Late-Holocene Human Resilience in a Fluvial Environment: A Geoarchaeological Dataset for the Central Po Plain (N Italy)

The dataset was originally collected as part of the doctoral projects of the author, with the aim of understanding human-environmental dynamics in a fluvial context. The project methodology employed environmental archaeology techniques to reconstruct the main phases of the diachronic landscape evolution. Landscapes represent a worthwhile dataset about the millennial human-environment interaction. In this regard, past landscapes reconstruction allows to evaluate diachronically the impact of anthropogenic activities on modifying the natural assets of a region, even including early evidence of the inception of the Anthropocene [1]. The project methodology has been tested especially on floodplains because fluvial environments have always played a crucial role in human history: the necessity of fertile land and freshwater for agriculture has led populations to settle in floodplains more frequently than in other environments altering natural landscapes features. The Po Plain (Figure 1) operates as a key area for the interpretation of environmental and cultural influences between the Mediterranean regions and continental Europe [2]. Its complex settlement and land-management history make it an ideal study-area to investigate the adaptive dynamics of human communities in alluvial areas. The natural factors that influenced the environmental development of the Central Po Plain fluvial landscape are mostly due to alluvial geomorphological dynamics. Since the Pleistocene, the Apennine watercourses shaped the landscape developing alluvial megafans with their sediments. In the distal parts of Holocene alluvial fans are characterised by a telescopic shape, a result of subsequent aggradation —entrenchment phases due to the alternation of glacial-interglacial periods; each aggradational cycle [3] causes an incision on the top of the previous fan, while a new fan prograded in a more distal position [4]. In the study area, the alluvial ridges of the Enza, Crostolo and Tresinaro rivers, emerging from the flat floodplain, flank depression areas known in fluvial geomorphology as backswamps, which are characterised by deposits of fine silts and clays deposited after flood events [5]. The landscape evolution of this portion of the Central Po Plain (Figure 1) has a long-standing connection with human activities as well. Since the Bronze Age, [6] human communities settled in the Po Valley for its suitability to agriculture, altering the natural fluvial landscape and handling the flood hazard [6]. In the Roman period, the risk of inundation was managed and mitigated by the construction of embankments and drainages [7]. The transition from Roman into Early Medieval Period (6th – 10th centuries CE) represented a crucial moment for the reorganisation of human settlement strategies in Po Valley. Many authors point out that this transition led to a reduction of the cultivable and settled area due to the collapse DATA PAPER


(1) Context
The dataset was originally collected as part of the doctoral projects of the author, with the aim of understanding human-environmental dynamics in a fluvial context. The project methodology employed environmental archaeology techniques to reconstruct the main phases of the diachronic landscape evolution. Landscapes represent a worthwhile dataset about the millennial human-environment interaction. In this regard, past landscapes reconstruction allows to evaluate diachronically the impact of anthropogenic activities on modifying the natural assets of a region, even including early evidence of the inception of the Anthropocene [1]. The project methodology has been tested especially on floodplains because fluvial environments have always played a crucial role in human history: the necessity of fertile land and freshwater for agriculture has led populations to settle in floodplains more frequently than in other environments altering natural landscapes features.
The Po Plain (Figure 1) operates as a key area for the interpretation of environmental and cultural influences between the Mediterranean regions and continental Europe [2]. Its complex settlement and land-management history make it an ideal study-area to investigate the adaptive dynamics of human communities in alluvial areas. The natural factors that influenced the environmental development of the Central Po Plain fluvial landscape are mostly due to alluvial geomorphological dynamics. Since the Pleistocene, the Apennine watercourses shaped the landscape developing alluvial megafans with their sediments. In the distal parts of Holocene alluvial fans are characterised by a telescopic shape, a result of subsequent aggradation -entrenchment phases due to the alternation of glacial-interglacial periods; each aggradational cycle [3] causes an incision on the top of the previous fan, while a new fan prograded in a more distal position [4]. In the study area, the alluvial ridges of the Enza, Crostolo and Tresinaro rivers, emerging from the flat floodplain, flank depression areas known in fluvial geomorphology as backswamps, which are characterised by deposits of fine silts and clays deposited after flood events [5].
The landscape evolution of this portion of the Central Po Plain (Figure 1) has a long-standing connection with human activities as well. Since the Bronze Age, [6] human communities settled in the Po Valley for its suitability to agriculture, altering the natural fluvial landscape and handling the flood hazard [6]. In the Roman period, the risk of inundation was managed and mitigated by the construction of embankments and drainages [7]. The transition from Roman into Early Medieval Period (6 th -10 th centuries CE) represented a crucial moment for the reorganisation of human settlement strategies in Po Valley. Many authors point out that this transition led to a reduction of the cultivable and settled area due to the collapse

