Greater than 11,000 individuals have been killed and tens of hundreds are lacking following the catastrophic collapse of two dams within the japanese Libyan metropolis of Derna. The dam collapse got here after an excessive storm, Storm Daniel, slammed into the north African nation. The Dialog Africa’s Moina Spooner requested water sources and engineering skilled 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 steadiness of dams?
Dams are often constructed to face up to heavy rainfall or drought. The design and development of a dam takes into consideration all attainable results. All elements, together with the kind of constructing supplies, the design of the inspiration and the steadiness of a dam, in addition to anticipated floods and earthquakes and even navy motion, are considered when planning a dam.
Except for how the dam is constructed, there must be security provisions in place. As an illustration, in circumstances of storms, the engineers ought to launch the water to make sure that a dam’s most carrying capability is just not exceeded.
Within the Libyan case, I consider 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 an enormous quantity of water was getting into the reservoir he ought to have launched giant portions of water to maintain its degree decrease than the higher restrict.
Analysis exhibits that the primary causes of dam failure are basis issues (40%), insufficient spillway (23%), poor development (12%) and uneven settlement (10%). A website for a dam won’t at all times be degree as a result of dams are in-built mountain areas, however the designers should take that into consideration. The dam design should swimsuit the topography. Among the many 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.
May this tragedy have been prevented?
Sure, 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 count on 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 predicted, the meteorology division ought to inform dam managers who can then make preparations for the discharge of water to maintain it throughout the dam’s operational limits. That is the same old observe in all of the dams I’ve studied in Iraq.
On this case, there should have been a breakdown in communication between meteorological division and engineers managing the dams.
How do engineers and authorities usually monitor the structural integrity of dams?
Dams ought to have an everyday inspection programme that takes into consideration all elements of the dam. All nations with dams, whether or not within the US, Iraq or Sweden, have common inspections. There must be devices for monitoring cracks in a dam’s partitions and any adjustments in its construction. As soon as recognized, they should be attended to instantly.
In Libya’s case, if they’d opened the sluice gates to maintain water throughout the dam’s carrying capability, the collapse of the dams would have brought about much less injury.
Are there rising applied sciences or improvements to enhance security?
There are a selection of fashions and strategies and every dam has its personal mannequin or approach that the designer suggests. Planning for excessive climate occasions is often completed on the design stage of the dam. The designer is supposed to present a radical report on the steadiness of the dam in opposition to numerous elements, together with climate.
Totally different situations are given in accordance with the water degree within the reservoir of the dam to forestall dam failure. The federal government involved ought to know what to do in case of dam failure, guided by the design data. As an illustration, in my examine of Iraq’s Mosul dam, which passed off after the dam was constructed, I steered {that a} safety dam be constructed downstream to safe the security of the downstream space and its inhabitants. Security steps may be taken even after development of the dam.
The opposite 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.
Finally, 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.
