Exploring the potentiality of InSAR data to estimate land subsidence of the Nile Delta

Nile Delta has been historically targeted for various types of human activities since the Pharaohs’ era due to abundance of its natural resources. The increasing land subsidence in the northern delta is a significant concern for the Egyptian government. Moreover, the cumulative subsidence coupled with the scenarios of sea level rise worsens the situation. In the present work, we utilize SNAPPING service on the Geohazards Exploitation Platform (GEP) to measure the spatial and temporal trends, as well as the extent of subsidence in urban areas within the Nile Delta. The study analyzed the period between 2015 and 2020 using 225 Copernicus Sentinel-1 radar imagery using the Persistent Scatterers Interferometry (PSI) technique and reported surface motion with an average of −5 mm/year in the Nile Delta surface. Subsidence is relatively higher in the eastern part with more patterns specific to particular regions. The northern part recorded subsidence ranged from 0 to 7 mm/year. High rates of subsidence up to 17 mm/year localized in locations of Port Said, Damietta, Ad Dakahlia and Al Sharkia governorates and around Manzala Lake. On the other side, medium uplift rates up to 6 mm/year concentrated around Bardaweel Lake, Parts of Ismailia governorate and Baltim city. On-site visual inspections in these areas documented tilting in buildings and clear cracks which confirm the impact of land subsidence on the structural integrity of the buildings. The GEP platform and the SNAPPING service demonstrated the capability of cloud-based solutions to provide precise surface motion information within a short time.