Remote Sensing and Geo-Archaeological Data: Inland Water Studies for the Conservation of Underwater Cultural Heritage in the Ferrara District, Italy

remote sensing

Article Remote Sensing and Geo-Archaeological Data: Inland Water Studies for the Conservation of Underwater Cultural Heritage in the Ferrara District, Italy

Giovanna Bucci 1,2

1 Cultural Heritage Department, University of Padova, 35122 Padova, Italy; [email protected] or [email protected]; Tel.: +39-338-5272557 2 Confédération Mondiale des Activités Subaquatiques, Federation ITA F07 A.CDCI., 40124 Bologna, Italy

Received: 26 December 2017; Accepted: 10 February 2018; Published: 1 March 2018

Abstract: In the southern area of the Ferrara District, Italy, remote sensing investigations associated with geo-archaeological drilling in underwater archaeological studies, have helped to broad our understanding of the historical evolution and cultural heritage of inland waterways. In working on prototype sites, we have taken a multidisciplinary approach of surveillance and preventive archaeology, and have collaborated with archaeologists, geologists, hydro-biologists, and engineers. In this area of research, often lakes, lagoons, and rivers are characterized by low visibility. Some Quaternary events have deeply modified Ferrara’s landscape. Analysis of preserved samples from micro-drillings, underwater direct and indirect surveys, and the cataloguing of historical artefacts, are giving to the researchers a remarkable ancient chronology line. Recent studies confirmed anthropization sequences from the 1st Century B.C. to the 6th Century A.D. Waterscape archaeology, a multidisciplinary science devoted to the study of the human use of wetlands and anthropological connection with the water environment, testifies the ways in which people, in the past, constructed and used the water environment. In this article, we describe underwater cultural heritage research using 3D side scan sonar surveys and artifacts analysis, comparing data from direct diving investigations and stratigraphic data from micro-geological drillings on sites of Lago Tramonto, Gambulaga, Portomaggiore (Ferrara).

Keywords: underwater cultural heritage; palaeo-watercourses; geo-archaeology; remote sensing; Late Roman; Ferrara

1. Introduction The Project Underwater Archaeology of the Inland Waters- Investigations at Lago Tramonto Gambulaga (FE-Italy) is a collaboration between Federation ITA F07-CMAS Diving Center Italia, Confédération Mondiale des Activités Subaquatiques and Superintendence of Emilia Romagna, Archaeology sector, directed by who is writing with the scientific supervision of the Functionaries of the Superintendence F. Berti, V. Nizzo, M. Cesarano, C. Guarnieri. This research utilized an experimental approach and new methodologies regarding the surveillance archaeology of inland waters, including underwater and landscape research. In Italy, legislation requires that preliminary archaeological studies, defined as “preventive verification of potential archaeological interests and surveillance during excavations”, follow the United Nations Educational, Scientific and Cultural Organization (UNESCO) conventions for underwater cultural heritage (for more information on the Italian Legislation see http://www.archeologiapreventiva. beniculturali.it/rifelegi.php; or for the UNESCO conventions, see http://www.unesco.org/new/ en/culture/themes/underwater-cultural-heritage/2001-convention/). Archaeology is a discipline connected to geo-resources, oil and gas, and big engineering works. Geo-resources, especially

Remote Sens. 2018, 10, 380; doi:10.3390/rs10030380 www.mdpi.com/journal/remotesensing Remote Sens. 2018, 10, x FOR PEER REVIEW 2 of 21

Archaeology is a discipline connected to geo-resources, oil and gas, and big engineering works. RemoteRemote Sens. Sens.2018 ,201810,, 380 10, x FOR PEER REVIEW 2 of 21 2 of 21 Geo-resources, especially geo-technic and quarry studies, are involved in the stratigraphic evolution of territory,Archaeology as well is aas discipline archaeology. connected Methodologie to geo-resos,urces, techniques, oil and and gas, newand approachesbig engineering to territoryworks. are thegeo-technic sameGeo-resources, for andall of quarry theseespecially disciplines, studies, geo-technic are and involved and are quarry orie inntated st theudies, stratigraphic to are the involved preservation evolution in the stratigraphicof cultural of territory, heritage. evolution as well as archaeology.ofThe territory, sand Methodologies, quarries as well as of archaeology. Ferrara techniques, ar eMethodologie diffuse. and new Theys, approaches techniques, are projected, toand territory newby geologists approaches are the sameand to territory engineers for all are of thesewho the same for all of these disciplines, and are orientated to the preservation of cultural heritage. undertakedisciplines, sedimentological and are orientated and to thehydrogeological preservation of research, cultural heritage.before, during, and after excavations. The sand quarries of Ferrara are diffuse. They are projected, by geologists and engineers who PianuraThe Padana sand quarries is a late of geological Ferrara are structure, diffuse. crossed They are by projected, big rivers, by of geologistswhich, some and still engineers survive whoand undertake sedimentological and hydrogeological research, before, during, and after excavations. haveundertakePianura become sedimentological Padana palaeo-watercourse is a late geological ands, hydrogeological filled structure, by sediments crossed research, by [1,2]. big rivers, before, of which, during, some and still after survive excavations. and PianurahavePalaeo-watercourse Padana become ispalaeo-watercourse a late geologicalsystems ares, structure, filled mainly by sediments evidenced crossed by[1,2]. by big old rivers, traces of of which, the Po some River. still From survive satellite and andhave aerial becomePalaeo-watercourse photos, palaeo-watercourses, the ancient systems courses filledare mainly byare sediments stillevidenced highly [by1 ,2visible. ].old traces Our of thefirst Po analysis, River. From with satellite geologist collaboration,andPalaeo-watercourse aerial isphotos, dedicated the systems ancient to the are examinationcourses mainly are evidenced still of highlysuchby ancient visible. old traces courses,Our of first the including analysis, Po River. withtheir From geologist morphology satellite and andaerial theircollaboration, photos, flow. the ancientis dedicated courses to the are examination still highly of visible. such ancient Our first courses, analysis, including with geologist their morphology collaboration, is dedicatedandThe theirsouthern to flow. the examinationbranch of the of Po such is subdivided ancient courses, in the including direction theirof the morphology Reno River, and parallel their flow.to the SandalusThe The southern(ex southernriver), branch to branch divert of of thea thesmall Po Po is fractionis subdividedsubdivided to a municipalityin in the the direction direction in of Portomaggiore, ofthe the Reno Reno River, River, parallelGambulaga parallel to the to[3–5], the Sandalus (ex river), to divert a small fraction to a municipality in Portomaggiore, Gambulaga [3–5], whichSandalus is an (ex area river), with to old divert geo-reso a smallurce fraction poles, to now a municipality converted ininto Portomaggiore, naturalistic oasis Gambulaga lakes (Figures [3–5], which1 and which is an area with old geo-resource poles, now converted into naturalistic oasis lakes (Figures 1 and 2).is an area with old geo-resource poles, now converted into naturalistic oasis lakes (Figures1 and2). 2).

(a) (b) (a) (b) Figure 1. Satellite images of Gambulaga, Portomaggiore (Ferrara District (FE), Italy): (a) Position of Figure 1. Satellite images of Gambulaga, Portomaggiore (Ferrara District (FE), Italy): (a) Position of the Figurethe 1. site; Satellite (b) River images Po Delta of Gambulaga,(Google Earth PortomaSatellite Images,ggiore accessed(Ferrara on District 22 Janurary (FE), 2018).Italy): (a) Position of site; (b) River Po Delta (Google Earth Satellite Images, accessed on 22 Janurary 2018). the site; (b) River Po Delta (Google Earth Satellite Images, accessed on 22 Janurary 2018).

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Figure 2. Satellite images of Gambulaga, Portomaggiore (FE, Italy): (a) Lago Tramonto and Lago Alba (Google Earth(a Satellite) Image, accessed on 23 November 2017); (b) Sunset(b at) Lago Tramonto, panorama from Northeast side. Figure 2. Satellite images of Gambulaga, Portomaggiore (FE, Italy): (a) Lago Tramonto and Lago Figure 2. Satellite images of Gambulaga, Portomaggiore (FE, Italy): (a) Lago Tramonto and Lago Alba Alba (Google Earth Satellite Image, accessed on 23 November 2017); (b) Sunset at Lago Tramonto, (GoogleThe Earth lakes Satellite are inside Image, a palaeo-alveo, accessed on which 23 November meanders 2017); in (ab northeast) Sunset at direction, Lago Tramonto, with a panoramanorthern panorama from Northeast side. marginfrom Northeast characterized side. by high elevation (2.5 m above sea level). The lakes were excavated by dredge during the decade 1980–1990. The Thelakes excavations are inside of a thepalaeo-alveo, Fadieni necropolis which, close meanders to the north in a sidenortheast of Lago direction, Tramonto, with (Figure a northern 3) The lakes are inside a palaeo-alveo, which meanders in a northeast direction, with a northern marginunderline characterized the archaeological by high elevation interest in(2.5 this m area,abov whiche sea level). is connected The lakes to life were in excavatedRoman and by Late dredge duringmarginRoman the characterized decade Periods, 1980–1990. attested by high by its elevation proximity (2.5 to mVicus above Aventiae sea level).or Voghenza The lakes (FE) [6]. were excavated by dredge duringThe the excavations decade 1980–1990. of the Fadieni necropolis, close to the north side of Lago Tramonto, (Figure 3) underlineThe excavations the archaeological of the Fadieni interest necropolis in this ,area, close which to the is north connected side of to Lago life Tramonto,in Roman (Figureand Late3) Romanunderline Periods, the archaeological attested by its interest proximity in this to area, Vicus which Aventiae is connected or Voghenza to life (FE) in Roman[6]. and Late Roman Periods, attested by its proximity to Vicus Aventiae or Voghenza (FE) [6].

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Figure 3. Evidence of the archeological interest in Gambulaga, Portomaggiore (FE, Italy): (a) Artifacts Figure 3. Evidence of the archeological interest in Gambulaga, Portomaggiore (FE, Italy): (a) Artifacts found via excavation of the Fadieni necropolis site http://www.archeobo.arti.beniculturali.it/mostre/ found via excavation of the Fadieni necropolis site http://www.archeobo.arti.beniculturali.it/mostre/ settimana_cultura_06.htm; (b) Permanent exhibition of the artifacts found at the castle, Delizia del settimana_cultura_06.htm;(b) Permanent exhibition of the artifacts found at the castle, Delizia del Verginese http://www.archeobologna.beniculturali.it/mostre/gambulaga.htm. Verginese http://www.archeobologna.beniculturali.it/mostre/gambulaga.htm.

