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The working features of innovative coastal defense structures that can dissipate the energy of incoming waves by the action of large-scale bottom unevennesses (rigid blades covering the lower half of the water depth) were investigated by means of a laboratory experimental campaign. The goal of the study was to characterize the ability of the structures to efficiently reduce the wave height with a minimal change in the mean water superelevations. Similar wave height reductions were achieved for both vertical and inclined blades; their efficiency was slightly superior to that of traditional submerged rubble-mound breakwaters of the same cross-shore extension. For the incident waves examined, very low mean water elevations were observed inshore of the structures, with the inclined blades producing the smallest values. These results suggest that the structures analyzed here could represent an alternative to submerged rubble-mound breakwaters from a hydrodynamic point of view to protect coastlines prone to erosion with minimal risk of dangerous rip currents. DOI: 10.1061/(ASCE)WW.1943-5460.0000028 CE Database subject headings: Coastal structures; Dissipating submerged structures. Author keywords: Coastal structures; Submerging; Hydraulic roughness; Wave forces.

A comparative assessment of available formulae for the water setup inshore of submerged breakwaters is made on the basis of a wide and varied dataset derived from basin and flume laboratory experiments. Formulae derived from a simplified view which does not account for the horizontal flow circulation provide a large overestimate (up to one order of magnitude) of the smaller setup values. A much better overall approximation of the measured data is obtained through formulae that consider the setup as part of a complete flow description, be it partially or fully accounting for the horizontal flow motion. DOI: 10.1061/(ASCE)0733-950X(2009)135:2(38) CE Database subject headings: Breakwaters; Wave measurement; Beach erosion; Submerging.

In recent years, attention has been paid to beach protection by means of soft and hard defenses. Along the Italian coast of the Adriatic Sea, sandy beaches are the most common landscape feature and around 70% of the Marche region's coast (central Adriatic) is protected by defense structures. The longest free-from-obstacle nearshore area in the region includes the beach of Senigallia, frequently monitored in the last decades and characterized by a multiple bar system, which represents a natural beach defense. The bathymetries surveyed in 2006, 2010, 2011, 2012 and 2013 show long-term stability, confirmed by a good adaptation of an analyzed stretch of the beach to the Dean-type equilibrium profile, though a strong short- to medium-term variability of the wave climate has been observed during the monitored periods. The medium-term dynamics of the beach, which deal with the evolution of submerged bars and are of the order of years or seasons, have been related to the wave climate collected, during the analyzed temporal windows, by a wave buoy located about 40 km off Senigallia. An overall interpretation of the hydrodynamics, sediment characteristics and seabed morphology suggests that the wave climate is fundamental for the morphodynamic changes of the beach in the medium term. These medium-term time ranges during which waves mainly come from NNE/ESE are characterized by a larger/smaller steepness and by a larger/smaller relative wave height, and seem to induce seaward/shoreward bar migration as well as bar smoothing/steepening. Moving southeastward, the bar dimension increases, while the equilibrium profile shape suggests the adaptation to a decreasing sediment size in the submerged beach. This is probably due to the presence of both the harbor jetty and river mouth north of the investigated area. [ABSTRACT FROM AUTHOR]

A statistical analysis of the rainfalls is carried out for detecting a possible trend in the observed data. The rainfall dataset refers to the historical series collected in the hydrographic basins of the Marche region. On the one hand, the annual maximum daily, hourly and sub-hourly rainfalls have been analysed, on the other hand Climate Change Indices by Expert Team on Climate Change Detection and Indices (ETCCDI) (R1 mm, Rx1day, R20 mm, R95pTOT, PRCPTOT) have been computed to verify an eventual variation of the frequency of the rainfall regime in the Marche region. The time series, selected in the reference period 1951-2013, have been processed by using the non-parametric Mann-Kendall test. The results confirm that most of the series relating to the annual maximum rainfalls do not exhibit any trend. The absence of trend or the presence of negative trend prevail also in the analysis of the ETCCDI indices. The annual average anomalies of the same indices computed with respect to the climatological reference period 1961-1990 are negative since the mid-1980s, but they appear to show an increasing behaviour in the period 2009-2013. [ABSTRACT FROM AUTHOR]

