Settling the riverscape of Erbil (Kurdistan Region of Iraq): long-term human overprint on landforms and present-day geomorphological hazard

This paper presents a geomorphological reconstruction of the urban landscape of Erbil (Kurdistan Region of Iraq), aimed at explaining how human groups settled the region since the prehistory and contributed modifying natural surface processes. Our reconstruction on landforms evolution is based on satellite and historical aerial images and field control allowing the reconstruction of changes in land use over time. The city of Erbil was established along a fertile alluvial plain during the Chalcolithic period and grew around the pristine citadel, which was likely built on top of fluvial features. Prior to the mid-20th century, Erbil was centred around the citadel and relied on traditional systems for water management such as artificial basins and qanats. The city underwent intense urban expansion since the 1950 s and changed its shape due to the construction of roads and residential and industrial areas, which led to the obliteration of the pristine fluvial network. The analysis of historical and current satellite images highlights the profound modification of the landscape triggered by human actions and a progressive shift of local land use from agricultural to urban. This, coupled with human agency on the natural hydrography led to the increase susceptibility of the city to geomorphological hazard (especially floods). Our investigation suggests that during the Anthropocene the dynamic of urbanization reach a tipping point, when excessive urban growth suffers the effect of geomorphological hazard. For that reason, urbanization in the Anthropocene must consider the existence of natural geomorphological processes.