Dams in Stable Continental Interiors: The Case for the Great Ethiopian Renaissance Dam (GERD)
Updated: Jun 7, 2021
Prof. Atalay Ayele, Institute of Geophysics Space Science and Astronomy, Addis Ababa University, Ethiopia
Dam construction has come a long way since the Pharaonic Egyptians first erected earthen berms to control the periodical flooding of the Nile. However, while those early structures may have been considered ingenious methods of taming a mighty river, they no doubt have only a passing resemblance to what we associate with dams today. In purely technical terms, dams fall into several distinct classes, defined by structural design and type of building material employed. Thus, while the ancient Egyptians deserve honour for being the earliest practitioners, it is the Romans who are credited with building the first “arch” dams. Even then, it was not until much later--as close to the modern era as the 19th century--that engineering skills and construction materials attained the level of sophistication required to build the first large-scale arch dams. Viewed against such a backdrop, dam building in Ethiopia covers a much shorter time-span, since it probably started no earlier than the advent of the 20th century. However, delving into this history is beyond the scope of this article, since its main goal is to set the record straight regarding some specious pronouncements that have been lobbed against the Grand Ethiopian Renaissance Dam (GERD).
Ethiopia possesses a distinctly rugged terrain, and it is a country where some of the highest-elevation areas in the whole of Africa can be found. One striking feature of the country’s topography is the huge disparity between the elevation of different parts of the country, with the highest point, Ras Dejen (Semien Mountains), rising to an elevation of 4,550 meters above sea level, and the lowest point, Dallol (the Afar Depression), descending as low as 125 meters below sea level. One result of this stark contrast in elevation is the enormous diversity in the flora and fauna which flourishes in Ethiopia, and the rugged nature of the country, combined with its many perennial rivers, has bestowed another salutary feature: This rugged terrain and abundant river-water supply affords Ethiopia ample opportunity to build dams for hydro-power generation and irrigation, both of which could benefit not only Ethiopians but also people in neighbouring countries. Realizing this potential, Ethiopia has, in the last couple of decades, aggressively initiated several dam-construction projects for power generation--with the Grand Ethiopian Renaissance Dam (GERD) being the largest and the most ambitious of these. This particular dam comprises a Roller Compacted Concrete (RCC) gravity dam on the Blue Nile River, with a storage capacity of 70 billion cubic metres (BCM) of water, an outdoor powerhouse on each bank of the river, three spillways, and a saddle dam. The project, which was initiated in 2011, is overseen by a state-owned public utility corporation, the Ethiopian Electric Power Corporation (EEPC).
Figure 1. Seismicity of Ethiopia and the neighbouring region. Red dots show locations of earth-quakes where each circle size is proportional with the corresponding earthquake magnitude. The white stars show capital cities in the region and the yellow stars show major towns in Ethiopia and the green rectangle shows the location of GERD. It is evident that there is no red dot around the GERD location which implies that there is no earthquake record in that neighbourhood.
The rationale behind the construction of this dam was to relieve Ethiopia’s acute energy shortage, as well as to export excess electricity to neighbouring countries. With a planned installed capacity of 6.45 gigawatts, upon its completion, it will be the largest hydroelectric power plant in Africa, and the seventh largest in the world. Clearly, this dam heralds an era of unprecedented energy sufficiency in the Horn of Africa, but the project has had vocal detractors, chief among these being Sudan and Egypt. For too long, the hostility and active interference of these nations has not only deterred Ethiopia from tapping into its considerable natural resources, but it has also wreaked havoc on the country’s socio-political stability for at least the last half century. On a superficial level, it is not surprising that the two riparian nations, which may be directly affected by any alteration to the course of the Nile, should sound the alarm. Upon closer examination, however, it becomes clear that their opposition to the GERD is based on two highly questionable claims:
First, Sudan and Egypt would have the international community believe that the GERD will reduce the amount of water that flows to their countries, but this claim does not hold any water--for three reasons: First, as Ugandan President Yoweri Museveni recently pointed out to an Egyptian journalist, since the water used for propelling the GERD’s turbines flows back to the river, any claim of water-loss is bogus. Second, during times of heavy rainfall, the excess water can be safely stored in a much cooler catchment area, sparing the two countries, especially Sudan, the perennial threat of over-flooding, while the extra water can, meantime, be used for irrigation purposes, or released in times of drought. Third, with a bit of farsightedness, Sudan and Egypt should, in fact, support it, since it will increase electrification of the hitherto neglected rural areas in the Nile Basin of western Ethiopia, a long overdue measure which will eliminate the wanton chopping down of trees and bushes for fuel. Although dire necessity is behind reliance on firewood for fuel, it harms the region in many ways: the absence of trees reduces the region’s ability to absorb carbon from the atmosphere, sets free carbon normally trapped by the soil below, degrades soil quality and moisture-retention capacity, and contributes to a rise in both global warming and desertification.
The second claim, perpetuated by “senior,” Egyptian writers, such as (Mohamed and Ismail Elmahdya, 2017) and (El Said, 2020), is that the dam will be a geo-hazard threat for downstream countries, a claim without any merit whatsoever. To be specific, such writers claim that the GERD’s location is unsafe for constructing a dam of its size, since the site is not far enough from tectonically active areas. Such an alarmist statement might impress lay readers and the denizens of social media, but in reality, the GERD’s location is, in fact, one of the safest spots on Earth for dam construction! In contrast, Egypt’s own Aswan High Dam (AHD) is intersected by the seismically active Kalabsha Fault Zone (KFZ) (Hamimi et al., 2018) and also relatively close to the Red Sea rift, yet even with its less-than-ideal location, the AHD has safely provided Egypt with ample electric power for the last 50 years, helping accelerate its economy. Thus, as we shall show below, sounding the alarm over the much safer GERD site is disingenuous, to say the least.
