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Policy ideas are often crafted in international fora, such as international organisations, multilateral institutions, and high-level summits. However, whether and how ideas will eventually inform policymakers at the domestic level remains an understudied subject. This paper contributes to this debate by tracing the domestic consolidation and eventual erosion of ‘Crisis Management’, a policy paradigm that emerged after the end of the Cold War and became dominant among NATO members in the 2010s. We investigate Germany and Italy as two case studies that followed two distinct trajectories. Policy elites suddenly adopted the paradigm in Italy and built a broad consensus on it. In Germany, crisis management has emerged lately and remains contested, as the territorial defense has maintained legitimacy among elites. Understanding the mechanisms underpinning such trajectories is the key to uncovering whether a consensus on a new version of territorial defense as a dominant paradigm will consolidate. [ABSTRACT FROM AUTHOR]

Coastal managers, policymakers, and scientists use shoreline accretion/erosion trends to determine the coastline's historical evolution and generate models capable of predicting future changes. Different solutions have been developed to obtain shoreline positions from Earth observation data in recent years, the so-called Satellite-Derived Shorelines (SDS). Most of the methodologies available in the literature use multispectral optical satellite imagery. This paper proposes two new methods for shoreline mapping at the subpixel level based on PRISMA hyperspectral imagery. The first one analyses the spectral signatures along defined beach profiles. The second method uses techniques more commonly applied to multispectral image analysis, such as Spectral Unmixing algorithms and Spatial Attraction Models. The results obtained with both methodologies are validated on three Mediterranean microtidal beaches located in two different countries, Italy and Greece, using image-based ground truth shorelines manually photointerpreted and digitised. The obtained errors are around 6 and 7 m for the first and second methods, respectively. These results are comparable to the errors obtained from multispectral data. The paper also discusses the capability of the two methods to identify two different shoreline proxies. [ABSTRACT FROM AUTHOR]

The present paper further develops a coastal vulnerability index formulation (CVI) previously proposed by the authors by integrating a new variable and redefining three variables to improve the suitability of the index for low-lying coasts. Eleven variables are divided into three typological groups: geological, hydro-physical process and vegetation. The geological variables are: geomorphology, shoreline erosion/accretion rates, coastal slope, emerged beach width, and dune. The hydro-physical process group includes: river discharge, sea-level change, mean significant wave height and mean tide range. The vegetation variables are: vegetation behind the back-beach and coverage of Posidonia oceanica. The index was applied to a stretch of the Ionian coast in the province of Crotone in the Calabria region (Southern Italy), and a vulnerability map was produced. A geography information system (GIS) platform was used to better process the data. For the case study area, the most influential variables are shoreline erosion/accretion rates, coastal slope, emerged beach width, dune, vegetation behind the back-beach, and coverage of Posidonia oceanica. The most vulnerable transects are those near urban areas characterized by the absence of dunes and vegetation. Statistical and sensitivity analyses were performed, and the proposed CVI was compared with the previous formulation proposed by the authors and with two other CVI methods present in the literature. [ABSTRACT FROM AUTHOR]

The ongoing erosion of beaches due to anthropic pressure, together with the effects of sea level rise are expected to have devastating effects on sandy coastlines. This paper identifies the Italian beaches under threat and their regional distribution, examining the implications for beach-dependent activities and coastal management, based on the integration of various projections and datasets. As a result, by the year 2050 erosion is expected to affect 70% of Italian beaches. One-fifth of the current beaches' surface is likely to be almost completely submerged by 2050 and 45% by the end of the century, with the regions of Sardinia, Campania, Lazio, and Apulia likely to lose more than half of their equipped beaches. Although beaches naturally tend to migrate landward when subjected to erosion, and such shift can be favoured by managed retreat measures, these solutions are severely limited by the increasing urbanisation of back beaches. Adaptation in Italy is almost exclusively based on coastal protections, which exacerbate overall erosion and undermine beaches' natural resilience. A transformative and nature-based rethinking of the coastal management regime is needed to avoid the artificialization of a huge portion of the sandy coastline and increasing threats to coastal settlements and economies. [Display omitted] • 20% and 45% of Italian beaches risk almost complete submersion by 2050 and 2100. • In almost all Italian Regions a third or more of equipped beaches are at risk. • Managed retreat is severely limited by coastal urbanization and artificialization. • Current coastal management regimes exacerbate erosion and artificialization. • A transformative and nature-based rethinking of coastal management is urgently needed. [ABSTRACT FROM AUTHOR]