The underwater investigations described in this study began in 2009 [7–9] and continued until 2016.The underwater investigations described in this study began in 2009 [7–9] and continued untilIn 2016. 2014, we performed two sections of remote sensing investigations. In 2015, we made a completeIn 2014, inventory we performed of the artifacts two sections found of since remote 2009 sensing (180 investigations.findings) and, Induring 2015, the we summer made a complete of 2016, weinventory organized of the two artifacts underwater found since inspections, 2009 (180 which findings) were and, characterized during the summer by extraordinary of 2016, we organizedvisibility (duetwo underwater to exceptional inspections, droughts which and the were absence characterized of rain bythat extraordinary would usually visibility drain clay (due into to exceptional the lake). Duringdroughts 2017, and we the made absence two of geo-archaeological rain that would usually drillings drain to clayinvestigate into the the lake). stratigraphy During 2017, of the we North made andtwo geo-archaeologicalSouth sides of Lago drillings Tramonto, to investigate whose sediment the stratigraphyology was of only the Northpartially and individuated South sides ofduring Lago Tramonto,underwater whose direct sedimentology surveys. was only partially individuated during underwater direct surveys. Following the stratigraphic sequences that were found in 2009 from diving surveys and after having carried out a polygonal back backgroundground of of 250 m in length along the northern shore shore of of the lake, sporadic objects were found on the bottom of thethe lakelake betweenbetween aa depthdepth ofof 3–4.53–4.5 m.m. These objects were heterogeneousheterogeneous ceramic ceramic fragments, fragments, orange orange and and yellow yellow amphorae amphorae pieces, pieces, and fragmentsand fragments of bricks of bricksand tiles. and We tiles. conducted We conducted studies studies that would that would extend ex thistend past thisresearch. past research. In 2016, In 2016, we performed we performed new newunderwater underwater surveys surveys and re-examinedand re-examined the oldthe geologicalold geological documentation documentation that that was was preserved preserved in the in theregional regional online online database. database. In 2017, In 2017, we made we newmade geo-archaeological new geo-archaeological drillings, drillings, with particular with particular analysis analysisof the local of stratigraphy.the local stratigraphy. In this paper, In wethis illustrate paper, newwe illustrate archaeological new discoveriesarchaeological and discoveries their connection and theirto new connection methodological to new applications.methodological applications. 2. Materials and Methods 2. Materials and Methods 2.1. Remote Sensing Surveys 2.1. Remote Sensing Surveys Indirect surveys were performed in collaboration with Hydrosynergy (a spin-off of Alma Mater StudiorumIndirect University surveys were of Bologna, performed Bologna, in collaboration Italy) during with 2013. Hydrosynergy Thanks to an(a spin-off integrated of Alma instrument, Mater Studiorumecho sound University scan sonar ofHumminbird Bologna, Bologna, 1198c SI ComboItaly) during, and the 2013. software, Thanks Dr. to Depth, an integrated set on an instrument, aluminum echosmall sound boat with scan ansonar electric Humminbird powered 1198c engine, SI Combo we completed, and the software, a sequence Dr. of Depth, 20 parallel set on swaths, an aluminum as well smallas perimeter boat with scanning, an electric beginning powered from engine, the East we sidecompleted of Lake a Tramonto.sequence of This 20 parallel hydrographical swaths, as survey well permittedas perimeter us scanning, to draw, in beginning scale, seven from 3D the plan-views East side (seeof Lake Figure Tramonto.4a for example) This hydrographical and two 3D sections survey (North–Southpermitted us to and draw, West–East, in scale, asseven shown 3D plan-views in Figure4b), (see showing Figure the4a for maximum example) extension and two of3D the sections lake, (North–Souththe maximum and depth, West–East, and the most as shown dangerous in Figure area 4b), to avoid showing during the underwater maximum extension inspections of (forthe morelake, theabout maximum safety in underwaterdepth, and quarrythe most investigations dangerous seearea [7 ]).to Theavoid echo during scan recordsunderwater latitude inspections and longitude (for morecoordinates about forsafety later in examination; underwater andquarry depth investigat informationions forsee each[7]). coordinateThe echo scan value records is stored latitude differently and longitudefor each khz coordinates beam from for the later transducer. examination; The recorded and depth files information are stored in for two each formats, coordinate directly, value when is storedrecorded. differently The first for format each is khz a general beam allocation from the filetransducer. for a Humminbird The recorded unit (.DATfiles are files, stored which in recall two formats,spatial information directly, when and recorded. connect this The to first depth format information). is a general The allocation second file format for a is Humminbird .SON and this unit is (.DATlocated files, in the which folder recall associated spatial with information the waypoint and connect that started this to the depth original information). recording trackThe second (depth format is .SON and this is located in the folder associated with the waypoint that started the original recording track (depth information from each khz). The software, Dr. Depth, for bathymetric

Remote Sens. 2018, 10, 380 4 of 21 informationRemote Sens. from2018, 10 each, x FOR khz). PEER The REVIEW software, Dr. Depth, for bathymetric mapping, utilizes a multi-staged4 of 21 Remote Sens. 2018, 10, x FOR PEER REVIEW 4 of 21 anisotropic smoothing spline algorithm to pair depth and location data into a 3D bathymetric map. mapping, utilizes a multi-staged anisotropic smoothing spline algorithm to pair depth and location Mapsmapping,data and into sections a utilizes 3D bathymetric area multi-staged drawn map. per Maps asanisotropic isobaths, and sections smoothing with slopingare drawn spline contours per algorithm as isobaths, from to 0 pair to with 20 depth m sloping in and shades contours location of blue to red,datafrom respectively,into 0 to a20 3D m bathymetricin shades integrated of map.blue with toMaps metricred, andrespecti reference sectionsvely, are andintegrated drawn orientation per with as metric (Figureisobaths, reference4) with data, sloping georeferencedand orientation contours on Googlefrom(Figure 0 Earth. to 4) 20 data, m in georeferenced shades of blue on to Google red, respecti Earth.vely, integrated with metric reference and orientation (Figure 4) data, georeferenced on Google Earth.

(a) (b) (a) (b) Figure 4. Tridimensional elaborations of Lago Tramonto in Gambulaga, Portomaggiore (FE, Italy): Figure 4. Tridimensional elaborations of Lago Tramonto in Gambulaga, Portomaggiore (FE, Italy): Figure(a) 3D bathymetry;4. Tridimensional (b) 3D elaborationssection West-East of Lago (using Tramonto Hydrosynergy). in Gambulaga, Portomaggiore (FE, Italy): (a) 3D bathymetry; (b) 3D section West-East (using Hydrosynergy). (a) 3D bathymetry; (b) 3D section West-East (using Hydrosynergy). From the database of the scanned lake-bottom, we detected 25 anomalies, both natural and artificial.FromFrom theThe the databasearchaeological database of of the the evidence scanned scanned was lake-bottom,lake-bottom, concentrated we predominantly detected detected 25 25 anomalies, anomalies,in the northern both both sectornatural natural of and the and artiﬁcial.artificial.lake, at Thea depthThe archaeological archaeological between 4–12 evidence evidence m (Figure waswas 5a,b). concentratedconcentr ated predominantly predominantly in in the the northern northern sector sector of ofthe the lake,lake, at at a deptha depth between between 4–12 4–12 m m (Figure (Figure5 a,b).5a,b).

(a) (b) (a) (b) Figure 5. Lago Tramonto in Gambulaga, Portomaggiore (FE, Italy): (a) A view of the georeferenced Figurebathymetrical 5. Lago plan, Tramonto with inan Gambulaga,indication of Portomaggiore the underwater (FE, site; Italy): (b) Positioning(a) A view ofof thethe georeferenced main ancient Figure 5. Lago Tramonto in Gambulaga, Portomaggiore (FE, Italy): (a) A view of the georeferenced bathymetricalanomalies (yellow plan, oval). with an indication of the underwater site; (b) Positioning of the main ancient bathymetrical plan, with an indication of the underwater site; (b) Positioning of the main ancient anomalies (yellow oval). anomaliesThe instruments (yellow oval). detected ancient and modern anomalies. The criteria for identification of anomaliesThe instruments was the comprehension detected ancient of peculiar and modern shapes andanomalies. shadows, The identified criteria byfor watching identification the DAT of anomaliessideThe and instruments down was theimage comprehension detected files on the ancient computer, of peculiar and disp modern shapeslayed and anomalies.by theshadows, software, Theidentified Hum criteria Viewer. by forwatching identificationExamining the DAT the of anomaliessiderecorded and wasdown echo the scan image comprehension track files files, on the we computer,isolated of peculiar the disp pr shapesesencelayedand byof naturalthe shadows, software, downslopes identified Hum Viewer. from by watchingthe Examining settlement the the DATof siderecordedsediment and down echo(after image scan quarry track files excavation), files, on the we computer, isolated tree trunks the displayed pr beloesencenging byof naturalto the an software, ancient downslopes phase Hum offrom Viewer. forestry the settlement Examining [1,5], wood of the recordedsedimentpoles, and echo (after some scan quarry accumulations track excavation), files, we of isolated bricks tree trunks and the fragme presencebelongingnts of to naturalpottery.an ancient downslopesThe phase shapes of offorestry from the artifacts the [1,5], settlement wood with ofpoles,sharp sediment andedges (aftersome were accumulations quarry evident excavation), on ofthe bricks sediment tree and trunks fragmebed. belongingViewingnts of pottery. the to animages, The ancient shapes we phase identifiedof the of artifacts forestry collapsed with [1, 5], woodsharphorizontals poles, edges and poles were some due evident accumulationsto their on length the andsediment of bricksmorphology bed. and fragmentsViewing, with circular the of pottery.images, sections. Thewe A vertical shapesidentified wood of thecollapsed system artifacts withhorizontalswas sharp clear edgesfrom poles the were due echo to evident scantheir recordedlength on the and sedimentfiles morphology when bed.changing, with Viewing circularthe chromatics the sections. images, of A the we vertical file identified track wood shadows. collapsedsystem horizontalswas clearWith polesfromsite the duesurveys, echo to their scan we length recordedhad andthe files morphology,chance when to ch angingcheck with theevidence circular chromatics sections. and ofcollect the A verticalfile diagnostic track wood shadows. data, system wasconcentrated clearWith from site thein surveys,the echo northwest scan we recorded hadarea (Figurethe files chance when 5a,b). to changingWe check detected theevidence that chromatics the and northern ofcollect the bank filediagnostic trackof the shadows. ancient data, concentratedriverWith was site made surveys, in ofthe compact northwest we had clay, the area with chance (Figure quite to 5a,b).vertical check We evidence excavated detected and marginthat collect the and northern diagnostic micro-depositional bank data, of the concentrated ancient levels river was made of compact clay, with quite vertical excavated margin and micro-depositional levels in theof clay northwest and silt, areavisible (Figure on .DAT5a,b). files We as detected a long dark that rectilinear the northern shadow bank running of the ancient West–East river (Figure was made 6). of clay and silt, visible on .DAT files as a long dark rectilinear shadow running West–East (Figure 6). of compact clay, with quite vertical excavated margin and micro-depositional levels of clay and silt, visible on .DAT files as a long dark rectilinear shadow running West–East (Figure6).

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Figure 6. Visualization of the echo side scan sonar snap shots with Hum viewer software, in Lago Figure 6. Visualization of the echo side scan sonar snap shots with Hum viewer software, Tramonto, Gambulaga, Portomaggiore (FE, Italy): (a) Down image of the northern, ancient riverside in Lago Tramonto, Gambulaga, Portomaggiore (FE, Italy): (a) Down image of the northern, ancient (indicated by yellow arrow) with fallen posts (red arrows); (b) Down image of mudslide and riverside (indicated by yellow arrow) with fallen posts (red arrows); (b) Down image of mudslide and collapsed structures. collapsed structures. As visible in the Arcgis photo in Figure 9 (see Section 2.2), and the echo side scan sonar, the northernAs visible edge in of the the Arcgisriver coincided photo in perfectly Figure 9 with (see the Section bank 2.2 of), compact and the clay echo we side documented scan sonar, theunderwater northern edgein the of direct the river surveys, coincided as well perfectly as with remote with the sensing bank investigation, of compact clay with we a better documented long underwaterdistance perspective. in the direct We surveys, also found as trees, well ascut withwood remote, bricks, sensing and tiles. investigation, Many downslopes with aand better partial long distancebank collapses perspective. were We located also foundalong trees,the same cut wood,direction, bricks, South–West and tiles. to Many North–East, downslopes following and partialthe bankdirection collapses of the were river located flow. Post-pro along thecessing same analysis direction, of the South–West echo side scan to North–East,sonar data allowed following us to the directiontake measurements of the river ﬂow. of the Post-processing big trunks laying analysis on the of silty the echoclay, sideclose scanto the sonar northern data allowedriver bank, us tothat take measurementswere almost 10 of m the in biglength trunks (Figure laying 7). on the silty clay, close to the northern river bank, that were almost 10 m in length (Figure7).

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Figure 7. Visualization of the echo side scan sonar snap shots with Hum viewer software, in Lago Figure 7. Visualization of the echo side scan sonar snap shots with Hum viewer software, in Lago Tramonto, Gambulaga, Portomaggiore (FE, Italy): (a) Bottom, down image and position with Tramonto, Gambulaga, Portomaggiore (FE, Italy): (a) Bottom, down image and position with metrical metrical reference of a big trunk; (b) Bottom, down image and position of anthropic traces. reference of a big trunk; (b) Bottom, down image and position of anthropic traces. A tiny current could still be detected in the alveo because of the natural course of the falda water,A tiny following current the could morphology still be detected of the ancient in the alveo hydrographical because of thecontext. natural course of the falda water, followingWe thealso morphology saw traces of thethe ancientquarry hydrographicalexcavations that context. were better understood with immersion on-siteWe (Figure also saw 8a,b). traces of the quarry excavations that were better understood with immersion on-site (Figure8a,b).

