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Abstract. Several record-breaking precipitation events have struck the mountainous area of the Emilia–Romagna region (northern Apennines, Italy) over the last 10 years. As a consequence, severe geomorphological processes such as debris avalanches and debris flows, shallow landslides, and overbank flooding have affected the territory, causing severe damage to human-made structures. The unusual intensity of these phenomena prompted an investigation into their frequency in the past, beyond instrumental time. In the quest for an understanding of whether these phenomena are unprecedented in the region, peat bog and lake deposits were analyzed to infer the frequency of extreme precipitation events that may have occurred in the past. We present the results of a dedicated field campaign performed in summer 2017 at Lake Moo in the northern Apennines, a 0.15 km2 peat bog located at an altitude of 1130 m a.s.l. During the extreme precipitation event of 13–14 September 2015, several debris flows generated by small streams affected the Lake Moo plain. In such a small drainage basin (<2 km2), high-density floods can be triggered only by high-intensity precipitation events. The sedimentary succession (ca. 13 m thick) was studied through the drilling of two cores and one trench. The sequence, characterized by clusters of coarse-grained alluvial deposits interbedded with organic-rich silty clays and peat layers, was analyzed by combining sedimentological, pollen, microanthracological and pedological data with radiocarbon dating (AMS 14C) in an innovative multidisciplinary approach for this area. Original data acquired during the field campaign were also correlated with other specific paleoclimatic proxies available in the literature for the northern Apennines area. We discover that the increase in extreme paleoflooding, associated with coarse-grained deposits similar to the ones observed recently, correlates well with the warm phases of the Holocene Thermal Maximum and with the ongoing warming trend observed that started at the beginning of the last century.

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The coastal area at Riccione, in the southern Emilia-Romagna littoral region, is exposed to erosive processes, which are expected to be enhanced by climate change. The beach, mostly composed of fine sand, is maintained through various defense strategies, including frequent nourishment interventions for balancing the sediment deficit and other experimental solutions for reducing coastal erosion. Artificial reshaping of the beach and “common practices” in the sediment management redefine the beach morphology and the sediment redistribution almost continuously. These activities overlap each other and with the coastal dynamics, and this makes it very difficult to evaluate their effectiveness, as well as the role of natural processes on the beach morphological evolution. Topo-bathymetric and sedimentological monitoring of the beach has been carried out on a regular basis since 2000 by the Regional Agency for Prevention, Environment and Energy of Emilia-Romagna (Arpae). Further monitoring of the emerged and submerged beach has been carried out in 2019–2021 in the framework of the research project STIMARE, focusing on innovative strategies for coastal monitoring in relation with erosion risk. The aim of this study is to assess the coastal behavior at the interannual/seasonal scale in the southern coastal stretch of Riccione, where the adopted coastal defense strategies and management actions mostly control the morphological variations in the emerged and submerged beach besides the wave and current regime. The topo-bathymetric variations and erosion/accretion patterns provided by multitemporal monitoring have been related to natural processes and to anthropogenic activities. The morphological variations have been also assessed in volumetric terms in the different subzones of the beach, with the aim of better understanding the onshore/offshore sediment exchange in relation with nourishments and in the presence of protection structures. The effectiveness of the adopted interventions to combat erosion, and to cope with future climate change-related impacts, appears not fully successful in the presence of an overall sediment deficit at the coast. This demonstrates the need for repeated monitoring of the emerged and submerged beach in such a critical setting.