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[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]

[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]

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: 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]