Rescuers and family of victims arrange tents in entrance of collapsed buildings in Derna, Libya, Monday, Sept. 18, 2023. Some 11,300 individuals died when two dams collapsed throughout Mediterranean storm Daniel final week sending a wall of water gushing by town, in keeping with the Red Crescent help group. An additional 10,000 persons are lacking, and presumed useless.
| Photo Credit: AP
More than 11,000 individuals have been killed and tens of 1000’s are lacking following the catastrophic collapse of two dams within the jap Libyan metropolis of Derna. The dam collapse got here after an excessive storm, Storm Daniel, slammed into the north African nation. The Conversation Africa’s Moina Spooner requested water sources and engineering expert Nadhir Al-Ansari, who has researched the design and security of dams, to supply insights into the catastrophe.
How does excessive climate have an effect on the soundness of dams?
Dams are often constructed to resist heavy rainfall or drought. The design and building of a dam takes into consideration all potential results. All components, together with the kind of constructing supplies, the design of the muse and the soundness of a dam, in addition to anticipated floods and earthquakes and even navy motion, are considered when planning a dam.
Aside from how the dam is constructed, there needs to be security provisions in place. For occasion, in instances of storms, the engineers ought to launch the water to make sure that a dam’s most carrying capability just isn’t exceeded.
In the Libyan case, I imagine that the administration of the dams was not good. The engineer liable for the dam ought to have made positive the water didn’t exceed the dam’s higher carrying capability. When he observed that a large quantity of water was getting into the reservoir he ought to have launched giant portions of water to maintain its stage decrease than the higher restrict.
Research exhibits that the major causes of dam failure are basis issues (40%), insufficient spillway (23%), poor building (12%) and uneven settlement (10%). A website for a dam won’t at all times be stage as a result of dams are inbuilt mountain areas, however the designers should take that into consideration. The dam design should swimsuit the topography. Among the rarer causes of dam failures are acts of warfare (3%), faulty materials (2%) and earthquakes (1%).
In Libya’s case, unhealthy administration seems to have been the reason for the dam’s collapse.
Also Read | Libya investigates dams’ collapse after flood killed over 11,000
Could this tragedy have been averted?
Yes, if the accountable individuals working the dams had opened the gates to launch water. When these liable for the water administration of the dam ignore heavy rainfall then one can anticipate such disasters to happen.
Dam managers also needs to know every dam’s catchment space and the way a lot rainfall is forecast. This requires coordination between meteorologists and the workers liable for the administration of dams. When heavy rainfall is anticipated, the meteorology division ought to inform dam managers who can then make preparations for the discharge of water to maintain it inside the dam’s operational limits. This is the same old apply in all of the dams I’ve studied in Iraq.
In this case, there should have been a breakdown in communication between meteorological division and engineers managing the dams.
Infographics | Mapping Libya’s flood injury
How do engineers and authorities sometimes monitor the structural integrity of dams?
Dams ought to have an everyday inspection programme that takes into consideration all components of the dam. All nations with dams, whether or not within the US, Iraq or Sweden, have common inspections. There needs to be devices for monitoring cracks in a dam’s partitions and any modifications in its construction. Once recognized, they should be attended to right away.
In Libya’s case, if that they had opened the sluice gates to maintain water inside the dam’s carrying capability, the collapse of the dams would have triggered much less injury.
Also Read | Libya’s flood-ravaged Derna struggles to deal with 1000’s of corpses
Are there rising applied sciences or improvements to enhance security?
There are a variety of fashions and methods and every dam has its personal mannequin or method that the designer suggests. Planning for excessive climate occasions is often carried out on the design stage of the dam. The designer is supposed to provide an intensive report on the soundness of the dam towards varied components, together with climate.
Different eventualities are given in keeping with the water stage within the reservoir of the dam to stop dam failure. The authorities involved ought to know what to do in case of dam failure, guided by the design info. For occasion, in my examine of Iraq’s Mosul dam, which befell after the dam was constructed, I prompt {that a} safety dam be constructed downstream to safe the security of the downstream space and its inhabitants. Safety steps will be taken even after building of the dam.
The different security measures relate to housing and different developments in areas downstream. In Libya’s case, there was poor planning. The areas downstream from the dams mustn’t have been used for housing.
Ultimately, the dam failure in Libya might have been prevented, or no less than the losses might have been minimised, if the engineers on website had launched the water from the reservoir as soon as the storm began.
Nadhir Al-Ansari, Professor, Luleå University of Technology
This article is republished from The Conversation below a Creative Commons license. Read the unique article.
