Introduction
Grand Ethiopian Renaissance Dam (GERD or TaIHiGe, Amharic: Tālāqu ye-Ītyōppyā Hidāsē Gidib, Roman: Tālāqu ye-Ītyōppyā Hidāsē Gidib, Tigriña: Ethiopian Renaissance Dam, Oromo: Greater Ethiopian Renaissance Dam), formerly known as the Millennium Dam, It was sometimes known as the Millennium Dam. The Hidase Dam (Amharic: Hidase Dam, Romanization: Hidāsē Gidib, Oromo: Hidha Hidāsē) is a gravity dam on the Blue Nile in Ethiopia. The dam is located in the Benishangul-Gumuz region of Ethiopia, about 45 kilometers (28 miles) east of the border with Sudan. With a planned installed capacity of 5.15 gigawatts, the dam will be Africa’s largest hydroelectric power plant when completed. The first phase of filling the reservoir began in July 2020 and by August 2020 the water level had risen to 540 meters (40 meters above the river bed at 500 meters above sea level) ) . . . . The second stage of reclamation was completed on July 19, 2021, raising the water level to approximately 575 meters. The third reclamation was completed on August 12, 2022, at a height of 600 m (2,000 ft), 25 m (82 ft) higher than the second reclamation completed the previous year. The current (November 2022) water level is about 605 meters. It takes 4 to 7 years for the water to fill up. On February 20, 2022, the dam generated electricity for the first time, supplying 375 MW of electricity to the grid. A second 375 MW turbine was commissioned in August
Scholarly Articles
Background
The name of the Blue Nile in Ethiopia (‘Abey’) comes from the Ge’ez word meaning ‘great’, which means ‘a river of rivers’. The word “Abai” still exists in the main Ethiopian languages and refers to something or someone considered superior. The final site for the Grand Ethiopian Renaissance Dam was identified by the United States Reclamation Service during the course of the Blue Nile Survey conducted from 1956 to 1964 during the reign of Emperor Haile Selassie. However, the 1974 coup and 17-year Ethiopian civil war prevented the project from progressing. The Ethiopian government inspected the site in October 2009 and August 2010. In November 2010, the dam design was submitted by James Kelston. On March 31, 2011, the day after the project went public, a US$4.8 billion contract was signed for free. The foundation stone for the dam was laid by Prime Minister Meles Zenawi on April 2, 2011, following a competitive bid by Italian company Salini Impresiro. A rock crushing plant was built along with a small runway for rapid transit. The first two power generating turbines were expected to be operational by early 2015, after a 44-month construction period. Egypt, located more than 2,500 kilometers (1,600 miles) downstream from the proposed site, opposes the dam, believing it will reduce power generation. Water obtained from the Nile River. Based on anonymous research, Zenawi argued that dams would not reduce downstream water availability and would also regulate irrigation water. In May 2011, Ethiopia announced that it would share dam plans with Egypt so that downstream impacts could be studied. The dam was originally called “Project X”, but became known as the Millennium Dam after the contract was announced. On 15 April 2011, the Council of Ministers renamed the dam the Grand Ethiopian Renaissance Dam. Ethiopia has about 45 GW of hydropower potential. The dam is funded by government bonds and private donations. It was scheduled to be completed in July 2017. The potential impact of the dam has been the source of intense controversy in the region. The Egyptian government, which depends on the Nile for about 97% of its irrigation and drinking water, has demanded Ethiopia stop building dams as a precondition to negotiations and seeks regional support for its position, which has led some political There are also leaders. We discussed how to sabotage it. Egypt plans a diplomatic effort to weaken support for the dam not only in the region, but also in other countries backing the project, such as China and Italy. However, although Sudan’s position on the dam has changed over time, other countries participating in the Nile Initiative, including Sudan, the only country in the Lower Blue Nile, have also expressed support for the dam. are doing. In 2014, Sudan accused Egypt of fomenting the situation. Ethiopia denied that the dam had a negative impact on downstream water flows, and in fact claimed that the dam would increase water flow to Egypt by reducing evaporation in Lake Nasser. Ethiopia accused Egypt of being unreasonable. In October 2019, Egypt announced that negotiations with Sudan and Ethiopia over the operation of a $4 billion hydroelectric dam Ethiopia is building on the Nile River had stalled. Starting in November 2019, US Treasury Secretary Steven T. Mnuchin began facilitating trilateral negotiations.