DATA PAPER
Late-Holocene Human Resilience in a Fluvial Environment: A Geoarchaeological Dataset for the Central Po Plain (N Italy) of the Po Valley Roman hydrogeological systems [8]. The Roman water management system was abandoned, and woods, swamps and uncultivated areas became the typical features of the Early Medieval landscape (6 th -10 th centuries CE). Channelisation and reclamation works started only in the 10th century CE and intensified between the 12 th and 13 th centuries CE [9] as a consequence of a general increasing demand for cultivated lands throughout Europe [10]. In the Central Po Plain, large-scale ground reclamation is dated to Renaissance (15 th century CE), it was renovated and updated many times in Modern Age (17 th and 19 th centuries CE), and it was completed only in the 20 th century CE resulting in the modern completely artificial landscape [11].
Heterogeneous sources were used to build the dataset here described. In particular, archaeological records, historical maps and documents and geomorphological maps served as a useful starting point to construct the dataset in association with terrain surveys. The combination of geosciences data and archaeo-historical records were fundamental in understanding the Late Holocene landscape evolution of this portion of the Po Plain.

Spatial coverage
The research area considered is located in the Emilia Romagna region (Northern Italy) and is comprised between the Po river at North, the Enza and Secchia rivers at West and East respectively. The southern limit corresponds to the Apennines foothills.
Coordinates Whilst the majority of data falls within this time range, some sites and features exceed these chronological limits. Particularly, Neolithic and Chalcolithic archaeological sites are comprised in this digital archive for the relevance of prehistoric studies in the research area [4,12,13]. Similarly, the contemporary drainage system (20 th -21 st century CE) is included in the dataset to have a full overview on the land and water management activities occurred in the area. Moreover, in the contemporary channelization many historical canals and ditches are recognizable since they have been renovated in the 19 th -20 th century CE.

(2) Methods
The majority of data in this dataset was obtained directly from source publications. The data have been collected by using all known published archaeological excavations reports, maps and regional databases. The geopedological data have been retrieved from the Emilia Romagna regional geodatabase.

Steps Archaeological and historical resources
Archaeological sites have been retrieved from various records (scientific literature, regional web databases, terrain surveys) listed in the List_of_References.txt file. These data have been digitised in GIS, enabling the chronological analysis of landforms identified in the Central Po Plain. The 18th and 19th-century transcriptions of medieval chronicles ( Table 1) represented an advantageous starting point in the identification of past landscape features such as described precisely fluvial landforms or unknown settlement locations. The Post -Medieval historical cartography helped in understanding the geomorphological development of fluvial features as well as anthropogenic water management activities [9]. SfM-photogrammetry served as a contactless, highly flexible approach to digitise historical cartography [14] (retrieved at the Modena National Historical Archive, folder: "Congregazione delle Acque e delle Strade, Reggio e Reggiano") producing High Definition (HD) digital copies that eased the georeferencing process in GIS (Figure 2). Furthermore, the regional WMS format of the Historical Cadastral Map of Emilia Romagna Region 1850 1 represented a valuable source of information to detect historic channelization in the area. The Emilia Romagna Region topographic service derived this digital historic map (scale 1:50.000) elaborating 19 th -century historic cadastral maps ( Table 2).
Historical maps offer a glimpse into a long and dynamic history of landscape change [15]. Both archaeological and historical resources considered are reported in the List_ of_References.txt file.