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Figure 8. Underwater surveys from 2016 in Lago Tramonto, Gambulaga, Portomaggiore (FE, Italy: Figure 8. Underwater surveys from 2016 in Lago Tramonto, Gambulaga, Portomaggiore (FE, Italy: (a) Clay banks cut by the dredge; (b) A vertical hole caused by the fixing pile of the dredge (photo by (a) Clay banks cut by the dredge; (b) A vertical hole caused by the fixing pile of the dredge (photo by Giovanna Bucci). Giovanna Bucci). 2.2. Geological and Geo-Archaeological Drillings 2.2. Geological and Geo-Archaeological Drillings We analyzed 18 local geological drillings and three penetrometric tests performed in 1990, We analyzed 18 local geological drillings and three penetrometric tests performed in 1990, preliminary to the quarry excavation. preliminary to the quarry excavation. Documentation from this preliminary investigation related to a sand quarry project are Documentation from this preliminary investigation related to a sand quarry project are available available online, on the geological webgis cartographical database of Emilia Romagna online, on the geological webgis cartographical database of Emilia Romagna (http://ambiente.regione. (http://ambiente.regione.emilia-romagna.it/geologia/cartografia/webgis-banchedati). emilia-romagna.it/geologia/cartografia/webgis-banchedati). Perforation No. 204060 P4242 Comune di Portomaggiore Dato R/7 SONGEO (position 9.7 in Perforation No. 204060 P4242 Comune di Portomaggiore Dato R/7 SONGEO (position 9.7 in Figure 9a), after 3 m of silt alternated to gray sand, shows a level of grey medium sand with wood at Figure9a), after 3 m of silt alternated to gray sand, shows a level of grey medium sand with wood a depth of 6.8–7.7 m (from the ground level). The presence of wood gives a useful comparison to our at a depth of 6.8–7.7 m (from the ground level). The presence of wood gives a useful comparison to database, coming from direct investigations. This data, compared with the lake-bottom measures, our database, coming from direct investigations. This data, compared with the lake-bottom measures, coincides with our main, detected archaeological, underwater findings. The falda level at the time of coincides with our main, detected archaeological, underwater findings. The falda level at the time of the 1990 drillings and penetrometric analysis was found to be 2.5 m, which means the archaeological the 1990 drillings and penetrometric analysis was found to be 2.5 m, which means the archaeological level was at a depth of 5.5 m. As visible from the Arcgis photo below (Figure 9b, blue arrow), the level was at a depth of 5.5 m. As visible from the Arcgis photo below (Figure9b, blue arrow), palaeo-alveo is partially obliterated, exactly in coincidence with the archaeological site. As we can the palaeo-alveo is partially obliterated, exactly in coincidence with the archaeological site. As we see from Figure 9c, geologists isolated a flow in this area. The Google Earth elevation section (Figure can see from Figure9c, geologists isolated a flow in this area. The Google Earth elevation section 9d) shows the fluvial palaeo-bank of the river with anthropic traces. (Figure9d) shows the fluvial palaeo-bank of the river with anthropic traces. There was a big flow, that has already been studied by geologists, at the southeastern side of the There was a big flow, that has already been studied by geologists, at the southeastern side lake [5], which likely modified the local landscape at the time of the event. Our research suggests this of the lake [5], which likely modified the local landscape at the time of the event. Our research catastrophe of Late Quaternary happened at the beginning of the Early Middle Ages (see section 5). suggests this catastrophe of Late Quaternary happened at the beginning of the Early Middle Ages The chronology, as we already know, concerns Roman and Late Roman—Early Mediaeval Cultural (see Section5). The chronology, as we already know, concerns Roman and Late Roman—Early Heritage. Mediaeval Cultural Heritage. The geo-archaeological drillings of 2017 were dedicated to providing a better understanding of The geo-archaeological drillings of 2017 were dedicated to providing a better understanding of the the local stratigraphy, giving special attention to the presence of palaeo-soils and ancient local stratigraphy, giving special attention to the presence of palaeo-soils and ancient anthropization, anthropization, and looking for an untouched, well-preserved stratigraphy, close to the fluvial and looking for an untouched, well-preserved stratigraphy, close to the fluvial anthropized bank. anthropized bank. We positioned the drillings at the South and North sides of the lake to make a We positioned the drillings at the South and North sides of the lake to make a section of the western section of the western area of the palaeo-watercourse (Figure 9c,d). area of the palaeo-watercourse (Figure9c,d). The lower part of Figure 9d shows the elevated section of the sedimentary deposits along the The lower part of Figure9d shows the elevated section of the sedimentary deposits along the old old river. The north side shows the biggest depositional bump inside the meander, while the South river. The north side shows the biggest depositional bump inside the meander, while the South side is side is the most erosive side, as visible from the red arrows indicating the right side of the the most erosive side, as visible from the red arrows indicating the right side of the palaeo-watercourse. palaeo-watercourse. The lake is not as wide as the river. We confirmed this by analyzing the The lake is not as wide as the river. We confirmed this by analyzing the stratigraphy data from the stratigraphy data from the first, 2017 drill (Figure 10). first, 2017 drill (Figure 10).

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Figure 9. Lago Tramonto, Gambulaga, Portomaggiore (FE, Italy): (a) Extracted plan view from Figure 9. Lago Tramonto, Gambulaga, Portomaggiore (FE, Italy): (a) Extracted plan view from Figurehttp://ambiente.regione.emilia-rom 9. Lago Tramonto, Gambulaga,agna.it/geologia/cartografia/web Portomaggiore (FE, Italy):gis-banchedati (a) Extracted (accessed plan view on from30 http://ambiente.regione.emilia-romagna.it/geologia/cartograﬁa/webgis-banchedati (accessed on http://ambiente.regione.emilia-romNovember 2017) with the positioningagna.it/geologia/cartografia/web of the 1990 drillings; (b) Palaeo-watercoursegis-banchedati of the(accessed River Po on on 30 30 November 2017) with the positioning of the 1990 drillings; (b) Palaeo-watercourse of the River Po on Novemberthe site of 2017) the futurewith the quarry positioning (1989), ofextracted the 1990 from drillings; http://www.arcgis.com (b) Palaeo-watercourse (accessed of the 1 December River Po on the site of the future quarry (1989), extracted from http://www.arcgis.com (accessed 1 December 2017), the2017), site ofwhere the futurethe blue quarry arrows (1989), indicate extracted the archaeol fromogical http://www.arcgis.com site and the yellow (accessedarrows indicate 1 December the where the blue arrows indicate the archaeological site and the yellow arrows indicate the palaeo-alveo 2017),palaeo-alveo where the traces; blue (c arrows) Palaeo-watercourses indicate the archaeoland floodsogical (extracted site and from the [3]) yellow; (d) Google arrows Earth indicate Image the traces; (c) Palaeo-watercourses and ﬂoods (extracted from [3]); (d) Google Earth Image with position of palaeo-alveowith position traces; of the ( c2017) Palaeo-watercourses drillings and 1km altitude and floods section (extracted crossing from the tw [3])o points; (d) Google of the drill. Earth Image the 2017 drillings and 1km altitude section crossing the two points of the drill. with position of the 2017 drillings and 1km altitude section crossing the two points of the drill.

(a) (b)

Figure 10. Drilling No. 1 in(a 2017) in Lago Tramonto, Gambulaga, Portomaggiore(b) (FE, Italy): (a) The drilling machine; (b) Work in progress while drilling, sediment check (photo by Giovanna Bucci). Figure 10. Drilling No. 1 in 2017 in Lago Tramonto, Gambulaga, Portomaggiore (FE, Italy): (a) The Figure 10. Drilling No. 1 in 2017 in Lago Tramonto, Gambulaga, Portomaggiore (FE, Italy): (a) The drilling drilling machine; (b) Work in progress while drilling, sediment check (photo by Giovanna Bucci). machine;Drill No. (b) Work1/2017 in reached progress 5 while m depth drilling, and sediment presented check the (photo following by Giovanna stratigraphy Bucci). (expressed in meters): from 0 to 0.60 there was beige silt, 0.60−1.25 sandy silt (beige and orange), 1.25−1.55 grey siltyDrill sand, No. 1.55 1/2017−1.80 reachedgrey coarse 5 m sand, depth 1.80 and−2.20 presented grey sand, the 2.20 following−3.10 beige stratigraphy lightly silty (expressed sand, and in Drill No. 1/2017 reached 5 m depth and presented the following stratigraphy (expressed in meters):from 3.10 from−5.00 0 tothere 0.60 was there grey was coarse beige sand silt, (see 0.60 Appendix−1.25 sandy A and silt Figure (beige A1). and orange), 1.25−1.55 grey meters): from 0 to 0.60 there was beige silt, 0.60−1.25 sandy silt (beige and orange), 1.25−1.55 grey silty silty sand,The second1.55−1.80 drill, grey on thecoarse North sand, shore, 1.80 was−2.20 8 m grey deep sand, and showed 2.20−3.10 the beigefollowing lightly levels silty (expressed sand, and sand, 1.55−1.80 grey coarse sand, 1.80−2.20 grey sand, 2.20−3.10 beige lightly silty sand, and from fromin meters):3.10−5.00 from there 0− was0.50 greythere coarsewas beige sand silty (see clay, Appendix 0.50−1.35 A andbrown Figure mottled A1). silty clay with vegetal 3.10−5.00 there was grey coarse sand (see AppendixA and Figure A1). traces,The 1.35second−2.40 drill, beige on orange the North mottled shore, clayey was silt8 m with deep traces and showedof reeds, the2.40 following−3.15 beige levels silt, 3.15(expressed−3.65 in greymeters):The clay second from(palaeo-soil), drill,0−0.50 on there the3.65 North− 4.30was grey shore,beige−light wassilty blue 8clay, m deepsilt, 0.50 4.30 and−1.35−4.50 showed brown grey the mottledclay following with silty micro levels clay fragments (expressedwith vegetal of in meters): from 0–0.50 there was beige silty clay, 0.50−1.35 brown mottled silty clay with vegetal traces, traces,torba, 1.35 4.50−2.40−5.10 beige grey orangesand, 5.10 mottled−5.40 grey clayey clay silt with with a nucleustraces of of reeds, CaCo 2.403, 5.40−3.15−5.60 beige violet silt, clay 3.15 with−3.65 1.35greymicro-carbonaceous− clay2.40 beige(palaeo-soil), orange cores mottled3.65 and−4.30 clayeyvegetal grey silt− traceslight with blue(palaeo-soil), traces silt, of 4.30 reeds, 5.60−4.50 2.40−6.10 grey− 3.15grey clay beigesilt withwith silt, vegetalmicro 3.15− 3.65fragments traces grey and clay of (palaeo-soil), 3.65−4.30 grey−light blue silt, 4.30−4.50 grey clay with micro fragments of torba, torba,malacofauna, 4.50−5.10 grey6.10− 7.40sand, violet 5.10− 5.40silty grey clay clay with with micro-carbonaceous a nucleus of CaCo cores3, 5.40 and−5.60 vegetalviolet claytraces with micro-carbonaceous4.50−5.10 grey sand, cores 5.10 and−5.40 vegetal grey traces clay with(palaeo-soil), a nucleus 5.60 of−6.10 CaCo grey3, 5.40silt −with5.60 vegetal violet traces clay with and malacofauna,micro-carbonaceous 6.10−7.40 cores violet and vegetal silty tracesclay (palaeo-soil),with micro-carbonaceous 5.60−6.10 grey cores silt with and vegetal vegetal traces traces and