Dune restoration projects that integrate vegetation efforts with natural, sustainable, and soft solutions have become increasingly popular in coastal communities. Eco-restored dunes have high aesthetic value and are likely to be more resilient to near-surface wind effects and/or minor storms events. However, environmental-friendly restoration strategies still lack scientific insight from systematic research and the role of eco-restoration in dune erosion resistance and resilience has not yet been rigorously investigated. The question is: how can we optimize eco-friendly solutions in dune ecosystem restoration to maximize the resistance and resilience of coastal dunes against erosion from wind, wave, and storm surge attack? The present paper proposes an innovative colloidal silica-based consolidation technique for coastal sand dunes. A special focus is placed on the description of the experience gained from two pilot field studies started in Salento coastal area, in the south of Italy. The preliminary observations clearly show that mineral colloidal silica increases the mechanical strength of non-cohesive sediments allowing the adopted solution to reduce the volume of dune erosion and the dune scarp retreat rate, thus improving the resistance and resilience of the dune system. Besides furthering our knowledge of coastal erosion, the results of these and future studies will be of value to coastal managers and policy makers responsible for dune restoration projects. [ABSTRACT FROM AUTHOR]

Abstract: Experimental test sites are important to understand the physical flow processes occurring within an avalanche. They can be at different scale: laboratory or real scale. In Europe, a dozen of real-scale test sites have been realized, though at present only a few of them are still operative. The primary goal is to measure avalanche dynamical variables under controlled conditions. Not all the observed phenomena have been fully understood yet and more work is needed especially regarding small to medium avalanches. The aim of this paper is to present a new experimental test site at a real scale in order to study specific topics: the dynamics of small and medium avalanches, the avalanche release processes and the interaction between avalanche flows and obstacles. The test site, called Seehore, is located in Aosta Valley in the North-western Italian Alps. The slope, with an elevation difference of about 300m (from 2300 to 2570m asl), has a mean slope angle of about 28°. Avalanches are artificially released on a routine basis to secure the ski-runs, as the site is located within a ski resort (Monterosa Ski); they are usually dense slab avalanches of small or medium size, but also a powder cloud may occasionally form. The site is instrumented with a steel obstacle, described in details in a companion paper, which measures the effects of avalanches impacting on it. Before, during and after each artificial release physical properties of the snow in the avalanche release, track and deposition zones are recorded; front velocity, erosion and deposition mass are estimated by field surveys or by videogrammetry and terrestrial laser-scan measurements. [Copyright &y& Elsevier]