ADVERTISEMENT
Cost and financing
The construction cost of the Grand Ethiopian Renaissance Dam (GERD) is estimated at nearly US$5 billion, equivalent to about 7% of Ethiopia’s gross national product in 2016. The lack of international funding for the Blue Nile project has long been attributed to Egypt’s campaign to maintain control of its water share. Ethiopia has been forced to crowdfund GERD by raising internal funds in the form of selling bonds and persuading employees to donate a portion of their earnings. Donations are made on the new official website verified by the Ethiopian Prime Minister’s Office verified account. Of the total cost, $1 billion for turbines and electrical equipment was funded by the China Exim Bank.
Design
The design changed several times between 2011 and 2019. This affected both the electrical parameters and the storage His parameters. Initially, in 2011, the hydropower station will have 15 generating units with a nameplate capacity of 350 MW each, resulting in a total installed capacity of 5,250 MW and an annual output of 15,128 GWh. It is expected. The planned generation capacity has since increased to 6,000 MW through 16 power generation units with a nominal capacity of 375 MW each. The expected power generation was estimated at 15,692 GWh per year. In 2017, the design was changed again, adding another 450 MW, bringing the total to 6,450 MW, with a projected annual capacity of 16,153 GWh. This was achieved by upgrading 14 of the 16 generating units from 375 MW to 400 MW without changing the nominal capacity. As of October 17, 2019, GERD’s generating capacity is now 5,150 MW, down from 16 turbines by 13 (2 x 375 MW and 11 x 400 MW), according to a senior Ethiopian official. Not only power parameters but also storage parameters changed over time. Originally, in 2011, the dam was planned to be 145 m (476 ft) high and have a volume of 10.1 million m3. The reservoir was planned to have a volume of 66 km3 (54,000,000 acre feet) and a surface area of 1,680 km2 (650 square miles) at full supply level. The rock-filled saddle dam next to the main dam was planned to be 45 m (148 ft) high, 4,800 m (15,700 ft) long and have a volume of 15 million m3. In 2013, an independent panel of experts (IPoE) evaluated the dam and its technical parameters. At that point, the reservoir had already been resized. The area of the full reservoir increased by 194 km2 (75 square miles) to reach 1,874 km2 (724 square miles). Storage at maximum supply level increased by 7 km3 (1.7 cubic meters) to 74 km3 (60,000,000 acre-feet). These numbers have remained unchanged since 2013. The 74 km3 (60,000,000 acre-feet) storage capacity represents almost all of the 84 km3 (68,000,000 acre-feet) of the Nile’s annual flow. In 2013, after IPoE made recommendations, the dam parameters were changed to account for higher discharges in case of extreme flooding: the height of the main dam is 155 m (509 ft), the height of the main dam is 10 m (33 ft); ) increase, length is 1,780 m (5,840 ft) (unchanged) Dam volume is 10.2 million cubic meters (360 x 10^6 cubic feet), an increase of 100,000 cubic meters (3,500,000 cubic feet). Outlet parameters did not change, only the crest of the main dam rose. The Iwakura Dam increased by 5 meters (16 ft) to a height of 50 m (160 ft) and increased in length by 400 meters (1,300 ft) to 5,200 m (17,100 ft). The volume of Iwakura Dam increased by 1.5 million cubic meters (53 x 10^6 cubic feet) to 16.5 million cubic meters (580 x 10^6 cubic feet). The design parameters as of August 2017 are as follows. Considering the changes outlined above:
= Two dams =
The zero level, or ground level, of the main dam is approximately 500 m (1,600 ft) above sea level, approximately the height of the Blue Nile River bed. Counting from the ground, the main gravity dam is 145 m (476 ft) high and 1,780 m (5,840 ft) long and is constructed of roller compacted concrete. The top of the dam will be 655 m (2,149 ft) above sea level. The total height of the dam is slightly higher than the given dam height because the exits of the two power plants are below the ground. In some publications, the prime contractor building the dam suggests a height of 170 m (560 ft) for the dam, which takes into account the dam’s additional