Remote Sens. 2018, 10, 380 9 of 21 malacofauna, 6.10−7.40 violet silty clay with micro-carbonaceous cores and vegetal traces (palaeo-soil), and fromRemote 7.40 Sens.− 20188.00, 10 there, x FOR wasPEER violetREVIEW silty clay with torba micro levels (see AppendixA and Figure9 of 21 A2). The two investigations concerned two different depositional situations. To the South side we have(palaeo-soil), the river itself and with from its 7.40 “clean”−8.00 there sediments, was violet and silty to the clay North with torba sidethere micro are levels traces (see of Appendix ancient humanA settlements,and Figure confirming A2). all our preceding research. ThereThe were two someinvestigations extra considerations concerned two regardingdifferent de thepositional second situations. drilling. To The the areaSouth wasside coveredwe have the river itself with its “clean” sediments, and to the North side there are traces of ancient by beige silty clay that lay on a brown mottled silty clay with vegetal traces, concerning the last human settlements, confirming all our preceding research. centuries (see AppendixA for a graphic depiction) Stratigraphic Units 1, 2, and 3. A natural alluvional There were some extra considerations regarding the second drilling. The area was covered by levelbeige of beige silty silt clay (US that 3) lay covered on a brown the first mottled palaeo-soil, silty clay connected with vegetal to a traces, downslope concerning of the the river last bank. The naturalcenturies matrix (see Appendix of grey clay A includedfor a graphic micro-fragments depiction) Stratigraphic of bricks belongingUnits 1, 2, to and the 3. Roman A natural and Late Romanalluvional Periods. level of beige silt (US 3) covered the first palaeo-soil, connected to a downslope of the Thereriver bank. were The a couple natural of typicalmatrix inlandof greywater clay included layers, with micro-fragments gray and light-blue of bricks silt, belonging possibly to indicating the a slowRoman phase and of theLate watercourse Roman Periods. from palaeo-soils or beds of inland waterscapes. The sedimentologicalThere were a couple characterization of typical inland of thewater samples layers, performed with gray duringand light-blue 2017 [10 silt,] supported possibly the presence,indicating in many a slow samples, phase of of the seeds watercourse belonging from to flora palaeo-soils palustris or, typicalbeds of ofinland inland waterscapes. waters: Nymphaea alba, The sedimentological characterization of the samples performed during 2017 [10] supported the Apium inondatum, Typha latifolia, and Sparganium erectum. Isotopic analysis confirmed the presence of presence, in many samples, of seeds belonging to flora palustris, typical of inland waters: Nymphaea organic components. alba, Apium inondatum, Typha latifolia, and Sparganium erectum. Isotopic analysis confirmed the presence of organic components. 2.3. Underwater Surveys The2.3. Underwater 2016 dive sessionSurveys was dedicated to the documentation of the submerged site of Lago Tramonto, in light ofThe the 2016 data dive collected session by was echo dedicated side scan to sonar the documentation in 2013. of the submerged site of Lago TheTramonto, underwater in light of surveys the data werecollected performed by echo side thanks scan sonar to a teamin 2013. of divers, using simple diving equipmentThe with underwater 12 or 15 surveys l tanks, were filled performed with air, thanks fitted to with a team double of divers, first stage, using separatedsimple diving primary and secondaryequipment with regulators, 12 or 15 togetherl tanks, filled with with all ofair, the fitted safety with equipmentdouble first stage, required separated by current primary legislation. and The usesecondary of compasses regulators, was together fundamental, with all of along the safe withty canonicequipment topographical required by current instruments, legislation. including The a use of compasses was fundamental, along with canonic topographical instruments, including a total total station Leica 1205 reflector (settled at the edge of the lake), capable of positioning our reference station Leica 1205 reflector (settled at the edge of the lake), capable of positioning our reference buys buys on the surface and connecting our measures to a local topographical grid (Figure 11a,b). on the surface and connecting our measures to a local topographical grid (Figure 11a,b).

(a) (b)

Figure 11. Photographs of the underwater survey operation in Lago Tramonto, Gambulaga, Figure 11. Photographs of the underwater survey operation in Lago Tramonto, Gambulaga, Portomaggiore (FE, Italy): (a) Setting of the equipment before the survey; (b) Pegging the underwater Portomaggioretopographical (FE, reference Italy): (pointa) Setting (photo of by the Antonio equipment Duccoli before and Paolo the survey; Farina). ( b) Pegging the underwater topographical reference point (photo by Antonio Duccoli and Paolo Farina). There were three main underwater surveys. Table 1 reports the main data with satellite Google ThereEarth positioning were three of main the main underwater tracks performed. surveys. Table1 reports the main data with satellite Google The first survey, carried out in May 2016, took place in the west sector of the lake and along the Earth positioning of the main tracks performed. eastern edge; the second survey took place in August along the circumnavigation of the lake; and The ﬁrst survey, carried out in May 2016, took place in the west sector of the lake and along the the third survey focused on the northwest area of the basin, where we have documented traces of easternfrequentation edge; the and second the sporadic survey tookpresence place of inartifacts. August Excellent along thewater circumnavigation visibility between ofAugust the lake; and and the thirdSeptember survey 2016 focused made it on possible the northwest to take videos area and of the photographs, basin, where bringing we haveto light documented new information traces of frequentationabout cultural and heritage. the sporadic presence of artifacts. Excellent water visibility between August and September 2016 made it possible to take videos and photographs, bringing to light new information about cultural heritage.

Remote Sens. 2018, 10, 380 10 of 21

Table 1. The underwater surveys recording sheet, which includes the number of the survey, date, length of the track, diving time, maximum depth, temperature of the water, remarks, and Google Earth GPS mapping of the surveys. Remote Sens. 2018, 10, x FOR PEER REVIEW 11 of 23 Remote Sens. 2018, 10, x FOR PEER REVIEW 11 of 23 S No. Date Track [km] Diving Time [h] Max Depth [m] T [◦C] RemarksRemote Satellite Sens. 2018 Photo-Plan, 10, x FOR PEER Google REVIEW Earth with Survey Track 11 of 23

Very poor visibility, 1 22 May 2016 0.57 01:02:05 7.4 16.4 absence of archaeological ﬁndings

Good visibility, 2 15 August 2016 1.27 02:50:50 7.8 24.4 documentation of the archaeological site

Very good visibility, 3 15 September 2016 0.38 01:05:20 6.9 26.3 documentation of the archaeological site

Material emerged from the bottom of the lake due to local underwater sediment landslides has increased Material the emerged knowledge from of the the bottom site, the of possibilitythe lake due of to new local investigations, underwater sediment and has landslides expanded has the increasedchronoloMaterialgy the of emerged knowledgeattendance. from of the the bottom site, the of possibilitythe lake due of to new local investigations, underwater sediment and has landslides expanded has the increasedchronoloFromgy thea of methodological knowledgeattendance. of point the site, of view, the possibility research was of newcarried investigations, out using the and parallel has expandedswath system the chronolo(methodFrom gyof a ofcrossbarsmethodological attendance. or parallels), point of even view, over research the longer was carrieddistance out by using remote the sensing. parallel Weswath proceeded system (methodby followingFrom of a crossbarsmethodological the best orvisibility parallels), point and ofeven anthropicview, over research the traces. longer was For carrieddistance the most out by evident usingremote the structures, sensing. parallel We swath on proceeded which system we (methodbyconcentrated following of crossbars the our best work, orvisibility parallels), we provide and even anthropic a doubleover the traces. topographical longer For distance the most net by evident connected remote structures, sensing. to the We old on proceeded onewhich made we byconcentratedbetween following 2009 the our and best work, 2010 visibility we [9], provide withand anthropic a a polygonal double traces. topographical line For on the the most net lakebed connectedevident and structures, tonew the parallel old on onewhich grid made we of concentratedbetweeninvestigation 2009 ouroriented and work, 2010 with we [9], compasses, provide with a a polygonal meters, double and topographical line “floating on the GPS”. net lakebed connected Positioning and new to was the parallel achieved old one grid madeusing of betweeninvestigationa GPS receiver 2009 oriented and in 2010a with watertight [9], compasses, with container, a polygonalmeters, placed and line “floating in on the the subGPS”. lakebed-marks Positioning and buoy new andwas parallel achieved equipped grid using with of investigationaappropriate GPS receiver housing. oriented in a with watertight compasses, container, meters, placed and “floating in the subGPS”.-marks Positioning buoy andwas equippedachieved using with aappropriate GPSThe receiver underwater housing. in a photographic watertight container, and video placed documentation in the sub was-marks undertaken buoy andwit h equippeda Nikon Coolpix with appropriateAW110The digital underwater housing. camera photographic and a Go Pro andHero3 video Black documentation. was undertaken with a Nikon Coolpix AW110The digital underwater camera photographic and a Go Pro Hero3and video Black documentation. was undertaken with a Nikon Coolpix AW1103. Results digital camera and a Go Pro Hero3 Black. 3. Results Surveys number 2 and 3, in 2016, were designed to discriminate objects for the interpretation of 3. Results the archaeologicalSurveys number history 2 and of 3 ,the in 2016lake., were designed to discriminate objects for the interpretation of the archaeologicalSWeurveys documented number history 2part and of of 3 the ,the in l 2016ancientake., were natural designed bank to of discriminate the river, made objects of very for thecompact interpretation gray–beige of theclay archaeological Weand documented a palisade. history Thispart ofofnatural thethe lancientake. structure natural was bank well -ofidentified the river, thanks made ofto verythe echo compact side grayscan– beigesonar clayinvestigation. Weand documented a palisade. Natural This part achievement naturalof the ancient structure of naturalthe wasresting bankwell angle- ofidentified the of river, the thanks madesediments toof verythe and echo compact perhaps side grayscan also– sonarbeige the clayinvestigation. and a palisade. Natural This achievement natural structure of the wasresting well angle-identified of the thanks sediments to the and echo perhaps side scan also sonar the investigation. Natural achievement of the resting angle of the sediments and perhaps also the

