Dr. Sassi’s talking points on the anniversary of Derna’s tragedy
Dr. Hassan Sassi's talking points at the “A Year After the Derna Daniel Storm Tragedy; What Does the Future Hold for the City and Libya?” webinar organized by the NCUSLR (Dr. Sassi is a founder and Vice Chairman of the Board of the NCUSLR).
In preparing this talk, I asked myself, “How can I cover a 300-year storm in 5 minutes?
Storm Daniel was a “Medicane,” or Mediterranean Hurricane, which formed over Greece (in a Greek Omega, or horse-shoe shape) and dissipated in Egypt after leaving thousands of people dead, injured, or missing in the coastal city of Derna, in Libya, following the collapse of two upstream dams. No one was spared, old or young. The cost of recovery may exceed $20 billion, according to published estimates.
The deluge swept away not only buildings and infrastructure, and irreplaceable cultural heritage, but it also caused human damage of extraordinary scale: it killed more than 12,000 (my estimate); it left residents without their families, and in many cases left children without parents, it ripped through the surrounding environment, damaging crops, trees, and loss of livestock, and contaminated water sources – for years to come.
It is difficult for me to absorb, and to convey the enormity of the loss, particularly as I am originally from Derna. When I returned to the city five months after the flood, I found a scene of complete devastation.
But one answerable question is what happened, and what can be done now. One obvious question is why Derna suffered such catastrophic loss, while other cities and towns in the Green Mountains such as Al Beyda, Cyrene, (Shahat), and Sousa were spared?”
In my opinion, the answer lies with the dams – not their failure, which was predictable, but why they were there in the first place. Many have asked me if proper maintenance of the dams would have prevented the disaster.
My answer is no. Let me explain.
This question of the dams is of particular interest and concern to me. I witnessed two storms that caused major floods in the city in 1955 and 1959. Neither of those floods caused the extent of damage that Daniel left behind. And this was before the dams were built.
On September 5, the Greek island of Skiathos experienced rainfall of 754 mm -- that’s 29 inches -- in 18 hours, which caused some $2 billion in damages. This is far higher than its normal annual rainfall. A week later, Libya’s Green Mountains experienced 414 mm -- 16 inches -- of rainfall in 24 hours. Derna received approximately 250 mm of rain – 10 inches -- during that period. So the level of rainfall in Derna, while substantial, was half the regional average during the same period, and a third of that experienced on Skiathos. The problem is that Derna’s failed dams were designed for only 150mm -- 6 inches -- of rainfall annually. In this case, Derna received 100 mm more rain in 24 hours than it normally does all year.
Storm Daniel was regarded by researchers from Yale University as the deadliest single flood event to hit Africa in recorded history. It was also regarded as the deadliest storm globally since at least Typhoon Haiyan in 2013, and possibly Cyclone Nargis in 2008.
The storm/floods caused the displacement of tens of thousands, including children, the elderly, pregnant women, and those with disabilities. I met with members of all groups during my recent visit.
Why were the dams a problem, and how can we mitigate and neutralize potential future disasters in Derna by storm or flood? Even though we cannot prevent rain and floods, we should be able to prevent human errors that lead to the breaking of a dam. Let’s take the case in point.
The Wadi valley, that runs through Derna is not a river and therefore isn’t suitable for a dam. Dams are meant to stop and manage river flow, not contain storm floods. So when thinking about the future, which is always uncertain, but perhaps more so now than in the past, in many respects, we should take care to avoid mistakes that could have devastating consequences. If there is one positive aspect to rebuilding, it is the opportunity to fix past mistakes, some of which may not be as obvious, in hindsight, as building a dam on a wadi. We have an opportunity now, authorities and citizens, to build a Smart City of the future, from a master plan that does not include dams.
One question I have also been concerned about is how the Dernawi and Libyan communities care for those children orphaned by the floods. My colleague Hamdi Burwag and I have proposed the design and construction of Derna Children’s Academy, such a modest but needed project. Architect Helmi Soufrakis put together the conceptional layout and the 6 minute virtual tour, which have been submitted to the Libyan authorities for funding. We are currently waiting to hear their decision.
