BY BINIAM ALEMAYEHU, DANIEL KASSAHUN AND SINTAYEHU TAMIRAT
In recent times, the world seems to be teetering on the brink of total disaster as catastrophes-some natural and others manmade-continue to cast their bad spell on it. One of these with colossal damage is the sudden, rapid, and uncontrolled release of impounded water or the likelihood of such an uncontrolled release, an event that experts call dam failure.
Between the years 2000 and 2009 more than 200 notable dam failures happened worldwide. The collapse of two Libyan dams earlier in September will likely conjure up an image of a new era in which deadly dam failures become more and more common. The aftermath of dam burst in the city of Derna in the Mediterranean Sea witnessed the drowning of thousands of people, not to mention the displacement of tens of thousands more.
This kind of disaster poses caution to the safety of existing and emerging dams across the world.
When it comes to the Grand Ethiopian Renaissance Dam, however, there is cause for relief. GERD, expected to be Africa’s biggest hydropower dam upon completion, is in safe hands for shocks which may arise due to internal or external causes. The grand dam is being constructed with the state-of-the-art techs. It has also been receiving pretty much acclamation from experts in the field for the notable safety measures taken to make it by far the safest dam in the region.
Experts evidence their arguments on the highest possible safety of GERD with multiple justifications. Safe site identification is one evidence. The site for the construction of the Grand Ethiopian Renaissance Dam was not only identified by local engineers. It was after a serious of surveys conducted by renowned overseas firms, including the one carried out between 1956 and1964 by the United States Bureau of Reclamation, the site was aggregately acknowledged.
Next evidence to GERD’s safety is founded on something attributed to the construction of the dam, which is Roller Compacted Concrete dam (RCC)- a novelty that has won worldwide acceptance in recent times. The GERD is expected to have consumed over 10 million metric tons of concrete. To this end, the world had witnessed GERD’s record breaking RCC placement back in 2014. Between Dec. 27and 28, 2014 GERD’s RCC filling reached the maximum continuous production of 23,200m3 in 24 hours. Its RCC feature therefore is another fundamental depiction to the deterrence of seepage and cracking due to unprecedented calamities.
Moreover, GERD is in fact safeguarded against potential maximum flood of 30’200 m3/s peak and 18,000 m3/s directed discharges with a system of three spillways-a well-thought-well-innovated design. This feature of the dam is also enhanced with emergency spillways and two steel-lined bottom outlets with a diameter of 6m embedded in the dam body, which allow the control of reservoir level and the discharge during plant outage period, in addition to the main spillways.
More importantly, the meticulously managed feasibility study, designs and construction phases, which have obtained close monitoring of international experts consolidate the proof of GERD’s safety. An outstanding illustration to this can be the study results revealed by the international panel of experts (IPOEs) drawn from Germany, South Africa, France and Britain and additional 6 experts from Ethiopia, Sudan and Egypt -two from each.
This bold initiative by the Ethiopian government to invite Egypt and Sudan to set up an IPOEs in 2012 testifies Ethiopia’s unwavering stance on GERD’s high level safety profile because its construction has been progressing with professional competence and with due regard to internationally recognized standards.
In 2013, the IPOEs unearthed, among other elements of their investigation, data related to the GERD safety. This finding was a breakthrough in addressing the GERD safety concerns and demands of downstream states. It is also a final reassurance to the so-called experts misinforming and misguiding politicians in downstream states that GERD cannot and will not be concern of safety for any parties.
Furthermore, mention must be made to the occurrence of natural hazards and the geology of the GERD. All feasibility studies show that the GERD is under construction at a sight which is tectonically inactive. This means there would be no high or excess pressure which could potentially cause cracks or any other damages to the dam. By the same token, the rewarding findings of seismicity assessment on the dam area and its surroundings makes GERD safety out of concern.
Last but not least, despite the aforementioned facts, there could still be yearning for furtherance of investigation into GERD safety. Hence, apart from a number of data on the issues that Ethiopia has handed over to downstream states, some can apply remote sensing techniques and a geographic information system to analyze different satellite images.
The current water holding capacity of Ethiopia’s colossal dam on the Blue Nile has reached over 42 BCM, thanks to the fourth and final water filling of GERD in September. There has so far been no signal of safety issue sent to the control station from the hundreds of safety apparatuses installed in and around the main and saddle dams.
Unbelievably galloping prices of dam repairs, constrained budget for high quality dams in several parts of the globe as well as climate change are some of the factors to guard against when it comes to risks of dam burst. Ethiopia, in this respect, has accomplished much of the assignment when it comes to GERD.
Be that as it may, Ethiopia continues to speed through the waters of prosperity having been assured that the GERD, a project heralding its return to former glory, is in safe hands.