Monitoring Archaeological Sites Affected by Natural and Anthropogenic Hazards Using Multitemporal UAV-Photogrammetry: A Case Study from the Barranca Valleys, Peru

Archaeological sites are increasingly threatened by human activities and natural processes, causing irreversible heritage loss. Unmanned aerial vehicle (UAV) photogrammetry has advanced documentation and monitoring, yet many applications lack accuracy assessment or rely on a single data source. This study applies high-resolution, multi-temporal UAV-photogrammetry to nine archaeological sites in the Barranca Valleys, Peru—the first case study of this scale in the region. Surveys were scheduled to capture geomorphic responses to the forecasted 2023–2024 mega El Niño, while also documenting pressures such as urbanization, agricultural expansion, and looting. By combining orthomosaics, digital elevation models, image cross-correlation, and horizontal displacement analysis—supported by explicit accuracy evaluation—this research provides a robust framework for assessing site degradation and highlights the added value of multi-source approaches for long-term monitoring.