[Display omitted] • New empirical estimates are provided for monthly R-factors over Italy for 1981–2010. • R-factor is currently larger in autumn and summer, lower in spring and winter. • 29 EURO-CORDEX projections for 2021–2050 and 2051–2080 under three RCPs are used. • Future anomalies are critical in autumn (whole Italy), and in summer (North). • There is a large variability associated with the use of an ensemble of projections. The estimation of rainfall erosivity in the Revised Universal Soil Loss Equation (RUSLE) requires long series of sub-hourly rainfall observations. Due to the endemic unavailability of this information, at least with the required degree of detail and coverage, empirical models are frequently used for the estimation of rainfall erosivity basing on easily retrievable rainfall values at the monthly or annual scale. In this paper, an empirical model is calibrated for Italy to bridge the annual to monthly scale gap by means of 10-year series of monthly rainfall observations at 171 Italian rain gauges, and then applied using the ERA5-Land gridded rainfall dataset to obtain maps of monthly and seasonal rainfall erosivity covering the reference period 1981–2010. Successively, 29 EURO-CORDEX bias-corrected rainfall projections for two future horizons (2021–2050 and 2051–2080 under RCP 2.6, 4.5 and 8.5) are used to obtain expected anomalies of seasonal rainfall erosivity over Italy with respect to the reference period. Statistical and visual analysis of results shows that positive percentage anomalies are expected in large portions of the country, especially under RCP 2.6 but with significant increases expected also under RCPs 4.5 and 8.5, especially in autumn and, secondarily, in summer. This intra-annual rainfall erosivity anomaly pattern entails the existence of increasing trends in the erosion hazard that cannot be captured by empirical models only relying on annual rainfall. The position of those results in the related literature is deeply discussed, providing significant insights on uncertainty sources and possible future research developments. [ABSTRACT FROM AUTHOR]

In this paper the abrasion rate on a coarse-clastic beach was evaluated by calculating the volume loss recorded on indigenous pebbles within a 13-month timespan. The experiment was carried out at Marina di Pisa (Italy) on an artificial beach that was built to counteract the erosion processes affecting this sector of the coast. A total of 240 marble pebbles (120 rounded and 120 angular) were marked using the RFID technology and injected on the beach. The volume loss measured after consecutive recovery campaigns was progressively increasing, reaching the maximum value after 13 months (61% overall). The average volume loss is consistent between rounded and angular pebbles at any time (59.3% and 64.2% after 13 months respectively), meaning that the roundness is not a primary control factor on abrasion rate. The pebbles that did not reach such abrasion rates after 8 and 10 months (volume loss less than 20%) were found at heights equal or greater than 2 m above mean sea level, on the crest of the storm berm that formed during the strongest storms. This implies that the highest wearing is achieved in the lower portion of the backshore, which is also the area that underwent major topographic modifications. Here, sea water action might also exert chemical influence on the pebbles, adding to the mechanical abrasion. The main result of this research, indicating an impressive volume loss on beach pebbles in a short timespan, could be of key importance for coastal managers. The optimization of coarse sediment beach nourishments is also relevant, taking into right consideration that the volume loss due to sediment abrasion might exceed 50% of the original fill volume just after 1 year in the most dynamic portion of the beach. [ABSTRACT FROM AUTHOR]

Several recent hydrocarbon discoveries were detected in extensional areas located around fault-bounded tectonic highs. These tectonically-controlled mini-basins are diffusely characterised by terrestrial and shallow-marine successions with complex geometrical relationships. The degree of seismic resolution and the punctual well-log lithostratigraphic data do not allow suitable reconstructions of these plays and, thus, the use of good outcrop analogues is crucial in their reservoir characterisations. In this paper, we present the results of a sedimentological study carried on continental deposits filling a segment of the Oligo-Miocene south-eastern basin margin of the Sardinia Graben System, in the central-western Mediterranean. This well-exposed terrestrial succession results from the erosion of Palaeozoic metamorphic and magmatic basement rocks exposed along the basin margin. Continental, coarse-grained eluvio-colluvial, alluvial and fluvial sediments exhibit changes both in thickness and lateral extensions due to the existence of several endorheic depocentres, which were aligned along major normal faults. Based on the stratigraphic and sedimentological analysis of a number of exposed stratigraphic sections, the main depositional processes are identified for each specific facies association. Due to the grain-size of the dominant deposits, porosity is estimated by using an image analysis software on high-resolution digital photographs from a number of outcrop samples. The results show how porosity changes dramatically across the reconstructed sections due to the complexity of the reciprocal geometrical passages among all these lithofacies. The dominance of colluvial/alluvial fans or river braidplain systems and the different nature of sediment occupying each depositional areas are interpreted as the response to the interplay between the capacity generated by the vertical tectonic displacement of major normal-faults and the interception of the base-level with the topography of these mini-basins. Our observations suggest six possible depositional scenarios that resume as many reservoir types in fault-controlled half-grabens with dominant continental lithofacies. [ABSTRACT FROM AUTHOR]