depth below the surface. Possibly, which means 15 m (49 ft). Excavated from underground before filling the reservoir. The dam will have a structural volume of 10,200,000 cubic meters (13.3 million cubic meters). The main dam is located 40 kilometers (25 miles) from the border with Sudan. Supporting the main dam and reservoir is a 4.9 km (3 mi) long, 50 m (164 ft) high curved rockfill saddle dam. The ground level of the saddle dam is about 600 m (2,000 ft) above sea level. The surface of the saddle dam is asphalted to keep the inside of the dam dry. The Sadr Dam is only 2 to 2 miles (3.3 to 3.5 km) from the border with Sudan, much closer to the border than the main dam. The reservoirs behind both dams have a reservoir capacity of 74 km3 (60,000,000 acre feet) and a surface area of 1,874 km2 (724 square miles) at a full level of 640 m (2,100 ft) above sea level. The dam body is therefore 140 m (460 ft) above the ground. Hydropower occurs between the so-called minimum operating level of the reservoir, 590 m (1,940 ft), and the maximum supply level, 640 m (2,100 ft). The actual storage available for power generation between both levels will be 59.2 km3 (48 million acre-feet). The first 90 m (300 ft) of dam height is the dead height of the reservoir, giving the reservoir dead storage volume of 12,000,000 acre feet (14.8 km3).
= Three spillways =
The dam has three spillways. All (each?) use about 18,000 cubic meters of concrete. Together, these spillways are designed for floods of up to 38,500 m3/s (1,360,000 cubic feet/s), which is the so-called ‘maximum expected flood’, so such an event would not occur. It is believed that it will not happen at all. All three spillways are designed to discharge water into the Blue Nile before it enters Sudanese territory. The main gated spillway is located to the left of the main dam and is controlled by six locks with a total design discharge of 14,700 m3/s (520,000 cu ft/s). The spillway width will be 84 m (276 ft) at the outflow gate. The spillway base level is 624.9 m (2,050 ft), well below the full level. The Auxiliary Discharge Channel, an ungated spillway, is located in the center of the main dam and has an opening width of approximately 205 m (673 ft). The nominal water level for this spillway is 640 m (2,100 ft), which is exactly the high water level of the reservoir. The top of the dam rises 15 m (49 ft) to the left and right of the spillway. This ungated spillway is expected to be used only when the reservoir is full and flow rates exceed 14,700 m3/s (520,000 cu ft/s), which is exceeded once every ten years. is expected. The third spillway, the emergency spillway, is located on the right side of the curved saddle dam and has a foundation level of 642 m (2,106 ft). This emergency spillway has approximately 1,200 m (3,900 ft) of open space along its rim. This third spillway will only carry water in the event of flood conditions in excess of approximately 30,000 m3/s (1,100,000 cu ft/s). This corresponds to a flood that occurs only once in 10,000 years.
= Power generation and distribution =
There are two powerhouses on either side of the gateless auxiliary spillway at the center of the dam, equipped with two 375 MW Francis turbine generators and eleven 400 MW turbines. The total installed capacity of all turbogenerators will be 5,150 MW. The average annual discharge of the Blue Nile available for power generation is expected to be 1,547 m3/s (54,600 cu ft/s), which is expected to generate 16,153 GWh of annual electricity production, corresponding to the load factor of the power plant (or capacity factor) 28.6%. The Francis turbine in the power station is mounted vertically, 7 m (23 ft) above the ground. With projected operation between minimum operating and maximum supply levels, the available head height for the turbine will be 83 to 133 m (272 to 436 ft). The switchyards will be located near the main dams and the electricity generated will feed the national grid. Four 500 kV main transmission lines were completed in August 2017, all going to Horeta, followed by several 400 kV transmission lines to the Addis Ababa metropolitan area. Two 400 kV transmission lines run from the dam to the Veles Hydroelectric Power Station. A 500 kV high voltage DC line is also planned.
