 descriptive parameters each that differ in the evaluation of culverting in the terminal part of the hydrographical network; the analysis has been conducted identifying the optimal number of descriptive parameters and the corresponding best number of clusters on quantitative basis. The results show that three classes clustering is the more appropriate from a computational point of view. That division looks coherent with the features of the studied basins and is well correlated with floods occurrence in the last 100 years.
Finally, the proposed methodology of anthropogenic disturbance classification at catchment scale may be applied to other areas even adapting and implementing other descriptive parameters. Then, it may be used to support the planning of mitigation strategies in term of flood risk.
... Their origin and characteristics have previously been described by several authors [23][24][25]. There are also considerable terraced areas in Paraggi, Portofino, and San Fruttuoso creeks, and they all represent important cultural assets in this area [26]. (14) culvert; (15) Portofino Natural Regional Park boundary (map obtained from data survey and data integration of [20][21][22]26]). ...
... There are also considerable terraced areas in Paraggi, Portofino, and San Fruttuoso creeks, and they all represent important cultural assets in this area [26]. (14) culvert; (15) Portofino Natural Regional Park boundary (map obtained from data survey and data integration of [20][21][22]26]). (A) mountain slope deformation. ...
... The occurrence of landslides in this area is rather widespread and frequent. These are large relict landslides with slow kinematics [22,26]. Among the latter, rockfall and rock-topple-like phenomena in the conglomerate can become particularly destructive (e.g., the landslides of 1987 [37,44], which required repeated consolidations of the slope). ...
Nature-based solutions (NBS) are usually defined as complementary or alternative solutions to "grey infrastructures" (traditionally made with cement) aimed at conserving and regenerating the functionality of natural and semi-natural ecosystems. The research to date shows a considerable potential of NBS to address the current challenges related to climate change and geo-hydrological risks. Despite significant interest in NBS by researchers and practitioners, knowledge concerning their practical implementation, monitoring, and evaluation is still lacking. This is particularly true for large-scale NBS. The present paper discusses how such solutions can be implemented in the context of hydro-meteorological risk reduction in small Mediterranean catchments with a strong tourist vocation. The work presented here is situated within the RECONECT Project (Regenerating ECOsystems with Nature-based solutions for hydro-meteorological risk rEduCTion), which aims to contribute to a European reference framework on NBS by demonstrating, upscaling, and replicating large-scale NBS in rural and natural areas. The Italian case study of RECONECT is the Portofino Natural Regional Park, which represents a unique natural landscape element with high ecologic, social, and economic (touristic) value, which is threatened by a range of geo-hydrological hazards, such as flash floods, hyper-concentrated floods, shallow landslides, rockfalls, and storm surges. This paper also presents details of NBS interventions in two pilot catchments (San Fruttuoso and Paraggi) visited by thousands of tourists throughout the year. It addresses some of the key aspects related to monitoring meteorological and hydrological processes, as well as remote sensing activities (i.e., LiDAR surveys), which are necessary for the identification of critical-instability areas along waterways and the reconstruction of dry stone walls. Lastly, a discussion of relevant mitigation and adaptation strategies that are potentially replicable at national and international levels is also provided.
... Recently, research interest on terraces has been increasing [1][2][3][4][5][6], in part due to 2018 "Art of drystone walling, knowledge and techniques" inclusion in United Nations Educational Scientific and Cultural Organization (UNESCO) Intangible Cultural Heritage [7], while some peculiar landscapes, such as Portovenere, Cinque Terre, and the Islands' terraced vineyards, were already part of the UNESCO Heritage Site. Terraces are commonly recognized as a crucial component of agricultural practices both for the cultural value they represent and for their importance in food production in mountain environment [8][9][10]. ...
... Particularly widespread in the Mediterranean area [6], terraces may be found in the Balearic Islands, in Spain, in France, along the Italian peninsula, in the Balkans and in Greece. In Italy, many authors studied terraced landscapes in the different and various contexts in the country [3,4,8,12,23,[26][27][28][29]. The original morphology has been modified (Figure 1) by terraced system that in some cases extended to the entire slope or even to high percentage of a catchment's surface, with challenging implications in water infiltration and superficial runoff [26,30,31]. ...
... The scope of our research has been identifying and mapping dry stone wall terraces in an area that has been modified by human action from, at least, the Middle Ages [8,23] period and evaluating the spatial relationships with the possible risk-exposed elements. The Monte di Portofino promontory is famous both for its landscape and its high natural value, attracting more than 1 million between tourists and hikers per year [46,47]. ...
Stone wall terraces are a largely investigated topic in research for both their landscape and cultural/historical value. Terraces are anthropogenic landforms that interact with natural processes and need permanent maintenance to preserve their functionality. In the Mediterranean region, ground effects related to intense rain events often involve terraced slopes that, in some situations, are directly sourced areas of debris/mud flow. Starting from the 1950s, the changing socioeconomic conditions caused the abandonment of large portions of rural areas. Nowadays, at the catchment scale, it is frequently difficult recognizing stone wall terraces because of their abandonment and the uncontrolled re-vegetation. This research faces the issue of identifying terraces in the Monte di Portofino promontory, which is internationally famous for its high-value natural and landscape involving broad anthropogenic modifications dating back to the Middle Ages. A remote sensing application, with LIDAR data and orthophotography, identified terraces on the Portofino promontory, enabling investigating even barely accessible areas and increasing knowledge on the territory. The aim of this paper is first of all to point out the presence of such anthropogenic morphologies in the promontory of Monte di Portofino and then to asses and highlight the related hazard. In fact, terraces can be a source of debris/hyper-concentrated flow with highly damaging power, as occurred in the recent years in neighboring areas during particularly intense hydrological events. Then, terraced area mapping, including in use and in abandonment information, is crucial to perform a spatial relationship analysis that includes hazard-exposed elements and to evaluate the possible connectivity factor of buildings, infrastructures, tourism facilities and Cultural Heritage within the hydrographical network.