[Display omitted] • Watercourses play a key role in transferring sediments from mountain to the coast. • Calabrian streams were intensely regulated with check dams in the lower reaches. • In the studied fiumara check dam system traps large amount of sediments. • Coastal retreatment is intimately correlated to sediments stored behind check dams. Currently, most of the world's coastal territories are subject to erosive processes, often caused by an alteration of sediment balance due to both natural and anthropogenic factors. This issue is relevant in many Mediterranean territories such as Calabria region, in southern Italy. Here, considerable anthropogenic pressures affect about 750 km of coast on which debouch short torrential rivers locally termed 'fiumare'. The regional climate, hydrology and geomorphology leads to intensive fiumare catchment erosion and high fluvial solid loads. The work focuses on the Gallico fiumara , chosen as case study affected by an intense hydraulic regulation programme in order to investigate the poorly studied effects of engineering control works on shoreline changes. The paper has considered the effects of the 264 check dams (completely filled a few years after their realization) only investigating the relationships between the volume retained by the structures and shoreline change during the several arrangement campaigns. Although the work does not consider the other processes that explain the complexity of the watershed-coast sediment balance, it has been clearly demonstrated an influence of check dam system on the evolution of the shoreline, especially due to the hydraulic works installed in the lower part of the watershed. In the light of the results obtained, it would be desirable to promote a debate on the opportunity to convert or demolish the check dams in the torrent reaches closest to the coast, where, moreover, the engineering control most reduced the already limited natural riverbed slope. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sentinel-2 and PlanetScope used for the first time for grassland FVC estimation. • Vegetation indices enhance the band spectral separability of bright soils. • Best indices based on NIR and red for Sentinel-2, NIR and red-edge for PlanetScope. • High resolution necessary to effectively describe grassland FVC spatial variability. Grassland fractional vegetation cover (FVC) accurate mapping on a large scale is crucial, since degraded grasslands contribute less to provisioning services, carbon storage, water purification, erosion control and biodiversity conservation. The spatial and temporal resolution of Sentinel-2 (S2) and PlanetScope (PS) data has never been explored for grassland FVC estimation so far and will enable researchers and agencies to quantify and map timelier and more precisely grassland processes. In this paper we compare FVC estimation models developed from Landsat-8 (L8), S2 and PS imagery. The reference grassland FVC dataset was obtained on the Paganella ski runs (46.15°N, 11.01°E, Italy) applying unsupervised classification to nadir grassland RGB photographs taken from 1.35 m above the soil. Fractional Response Models between reference FVC and 18 vegetation indices (VIs) extracted from satellite imagery were fitted and analysed. Then, leave-one-out cross validation and spatiotemporal change analysis were also performed. Our study confirms the robustness of the commonly used VIs based on the difference between NIR and the red wavelength region (R2 = 0.91 for EVI using S2 imagery) and indicate that VIs based on the red-edge spectral region are the best performing for PS imagery (R2 = 0.89 for RECI). Only medium to high spatial resolution imagery (S2 and PS) precisely mapped spatial patterns at the study site, since grasslands FVC varies at a fine scale. Previously available imagery at medium to low spatial and temporal resolution (e.g., L8) may still be interesting for analysis requiring long time-series of data. [ABSTRACT FROM AUTHOR]