= Early power generation =
Two non-upgraded turbine generators of 375 MW were commissioned first, supplying 750 MW to the national grid. Meanwhile, the first turbine was commissioned in his February 2022 and the second in his August 2022. These two units are within a range of 10 units. Unit powerhouse to the right of the dam on the auxiliary spillway. Water is fed from two special intakes located 540 m (1,770 ft) above sea level within the dam structure. This generation started at a water level of 560 m (1,840 ft), 30 m (98 ft) below the minimum operating water level of the other 11 turbine generators. At this level, the reservoir is filled with about 5.5 km3 (1.3 cubic meters) of water, which is about 11% of the annual inflow of 48.8 km3 (11.7 cubic meters). During the rainy season, expect this to happen within days to weeks. The first stage filling of the reservoir for the early generation was completed on July 20, 2020.
= Siltation, evaporation =
Two ‘bottom’ outlets at 542 m (1,778 ft) above sea level or 42 m (138 ft) above local river bed level are designed to provide water under special circumstances, especially for downstream irrigation purposes. can be used for The reservoir level is below the minimum operating level of 590 m (1,940 ft), but also drops during the initial reservoir filling process. The space below the ‘bottom’ outlet is the primary buffer space of the alluvium due to silt and sedimentation. For the Rozelle Reservoir, immediately downstream of the GERD site, average siltation and sedimentation (without GERD installed) would be approximately 0.035 km3 (28,000 acre-feet) per year. Due to the large size of the GERD reservoir, siltation and sedimentation volumes in this case are expected to be much higher, at 0.21 km3 (170,000 acre-feet) per year. The GERD Reservoir is expected to almost completely eliminate the silt threat from the Rozelle Reservoir. The base of the GERD Dam is approximately 500 meters (1,600 feet) above sea level. The water discharged from the dam is released back into the Blue Nile, where it flows for about 30 kilometers (19 miles) and, when full, joins the Lozaire Reservoir at 490 meters (1,610 feet) above sea level. above sea level. The elevation difference between both projects is only 10 m (33 ft). The two reservoirs and associated hydropower projects, if properly coordinated across the borders of Ethiopia and Sudan, have the potential to be a cascading system for more efficient hydropower and better irrigation (especially in Sudan). there is. Water from the 140 m (460 ft) pillar of the GERD Reservoir reservoir could be diverted through tunnels to facilitate new irrigation schemes in Sudan near the border with South Sudan. In Ethiopia itself, no irrigation scheme is planned because the dam is close downstream to the Sudanese border. Evaporation of water from the reservoir is expected to be 3% of the annual inflow of 48.8 km3 (11.7 cu mi), corresponding to an average loss through evaporation of about 1.5 km3 (0.36 cu mi) per year. In IPoE this was considered negligible. For comparison, Lake Nasser in Egypt loses 10-16 km3 (2.4-3.8 cubic miles) per year to evaporation.
