**5. Conclusions**

This paper presents a successful integrated approach to analyze the distribution of sedimentary facies of a paleomeander in the Southern Venetian Plain, Northeastern Italy. The approach is based on a combination of remote-sensing (aerial and satellite) data, geophysical investigations (electromagnetic surveys) and direct sedimentary coring.

From the methodological point of view, we show that the combined use of noninvasive techniques such as remote sensing and ground-based geophysical data provides an effective method for the purpose at hand. In particular, remote sensing is quite effective for the identification of sites of interest and features at a metric scale, which is potentially linked to different subsoil structures. In the case considered here, cropmarks are the most useful features observed from the satellite images, due specifically to the water stress induced in crops by the higher permeability of sandy bodies with respect to silty sediments. However, remote sensing can only provide information on the ground surface. On the contrary, geophysical methods are specifically designed to reconstruct the subsurface structure on the basis of contrasts of geophysical parameters. In this case, we used electromagnetic induction (EMI) methods, and particularly an FDEM small-scale multicoil system. Well-designed, acquired, processed, and inverted EMI data allowed us to extend the surface information provided by remote sensing to a maximum depth exceeding 6 m below ground level, allowing the construction of a 3D model of electrical conductivity of the subsoil. Direct investigations via sedimentary core drilling were positioned on the basis of remote sensing and geophysical data, in order to confirm and calibrate the geophysical investigations, which were also partly reinverted on the basis of the new evidence. The overall cycle of investigations thus allowed us to set up a 3D stratigraphic model of the site, consistent with all available data. On the other hand, the sequence of investigation activities was designed in such a manner that the information collected at one step optimized the design of the next step, thus reducing the overall effort required to complete the task.

From the sedimentary point of view, the point bar studied shows an uncommon arcuate morphology, that contrasts the common assumption that point bars originate from a progressive sinuosity increase of a relatively straight channel that migrates laterally until reaching a sinuous configuration. This can be explained by considering the variety of alluvial subenvironments in the floodplain. These floodplain heterogeneities likely controlled water fluxes over the platform, by facilitating water drainage within traces of depressed areas, defining the sinuous shape of the study channel during the very first phases of channel formation. As far as grain size distribution is concerned, although classical facies models highlight overall trends of upward and downstream fining of grain size within point-bar deposits, the grain-size trends of the study bar do not vary significantly either vertically or laterally. The bar is, indeed, characterized by a widespread weak vertical grain-size trend, and it appears as a homogeneous body of medium to fine sand. The lower mud content in the downstream portion was probably a result of the open morphology of the bend that could have prevented the formation of the dead zone, which is commonly directly linked to mud accumulation in the downstream portion of the sharp bends.

This study provides a solid basis for developing more detailed sedimentological investigations, which could be improved including acquisition of data concerning internal stratal architecture of the alluvial deposits. GPR investigations and recovery of undisturbed sedimentary cores would provide further relevant insights to this approach, with relevant follow up in the frame of subsurface exploration or managemen<sup>t</sup> of surficial aquifers. Detection of the distinctive morphometric and sedimentological features of Late Holocene paleochannels would allow a comparison with those of the rivers draining the area currently, and allow quantification of human impact on riverine dynamics [18].

**Author Contributions:** Data curation, E.B.; formal analysis, J.B. and G.C.; funding acquisition, M.G.; investigation, E.B., M.G., A.F. and J.B.; methodology, G.C., M.G. and J.B.; project administration, E.B. and M.G.; resources, M.G., J.B. and G.C.; software, G.C.; supervision, M.G.; validation, A.D.; visualization, E.B. and M.G.; writing—original draft, E.B., A.F., G.C. and J.B.; writing—review and editing, M.G., G.C. and A.D. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work has been supported by project HYDROSEM (Progetti di Eccellenza CARIPARO 2017, Cassa di Risparmio di Padova e Rovigo): "Fluvial and tidal meanders of the Venetian-Po plain: From hydrodynamics to stratigraphy" project (PI. M. Ghinassi).

**Acknowledgments:** Reviewers and editors will be acknowledged. The authors thank M. Cosma for logistic support during field work and R. Bonato, the land owner of the study area.

**Conflicts of Interest:** The authors declare no conflict of interest.