Abstract: In 2007, we installed seven micro-erosion meter stations on a vertical limestone slab located in the intertidal zone in the Gulf of Trieste (Italy) in order to observe rock surface changes at elevations ranging between −0.75m and +0.75mm.s.l. (Furlani et al., 2010). In this paper, we present the micro-erosion metre (MEM) data for most months between February 2008 and May 2013 and the traversing micro-erosion metre (TMEM) data collected twice a year since 2007. The MEM and TMEM data were consistent and indicated that the mean lowering rate ranged between 0.007mm/yr and 0.205mm/yr and −0.001mm/yr and 0.260mm/yr, according to the elevation of the stations. Maximum downwearing rates were observed in the mid-lower intertidal zone and decreased upward and downward. The natural trend of erosion started in 2010, after 2years of exposure, when the slab, formerly smoothed and not colonized by marine organisms, started to be acclimated to the local environment. After 2010, the erosion rate increased to a maximum of 0.31mm/yr. This value can be more representative for long-term studies and is similar to the downwearing rates locally collected on natural limestone surfaces. This dataset represents the first collection of downwearing rates mainly measured using MEMs, but also TMEMs on vertical limestone surfaces in an intertidal zone and provides interesting new information for addressing the debate on notch genesis and development. The shape of a tidal notch has been found to be consistent with the distribution of erosion rates along the slab, even if the present-day notch was not surveyed in the Gulf of Trieste due to the local tectonic subsidence. [Copyright &y& Elsevier]

Altomare, C., Gentile, G.M., 2013. An innovative methodology for the re-naturalization process of a shingle beach The gravel beach of Torre del Porto (Italy) was affected by a huge erosive phenomenon during the last 30 years. The causes which led to the erosion and the design lines through which to obtain the re-naturalization have been identified. Following a new methodological approach, the project consisted of entrusting assorted rubble stones with a proper weight to the area. Consequently the natural formation process can unfold again its effectiveness and the beach is recreated. The monitoring of the sediment transport was essential to provide the information about the correct results of prediction and analysis of the nourishment. The methodology, results and monitoring phases are described in this paper. [ABSTRACT FROM AUTHOR]

Abstract: This paper investigates wood recruitment and deposition dynamics in a large gravel-bed, braided river (Tagliamento River, Italy). We used a combination of field measurements, automatically repeated ground images, and remotely sensed surveys to quantify wood input through bank erosion and associated downstream deposition. Two sites were investigated where floods caused the erosion of vegetated island edges. A lidar survey preceding the erosion events provided data on the morphology and vegetation structure of the eroded areas, allowing estimation of the number of trees that were uprooted. Sequences of ground-based images acquired automatically (and supported by field measurements) showed the time, number, and location of deposited trees. Results show that the complex morphology of braided rivers induces specific deposition patterns. We observed wide dispersal of wood on gravel bars, with jams characterised by a small number of logs (on average 2–3) and, in many cases, only a single log. A large proportion of the eroded trees (up to 40%) were deposited on the nearest downstream bar. This illustrates significant wood retention close to the recruitment site, with the remaining wood dispersed widely downstream. Differences in the observed level of local wood retention were associated with the proximity of the erosion site to the main channel and differences were also observed in retention between the peak and the falling limb of flood events, confirming that water depth and probably flow velocity are the crucial parameters controlling wood deposition. [Copyright &y& Elsevier]

Abstract: Aim of this paper is to develop simple tools for mapping — at regional and local scale — coastal areas exposed at flooding risk. A two-step simplified procedure for coastal management purposes is presented and is applied to Emilia Romagna (Italy), whose low and sandy coast faces the relatively mild Northern Adriatic Sea. The procedure is composed by a 1D conceptual model to determine flooding probability along wide coastal stretches and by a more detailed 2D Level II reliability method, that provides local quantitative statistical maps of inland flooding propagation. Qualitative maps obtained by literature approaches and quantitative results of flooding probability along the littoral show a good agreement. A coastal flood state indicator is proposed to rapidly assess coastal hazard. [ABSTRACT FROM AUTHOR]

