Climate change and archaeological heritage at risk: monitoring water level changes at the lakeshore fortified settlement in Smuszewo (Poland) using Earth Observation data

Kurzfassung

Climate change increasingly threatens archaeological heritage, especially in dynamic environments like lakeshores. This study investigates the potential of high-resolution satellite imagery for detecting and monitoring subtle environmental changes. Specifically, it focuses on water level fluctuations in small inland water bodies – such as lakes – that can affect the preservation or degradation of fragile archaeological materials. Earth Observation (EO) programmes provide consistent, long-term, and large-scale data that are essential for understanding and monitoring heritage threats. The potential of EO data has been explored in various initiatives, including the EU-funded TRIQUETRA project (Toolbox for assessing and mitigating Climate Change risks and hazards threatening cultural heritage), which assessed their use for monitoring climate-related hazards. While the temporal resolution of these datasets is often sufficient, a critical question remains: can current spatial resolutions detect very subtle changes in relatively small features, such as water level variations in small lakes? One such case is the lakeshore site in Smuszewo (Poland) where well-preserved wooden structures – both on land and on the shoreline – were identified during archaeological surveys since the late 20th century. Environmental changes, including decreasing water levels, eutrophication, and peatland drainage, may increasingly expose these relics to harmful conditions, accelerating their deterioration. Understanding both seasonal and long-term lake dynamics is therefore vital for preservation. As part of the TRIQUETRA project, detailed site observations—such as water level measurements and UAV-based high-resolution digital elevation models and orthophotoplans—have revealed both seasonal water level patterns and extreme events caused by drought or heavy precipitation over the past three years. However, the ultimate goal is to translate these detailed, site-specific insights into a transferable tool for use in less-surveyed areas, relying solely on Earth Observation data. This research will explore whether high-resolution satellite imagery – particularly from PlanetScope – can effectively detect minor water level changes in small lakes. The proposed workflow includes: 1. Selection of key extreme events (droughts/floods) from the past decade using meteorological data with corresponding EO data, 2. AI-based analysis of PlanetScope imagery (supported by Sentinel-2), to map water extent, 3. Validation using very high-resolution remote sensing data (orthophotomaps and WorldView images), and 4. Integration of water extent data with digital elevation models to calculate metric water level changes. Ultimately, we seek to provide tools for assessing the impact of climate change on lake systems and cultural heritage—particularly the effects of increasing temperatures on seasonal water condition, including extreme events. The results will hopefully contribute to integrating EO technologies into heritage monitoring and climate adaptation strategies, offering practical insights into bridging the scale gap between environmental processes and cultural heritage protection.