Geologic and Seismic Safety of the GERD
The GERD, located in the Blue Nile Basin (southwest of the north-western Ethiopian plateau), is bounded, to the east and southeast, by the tectonic escarpment of the Main Ethiopian Rift (MER), uplifted western flank, and to the north and south, by the Axum–Adigrat and Ambo lineaments, respectively. The Basin contains a 1400m-thick section of Mesozoic sedimentary rock, unconformably overlaying Neoproterozoic basement rocks (Gani et al, 2009), while the 1600m deep Blue Nile Gorge (Gani and Abdelsalam, 2006) bisects the Basin. As shown in the seismicity or earthquake distribution in Figure 1, the GERD is located in a stable continental terrain, far away from active rifts, and no documented ground deformation at the dam site has been observed in the recent geologic past. Indeed, Figure 1 shows that the site is one of the most desirable locations to build a dam on. [Of course, when any dam is built, and its reservoir gets filled, the amount of pressure exerted on that site may trigger reservoir-induced seismicity (Simpson et al., 1998)].
Figure 2. Picture of the current status of the GERD.
GERD and the Future
Dam-construction, is by nature, a controversial undertaking, and for good reason. In 1889, a shoddily constructed dam in the outskirts of Jonestown, PA failed catastrophically, killing upwards of 2000 people (McCullough, 1987). Such calamities, as well as genuine concerns over a dam’s capacity to radically transform a region have long prompted environmentalists and safety experts to voice grave concerns. Such concerns notwithstanding, the socio-economic benefits of dams have always been shown to outweigh the costs. For instance, the Tennessee Valley Authority’s (TVA) dam-building frenzy between 1933 and 1944 transformed the hitherto agriculture-based U.S. economy not only to ramp up armament production for the World War II effort, but also to usher in the economic miracle of the post-war era. More recently, the highly controversial Three-Rivers Gorge Dam has enabled China to become the world’s manufacturer of goods. However, this is not to down-play the fact that dam-construction can sometimes cause regional tension if they are not handled with foresight. For instance, dam construction can disproportionally impact minorities whose livelihoods are dependent on river resources. In this respect, the Nile is a lifeline for hundreds of millions of people in East Africa, and it needs to be used as a vehicle for prosperity, regional cohesion and stability, and environmental protection. Sadly, as the GERD construction draws to a close, there has been a proportionate rise in unrest in Ethiopia. It is widely believed that Egypt has been financing ethno-extremists to stir up intense rivalry throughout the country, thereby stretching the country’s resources and creating formidable stumbling blocks for the dam’s construction and completion.
However, now that 80% of the project is complete, one might assume that the point-of-no-return has been crossed. Some thoughtful Egyptian experts have, in fact, publicly observed that, if Egypt used the billions of dollars it is squandering in an effort to destabilize Ethiopia, for mutual cooperation and development, the Horn of Africa would be a haven for prosperity and tranquillity, and we agree. An enlightened view of the matter would, indeed, show Sudan and Egypt that the GERD will not only create energy abundance, but also protect the environment and actually boost water flow to downstream countries, making it an exemplary project to be emulated by other upstream countries of the Nile. Given this, one would have hoped that Sudan and Egypt would see the GERD in a positive light; sadly, these countries have persisted in sabotaging the project, misinforming the international community, using the project as a bogey-man for rallying public support against their internal opponents, in so doing hoping to prolong their misrule over their own people. Ethiopians from all walks of life and different backgrounds should see through such machinations on the part of Sudan and Egypt, rally around this worthy regional project, defend Ethiopia’s interests, and help make the GERD a reality.
1. El-Said, M. (2020), Will Ethiopia’s disputed dam collapse?, Eos, 101, https://doi.org/10.1029/2020EO147811. Published on 06 August 2020.
2. Gani N. DS., Abdelsalam M.G., Gera S. and GANI M.R. 2009. Stratigraphic and structural evolution of the Blue Nile Basin, Northwestern Ethiopian Plateau, Geological Journal, 44(1), 30-56.
3. Gani ND, AbdelsalamMG. 2006. Remote sensing analysis of the Gorge of the Nile, Ethiopia with special emphasis on Dejen–Gohtsion region, Journal of African Earth Sciences 44: 135–150.
4. Hamimi, Z., Hagag, W., Osman, R., El-Bialy, M., Abu El-Nadr, I. 3 & M. Fadel, M., 2018, The active Kalabsha Fault Zone in Southern Egypt: detecting faulting activity using field-structural data and EMR-technique, and implications for seismic hazard assessment, Arabian Journal of Geosciences, 11:421, doi.org/10.1007/s12517-018-3774-1
5. Mohamed M. M., and Ismail Elmahdya, S., 2017, GEOMATICS, NATURAL HAZARDS AND RISK, 2017, VOL. 8, NO. 2, 1225–1240 https://doi.org/10.1080/19475705.2017.1309463.
6. McCullough, D. (1987). The Jonestown Flood. New York, NY: Simon and Schuster.
7. Simpson, D.W., Leith, W.S., and Scholz, C.H.. 1988. "Two types of reservoir-Induced seismicity." Bulletin of the Seismological Society of America 2025-2040.
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