Abstract: The stability of cohesive sediments from Venice lagoon has been measured in situ using the benthic flume Sea Carousel. Twenty four stations were occupied during summertime, and a sub-set of 13 stations was re-occupied during the following winter. Erosion thresholds and first-order erosion rates were estimated and showed a distinct difference between inter-tidal and sub-tidal stations. The higher values for inter-tidal stations are the result of exposure that influences consolidation, density, and organic adhesion. The thresholds for each state of sediment motion are well established. However, the rate of erosion once the erosion threshold has been exceeded has been poorly treated. This is because normally a time-series of sediment concentration (C) and bed shear stress (τ 0(t)) is used to define threshold stress or cohesion (τcrit,z ) and erosion rate (E). Whilst solution of the onset of erosion, τcrit ,0, is often reported, the evaluation of the erosion threshold variation through the process of erosion (eroded depth) is usually omitted or not estimated. This usually leads to assumptions on the strength profile of the bed which invariably has no credibility within the topmost mm of the bed where most erosion takes place. It is possible to extract this information from a time-series through the addition of a step in data processing. This paper describes how this is done, and the impact of this on the accuracy of estimates of the excess stress (τ 0(t)–τcrit,z ) on E. [Copyright &y& Elsevier]

Abstract: In this paper, different characteristics of runoff and eroded sediments were investigated as well as changes in textural composition of the original soil, on experimental plots. The objectives were to investigate the particle size distribution of the eroded sediments, as a function of soil, crop, and meteorological variables, and changes in texture due to water erosion over time. The study was performed on experimental plots in the Apennines mountain range, in northern Italy, where an automated system for measuring runoff water and sediment was installed. Runoff water, sediment yield and sediment mean diameters were analyzed as a function of land cover, rainfall kinetic energy and stream power. In particular, the study investigated: (a) the sediment particle size distribution using laser diffraction, (b) the effect of rainfall kinetic energy, stream power and crop coverage on runoff, sediment yield and sediment particle size distribution and (c) the changes in soil texture on the cultivated field plots, over a period of 15years. The results of this study showed: (a) the particle size distribution of the eroded sediment was generally unimodal and the dominant fraction characterizing the eroded sediments was the one with a mean particle diameter ranging from 4.3 to 13.1μm, comprised in the silt range, (b) the mean particle diameter changed depending on the rainfall kinetic energy and the stream power, with a positive correlation between particle diameter and rainfall kinetic energy under bare soil, and (c) the effect of long-term erosion showed that the original soil textural composition experienced a statistically significant change over a period of 15years, with a decrease in the silt fraction and a relative increase in the clay fraction, due to losses of silt in the eroded sediments. [Copyright &y& Elsevier]

Abstract: Studies on denudation rates can provide insight into the influence of climate change, tectonics, and human activities on landscape evolution. Research performed in Central Italy has shown considerable spatial variability of denudation rates in the major river basins. These studies have focused mainly on the Tyrrhenian side of the Italian peninsula, where Plio-Pleistocene marine deposits filling NW–SE elongated sedimentary basins have been uplifted during the Quaternary up to several hundreds of meters above present sea level. Small sub-catchments developed on clays are affected by sharp- and/or rounded-edged badlands (i.e. calanchi and biancane), representing denudation “hot spots” in the present-day morphoclimatic framework. In this paper, we analyze the relationships between indirectly estimated denudation rates at the catchment scale and field monitoring data at the hillslope scale. We attempt to better understand and quantify all hillslope processes that contribute to seasonal variability of denudation, to help with predicting the net input from “hot spots” to the overall estimated sediment yield at the basin outlets. At the hillslope scale, we discuss, in particular, the variability of denudation rates at calanchi and biancane badlands as a function of their different morphoevolution. [Copyright &y& Elsevier]

