Remote sensing of the Grand Ethiopian Renaissance Dam: a hazard and environmental impacts assessment

The Grand Ethiopian Renaissance Dam (GERD) is constructed in a mountainous area where limited information has been collected on key environmental factors and which is lacking of information about site condition, hazards and environmental impacts. To deal with problems, the Shuttle Radar Topographic Mission (SRTM) DEM and Advanced Land Observation Satellite Phased Array type L-band Synthetic Aperture Radar (ALOSPALSAR) were used to map factors that can lead to the GERD failure and predict the flooded area in Sudan and seawater intrusion in the Nile Delta, Egypt. The results showed that the Nubian Block and the GERD site are structurally controlled by sets of faults. Their trends are in the NNE–SSW, NE–SW, and NNW–SSE directions and share the similar trends with the shear stress and African Rift, which created some alarm. The results indicated that the maximum extent of the Sudanese inundation area, as estimated from a DEM using a flood basin model, was about 667,228 km2 along the Blue Nile River and was at high risk. The results also showed that one-third of the Nile Delta will experience seawater intrusions when the groundwater table depletes 5 m below sea level.