Geopedological resources
The term Geopedology refers to the integration of elements of geomorphology and pedology for soil and landscape studies [16]. Here the regional soil map has been implied to detect the maximum extension of the medieval swamps. The sediment deposition in floodplains  has a strong correlation with the river flow transport capacity and typically the finer fraction is deposited in a more distal position than the coarser fraction during flood events. The finer sediments provide an indication of waterlogged areas before Renaissance land reclamation since backswamps present a high concentration of clay and silty-clays sediments. On the other hand, the soil map provides a solid proxy for agricultural suitability. Since "heavy" and "light" soils require different types of plough, their distribution may have influenced human settlement dynamic in different epochs. Archaeological soil micromorphology (or micropedology) [17] enabled the micro-stratigraphical study of an early medieval rural village located at the limits of the medieval wetlands. This geoarchaeological technique led to understand the site process formation and the relationship between human settling practices and the fluvial geomorphology of the area [18].

Quality Control
The coordinates of sites were checked using the geographical information provided in the original publication when possible. Instead, we have georeferenced those archaeological sites missing geographical coordinates by using QGIS 3.4. Location and condition of archaeological and historical sites (when still recognisable on the surface) were checked directly with terrain survey. The medieval and post-medieval place names reported in the historical maps were checked with the use of historical documents. Thin Plate Spline (TPS) and cubic resampling methods (software QGIS 3.4) were employed to georeferencing the historical maps [19]. A minimum of three Ground Control Points (GCPs) [20] was detected but often the absence of a topographic regular grid made the georeferencing phase problematic. In this regard, the position of historic canals and ditches still active in the current drainage system served as reliable references. Moreover, to minimise the spatial inaccuracy of the historical maps the 'backdating approach has been employed: it consists in verifying and correcting the positions of the points in older maps (in this case, the historical maps retrieved at the Modena National Historical Archive) according to recent and most accurate cadastral maps (in this case WMS of the Historical Cadastral Map of Emilia Romagna Region -1853) [15]. This method cannot resolve all the positional inaccuracies mainly due to scale differences [21] but represents the most reliable approach to georeference historical maps when other more accurate methods are not applicable [22].

Constraints
The level of accuracy of each record varies according to the sources used. In particular, uncertain periodization and localisation of some sites is mainly due to the incomplete information provided by the published excavation reports of sites investigated in the 19 th and early 20 th -century CE. Especially in case of medieval and post-medieval sites and channelisation dating is limited at post quem (i.e. after) or ante quem (i.e. before) data derived from historical cartography and documents. For example, if a chronicler reports that channelisation works began in the 1518 but not when they ended, we can consider the 1518 as a "post quem" year to date the opening of those canals. Similarly, in a map of the year 1518, all the drainages represented were active when the map was drawn, so the 1518 correspond to a "ante quem" year to date those features

(3) Dataset description
This digital arhive includes all the data considered in the PhD project developed between the 2016 and 2019 at the Università degli Studi di Milano (Italy). The dataset contains especially the vectorial files of all the archaeological sites and the historical channelisation features recorded. Moreover, a GeoTiff of the Digital Elevation Model used in the project is included in the dataset along with all the original elevation checkpoints used to elaborate it. Finally, the regional soil map is stored in this dataset in a shapefile format. Lists of references and publications concerning the project results are stored in txt file format.

Object name
-research_area: a vector polygon layer representing the spatial extent of the study area from which the spatial dataset's data have been collected (as .shp and with associated files). -elevation_checkpoints: a vector point layer representing the regional elevation checkpoint considered to elaborated the Digital Elevation Model (as .shp and with associated files).