Construction
The prime contractor was the Italian company Webuild (formerly Salini Impregilo), which was also the prime contractor for the Gilgel Gibe II, Gilgel Gibe III and Tana Beles dams. Simegnyu Bekele served as GERD’s project manager from the start of construction in 2011 until his death on 26 July 2018. He was succeeded by Kifle Holo in October of the same year. The dam is expected to require 10 million cubic meters of concrete. The government has promised to use only domestic concrete. In March 2012, Salini signed an agreement with Italian company Tratos Cavi SPA to supply the dam with low and high voltage cables. Alstom will provide eight 375 MW Francis turbines for the first phase of the project at a cost of EUR 250 million. As of April 2013, nearly 32 percent of the project is complete. Excavation and concrete pouring were carried out at the site. One of the concrete batch plants is completed and another is under construction. The division of the Blue Nile was completed on May 28, 2013, a ceremony was held on the same day, and the work was about 70% complete in October 2019. As of March 2020, the steel mill is 35% complete, the civil engineering work is 87% complete, and the electro-mechanical work is 17% complete, for a total of 71% of construction, according to deputy project director Belashu Kasa. matter. On 26 June 2020, Egypt, Sudan and Ethiopia agreed to postpone the filling of the reservoirs for several weeks, and on 21 July 2020, Ethiopian Prime Minister Abiy Ahmed announced that the first phase of reservoir filling was completed. announced. The early landfill is thought to be due to heavy rain. “We successfully completed the first filling of the dam without disturbing or hurting anyone. The dam is now flooding downstream,” Abbey said in a statement. . In the first year, the landfill target was 4.9 cubic kilometers, but when the dam is completed it will have a storage capacity of 74 cubic kilometers. The first phase of filling the reservoir began in July 2020 and was filled to a maximum depth of 70 meters (230 feet) using the dam. Temporary threshold. Further construction work is required to fill the reservoir to a level where electricity can be generated. Phase 2 filling of the GERD Reservoir will be completed on July 19, 2021, reaching an estimated elevation level of 573 meters (1,880 feet) (midnight). Less than 4.5 km3 (1.1 cubic meters) remains at this stage. In February 2021, Ethiopia’s Water and Irrigation Minister Seresi Bekele said civil works for dam construction had reached 91%, with a total construction rate of 78.3%. . In May 2021, Water and Irrigation Minister Seresi Bekele said 80% of the dam construction was completed.
= Engineering questions =
In 2012, an international panel of experts was established bringing together experts from Egypt, Sudan, Ethiopia and other independent bodies to discuss mainly engineering and some impact-related issues. The panel concluded with a number of technical changes proposed to Ethiopia and the prime contractor for dam construction. One of the two major engineering issues, flood scale and constructive response to it, was later resolved by the contractor. The emergency diversion channel, located near the Iwakura Dam, has its rim length increased from 300m to 1,200m to accommodate the river’s largest floods. However, no immediate solution was found for the Commission’s second major recommendation. This second recommendation addressed the structural integrity of the dam in relation to the underlying bedrock to avoid the risk of dam slippage due to unstable foundations. The commission argued that the initial structural investigations did not consider special conditions such as faults or slip planes in the bedrock (gneiss), but only general bedrock. The Panel noted that there may indeed be an exposed slip plane in the rock basement that allows for downstream slip processes. The Panel did not argue that a catastrophic dam failure with the release of tens of cubic kilometers of water would be possible, likely or probable, but avoiding such a catastrophic failure argued that the margin of safety given for doing so could be unrealistic. Perfect for the Grand Ethiopian Renaissance Dam. It was later found that the foundations underlying the dam were completely different from all expectations and that the necessary excavation work had exposed the underlying gneiss, making it unsuitable for geological studies. After that, the earthwork had to be adjusted, and it had to be excavated deeper than originally planned, taking extra time and effort, and also requiring more concrete.
= Alleged over-sizing =