Remote Sens. 2018, 10, 380 11 of 21

Material emerged from the bottom of the lake due to local underwater sediment landslides has increasedRemote the Sens. knowledge 2018, 10, x FOR ofPEER the REVIEW site, the possibility of new investigations, and has expanded 11 of 21 the chronology of attendance. FromRemote aMaterial methodologicalSens. 2018 emerged, 10, x FOR PEERfrom point REVIEW the ofbottom view, of research the lake du wase to carriedlocal underwater out using sediment the parallel landslides swath 11 ofhas 21 system (methodincreased of crossbars the knowledge or parallels), of the evensite, the over possibility the longer of new distance investigations, by remote and sensing.has expanded We proceededthe chronology of attendance. by followingMaterial the best emerged visibility from andthe bottom anthropic of the traces.lake due For to local the underwater most evident sediment structures, landslides on has which we increasedFrom thea methodological knowledge of pointthe site, of view, the possibility research was of newcarried investigations, out using the and parallel has expandedswath system the concentrated(methodchronology our of work, crossbarsof attendance. we or provide parallels), a double even over topographical the longer distance net connected by remote tosensing. the old We one proceeded made between 2009 andby 2010 followingFrom [9], a withmethodological the best a polygonal visibility point and line of anthropic view, on the research lakebed traces. was For and carried the new most out parallel evident using the gridstructures, parallel of investigation swathon which system we oriented with compasses,concentrated(method of meters,crossbars our work, andor parallels),we “ﬂoating provide even a GPS”. doubleover the Positioning topographical longer distance was net by achievedconnected remote sensing. usingto the oldWe a GPS proceededone receivermade in a watertightbetweenby following container, 2009 the and placed best 2010 visibility in [9], the with and sub-marks anthropica polygonal buoy trac es.line and For on equipped the the most lakebed evident with and appropriate structures, new parallel on housing. which grid weof Theinvestigationconcentrated underwater orientedour photographic work, with we compasses, provide and a video meters,double documentation antopographicald “floating GPS”. net was connected Positioning undertaken to was the withachievedold one a Nikon usingmade Coolpix abetween GPS receiver 2009 and in a2010 watertight [9], with container, a polygonal placed line in onthe the sub-marks lakebed andbuoy new and parallelequipped grid with of AW110 digital camera and a Go Pro Hero3 Black. appropriateinvestigation housing. oriented with compasses, meters, and “floating GPS”. Positioning was achieved using a GPSThe receiver underwater in a photographicwatertight container, and video pl documentationaced in the sub-marks was undertaken buoy andwith equippeda Nikon Coolpix with 3. Results AW110appropriate digital housing. camera and a Go Pro Hero3 Black. SurveysThe number underwater 2 and photographic 3, in 2016, and were video designed documentation to discriminate was undertaken objects with for a the Nikon interpretation Coolpix of 3. Results the archaeologicalAW110 digital history cameraof and the a Go lake. Pro Hero3 Black. We documentedSurveys number part 2 of and the 3, ancientin 2016, were natural designed bank to of discriminate the river, madeobjects offorvery the interpretation compact gray–beige of the3. Results archaeological history of the lake. clay and a palisade. This natural structure was well-identiﬁed thanks to the echo side scan sonar WeSurveys documented number part2 and of 3, the in 2016,ancient were natural designed bank toof discriminatethe river, made objects of very for compactthe interpretation gray–beige of investigation.claythe archaeological and a Natural palisade. history achievement This naturalof the lake. structure of the was resting well-identified angle of thanks the sediments to the echo and side perhapsscan sonar also the earthquakeinvestigation.We of 2012,documented Natural gave partrise achievement of to the a ancient small of landslide,thenatural restin bankg angle with of the of a river, sandythe madesediments matrix, of very and in compact theperhaps vicinity gray–beige also ofthe an area alreadyearthquakeclay highlighted and a palisade.of 2012, in previous gaveThis risenatural studies to a structure small [7 –landslide,9 ].was Part well-identified ofwith the a outcroppingsandy thanks matrix, to clayinthe the echo material vicinity side scanof could an sonar area be traced back toalreadyinvestigation. Late Antiquity. highlighted Natural We in foundpreviousachievement a differentstudies of [7–9].the typology restin Partg of angle the of theoutcropping of amphora:the sediments clayLate material and Roman perhaps could 3 and be also tracedLate the Roman 5 (Figure backearthquake12a,b). to Late of Antiquity. 2012, gave We rise found to a a smalldifferent landslide, typology with of thea sandy amphora: matrix, Late in Roman the vicinity 3 and Lateof an Roman area 5already (Figure highlighted 12a,b). in previous studies [7–9]. Part of the outcropping clay material could be traced back to Late Antiquity. We found a different typology of the amphora: Late Roman 3 and Late Roman 5 (Figure 12a,b).

(a) (b)

Figure 12. Fragments of Late Roman Amphorae found during underwater surveys in Lago Figure 12.Tramonto,Fragments Gambulaga, of Late Portomaggiore Roman(a) Amphorae (FE, Italy): found (a) Foot during and part underwater of( bthe) body surveys of Late Roman in Lago 3; ( Tramonto,b) a Late Roman 3 b Gambulaga,HandleFigurePortomaggiore of12. Late Fragments Roman 5 (photoof (FE, Late Italy):by Roman Giovanna ( ) Amphorae Foot Bucci). and partfound of during the body underwater of surveys ;(in Lago) Handle of Late RomanTramonto, 5 (photo Gambulaga, by Giovanna Portomaggiore Bucci). (FE, Italy): (a) Foot and part of the body of Late Roman 3; (b) TheseHandle are of Latealso Roman fragments 5 (photo of doliaby Giovanna, tableware Bucci). and kitchenware (Figure 13a,b). These are also fragments of dolia, tableware and kitchenware (Figure 13a,b). These are also fragments of dolia, tableware and kitchenware (Figure 13a,b).

(a) (b)

Figure 13. Fragments found during underwater surveys in Lago Tramonto, Gambulaga, Portomaggiore (FE, Italy): (a()a Dolium) ; (b) Fragments of pottery (photo by Giovanna.(b) Bucci). Figure 13. Fragments found during underwater surveys in Lago Tramonto, Gambulaga, Figure 13.PortomaggioreFragments (FE, found Italy): during (a) Dolium underwater; (b) Fragments surveys of pottery in Lago (photo Tramonto, by Giovanna. Gambulaga, Bucci). Portomaggiore (FE, Italy): (a) Dolium;(b) Fragments of pottery (photo by Giovanna. Bucci). Remote Sens. 2018, 10, 380 12 of 21 Remote Sens. 2018, 10, x FOR PEER REVIEW 12 of 21 Remote Sens. 2018, 10, x FOR PEER REVIEW 12 of 21 TogetherTogether with with the the pottery pottery findings, findings, three three animal animal bone fragments were collected:collected: twotwo belongingbelonging to tohorses horsesTogether and and a with swinea swine the jaw. pottery Thesejaw. Thesefindings, finds werefinds three in were the animal same in thebone matrix same fragments as wood,matrix were logs,as collected:wood, and other logs, two non-diagnostic and belonging other non-diagnostictoceramic horses pieces.and ceramica swine pieces. jaw. These finds were in the same matrix as wood, logs, and other non-diagnosticParticularlyParticularly ceramic interesting interesting pieces. was thethe finding finding of of a Roman a Roman Common Common Ware Waremoney money box, which box, hadwhich evidently had evidentlyemergedParticularly emerged from the interesting stratigraphyfrom the stratigraphywas shortly the finding before shortly the of surveybea foreRoman andthe Common couldsurvey be and seenWare could in money the be large seenbox, area inwhich notthe covered large had areaevidentlyby calcareousnot covered emerged encrustations. by from calcareous the stratigraphy The encrustations. small object shortly wasThe be layingsmallfore the onobject thesurvey Eastwas and sidelaying could of theon the underwaterbe seenEast inside the landslide. of large the underwaterareaClose not to covered this landslide. area, by there calcareous Close were to pilesthis encrustations. area, driven there into were The the lake-bottompilessmall driven object (Figure intowas the laying 14 lake-bottoma,b). on the East (Figure side 14a,b). of the underwater landslide. Close to this area, there were piles driven into the lake-bottom (Figure 14a,b).

(a) (b) (a) (b) Figure 14. Silty clay bumps during underwater surveys in Lago Tramonto, Gambulaga, Figure 14. Silty clay bumps during underwater surveys in Lago Tramonto, Gambulaga, Portomaggiore PortomaggioreFigure 14. Silty (FE, clayItaly): bumps (a) Standing during pole underwater and tapered surveys pole with in engraved Lago Tramonto, lines; (b) Standing Gambulaga, pole (FE, Italy): (a) Standing pole and tapered pole with engraved lines; (b) Standing pole (photo by Giovanna (photoPortomaggiore by Giovanna (FE, Italy):Bucci). ( a) Standing pole and tapered pole with engraved lines; (b) Standing pole Bucci). (photo by Giovanna Bucci). Beside this area, there were numerous poles in the secondary laying, partially worked: some tapered,BesideBeside ending this this area,in area, a truncatedthere there were were cone, numerous numerous and others poles poles partially in in the the secondary secondaryor completely laying, laying, cut, partially partially with bricks worked: worked: and some tiles some dispersedtapered,tapered, ending (Figure ending in 15a,b). in a atruncated truncated cone, cone, and and others others partially partially or or completely completely cut, cut, with with bricks bricks and and tiles tiles disperseddispersed (Figure (Figure 15a,b). 15a,b).

(a) (b) (a) (b) Figure 15. Silty clay downslopes during underwater surveys in Lago Tramonto, Gambulaga, Figure 15. Silty clay downslopes during underwater surveys in Lago Tramonto, Gambulaga, PortomaggioreFigure 15. Silty(FE, Italy): clay downslopes(a) Cut trunk, during bricks, underwaterand tiles; (b) surveys fragment in of Lago brick Tramonto, (photo by Gambulaga,Giovanna Bucci).PortomaggiorePortomaggiore (FE, (FE, Italy): (aa)) CutCut trunk,trunk, bricks, bricks, and and tiles; tiles; (b )( fragmentb) fragment of brick of brick (photo (photo by Giovanna by Giovanna Bucci). Bucci). Survey No. 2 also highlighted the presence of fragments of monoxyl pirogues laying at an Survey No. 2 also highlighted the presence of fragments of monoxyl pirogues laying at an averageSurvey depth No. of 2 4also m, highlightednear the North the presence bank. Thofe fragmentspresence of monoxylmany pieces pirogues of pirogue laying atand, an average depth of 4 m, near the North bank. The presence of many pieces of pirogue and, importantly, importantly,average depth the offinding 4 m, ofnear a bow the or North stern (Figurebank. Th 16ea) presence of this kind of ofmany boat piecesalong withof pirogue parts of and, the the ﬁnding of a bow or stern (Figure 16a) of this kind of boat along with parts of the boards (Figure 16b), boardsimportantly, (Figure the 16b), finding is testimony of a bow of or the stern ancient (Figure navigation 16a) of ofthis the kind river of Po. boat along with parts of the is testimony of the ancient navigation of the river Po. boardsA few(Figure meters 16b), West is testimony of the bow, of the there ancient was navigation one trunk, of cutthe alongriver Po. its length (Figure 17a), and A few meters West of the bow, there was one trunk, cut along its length (Figure 17a), and another anotherA fewone meterspartially West internally of the excavated bow, there (Figure was one17b). trunk, cut along its length (Figure 17a), and one partially internally excavated (Figure 17b). anotherOther one fragments partially internallyof piroga sidesexcavated were (Figure dispersed 17b). close to the surviving North bank. The pieces Other fragments of piroga sides were dispersed close to the surviving North bank. The pieces with Otherwork infragments progress ofsupport piroga archaeological sides were dispersed evidence close of a tosmall the centersurviving of pirogue North bank.production. The pieces with work in progress support archaeological evidence of a small center of pirogue production. with work in progress support archaeological evidence of a small center of pirogue production.

Remote Sens. 2018, 10, 380 13 of 21 Remote Sens. 2018, 10, x FOR PEER REVIEW 13 of 21 Remote Sens. 2018, 10, x FOR PEER REVIEW 13 of 21

(a) (b) (a) (b) Figure 16. Fragments of piroga found during underwater surveys in Lago Tramonto, Gambulaga, Figure 16. Fragments of piroga found during underwater surveys in Lago Tramonto, Gambulaga, Figure 16. Fragments of piroga found during underwater surveys in Lago Tramonto, Gambulaga, Portomaggiore (FE, Italy): ( a)) Stern Stern or or bow; bow; ( b) Hull (photo by Giovanna Bucci). Portomaggiore (FE, Italy): (a) Stern or bow; (b) Hull (photo by Giovanna Bucci).