As part of the Estuarine Cohesive Sediments (EsCoSed) project, a field experiment was performed in a highly engineered environment, acting as a natural laboratory, to study the physico-chemical properties of estuarine sediments and the associated hydro-morphodynamics during different seasons. The present contribution focuses on the results obtained from the summertime monitoring of the most downstream part of the Misa River (Senigallia, Italy). The measured hydrodynamics suggested a strong interaction between river current, wave forcing and tidal motion; flow velocities, affected by wind waves traveling upstream, changed significantly along the water column in both direction and magnitude. Surficial salinities in the estuary were low in the upper reaches of the estuary and exceeded 10 psu before the river mouth. Montmorillonite dominated the clay mineral assemblage, suggesting that large, low density flocs with high settling velocities (>1 mm s-1) may dominate the suspended aggregate materials. [ABSTRACT FROM AUTHOR]

An analysis of the run-up over different beach profiles is performed to evaluate the influence of the seabed shape on shore flooding. The analysis was carried out on the basis of numerical solutions of the nonlinear shallow water equations. The chosen solver was shown to provide reliable (both quantitatively and qualitatively) run-up results by comparing numerical solutions (of both solitary and regular waves) with the only available analytical solution forced by a localized topographic change. The run-up patterns on both a natural beach profile and three simpler and schematic profiles derived from it were evaluated. Different wave conditions (both random and groups) were used for a total amount of 96 different cases of inundation. Results are expressed in terms of both maximum () and steady-state () run-up. It is found that both types of run-up depend on the offshore variable , as suggested by several available studies, and that, for all tested cases, random waves induce the largest compared with the wave groups. The largest is induced by the composite-planar profile for both random waves and groups. An important similarity is found for both and induced by all wave types over the natural and equilibrium profiles, giving further support to the use of an equilibrium profile as representative of the natural profile. Attempts at finding an equivalent planar beach highlight unavoidable difficulties in choosing such a profile and reinforce the idea that the concept of an equivalent planar beach cannot bridge dynamics occurring from the depth of closure to the run-up. More likely, such a concept is only suitable to describe dynamics that are local to the foreshore. [ABSTRACT FROM AUTHOR]

We investigate, within the framework of the nonlinear shallow water equations (NSWE), the generation and evolution of large-scale eddies with vertical axis (macrovortices hereinafter) which are responsible for much of the horizontal mixing occurring at the boundaries between the main channel and the flood planes of a compound channel. We show that the mechanism of generation of vorticity is essentially inviscid and is analogous to that occurring at a curved shock. Numerical experiments performed by means of a recently developed shock-capturing model for the solution of the NSWE, and described in Brocchini et al. (2001), clarify some features of macrovortices generation and allow us to quantify the momentum transfer across the channel. [ABSTRACT FROM AUTHOR]

Pump-As-Turbine (PAT) technology is a smart solution to produce energy in a sustainable way at small scale, e.g., through its exploitation in classical Water Distribution Networks (WDNs). PAT application may actually represent a suitable solution to obtain both pressure regulation and electrical energy production. This technology enables one to significantly reduce both design and maintenance costs if compared to traditional turbine applications. In this work, the potential hydropower generation was evaluated through laboratory tests focused on the characterization of a pump working in reverse mode, i.e., as a PAT. Both hydrodynamic (pressure and discharge) and mechanical (rotational speed and torque) conditions were varied during the tests, with the aim to identify the most efficient PAT configurations and provide useful hints for possible real-world applications. The experimental findings confirm the good performances of the PAT system, especially when rotational speed and water demand are, respectively, larger than 850 rpm and 8 L/s, thus leading to efficiencies greater than 50%. Such findings were applied to a small municipality, where daily distribution of pressure and discharge were recorded upstream of the local WDN, where a Pressure Reducing Valve (PRV) is installed. Under the hypothesis of PRV replacement with the tested PAT, three different scenarios were studied, based on the mean recorded water demand and each characterized by specific values of PAT rotational speed. The best performances were observed for the largest tested speeds (1050 and 1250 rpm), which lead to pressure drops smaller than those actually due to the PRV, thus guaranteeing the minimum pressure for users, but also to mechanical powers smaller than 100 W. When a larger mean water demand is assumed, much better performances are reached, especially for large speeds (1250 rpm) that lead to mechanical powers larger than 1 kW combined to head drops a bit larger than those observed using the PRV. A suitable design is thus fundamental for the real-world PAT application. [ABSTRACT FROM AUTHOR]

