The use of Unmanned Aerial Vehicles (UAV) on wetlands is becoming a common survey technique that is extremely useful for understanding tidal flats and salt marshes. However, its implementation is not straightforward because of the complexity of the environment and fieldwork conditions. This paper presents the morphological evolution of the Po della Pila tidal flat in the municipality of Porto Tolle (Italy) and discusses the reliability of UAV-derived Digital Surface Models (DSMs) for such environments. Four UAV surveys were performed between October 2018 and February 2020 on an 8 ha young tidal flat that was generated, amongst others, as a consequence of the massive sediment injection into the Po Delta system due to the floods of the 1950s and 1960s. The DSM accuracy was tested by processing (i.e., photogrammetry) diverse sets of pictures taken at different altitudes during the same survey day. The DSMs and the orthophotos show that the tidal flat is characterised by several crevasse splays and that the sediment provision depends strictly on the river. During the study period, the sediment budget was positive (gaining 800 m³/year and an average rate of vertical changes of 1.3 cm/year). Comparisons of DSMs demonstrated that neither lower flight altitudes (i.e., 20–100 m) nor the combination of more photos from different flights during the same surveys necessarily reduce the error in such environments. However, centimetric errors (i.e., RMSEs) are achievable flying at 80–100 m, as the increase of GCP (Ground Control Point) density is the most effective solution for enhancing the resolution. Guidelines are suggested for implementing high-quality UAV surveys in wetlands.

The present study investigates different combinations and methods for estimating the extreme Total Water Level (TWL) and its implications for predicting flood extension caused by coastal storms. This study analyses various TWL components and approaches and assesses how different methodologies alter flood predictions, with implications for warning systems and emergency responses. Using different combinations of individual TWL components, flood extension simulations were conducted using a hydrodynamic model in the Volano Beach area (Emilia-Romagna, Italy). A real coastal storm event was used as a reference for comparison. The findings indicate that the selection of individual TWL components and calculation methods significantly impacts flood extension predictions. The approaches, which involve calculating extreme values from a combined time series or the water level time series plus the extreme value of wave setup, yield the most realistic results, excluding the runup component. In comparison, the other combinations overestimate the flood. Incorporating hydromorphological models like XBeach could enhance the accuracy of runup estimations and improve the overall method reliability. Despite limitations such as runup estimation and the use of generic regional parameters, this study underscores the importance of the TWL combination selection in accurately predicting flood extents, emphasising the need for context-specific adaptations in environmental contexts.

It is increasingly recognised that nature‐based solutions in coastal ecosystems provide significant services compared to hard engineering measures. Several restoration projects are now being conducted worldwide to protect coastlines against flood risk and improve the ecosystems' quality. In the case of river deltas, managed realignment through levee breaching is becoming a recognised strategy for coastal wetland restoration. This study focusses on the formation of new wetlands in the Po River Delta after several natural dyke failures that occurred during the last century, when a large part of the land was abandoned and became wetlands. An historical review was performed to quantify the variation of the marsh extent in time developed after natural levee breaching in the easternmost lagoons of the delta and to understand the processes that determined their evolution. The analyses were based on orthophotos from the 1950s to the present‐day integrated with tidal records, water and sediment discharge records, and GPS survey for vegetation distribution. The review indicated that, between the 1950s and 1980s, anthropisation and natural processes caused a strong decline in marsh extent, thus leading to the recent shape of the lagoons. Several breaches and inlets were developed because of a combination of human intervention and erosive processes, and new tidal systems were born. Three main depositional areas connecting the main river branches were identified in three separated lagoons of the delta. These lagoons presented a ‘crevasse splay’ type of deposition which allowed the development of new tidal flats and, in certain cases, of large freshwater marsh systems within less than 8 years after the breach. The newly formed wetland systems (>100 ha) demonstrate the ability of the Po River Delta to build new wetlands, also during periods of human‐induced sediment starvation and high rates of subsidence, suggesting that further levee breaching should be exploited to favour marsh recovery.

Coastal wetlands play a crucial role because of their wide range of ecosystem services, including coastal protection, carbon sequestration and biodiversity support. However, these environments are increasingly threatened by land reclamation, sea‐level rise and sediment supply reductions, leading to widespread degradation. Managed realignment has emerged as a nature‐based solution, allowing tidal processes to restore coastal wetland function. While extensively studied in natural settings, the evolution of restored intertidal flats remains poorly understood. This study examines sediment deposition, vertical accretion and morphological evolution in three human‐induced intertidal flats across different tidal environments: Barbamarco Lagoon (microtidal, Italy), Perkpolder (macrotidal, The Netherlands) and Converse (hypertidal, Canada). The analyses followed the same procedure in all environments and were achieved through the use of sediment traps and digital elevation models, integrated with river and tidal records. Results indicate that during the early years of development, managed realignment sites experience rapid accretion in unusual locations of the intertidal flats (e.g. inside channels) and high erosion of artificial structures (e.g. creeks, inlets). This morphological instability influences sediment redistribution and intertidal flat evolution, potentially leading to self‐cannibalisation, where erosion of the artificial structures feed the system itself. These findings highlight the importance of long‐term monitoring to assess the sustainability of restored intertidal flats and improve predictions of their development. Future research should focus on how coastal wetland design influences long‐term evolution and how sediment supply, tidal range and human interventions shape their resilience in the face of climate change.

Sandy coasts, representing 40% of global shorelines, are essential for coastal defence and ecosystems. Natural solutions are increasingly studied to provide beach protection while enhancing ecosystem services, such as seagrass deposition on the coast. This study investigates the morphological evolution of a beach characterised by a low human impact, where Posidonia oceanica is present and forms banquettes. Fieldwork campaigns, including topographic surveys and drone mapping, were conducted over 1.5 years. A storm during one campaign led to the formation of extensive Posidonia banquettes, particularly in the southern part of the beach, a trend observed in all surveys. This distribution influenced erosion trends, with long medium-term analysis showing overall erosion, especially in northern areas with fewer banquettes and a dune retreat of around 3 meters. These findings highlight the critical role of Posidonia banquettes in protecting against dune erosion, at least locally, although significant erosion over 1.5 years occurred in the whole studied area, suggesting that further investigations are needed.