Dryland Nile waterscapes and human footprints at Giza (Egypt): 8000 years of Khufu-branch dynamics, harbour palaeotopography, agropastoral adaptation, and early copper pollution

The Giza Plateau lies at the desert-floodplain interface, where small variations in Nile waterscapes could decisively condition settlement, subsistence strategies, and large-scale engineering projects such as the construction of the pyramids. Here we synthesize multi-proxy geoarchaeological evidence to reconstruct the coupled evolution of a dryland river corridor and its cultural landscapes over the last ~8,000 years, focusing on the now-defunct Khufu branch and Khufu’s Pharaonic Harbour. First, pollen-derived vegetation patterns from floodplain cores (G1 and G4) are used to quantify long-term Khufu-branch level changes and their link to regional hydroclimate variability, including the termination of the African Humid Period (~3550 ± 80 BCE) and subsequent aridification trends, while highlighting water-level conditions during the 4th Dynasty that favoured navigation and logistics. Second, chronostratigraphy and sedimentology from the harbour core (Giza-3) constrain Holocene sedimentary units and allow reconstruction of local palaeotopography and harbour functionality, showing a shift from an earlier secondary palaeochannel to floodplain/harbour environments consistent with Old Kingdom use. Third, high-resolution palynological and non-pollen palynomorph indicators document a long record of agropastoral practices at the foot of the necropolis (from ~7980 ± 80 BCE to 375 ± 80 CE), enabling assessment of human adaptive thresholds under drought–flood stresses in a semi-arid setting. Finally, geochemical analyses (ICP-MS; Cu enrichment factors with crustal-element normalization) from harbour sediments reveal distinct phases of anthropogenic copper contamination from the Predynastic through Dynastic periods, including peaks during the reigns of Khufu, Khafre and Menkaure, providing an environmental signal of intensified metalworking associated with construction and subsequent activity. Together, these datasets show how dryland river dynamics, floodplain geomorphology, and human land use co-evolved at Giza, and demonstrate that monumental building in semi-arid landscapes left not only a cultural legacy but also detectable early geochemical pollution in sedimentary archives.