It is estimated that 20,000 people lost their lives in the dam disaster in Libya. As the true horror of Libya's Derna floods begins to emerge, more details are coming to light about the two dams on Wadi Derna that caused the disaster.
The names of the two dams are a source of misunderstanding, so we will use their major and minor names here.
According to the website, the upper dam had a storage capacity of 1,5 million cubic meters and was 45 meters high. The lower dam had a storage capacity of 18 million cubic meters and was 75 meters high. The last one is quite strange in my opinion because Google Earth DEM shows that this is an overestimation.
Both dams were built by the former Yugoslav company Hidroprojekt of Beograd for the Libyan Ministry of Agriculture. The construction period was between 1973-1977.
Frankly, the framework is a complete failure. There is a picture of the dam before it collapsed on Google Maps:
Visible indicators of poor maintenance, such as plants growing on the dam crest, are relevant. Also notable is the absence of an emergency spillway, as far as I could observe. The most likely cause of failure seems to be that the spillway was too small to handle the amount of water entering the basin and overflowed.
The dams have a good (though not perfect) safety record and are magnificent structures. Like all infrastructure, they must be maintained and it is crucial that their suitability for their intended use is routinely assessed. When rainfall amounts begin to exceed the capacity of the system's architecture, climate change poses an existential threat. In these cases, new engineering is required. This is possible in well-functioning civilizations, but some recent events raise the possibility that some dams in the US and UK are not properly maintained.
Derna can teach us many things. Unfortunately, there will be many more places where similar concerns arise, especially in nations with poorly functioning societies.
While Libya's internationally recognized interim government operates in Tripoli, there is a rival administration in the east. The disaster sparked rare displays of cooperation between conflicting countries. Aid planes carrying medical supplies were sent from Tripoli to the eastern city of Benghazi on Tuesday.
While Khalifa Haftar, leader of the self-proclaimed Libyan National Army that controls the east, has ignored international pledges of support from friends of the Tripoli-based western administration, partisan lines continue to divide sharply elsewhere.
Speaking to the BBC, Ali Bey was quick to criticize both administrations, claiming that they did not react sufficiently.
“Unfortunately, the country is divided between two governments, and unfortunately these two weak, unqualified governments have not been able to provide the assistance that people need,” Ali said.
Despite the UN pledging support for relief efforts and the Red Cross claiming to have personnel on the ground, Ali Bey claimed that little supplies had reached the survivors.
Ali claimed, “Only small-scale aid came from Turkey to the city of Derna.”
There are many people without clean water, food and shelter. People are trying to help each other.
“What we need now is massive international support that needs to come in immediately and help people.”
Source: 1) https://eos.org/thelandslideblog
2) https://www.bbc.com/news
📩 15/09/2023 12:11