Initially, in 2011, the hydropower station will have 15 generating units with a nameplate capacity of 350 MW each, resulting in a total installed capacity of 5,250 MW and an annual output of 15,128 GWh. It is expected. The planned hydropower plant capacity factor (the expected output of the plant at full permanent operation divided by the potential output) is 45% higher than that of other small hydropower plants in Ethiopia. It was only 32.9% compared to ~60%. Critics concluded that a smaller dam would have been more cost-effective. Shortly thereafter, in 2012, the hydropower station was upgraded to accommodate 16 generating units with a nameplate capacity of 375 MW each, increasing the total installed capacity to 6,000 MW. Power generation has increased slightly to 15,692 GWh per year. As a result, the capacity factor decreased to 29.9%. According to Asfau Beyen, a professor of mechanical engineering at San Diego State University in California, the dam and its hydroelectric power plant are very large, and “the utilization of GERD based on the average river flow throughout the year and the height of the dam. In 2017, the total installed capacity was moved to 6,450 MW (which has since remained at 6,000 MW total), without changing the number of generating units and the nameplate capacity. This is believed to be a result of enhancements made to the generator. Projected annual power generation increased to 16,153 GWh and the capacity factor shrank again to reach 28.6%. No one publicly expressed any concerns this time. Such optimization of Francis turbines used at dam sites is indeed possible and is usually done by the turbine provider considering site-specific conditions. Considering the criticism that the power output, which may now reach 6,450 MW, is too high. Ethiopia relies heavily on hydropower, but is often affected by droughts (see, for example, the 2011 East Africa drought). The size of reservoirs used for power generation in Ethiopia is limited. For example, the Gilgel-Gibe I Reservoir, which powers both the Gilgel-Gibe I and Gilgel-Gibe II power stations, has a capacity of 0.7 km3. During drought, there is no water to generate electricity. This had a major impact on Ethiopia during the 2015-2016 drought, but it was Gilgel Gibe, a 14-square-kilometer well-filled reservoir that just started testing in 2016, that saved the Ethiopian economy. It was only the III power plant. When filled, the GERD reservoir will have a total volume of 74 km3, three times the volume of Ethiopia’s largest lake, Lake Tana. It takes 5 to 15 years to fill this water, and even with all power generation units at full capacity, it will not be empty within a few months. The combined installed power of 6.450 MW and the size of the reservoir will help manage the side effects of the upcoming severe drought that will force other hydropower plants to shut down.
Security around dam
In recent years, due to the threat of possible airstrikes on the dam, the Ethiopian government has sought and purchased several air defense systems from Russia, including the Pantir-S1 air defense system, and Israel, including the SPYDER-MR medium-range missile. An air defense system installed at the dam. Egypt tried to block the sale between Israel and Ethiopia, but Israel ignored the demands.
Benefits
The main advantage of dams is hydroelectricity. All energy generated by GERD will be channeled into Ethiopia’s national grid, fully supporting the development of the entire country in both rural and urban areas. GERD’s role is to act as a stabilizing backbone for Ethiopia’s national power grid. There will be exports, but only if the total amount of energy produced in Ethiopia is surplus. This is expected to occur mainly during the rainy season when water for hydropower is plentiful. Ultimately, GERD’s surplus electricity that does not meet Ethiopia’s domestic demand will be sold and exported to neighboring countries, including Sudan and possibly Egypt. , but also Djibouti. Exporting power from the dam will require the construction of large-scale transmission lines to major consumption areas such as Khartoum, Sudan’s capital, more than 400 kilometers from the dam. These export sales will be on top of electricity expected to be sold from other large hydropower plants. Power plants that are ready or under construction in Ethiopia, such as Gilgel Gibe III and Koisha, are exported (if any) to Kenya mainly through 500 kV HVDC transmission lines. The volume of the reservoir will be two to three times that of Lake Tana. Up to 7,000 tons of fish are expected to be harvested annually. This reservoir could become a tourist attraction. Sudan hopes the dam will reduce flooding, but it has not yet been observed.
Environmental and social impacts
The NGO International Rivers commissioned a local researcher to conduct a field study as there is little publicly available information on environmental impacts. Public consultations on Ethiopia’s dams are influenced by the domestic political situation. International Rivers said: “Conversations with civil society groups in Ethiopia show that questioning the government’s energy sector plans is extremely dangerous and there are legitimate concerns of persecution by the government. Due to this political climate, no group is actively pursuing issues surrounding hydropower.” No concerns were raised publicly about the risks in this situation and very limited and inadequate public consultations were organized during the construction of the main dam. In June 2011, Ethiopian journalist Leeyot Alem was jailed after questioning plans for the Grand Millennium Dam. International Rivers staff have received death threats. Former Prime Minister Meles Zenawi described opponents of the project as “hydro extremists” and “close to criminals” at the International Hydropower Association (IHA) conference in Addis Ababa in April 2011. called. Ethiopia’s state-owned electricity company was welcomed at the meeting. Certified as a “Sustainability Partner” by IHA.