(a) (b) (a) (b) Figure 17. Partially processed trunks found during underwater surveys in Lago Tramonto, Figure 17. Partially processed trunks found during underwater surveys in Lago Tramonto, Gambulaga,Figure 17. Partially Portomaggiore processed (FE, trunks Italy): found (a during) A trunk underwater cut to surveysits maximum in Lago Tramonto,length with Gambulaga, metrical Gambulaga, Portomaggiore (FE, Italy): (a) A trunk cut to its maximum length with metrical references;Portomaggiore (b) A (FE, trunk, Italy): partially (a) A trunk excavated cut to inside its maximum (photo by length Giovanna with metrical Bucci). references; (b) A trunk, references; (b) A trunk, partially excavated inside (photo by Giovanna Bucci). partially excavated inside (photo by Giovanna Bucci). 4. Discussion 4. Discussion 4. DiscussionRemote sensing for underwater archaeology is mostly used for large-scale, extensive projects in Remote sensing for underwater archaeology is mostly used for large-scale, extensive projects in the seaRemote (deep sensingwater) [11,12], for underwater in combination archaeology with photogrammetry, is mostly used for and large-scale, 3D recording extensive and modelling projects in the sea (deep water) [11,12], in combination with photogrammetry, and 3D recording and modelling (seethe seahttps://www.int-arch-photogra (deep water) [11,12], in combinationmm-remote-sens-spatial-inf-sci.ne with photogrammetry, andt/XL-5-W5/index.html), 3D recording and modelling with a (see https://www.int-arch-photogramm-remote-sens-spatial-inf-sci.net/XL-5-W5/index.html), with a lot(see of https://www.int-arch-photogramm-remote-sens-spatial-inf-sci.net/XL-5-W5/index.html international attention dedicated to wrecks. Archaeology of inland water is a new area), with of lot of international attention dedicated to wrecks. Archaeology of inland water is a new area of research,a lot of international where we must attention introduce dedicated new methodologies to wrecks. Archaeology and techniques of inland of investigation. water is a new In marine area of research, where we must introduce new methodologies and techniques of investigation. In marine deep-waterresearch, where archaeology, we must much introduce research new is methodologies performed with and excellent techniques instruments of investigation. and boats. In What marine is deep-water archaeology, much research is performed with excellent instruments and boats. What is stilldeep-water missing, archaeology, is the introduction much research of small is performedremote sensing with excellentinstruments instruments for everyday and boats. archaeology What is still missing, is the introduction of small remote sensing instruments for everyday archaeology fields,still missing, such as is surveillance the introduction archaeology. of small remote sensing instruments for everyday archaeology fields, fields, such as surveillance archaeology. suchFreshwater-scape as surveillance archaeology. and underwater-scape archaeology remain the best approaches. Influential Freshwater-scape and underwater-scape archaeology remain the best approaches. Influential researchFreshwater-scape by Westley and underwater-scapeMcneary [13], published archaeology two remain years theago, best described approaches. archaeological Influential research by Westley and Mcneary [13], published two years ago, described archaeological applicationsresearch by Westley of low-cost and integrated Mcneary [13 side], published scan sona twor/single-beam years ago, echo described sounder archaeological systems in applicationsIrish Inland applications of low-cost integrated side scan sonar/single-beam echo sounder systems in Irish Inland Waterways.of low-cost integratedThey explained side scan how sonar/single-beam areas of “potential echo archaeological sounder systems interest” in Irish could Inland be detected Waterways. by Waterways. They explained how areas of “potential archaeological interest” could be detected by instrumentsThey explained like how echo areas sounders, of “potential if used archaeological by archaeologists interest” with could the benecessary detected byexperience. instruments Inland like instruments like echo sounders, if used by archaeologists with the necessary experience. Inland waterwaysecho sounders, may if usedbe a bysignificant archaeologists archaeological with the necessary resource experience. that is often Inland poorly waterways recorded may beand a waterways may be a significant archaeological resource that is often poorly recorded and quantified.significant archaeological resource that is often poorly recorded and quantified. quantified. InIn the ambitambit ofof preventivepreventive and and surveillance surveillance archaeology archaeology of inlandof inland waterways, waterways, the the use use of echo of echo side In the ambit of preventive and surveillance archaeology of inland waterways, the use of echo sidescan scan sonar sonar gives gives excellent excellent results. results. It is an It instrument is an instrument capable capable of working of working in low visibility, in low visibility, for example, for side scan sonar gives excellent results. It is an instrument capable of working in low visibility, for example,in very cold in very or polluted cold or water,polluted and water, it allows and forit allows oversight for oversight of the lake/river of the lake/river bottom without bottom thewithout need example, in very cold or polluted water, and it allows for oversight of the lake/river bottom without thefor diving.need for Completing diving. Completing a 3D bathymetry a 3D bathymetry before direct before investigation direct investigation is an important is an step, important not only step, on the need for diving. Completing a 3D bathymetry before direct investigation is an important step, notthe only side ofon scientific the side of results, scientific but alsoresults, in termbut also of safety in term for of the safety immersions. for the immersions. Knowing the Knowing exact focus the not only on the side of scientific results, but also in term of safety for the immersions. Knowing the exactpoint focus of the point main archaeologicalof the main archaeological evidence (position, evidence geomorphology, (position, geomorphology, and depth) gives and the depth) possibility gives exact focus point of the main archaeological evidence (position, geomorphology, and depth) gives theof organizing possibility and of organizing managing directand managing surveys or direct avoiding surveys them or if avoiding there are them too many if there risks are for too people. many risksthe possibility for people. of organizing and managing direct surveys or avoiding them if there are too many risks for people.

Remote Sens. 2018, 10, 380 14 of 21

Underwater visibility of inland waters is always very poor because of suspended clay (during and after quarry excavations). Very often, the maximum distance of perspective is 50 cm. Low visibility and frequent landslides create dangerous situations. The actual Italian legislation forbids any kind of immersion while dredging work is in progress, but sometimes dredges pick up findings and we need to check if it is only a dispersed artifact or if it is the signal of larger evidence, like a wreck, an ancient anthropic phase of the local history, or a palaeontological finding. The image files of the scan could be very useful to detect an array of objects or structures. We would also like to emphasize that remote sensing bathymetrical survey with our instruments is a low-cost investigation with zero impact on the ecosystem (we used a silent, electric engine on a small aluminum boat). Of course, however, this research involved a small area and shallow water environment. Archaeology of the Inland Water is an experimental project dedicated, not only to the investigation of ancient rivers, but to a new kind of approach to archaeology in artificial lakes. The combination of geological and geotechnical studies offers the possibility of full comprehension of a hydrographic story and aids in the conservation of local cultural heritage. The depositional system of artificial lake banks creates a soft layer of very light clay, which hides the stratigraphy, also often with tiny algae covering all the lakebed. In these cases, micro-geoarcheological drillings give us the chance to isolate particular sedimentary and anthropic levels, offering a guide for the matrix. On the historical side, studying and making comparisons to ancient cartography from 1400 to 1785, we remark that the river likely survived until the 17th Century. Retracing the cartographical data, we see that the big meander of the River Po is always attested with continuity in the same places. This means that it was frequented, potentially, until the Estense Period. Here, we show six plan views of the area, extracted from an essay by F. Cazzola [14], to demonstrate, using the documentation of cartographers of the 17th and 18th Centuries, the persistence of the river in post-antique periods (Figure 18). On the maps of G.B. Aleotti (Corographia dello Stao di Ferrara, 1603), Penna (1658), L.F. De Rossi (Legazione del Ducato di Ferrara, 1709), G.F. Bonfadini (Topografia dello Stato di Ferrara, 1709; https://www.igmi.org/carte-antiche/stati_preunitari/carta-14), A.F. Facci (Geografia dello Stato di Ferrara, 1716), and A. Baruffaldi (Geografia del Ducato di Ferrara, 1758), the name of the Estense Castle of Verginese is clearly attested, close to the course of the Po River. The Renaissance Structures are about 500 m away from the lake, with Roman and Late Roman cultural heritage evidenced (to read more about the Castle, see http://www.ferraradeltapo-unesco.it/delizie/verginese. The “end of the river” could also be connected to the land reclamation that began in the Renaissance Period. The cataloguing of 200 artifacts, including the last findings of the Late Roman Amphora, discriminates two different periods: Roman Proto-Imperial and Late Antiquity–Early Middle Ages. Of the artifacts found, 83% were pottery (amphorae, cooking, or tableware), 13% were tiles (wing tiles, often with trademarks), 3% were glass (bowls or goblets), and 1% were fragments of lithic artefacts. Actually tiles and pottery were the chronology indicators. The first terminus post quem, indicated by the Pansiana Tiles [15], was found to be from the first and the second century A.D. (Figure 19). The finding of a small part of Dressel 2–4 Amphora, with a double-listel handle (Figure 20), could show the continuity of use of the site during the third and fourth century A.D. Remote Sens. 2018, 10, 380 15 of 21

Remote Sens. 2018, 10, x FOR PEER REVIEW 15 of 21 Remote Sens. 2018, 10, x FOR PEER REVIEW 15 of 21

(a) (b) (a) (b)

(e) (f) (e) (f) Figure 18. Extracted maps from ancient Ferrara cartography with attested rivers (North to the top) Figure 18. Extracted maps from ancient Ferrara cartography with attested rivers (North to the top) and, Figureand, in 18. the Extracted circle, the maps Po Riverfrom ancientwith the Ferrara course cartograph running closey with to attestedVerginse rivers Castle, (North Gambulaga: to the top) (a) in the circle, the Po River with the course running close to Verginse Castle, Gambulaga: (a) Aleotti 1603; and,Aleotti in 1603;the circle, (b) Penna the Po 1658; River (c) Dewith Rossi the 1709;course (d )running Bonfadini close 1709; to (Verginsee) Facci 1716; Castle, (f) BaruffaldiGambulaga: 1758. (a) (b) Penna 1658; (c) De Rossi 1709; (d) Bonfadini 1709; (e) Facci 1716; (f) Baruffaldi 1758. Aleotti 1603; (b) Penna 1658; (c) De Rossi 1709; (d) Bonfadini 1709; (e) Facci 1716; (f) Baruffaldi 1758.

(a) (b) (a) (b) Figure 19. Fragments of Pansiana tiles found in Lago Tramonto, Gambulaga, Portomaggiore (FE, Figure 19. Fragments of Pansiana tiles found in Lago Tramonto, Gambulaga, Portomaggiore (FE, FigureItaly): ( 19.a) IncipitFragments of the of Pansianastamp TIPANtiles found [siana]; in Lago (b) Tramonto,Explicit of Gambulaga,the stamp NA Portomaggiore [Tipansia] (photo (FE, Italy): by Italy): (a) Incipit of the stamp TIPAN [siana]; (b) Explicit of the stamp NA [Tipansia] (photo by (Giovannaa) Incipit of Bucci). the stamp TIPAN [siana]; (b) Explicit of the stamp NA [Tipansia] (photo by Giovanna Bucci). Giovanna Bucci).

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(a) (b) (a) (b) Figure 20. Fragments of Dressel 2–4 Amphora found in Lago Tramonto, Gambulaga, Portomaggiore Figure 20. Fragments of Dressel(a) 2–4 Amphora found in Lago Tramonto,(b Gambulaga,) Portomaggiore (FE,Figure Italy): 20. ( aFragments) Photo with of metricDressel reference; 2–4 Amphora (b) 1:1found draw in (byLago Giovanna Tramonto, Bucci). Gambulaga, Portomaggiore (FE, Italy): (a) Photo with metric reference; (b) 1:1 draw (by Giovanna Bucci). (FE,Figure Italy): 20. ( aFragments) Photo with of metricDressel reference; 2–4 Amphora (b) 1:1found draw in (byLago Giovanna Tramonto, Bucci). Gambulaga, Portomaggiore There(FE, Italy): is second (a) Photo terminus with metric post reference; quem to (b ) comprehend1:1 draw (by Giovanna the time Bucci). of the destruction of the archaeologicalThereThere is is second settlement.secondterminus terminus It is post attested quempost to quemby comprehend the to neck comprehend with the handle time ofthe of the Latetime destruction Roman of the Amphora ofdestruction the archaeological No. 5 (Figure of the 21)settlement.archaeological andThere some It isfragments is settlement. attestedsecond of byterminus EarlyIt the is neckattested Mediaeval post with quemby handle the Cooking to neck comprehend of Latewith Ware Romanhandle (Figure the Amphora of 22).Latetime Roman No.of 5the (FigureAmphora destruction 21 No.) and 5 (Figure someof the fragments21)archaeological and some of Early fragments settlement. Mediaeval of EarlyIt is Cooking attested Mediaeval Ware by the Cooking (Figure neck 22with Ware). handle (Figure of 22).Late Roman Amphora No. 5 (Figure 21) and some fragments of Early Mediaeval Cooking Ware (Figure 22).

(a) (b) (a) (b) Figure 21. Fragments of Late Roman Amphora found in Lago Tramonto, Gambulaga, Portomaggiore (a) (b) (FE,Figure Italy): 21. ( aFragments) Photo with of metricLate Roman reference; Amphora (b) 1:1found draw in (byLago Giovanna Tramonto, Bucci). Gambulaga, Portomaggiore Figure 21. Fragments of Late Roman Amphora found in Lago Tramonto, Gambulaga, Portomaggiore (FE,Figure Italy): 21. ( aFragments) Photo with of metricLate Roman reference; Amphora (b) 1:1found draw in (byLago Giovanna Tramonto, Bucci). Gambulaga, Portomaggiore (FE, Italy): (a) Photo with metric reference; (b) 1:1 draw (by Giovanna Bucci). (FE, Italy): (a) Photo with metric reference; (b) 1:1 draw (by Giovanna Bucci).

