SUBSIDENCE IN THE NW NILE DELTA FROM PS-INSAR STUDIES

Recent studies have documented current subsidence rates in the northeast of the Nile Delta and average Holocene rates across the delta of up to 8mm/year of vertical motion a year. In this study, we use persistent scatterer radar interferometry techniques to measure modern land subsidence rates on the north-western Nile Delta. The Nile Delta is home to around 75 million people and the location of the majority of Egypt’s farmland and agricultural production. The area is currently threatened by Mediterranean waters due to factors such as sediment starvation, climate and sea level fluctuations as well as land surface subsidence. The low elevation and relief of the Nile Delta makes a large number of coastal communities, including the city of Alexandria particularly vulnerable to potential inundation. As a result, the situation has become a concern for the area’s residents and a better understanding of the natural processes occurring there can aid in determining suitable actions.

We apply ps-insar techniques to 23 ESA ERS1/2 radar scenes spanning from 1992 to 2000 in the NW portion of the Nile Delta, over the city of Alexandria, and the Rosetta promontory. We use these results to map the non-uniform subsidence along the Northwest Nile Delta coast. Preliminary results show maximum subsidence around the Rosetta channel, with lower rates in the vicinity of Alexandria. However, rates of subsidence are lower than were found in the NE Delta using the same techniques.