University of Southern California: a new study indicates the impact of rising seawater on Alexandria's infrastructure due to erosion

A breakthrough study on the state of buildings in the Egyptian city of Alexandria has been published by the University of Southern California in collaboration with the Technical University of Munich (TUM), Alexandria University in Egypt, and Delft University of Technology in the Netherlands. Researchers have observed a sharp increase in building collapses in Alexandria, largely due to rising Mediterranean Sea levels, which are causing erosion of the city's infrastructure.

According to the research, structural failures in this historic port city were once rare, occurring approximately once per year. However, over the last decade, this number has surged to 40 incidents annually. The researchers attribute this increase to rising sea levels and seawater infiltrating the ground beneath city foundations. Notably, Alexandria is one of the world's oldest cities, founded more than 2,000 years ago, and is among the most densely populated cities in Africa, with a population of approximately six million residents.

Sara Fouad, a landscape architect at the Technical University of Munich and the study’s lead author, noted that Alexandria contains a mix of modern mid-rise buildings and ancient structures built under various ruling dynasties. While these structures have withstood natural disasters such as earthquakes and tsunamis, the accelerating effects of climate change have intensified their deterioration.

To examine Alexandria’s changing shoreline, the research team used multiple analytical methods. They developed a digital map to identify locations of collapsed buildings and gathered data from site inspections, government records, news archives, and private construction reports spanning from 2001 to 2021. Additionally, they compared satellite images and historical maps from 1887, 1959, and 2001. Their findings demonstrate that Alexandria’s 50-mile coastline has shifted inland over the past 20 years.

Ibrahim H. Saleh, a soil radiation scientist at Alexandria University and a co-author of the study, added that soil isotope analysis confirmed foundation erosion as a primary cause of building failures.

Overall, the study indicates that nearly 7,000 older buildings in Alexandria are at risk of collapse. To mitigate further erosion and protect the city's infrastructure from seawater intrusion, researchers recommend constructing sand dunes and vegetation barriers along Alexandria’s coastline.