Abstract: This paper presents the main results of a series of geomorphological studies, aimed to the quantitative direct and indirect evaluation of denudation processes in Central Italy. These studies, which started in some sample areas since long ago, were further deepened and extended to a wider number of drainage basins, representative of a variety of morphostructural conditions. The complex cause/effect relationships among factors influencing both the morphogenesis and the plano-altimetric configurations of drainage basins resulted in a large variability in the values of the denudation index (Tu), which ranged from 200 to 2500 t/km2/year. Very high values (Tu>10,000 t/km2/year) were obtained for small catchments belonging to the wider basins of Ombrone River and Tevere River, where fast morphological modifications occur due to the action of surface running waters and gravity. In the drainage basins affected by the most powerful denudation processes direct measurements of denudation were performed: several monitoring stations were equipped with iron stakes and disks to record the local modifications of the topographic surface with time. Whereas some of these stations have been working continuously since 1993, some others have been running only periodically. Direct measurements pertinent to periods longer than a decade indicated that mean annual values of denudation range between 1 and 2.5 cm/year for slopes affected by sharp-edged and/or rounded edged badlands. Higher denudation rates (3–4 cm/year) were obtained for shorter observation periods; still higher rates were recorded for short periods at the gully bottom or in coincidence with mass movements before bench marks were turned up or damaged. Denudation processes are likely to occur discontinuously. They show a step-like trend with time and are triggered by rainfall events distributed over a number of consecutive days, though not greatly intense. Particularly, their amount should overcome the threshold of 60 mm per 5 consecutive days. Below this threshold the surface runoff does not seem to reach the power necessary to induce significant modifications of the topographic surface in the study area. [Copyright &y& Elsevier]

Abstract: This paper describes a qualitative model of erosion of loose volcaniclastic material on steep slopes of La Fossa cone (Vulcano Island, Italy) that generates small volume debris flows. The loose volcaniclastic cover rests on an almost impermeable substratum, which comprises a fine-grained hydromagmatic tuff. Morphologically, three sectors were distinguished: 1) a water supply zone (slope>32°) where rain water is enriched in mud and concentrated in the initiation zone; 2) an initiation zone (or source area sensu stricto slope with ∼30°) where debris flows form and; 3) a transport and deposition zone where debris flows deposited levees and terminal lobes (slope ∼30°). Main episodes of erosion of loose volcaniclastic cover and debris flow generation occur in response to thunderstorms. The erosion of tuff from superficial water added a significant amount of fines (mud fraction) to the initiating flows. Debris flow stoppage on steep slopes was interpreted as the result of a loss of mass (estimated between 35% and 53% of total mass) to form levees. From field and laboratory data the density of debris flows was estimated at about 1950 kg/m3. Morphological data, matrix texture, mass number (N m) and clay content of debris flow deposits suggest that they were deposited by saturated granular slurries. [Copyright &y& Elsevier]

Abstract: Recent research has shown the importance of ephemeral gully (EG) erosion in the context of global erosion and, at the same time, the lack of adequate models to estimate it. At present, the ephemeral gully erosion model (EGEM) is the only conceptual model specifically developed for ephemeral gully erosion estimation. The main aim of the paper is to evaluate the performance of EGEM model adapted to local conditions compared with that of simple empirical equations. A data set of 92 ephemeral gullies formed between 1995 and 2000 in a wheat-cultivated study area in Sicily, Italy, was used for the purpose. In order to improve EGEM performance, two important adaptations were made. Both the rain distribution type and the causative rainfall of the hydrological component of EGEM were modified to reproduce local conditions. The EGEM assumption of a constant depth for the entire length of the ephemeral gully was also modified. EGEM performance was tested with two different rain distribution types, three different causative rainfalls and two different EG depths. The adaptation of the EGEM hydrological component improves the volume prediction with respect to the standard version of EGEM; the improvement is mainly due to the rain distribution type, whereas causative rainfall seems to be less important. The use of adjusted EG depths is, however, essential to minimise the errors between measured and predicted volumes. The capability of EGEM to predict the ephemeral gully cross-section is weak and non-significant relationships were found between measured and estimated width. A regression analysis between ephemeral gully-eroded volume and different morphological, topographical and hydrological parameters confirms the great importance of EG length to explain eroded volume (R2=0.64 for the simple correlation between volume and length). Considering that the adaptation of the hydrological component and the measurement of EG depths are necessary for the EG volumes estimated by EGEM to be reliable, it seems more simple, as suggested by other authors, to use empirical relations between eroded volume and length performed in different environments, until more precise physically based models are developed. [Copyright &y& Elsevier]

