Filling canals in coastal cities reduces the ability of citizens living near coastal ports to feel the climate changes due to their inability to monitor the changes that occur and appear on these canals if they exist, says a recent study.
The study, published in the journal Cities, explains how the city of Alexandria, which is home to several UNESCO archaeological sites and has a population of six million, has become increasingly vulnerable to flooding and coastal erosion.
The authors warned of the increasing climatic and environmental pressures that are causing floods in Alexandria and other Arab coastal cities. The study is one of three studies that discuss the environmental risks facing Arab coastal cities in the cities of Alexandria in Egypt, Manama in Bahrain, and Tangier in Morocco.
In this paper, the team aimed to monitor the impact of changes in waterways on the ability of cities to cope with climate change. According to Sarah Fouad, the first author of the paper and Chair of Landscape Architecture and Transformation at the Technical University of Munich, Germany, the canals absorb floodwaters, whether coastal or floodwater, which reduces pressure on water structures such as dams.
She explained that the water canals in the Libyan city of Derna could not handle the amount of water that entered as a result of Storm Daniel, which struck it last month. This caused the dams to collapse and exacerbated the disaster.
In order to reach their findings, the researchers used field questionnaires on a random sample of residents to evaluate the societal impact of this urban transformation on residents’ perceptions of the resulting climate changes. The researchers also used satellite images to monitor environmental changes.
The researchers found that the younger generation’s perception of climate risks has particularly changed due to the city’s multiple transformations as well as the changing waterfront of the city, and that this is hampering efforts to mitigate the growing coastal risks, which explains the increase in deaths observed in these events over the past decade.
“In the German city of Hamburg, improvements made to its water canals have contributed to enhancing its ability to cope with floods.” Fouad added: “The presence of water canals, such as the Mahmoudiyah Canal, is a factor in flood resistance. The aim of the study was to discuss the impact of the changes that occurred in the water canals on the extent to which citizens feel climate change. The study found that 80% of the young people surveyed do not know the location of Alexandria Port.”
One of the relative advantages of the Mahmoudiyah Canal is that it passes through the entire city of Alexandria and passes through different segments of society, dividing the city into two social classes, the upper class in the north and the lower class in the south, according to the study’s first author. The canal provided an integrated ecosystem that included fish within it and green areas on its sides. It was one of the good fishing sites for a segment of the population, and it represented a lung and a park for the economically weaker groups.
Essam Heggy, an expert in earth sciences at the University of Southern California, US, and co-author of the paper, said that coastal cities represent great importance as their ports export vital energy resources and goods globally, in addition to being a gateway to vital food supplies. Heggy warns that the rapid deterioration of these cities could have regional and global consequences and make them vulnerable to serious environmental threats.
He attributed the reason for these threats to a series of urban projects implemented over the past decade, where priority was given to expanding highways and commercial areas by filling important water canals that played a fundamental role in regulating the movement of water, especially when storms or floods occur.
Mahmoudiyah Canal, along with other canals, played an important role in the process of flowing silt-laden water to the river mouths, which in turn transported sediments to the coast, which would create a natural fortress against erosion. Without these waterways, Alexandria’s coast is increasingly depleting these natural barriers against sea level rise and increased storm surge.
Therefore, Fouad recommends looking for environmental solutions to drain excess water and the presence of a buffer zone between the beach and residential areas, as well as planting plants such as mangroves that contribute to confronting sea waves and resisting beach erosion.
The researcher stresses the importance of re-digging canals that have been filled in, along with the necessity of integrating citizens and the local community into any canal development process and taking into account their social needs related to these waterways.