(a) (b) (a) (b) Figure 22. Digital reconstruction from diagnostic fragments of Late Roman-Mediaeval cookware (a) (b) foundFigure in 22. Lago Digital Tramonto, reconstruction Gambulaga, from Portomaggiorediagnostic fragments (FE, Italy): of Late (a) Roman-MediaevalOlla with a round cookware lip and sphericalfoundFigure in 22.body; Lago Digital ( bTramonto,) Olla reconstruction with Gambulaga,a flat lip from and Portomaggioregeometricaldiagnostic fragments decorations (FE, Italy): of on Late the(a) Roman-MediaevalshoulderOlla with (Giovanna a round cookware Bucci).lip and Figure 22. Digital reconstruction from diagnostic fragments of Late Roman-Mediaeval cookware found sphericalfound in body; Lago ( bTramonto,) Olla with Gambulaga,a flat lip and Portomaggioregeometrical decorations (FE, Italy): on the(a) shoulderOlla with (Giovanna a round lipBucci). and in Lago Tramonto, Gambulaga, Portomaggiore (FE, Italy): (a) Olla with a round lip and spherical body; 5. Conclusionsspherical body; (b) Olla with a flat lip and geometrical decorations on the shoulder (Giovanna Bucci). (b) Olla with a ﬂat lip and geometrical decorations on the shoulder (Giovanna Bucci). 5. Conclusions Through the use of 3D side scan sonar surveys, direct diving investigations, geo-archaeological 5. Conclusions drillings,5. ConclusionsThrough artifact the analysis,use of 3D andside historicalscan sonar resear surveys,ch, directgreat divingcontributions investigations, have been geo-archaeological made to the comprehensiondrillings,Through artifact theof the analysis,use Lago of 3D Tram andside onto scanhistorical archaeological sonar resear surveys,ch, panorama. directgreat divingcontributions investigations, have been geo-archaeological made to the Through the use of 3D side scan sonar surveys, direct diving investigations, geo-archaeological comprehensiondrillings,Studies artifact of waterscape of theanalysis, Lago archaeology Tramand ontohistorical archaeological analyze resear thech, panorama.anthropological great contributions connections have been of inland made waterto the drillings, artifact analysis, and historical research, great contributions have been made to the environments,comprehensionStudies of showing waterscape of the Lago the way archaeologyTram inonto which archaeological analyze people thebetween panorama.anthropological the Roman connectionsand the Early of Middleinland Ageswater comprehension of the Lago Tramonto archaeological panorama. constructedenvironments,Studies and of showing usedwaterscape their the territorywayarchaeology in which (i.e., analyze apeople river bankthebetween anthropological with the wooden Roman structures).connectionsand the Early Someof Middleinland piles Ageswater are identifiable,constructedenvironments, forand showing example,used their the a territorywaystructure in which (i.e., to supportapeople river bankbetweenthe riverwith the woodenembankment Roman structures).and the(linin Early Somepiles Middle runningpiles Ages are West–East),identifiable,constructed and forand others example,used connect their a territory structurewith buildings, (i.e., to supporta riverfor example, bankthe riverwith a watcht woodenembankmentower structures). with (linina square Somepiles plan runningpiles view. are West–East),identifiable, and for others example, connect a structurewith buildings, to support for example, the river a watcht embankmentower with (linin a square piles plan running view. West–East), and others connect with buildings, for example, a watchtower with a square plan view.

Remote Sens. 2018, 10, 380 17 of 21

Studies of waterscape archaeology analyze the anthropological connections of inland water environments, showing the way in which people between the Roman and the Early Middle Ages constructed and used their territory (i.e., a river bank with wooden structures). Some piles are identifiable, for example, a structure to support the river embankment (linin piles running West–East), and others connect with buildings, for example, a watchtower with a square plan view. The hypothesis of the watchtower is related, also, to the topographical location of high geomorphological sites and to the late attested Italian toponym, “La Vedetta”, which is the watchtower/observation point. Reading from east to west in the archaeological sequence (not necessarily in phase with each of the elements indicated here) we find the following context: there was a sandy boulder, with four poles driven into the ground and south of the hind, at a greater depth, a beam with four rectangular hollows was found (already previously detected and attributable to a watchtower at a depth 6 m, approximately). A tree trunk with bifurcation was found towards the center of the lake, next to landslide, with fragments of Roman and Late Roman pottery, bricks, tiles, and animal bones. Finally, a tree trunk with long bifurcation was found towards the center of the lake, with three perpendicular trunks. The ancient riverbank edge, made of compact clay and partially structured with vertical piles on the western side, continues to survive, with pieces of monoxyl pirogues and dispersed pieces of semi-finished wood boats found there (depth about 3.5 m ca.). At the center of the lake, in a deeper sector (more excavated from the dredge, southern to the individuated structures), outcropping at 7.9 m, a semi-fossilized tree trunk rises straight from unseen palaeo-soil, potentially belonging to Subsynthema AES8a [3]. The direct surveys, No. 1 and No. 2, allowed us to verify the absence of anthropogenic traces on the eastern and southern sides of the lake, as already documented in the first on-site research. The area of greatest archaeological interest is, therefore, confirmed to be near the northern side of the palaeo-watercourse, in the West sector. As a result of this research and the various methodologies employed (underwater direct investigation No. 3, remote sensing hydrographic surveys, and stratigraphic data from geo-archaeological drillings), it is possible to hypothesize that a catastrophic event of a hydrogeological nature, like violent flooding, along the Po branch in particular, caused the demolition of nearby structures on the northern bank. The large bifurcated trunks were iso-oriented and sub-parallel to the direction of the river current and they were oriented like the steles of the necropolis of Fadieni, knocked down from natural events, as evidenced by the stratigraphy. The presence of archaeological elements, predominantly in dispersion and deposition, is determined not only by quarrying and dredge work, but, above all, by older natural events, perhaps the deluvium aquarum described by Paulus Diaconus in Historia Langobardorum. III.23: Eo tempore fuit aquae diluvium in finibus Venetiarum et Liguriae seu ceteris regionibus Italiae, quale post Noe tempore creditur non fuisse. Archaeometrical analysis of some of the pottery fragments demonstrated the local production of the vases [16]. Additionally, the tiles were produced a few kilometers away from the Fadieni site (Gambulaga), in the Vicus Aventiae, Voghiera (FE), where there are traces of Roman Furnaces in relation to the figlina Pansiana [16]. The data establishes the archaeological site as covering the Ancient Delta Roman and Late Roman Contexts, in the great hydrographical system that crossed the Oriental side of Pianura Padana [17,18]. The next step in our research is to concentrate on archaeobotanical analysis of the wooden findings, actually preserved on site, underwater, on the lake bed, as UNESCO Conventions suggest. In the Ferrara District, the main discoveries of pirogues are related to the Mediaeval Period, with quite similar boats: two pirogues from Valle Volta, Massafiscaglia, one from Iolanda di Savoia, one from Valle Ponti, and two from Valle Isola, Comacchio [19]. Archaeobotanical studies might help us to isolate the chronology of the boats. In the ambit of valorization and preservation of the Underwater Cultural Heritage, we are working also on a project of a virtual reconstruction of the Roman Site visible on a digital totem placed on the welcome area and night projection with holograms directly on place of the archaeological site. This Remote Sens. 2018, 10, x FOR PEER REVIEW 18 of 23

aquarum described by Paulus Diaconus in Historia Langobardorum. III.23: Eo tempore fuit aquae diluvium in finibus Venetiarum et Liguriae seu ceteris regionibus Italiae, quale post Noe tempore creditur non fuisse. Archaeometrical analysis of some of the pottery fragments demonstrated the local production of the vases [16]. Additionally, the tiles were produced a few kilometers away from the Fadieni site (Gambulaga), in the Vicus Aventiae, Voghiera (FE), where there are traces of Roman Furnaces in Remote Sens. 2018, 10, x FOR PEER REVIEWrelation to the figlina Pansiana [16]. The data establishes the18 ofarchaeological 23 site as covering the Ancient Delta Roman and Late Roman Contexts, in the great hydrographical system that crossed the aquarum described by Paulus DiaconusOriental in sHistoriaide of Pianura Langobardorum Padana. [17,18III.23:]. Eo tempore fuit aquae diluvium in finibus Venetiarum et Liguriae seu ceterisThe regionib next stepus Italiae in our, quale research post Noe is totempore concentrate creditur onnon archaeobotanical fuisse. analysis of the wooden Archaeometrical analysis offindings, some of actuallythe pottery preserved fragments on site,demonstrate underwater,d the on local the lakeproduction bed, as UNESCO Conventions suggest. of the vases [16]. Additionally, theIn tilesthe Ferrara were produced District, athe few main kilometers discoveries away of from pirogues the Fadieni are related site to the Mediaeval Period, with (Gambulaga), in the Vicus Aventiaequite, Voghiera similar boats: (FE), twowhere pirogues there arefrom traces Valle of Volta Roman, Massafiscaglia, Furnaces in one from Iolanda di Savoia, one Remote Sens. 2018, 10, x FOR PEER REVIEW relation to the figlina Pansiana [16].from TheValle data Ponti establishes, and two18 from theof 23 archaeological Valle Isola, Comacchio site as covering [19]. Archaeobotanical the studies might help us Ancient Delta Roman and Late Romanto isolate Context the chronologys, in the great of thehydrograph boats. ical system that crossed the aquarum described by Paulus Diaconus in Historia Langobardorum. III.23: Eo tempore fuit aquae diluvium Oriental side of Pianura Padana [17,18In]. the ambit of valorization and preservation of the Underwater Cultural Heritage, we are Remote Sens. in2018 finibus, 10, 380 Venetiarum et Liguriae seu ceteris regionibus Italiae, quale post Noe tempore creditur non fuisse.18 of 21 The next step in our researchworking is to concentratealso on a project on archaeobotanical of a virtual reconstruction analysis of ofthe the wooden Roman Site visible on a digital totem Archaeometrical analysis of some of the pottery fragments demonstrated the local production findings, actually preserved on site,placed underwater, on the welcomeon the lake area bed, andas UNESCO night projection Convention withs sugges hologramst. directly on place of the of the vases [16]. Additionally, the tiles were produced a few kilometers away from the Fadieni site In the Ferrara District, the main archaeologicaldiscoveries of site.pirogues This programare related will to wethe performed Mediaeval step Period, by stepwith in collaboration with students of program will(Gambul we performedaga), in the step Vicus by Aventiae step in collaboration, Voghiera (FE), with where students there ofare the traces University of Roman of FerraraFurnaces and in quite similar boats: two piroguesthe from University Valle Volta of Ferrara, Massafiscaglia, and Padova. one fromIt would Iolanda be a di didactic Savoia, explaining one performance dedicated to Padova. Itrelation would to be the a didactic figlina Pansiana explaining [16]. performance The data establishes dedicated the to archaeological “public archaeology”. site as covering Actually the from Valle Ponti, and two from Valle“public Isola archaeology, Comacchio”. [19].Actually Archaeobotanical people can explore studies the might area helpwith us an underwater track with specific people canAncient explore Delta the Roman area with and an Late underwater Roman Context tracks, within the specific great hydrograph diving guideical system lines. that crossed the to isolate the chronology of the boats.diving guide lines. Oriental side of Pianura Padana [17,18]. In the ambit of valorization and preservation of the Underwater Cultural Heritage, we are Acknowledgments:The Anext special stepthanks in our to research the Executive is to Boardconcentrate of Soprintendenza on archaeobotanical Archeologia, analysis Belle Artiof the e Paesaggio wooden per la città metropolitana di Bologna e le provinceworking di Modena also; Reggio on a Emiliaproject eof Ferrara; a virtualAcknowledgments: Fede reconstruction Berti, the Archaeologist A specialof the thanksRoman to Site the visibleExecutive on Boarda digital of Soprintendenzatotem Archeologia, Belle Arti e findings, actually preserved on site, underwater, on the lake bed, as UNESCO Conventions suggest. ex Director of the National Archaeological Museumplaced of on Ferrara; the welcome Valentino area Nizzo andPaesaggio Functionaire, night per projection la città Archaeologist; metropolitana with holograms di Bologna directly e le province on place di Modena of the ; Reggio Emilia e Ferrara; Dr. Fede Mario CesaranoIn the andFerrara Alain District Rosa,, the underwater main discoveriesarchaeological technical of assistants; pirogues site. This Antonare program related Slanzi Bertito will Gamper,the, the we Mediaeval A performedrchaeologist owner Period, of step ex the Director bywith lake; step of in the collaboration National Archaeological with students Museum of of Ferrara; Drs. Valentino Nizzo Fabio Facchini,quite technicalsimilar boats: assistant two pirogues at the geological fromthe ValleUniversity drillings; Volta ,of Massafiscaglia, and Ferrara to all and the Padova. CMASoneFunctionaire from A.CDCI.It Iolandawould, Archaeologist instructorsbe di aSavoia, didactic; Ma andonerio explaining Cesarano andperformance Alain Rosa, dedicated underwater to technical assistants; Mr. Anton Slanzi Gamper, owner of the lake; Dr. Fabio Facchini, technical assistant at the geological drillings; and to all the members whofrom worked Valle Ponti on this, and project two from – student Valle“ andpublic Isola divers., Comacchioarchaeology [19].”. Actually Archaeobotanical people can studies explore might the area help with us an underwater track with specific CMAS A.CDCI. instructors and members who worked on this project – student and divers. Conflicts ofto Interest: isolate theThe chronology authors declare of the no boats. conflictdiving of guide interest. lines. In the ambit of valorization and preservation of the UnderwaterConflicts Cultural of Interest: Heritage, The authors we are de clare no conflict of interest. Appendixworking A also on a project of a virtualAcknowledgments: reconstruction ofA specialthe Roman thanks Site to visiblethe Executive on a digital Board totemof Soprintendenza Archeologia, Belle Arti e placed on the welcome area andPaesaggio night projection per la città withmetropolitana holograms di Bologna directly e le on province place ofdi Modena the ; Reggio Emilia e Ferrara; Dr. Fede archaeological site. This program willBerti we, the performed Archaeologist step exby Director step in ofcollaboration the National withArchaeological students Museumof of Ferrara; Drs. Valentino Nizzo the University of Ferrara and Padova.TableFunctionaire A1. It wouldDrilling, Archaeologistbe No. a didactic 1. ; Maexplainingrio Cesarano performance and Alain Rosa, dedicated underwater to technical assistants; Mr. Anton Slanzi “public archaeology”. Actually peopleGamper, can explore owner ofthe the area lake with; Dr. anFabio underwater Facchini, ttrackechnical with assistant specific at the geological drillings; and to all the CMAS A.CDCI. instructorsArea and members Southwho work Sectored on this project – student and divers. diving guideSite lines. Code GAM 2017 Conflicts of Interest:Drilling The authors No. deRemoteclare no Sens. conflict 12018, 10of, interest.x FOR PEER REVIEW 19 of 23 Acknowledgments: A special thanks to the Executive Board of Soprintendenza11 ◦Archeologia,49035.9”E Belle Arti e Topographical Data GPS position Paesaggio per la città metropolitanaDistrict di Bologna Ferrara e le province di Modena; Reggio ◦Emilia0 e Ferrara; Dr. Fede Gambulaga (FE), Via Bargellesi 44 44 44.2”N Berti, the Archaeologist ex Director of the National Archaeological Museum of Ferrara; Drs. Valentino Nizzo Functionaire, Archaeologist; Mario Cesarano and Alain Rosa,Elevation underwater [m] technical assistants; +2.50 Mr. Anton Slanzi Gamper, owner of the lake; Dr. Fabio Facchini,Context technical assistant at the geological drillings; and to all the CMAS A.CDCI. instructors and membersEx sandwho quarryworked lake on this project – student and divers. Photo 1: Site Photo 2: Work in Progress Photo 3: Sediment Conflicts of Interest: The authors declare no conflict of interest.