Debris flows are natural hazards causing fatalities and damages to infrastructures every year. One of the current challenges is to improve the predictability of such events using simulation tools. In this direction, the paper aims to model debris-flow generation starting from the water component and then simulating the motion of the bulked solid-fluid mixture mass flow. The debris component is progressively increased through entrainment of the channel bed material. The simulation has been performed exploiting the tool r.avaflow, which implements a physically-based model (Pudasaini and Mergili, 2019) for the flow propagation and an empirical multi-phase model for the entrainment processes. The investigated study case occurred in the Northeastern Alps of Italy, near the town of Cortina d'Ampezzo (Veneto Region), during the summer of 2017. The debris flow was triggered by a heavy rainstorm that caused extreme surface runoff, leading to entrainment of sediment from the channel bed. The debris flow obstructed the bridge of a regional road and consequently flooded the adjacent areas. Different types of debris flow simulations are performed, testing four specific functions to compute the entrainment rate. The simulated results are then compared against field observations. The analysis considers the differences in volume and depth of entrainment and in the output hydrograph. We conclude that entrainment is correlated with the terrain slope, particularly if it is calculated on a smoothed digital elevation model, which dilutes a less significant local steepness. We calibrate a spatially distributed slope-dependent erosion coefficient that successfully reproduced the observed entrainment volumes. The outcomes highlight the great importance of simulating debris flow entrainment processes adopting a multiphase model, which resulted particularly suitable for an accurate reproduction of the investigated event. The results, corroborated by further verifications, can improve the reliability of challenging predictive simulations on debris flow erosion. • Sediment entrainment is a fundamental process in debris-flow simulation. • A slope dependent empirical method to model sediment recruitment in debris flow simulation is proposed. • Debris flow erosion is correlated with the smoothed channel slope. [ABSTRACT FROM AUTHOR]

In fold and thrust belts developing at convergent margins, the migration of the advancing wedge is accompanied by bulging of the downgoing plate, followed by the development of a foredeep basin filled by a thick succession of syn-orogenic sediments. The transition from forebulge to foredeep marks a key moment in the evolution of the orogenic system. In deep water environments, the record of this transition is typically complete and progressive. Conversely, in the shallow-water/continental environment of many collisional systems, the uplift of the forebulge area can imply emersion and erosion, obliterating the stratigraphic record of key steps of the evolution of the orogenic system. The southern Apennines constitute one of these collisional fold and thrust belts where the development of the forebulge has implied emersion and erosion, with the development of a Miocene forebulge erosional unconformity, accompanied by extensional deformation associated with the bending of the lithosphere during the forebulge stage. In this paper, we use strontium isotope stratigraphy to constrain with unprecedented time-resolution the age of the forebulge unconformity in areas presently incorporated in the northern sector of the southern Apennines fold and thrust belt. Integration of our results and those of previous studies indicates, at the regional scale, a younging toward the foreland of the forebulge unconformity across the belt. Our high-resolution ages also reveal a diachronous onset of the flexural subsidence over short distances, associated with the occurrence of horst and graben structures, possibly resulting from inherited paleotopography along with forebulge extension. This work highlights how high-resolution dating is critical to unravel the evolution of foreland basin systems at different scales. [ABSTRACT FROM AUTHOR]