= Impact on Ethiopia =
As the Blue Nile is a highly seasonal river, the dam would reduce flooding downstream of the dam, including a 15-kilometer stretch of water in Ethiopia. On the one hand, flood mitigation is beneficial as it protects settlements from flood damage. On the other hand, farming in the valleys downstream of dams during a flood recession could be detrimental as the fields are deprived of water. But Sudan’s next hydroregulating dam, the Rozeres Dam, lies just a few dozen kilometers downstream. The dam could also serve as a bridge across the Blue Nile, complementary to a bridge under construction further upstream in 2009. An independent assessment estimates that at least 5,110 people will be displaced from the reservoir and downstream areas, and the dam is expected to bring significant changes to fish ecology. According to independent researchers who have surveyed the area, 20,000 people have been displaced. The same source said that “a solid plan has been put in place for those who have relocated” and that those who have already relocated have “been given more compensation than expected.” Despite explaining to victims about the dam’s impact on their livelihoods at community meetings, local residents have never seen the dam before and “have no idea what the dam really is,” he said. With the exception of a few elderly people, almost all local residents interviewed said, based on available information, that the project would bring them some benefit in terms of education, health services, or electricity supply. I am looking forward to it,” he said. At least part of the new community of displaced people is downstream of the dam. The area around the reservoir will be a 5 km buffer zone for malaria control, and permanent settlement will be prohibited. Erosion control measures will be taken to reduce silting of reservoirs, at least in some upstream areas.
= Impact on Sudan and Egypt =
The exact impact of the dam on downstream countries is unknown. Egypt is concerned about temporary reductions in water availability due to overfilling of reservoirs and permanent reductions due to evaporation from reservoirs. According to the study, the main factors that influence the impact during the filling stage of the reservoir include the elevation of the initial reservoir of the Aswan High Dam, the amount of rainfall occurring during the filling period, and the negotiated arrangements among the three countries. increase. These studies also show that only through close and continuous coordination can the risk of adverse effects be minimized or eliminated. The reservoir volume (74 cubic kilometers) is about 1.5 times the average annual flow (49 cubic kilometers) of the Blue Nile on the Egyptian-Sudan border. Losses to downstream countries could span years if countries reach an agreement. Depending on the initial storage capacity of the Aswan High Dam and this filling schedule of the GERD, inflows to Egypt could be temporarily reduced, potentially impacting the livelihoods of 2 million farmers during the period of filling the reservoir. there is. It will reportedly “impact 25-40 percent on Egypt’s electricity supply during construction of the dam.” However, hydropower accounted for less than 12 percent of Egypt’s total electricity production in 2010 (14 percent of its 121 billion kWh), so a temporary 25 percent decline in hydropower production would have a negative impact on overall electricity production in Egypt. Translated into a temporary reduction in production. less than 3 percent. The Grand Ethiopian Renaissance Dam could lead to a permanent drop in Lake Nasser water levels if floodwaters were to be stored in Ethiopia. While this would reduce current evaporation by more than 10 cubic kilometers per year, it would also reduce the hydropower capacity of the Aswan High Dam, losing 100 MW of capacity if the water level drops by 3 meters. . But if the two sides can compromise, increased storage in Ethiopia could provide a greater buffer against supply shortfalls during future years of drought in Sudan and Egypt. Dams store silt. This will extend the life of Sudan’s dams, including the Roseres Dam, Sennar Dam and Merowe Dam, as well as Egypt’s Aswan High Dam. The beneficial and detrimental effects of flood control will affect the Sudan portion of the Blue Nile just as it affects the Ethiopian portion of the Blue Nile Valley downstream of the dam. Specifically, the GERD has reduced the flooding of Sudan’s Kashum River by holding the reservoir in a deep canyon in the northern Ethiopian plateau, just as the GERD has reduced the flooding of the Lozeres Dam in Ad-Damazin in the plains surrounding the reservoir. would alleviate the sexual flood. El Gilba Dam. The reservoir is located in the temperate Ethiopian highlands, is up to 140 meters deep, and evaporates significantly less than downstream reservoirs such as Egypt’s Lake Nasser, which loses 12% of its water flow to evaporation. Left in the lake for 10 months. Controlled release of water downstream from reservoirs could facilitate up to 5% increase in water supply in Egypt and possibly Sudan