Remote Sens. 2018, 10, x FOR PEER REVIEW 19 of 23

Remote Sens. 2018, 10, x FOR PEER REVIEW 19 of 23 Photo 4: Sediment Photo 5: Sediment Photo 6: Samples

Levels [m] Stratigraphic Data from to Appendix A 0 0.60 Beige silt

0.60 1.25 Sandy silt (beige, orange) Table A1. Drilling No. 1. 1.25 1.55 Grey silty sand Area South Sector Site Code GAM 2017 1.55 1.80 Grey coarse sand Drilling No. 1

11°49′35.9″E 1.80 2.20 Grey sand Topographical Data GPS position District Ferrara 44°44′44.2″N Gambulaga (FE), Via Bargellesi 2.20 3.10 Beige lightly silty sand Elevation [m] +2.50 3.10 5.00 Grey coarse sand Context Appendix A Ex sand quarry lake Supervisor: Giovanna Bucci Day 1 February 2017 Photo 1: Site Photo 2: Work in Progress Photo 3: Sediment Technical Assistant: Fabio FacchiniTable A1. Drilling No. 1.

Area South Sector Site Code GAM 2017 Drilling No. 1 11°49′35.9″E Topographical Data GPS position District Ferrara 44°44′44.2″N Gambulaga (FE), Via Bargellesi Appendix A Elevation [m] +2.50 Context ExPhoto sand 4: quarry Sediment lake Photo 5: Sediment Photo 6: Samples Table A1. Drilling No. 1. Photo 1: Site Photo 2: Work in Progress Photo 3: Sediment Area South Sector Site Code GAM 2017 Drilling No. 1 11°49′35.9″E Topographical Data GPS position District Ferrara 44°44′44.2″N Gambulaga (FE), Via Bargellesi Elevation [m] +2.50 Context Ex sand quarry lake Levels [m] Photo 1: Site Photo 2: Work in Progress Photo 3: Sediment Stratigraphic Data Photo 4: Sediment fromPhoto 5: Sedimentto Photo 6: Samples 0 0.60 Beige silt 0.60 1.25 Sandy silt (beige, orange) 1.25 1.55 Grey silty sand 1.55 1.80 Grey coarse sand 1.80 2.20 Grey sand

Photo 4: Sediment Photo 5: Sediment Photo 6: Samples Levels [m] Stratigraphic Data from to 0 0.60 Beige silt 0.60 1.25 Sandy silt (beige, orange) 1.25 1.55 Grey silty sand 1.55 1.80 Grey coarse sand 1.80 2.20 Grey sand

Levels [m] Stratigraphic Data from to 0 0.60 Beige silt 0.60 1.25 Sandy silt (beige, orange) 1.25 1.55 Grey silty sand 1.55 1.80 Grey coarse sand 1.80 2.20 Grey sand

Remote Sens. 2018, 10, x FOR PEER REVIEW 21 of 23

Figure A2. Graphic depiction of drilling No. 2 in 2017 in Lago Tramonto, Gambulaga, Portomaggiore (FE, Italy).Table A2. Drilling No. 2.

Remote Sens. 2018, 10, x FOR PEER REVIEW 21 of 23

Figure A2. Graphic depiction of drilling No. 2 in 2017 in Lago Tramonto, Gambulaga, Portomaggiore (FE, Italy).Table A2. Drilling No. 2.

Remote Sens. 2018, 10, x FOR PEER REVIEW 21 of 23 Remote Sens. 2018, 10, x FOR PEER REVIEW 21 of 23 Figure A2. Graphic depiction of drilling No. 2 in 2017 in Lago Tramonto, Gambulaga, Portomaggiore Figure A2. Graphic depiction of drilling No. 2 in 2017 in Lago Tramonto, Gambulaga,(FE, Italy).PortomaggioreTable A2. Drilling No. 2. (FE, Italy).Table A2. Drilling No. 2. Remote Sens. 2018, 10, 380 19 of 21

Remote Sens. 2018, 10, x FOR PEER REVIEW 21 of 23 Table A2. Drilling No. 2. Figure A2. Graphic depiction of drilling No. 2 in 2017 in Lago Tramonto, Gambulaga, Portomaggiore Area North Sector Site Code Gam 2017 (FE, Italy).Table A2. Drilling No. 2. Drilling No. 2

11◦49025.5”E Topographical Data GPS position District Ferrara ◦ 0 Gambulaga (FE), Via Bargellesi 44 44 44.3”N Remote Sens. 2018, 10, x FOR PEER REVIEW Elevation [m] +2.10 21 of 23 Context Figure A2. Graphic depiction of drilling No.Ex 2 in sand 2017 quarry in Lago lake Tramonto, Gambulaga, Portomaggiore (FE, Italy).PhotoTable 1: SiteA2. Drilling No. 2. Photo 2: Work in Progress Photo 3: Sediment

Photo 4: Sediment Photo 5: Sediment Photo 6: Samples

Levels [m] Stratigraphic Data from to Area North Sector 0 0.50 Beige silty clay Site Code Gam 2017 Drilling No. 2 0.50 1.35 Brown mottled silty clay with vegetal traces 11° 49′25.5″E Topographical Data GPS position 1.35 2.40 Beige orange mottled clayey silt with traces of reeds District Ferrara 44° 44′44.3″N Gambulaga (FE), Via Bargellesi Elevation [m] +2.10 2.40 3.15 Beige silt 3.15 3.65 Grey clay (palaeo-soil)

3.65 4.30 Grey–light blue silt 4.30 4.50 Grey clay with micro-fragments of torba Area North Sector Site Code Gam 2017 4.50 5.10 Grey sand Drilling No. 2 11° 49′25.5″E Topographical Data GPS position 5.10 5.40 Grey clay with nucleusDistrict of CaCO Ferrara3 44° 44′44.3″N Gambulaga (FE), Via Bargellesi Elevation [m] +2.10 5.40 5.60 Violet clay with micro-carbonaceous cores and vegetal traces (palaeo-soil)

5.60 6.10 Grey silt with vegetal traces and malacofauna

6.10 7.40 Violet silty clay with micro-carbonaceous cores and vegetal traces (palaeo-soil) Area North Sector Site Code Gam 2017 Drilling No. 2 7.40 8.00 Violet siltyArea clay with torba micro-levelsNorth Sector Site Code Gam 2017 11° 49′25.5″E DrillingSupervisor: No. Giovanna Bucci Topographical2 Data GPS position Data 1 February 2017 District Ferrara 44° 44′44.3″N Technical Assistant: Fabio FacchiniGambulaga11° 49′25.5″E (FE), Via Bargellesi Topographical Data GPS position Elevation [m] +2.10 District Ferrara 44° 44′44.3″N Gambulaga (FE), Via Bargellesi Elevation [m] +2.10

Area North Sector Site Code Gam 2017 Drilling No. 2 11° 49′25.5″E Topographical Data GPS position District Ferrara 44° 44′44.3″N Gambulaga (FE), Via Bargellesi Elevation [m] +2.10

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Remote Sens. 2018, 10, x FOR PEER REVIEW 19 of 21 Remote Sens. 2018, 10, 380 20 of 21

Figure A1. Graphic depiction of drilling No. 1 in 2017 in Lago Tramonto, Gambulaga, Portomaggiore Figure A1. Graphic depiction of drilling No. 1 in 2017 in Lago Tramonto, Gambulaga, Portomaggiore (FE,(FE, Italy).Italy). Figure A1. Graphic depiction of drilling No. 1 in 2017 in Lago Tramonto, Gambulaga, Portomaggiore (FE, Italy).

Figure A2. Graphic depiction of drilling No. 2 in 2017 in in Lago Lago Tramonto, Tramonto, Gambulaga, Portomaggiore

(FE,(FE, Italy).Italy). Figure A2. Graphic depiction of drilling No. 2 in 2017 in Lago Tramonto, Gambulaga, Portomaggiore References (FE, Italy).

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