Water Table Fluctuations and Degradation Risk Assessment at the Waterlogged Site of La Draga (Lake Banyoles, Spain)

ABSTRACT

Pile dwelling sites in Mediterranean lakes face increasing threats to their conservation and safeguarding from climate change and its associated impacts. The primary objective of this study is to investigate the influence of climate change and water table fluctuations on the preservation of archaeological layers, with a particular focus on organic layers and wooden remains. Based on a combination of lake water level fluctuation analysis, water table measurements, and stratigraphic data, we managed to gauge the effects of recent water table fluctuations on the preservation of the occupation levels at the Neolithic site of La Draga (Lake Banyoles). By simulating and analysing the relationship between water table levels and their effects on the stratigraphic sequence, we were able to identify areas that are most susceptible to the impact of water table fluctuations and therefore potential post-depositional processes. Moreover, statistical analysis of recent hydrological data has shown that there is a direct relationship between lake level and water table at the settlement. This would have been a factor affecting the preservation of both artefacts and deposits since the occupation of La Draga. Thus, the importance of considering hydrological factors when analysing and interpreting lakeside archaeological sites is highlighted.

KEYWORDS:

• Wetlands
• climate change
• wood degradation
• 3D modelling
• environmental modelling
• water level changes

Acknowledgements

We would like to thank the anonymous reviewers for contributing to a more complete version of the article with their valuable remarks.

Disclosure Statement

No potential conflict of interest was reported by the author(s).

CRediT

Daniel Rábago (methodology; writing-review and editing); Vasiliki Andreaki (original draft-review and editing (lead); methodology; conceptualisation); Raquel Piqué (conceptualisation (lead); writing-review and editing (supporting); supervision; funding acquisition); Antoni Palomo (conceptualisation (lead); review and editing (supporting); supervision; funding acquisition); Xavier Terradas (conceptualisation (lead); review and editing (supporting);supervision; funding acquisition)

Additional information

Funding

The research has been carried out in the frame of the projects ‘Archaeological Wooden Pile-Dwellings in Mediterranean European lakes: strategies for their exploitation, monitoring, and conservation’ in the frame of the JPI-CH Joint Programming Initiative Cultural Heritage (PCI2020-111992), ‘Landscape modelling and resource management in the transition to farming in northeastern Iberia’ (PID2019-109254GB-C21) and ‘Territories, technical productions and technological innovation in the Mesolithic Neolithic transition’ (PID2019-109254GB-C22) funded by the Agencia Estatal de Investigación (Spain). The excavation campaigns at La Draga are currently undertaken in the frame of additional funding by Generalitat de Catalunya (CLT009/18/00050). R.P., A.P. and V.A. are members of the research group ‘Digital technologies for Social Archaeology’ (TEDAS 2021 SGR 00190), while X.T. and V.A. are members of the group ‘Archaeology of Social Dynamics’ (ASD 2021 SGR 501) funded by AGAUR (Generalitat de Catalunya). R.P’s. research was supported by ICREA Acadèmia (Generalitat de Catalunya). V.A. and D.R. are postdoctoral researchers granted by Margarita Salas programme of the Ministry of Universities of Spain funded by NextGenerationEU – European Union. Recent lake level data were provided by the meteorological association Meteobanyoles and the Ajuntament de Banyoles.

Notes on contributors

Daniel Rábago

Daniel Rábago is a physicist in a post-doctoral position at the University of Cantabria. His research is focused on ionizing radiation, environmental studies in archaeological sites, and natural radioactivity, specifically radon gas.

Vasiliki Andreaki

Vasiliki Andreaki is a Post-doctoral Researcher in Prehistoric archaeology at the Autonomous University of Barcelona. Her research is focused on micromorphological analysis of sediments and Bayesian analysis of radiometric dates for the detection of depositional events and the reconstruction of the biography of archaeological sites. She is the author of the article Absolute chronology at the waterlogged site of La Draga (Lake Banyoles, NE Iberia): Bayesian chronological models integrating tree-ring measurement radiocarbon dates and micro-stratigraphical data. Radiocarbon. 2022;64(5):907-948.

Xavier Terradas

Xavier Terradas is Research Professor at the Spanish National Research Council (CSIC-IMF, Barcelona). His research has focused on the origins of Neolithization and its dynamics of change in the western Mediterranean basin, with special interest on the study of the technical variability and technological innovation of its artefactual productions.

Antoni Palomo

Antoni Palomo is an associate lecturer in the Prehistory department of the Autonomous University of Barcelona. His research focuses on the study of the processes of production and use of tools during recent prehistory, the evolution of settlement, experimental archaeology, underwater archeology and didactics in the social sciences.

Raquel Piqué

Raquel Piqué is professor of Prehistory at the Universitat Autònoma de Barcelona. Her interest is centred in human-environment interactions and economic practices in past societies. Her research has provided new insights on plant raw materials, woodworking techniques, and crafts in prehistoric times in the Western Mediterranean during the early Holocene, expanding the understanding of environmental, economic, and social changes. She is codirector of La Draga project. She has been co-editor of the volume The missing woodland resources: Archaeobotanical studies of the use of plant raw materials (Barkhuis 2021).