Video-monitoring can be exploited as a valuable tool to acquire continuous, high-quality information on the evolution of beach morphology at a low cost and, on such basis, perform beach resilience analyses. This manuscript presents preliminary results of an ongoing, long-term monitoring programme of five sandy Italian beaches along the Adriatic and Tyrrhenian sea. The project aims at analyzing nearshore morphologic variabilities on a time period of several years, to link them to resilience indicators. The observations indicate that most of the beach width variations can be linked to discrete variations of sandbar systems, and most of all to an offshore migration and decay of the outermost bars. Further, the largest net shoreline displacements across the observation period are experienced by beaches with a clear NOM (Net Offshore Migration)-type evolution of the seabed. [ABSTRACT FROM AUTHOR]

We conducted, for the first time, a study of the long-term evolution of an inner mouth bar in a microtidal environment that complements field observations with detailed numerical modelling of the same morphodynamics. Images collected by a video-monitoring station, from 2016 to 2019, were processed to study the evolution of a persistent inner mouth bar formed inside the highly engineered Misa River estuary (Senigallia, Italy) after years of reduced precipitation and discharges. We developed a semi-automatic procedure to detect the emerged area of this deposit. We seek to quantify the relationship between the long-term evolution of the bar and the forcing from the river, waves and tides. The observed high peaks in river discharge caused a strong downriver bar migration (i.e. almost twice the river width). Conversely, the observed sea storms produced an upriver bar migration smaller than one river width. A much slower and weaker (less than half the river width) upriver migration was also observed during periods of large area accretion and due to mild wave climate. Moreover, results showed that the sea water level variation did not directly impact the morphodynamics of the estuary, affecting the emerged portion of the bar only. Numerical simulations, run with Delft3D, were used to complete the information coming from field observations. After some checks on the proper use of the solver for the scenarios and environments of interest, some parametric simulations were run to highlight the role of the different forcing on the bed evolution. Simulations showed, as expected, erosion of the riverbed and significant downriver migrations (four river widths) during peaks of river discharge comparable to the 1-year return period discharges. Numerical results also showed upriver sediment transport when the wave forcing was dominant, with 10-years return period waves inducing an upriver bar migration in the order of one river width. Then, one real-life event was simulated to inspect the interaction of the various forcing and to compare their effects with the observations. Our analysis provides new insight into the complex morphodynamics in a microtidal estuary when weak river discharge is opposed by sea waves driving upriver sediment transport. A more thorough understanding of the morphodynamics is needed for future forecasting of the formation and evolution of sediment deposits inside estuarine channels that can inhibit both navigation and the flux of sediment from the river to the estuary. • Detection of an inner bar at the mouth of a microtidal river from images acquired by a video-monitoring station. • Correlation of the bar area evolution and centre of mass migration with the estuarine forcings. • Field observations show the effect of different combinations of river flows and waves on the evolution of the bar. • Parametric simulations show that, at a given return period, the river discharge caused a larger bar migration than sea waves. • A real-life numerical simulation displays evolution behaviours in agreement with field observations. [ABSTRACT FROM AUTHOR]