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Aswan High Dam, Arabic Al-Sadd al-ʿĀlī, rockfill dam across the Nile River, at Aswān, Egypt, completed in 1970 (and formally inaugurated in January 1971) at a cost of about $1 billion. The dam, 364 feet (111 metres) high, with a crest length of 12,562 feet (3,830 metres) and a volume of 57,940,000 cubic yards (44,300,000 cubic metres), impounds a reservoir, Lake Nasser, that has a gross capacity of 5.97 trillion cubic feet (169 billion cubic metres). Of the Nile’s total annual discharge, some 2.6 trillion cubic feet (74 billion cubic metres) of water have been allocated by treaty between Egypt and Sudan, with about 1.96 trillion cubic feet (55.5 billion cubic metres) apportioned to Egypt and the remainder to Sudan. Lake Nasser backs up the Nile about 200 miles (320 km) in Egypt and almost 100 miles (160 km) farther upstream (south) in Sudan; creation of the reservoir necessitated the costly relocation of the ancient Egyptian temple complex of Abu Simbel, which would otherwise have been submerged. Ninety thousand Egyptian fellahin (peasants) and Sudanese Nubian nomads had to be relocated. Fifty thousand Egyptians were transported to the Kawm Umbū valley, 30 miles (50 km) north of Aswān, to form a new agricultural zone called Nubaria, and most of the Sudanese were resettled around Khashm al-Qirbah, Sudan.
The Aswan High Dam yields enormous benefits to the economy of Egypt. For the first time in history, the annual Nile flood can be controlled by man. The dam impounds the floodwaters, releasing them when needed to maximize their utility on irrigated land, to water hundreds of thousands of new acres, to improve navigation both above and below Aswān, and to generate enormous amounts of electric power (the dam’s 12 turbines can generate 10 billion kilowatt-hours annually). The reservoir, which has a depth of 300 feet (90 metres) and averages 14 miles (22 km) in width, supports a fishing industry.
The Aswan High Dam has produced several negative side effects, however, chief of which is a gradual decrease in the fertility and hence the productivity of Egypt’s riverside agricultural lands. This is because of the dam’s complete control of the Nile’s annual flooding. Much of the flood and its load of rich fertilizing silt is now impounded in reservoirs and canals; the silt is thus no longer deposited by the Nile’s rising waters on farmlands. Egypt’s annual application of about 1 million tons of artificial fertilizers is an inadequate substitute for the 40 million tons of silt formerly deposited annually by the Nile flood.
Completed in 1902, with its crest raised in 1912 and 1933, an earlier dam 4 miles (6 km) downstream from the Aswan High Dam holds back about 174.2 billion cubic feet (4.9 billion cubic metres) of water from the tail of the Nile flood in the late autumn. Once one of the largest dams in the world, it is 7,027 feet (2,142 metres) long and is pierced by 180 sluices that formerly passed the whole Nile flood, with its heavy load of silt.
After 11 years of construction, the Aswan High Dam across the Nile River in Egypt is completed on July 21, 1970. More than two miles long at its crest, the massive $1 billion dam ended the cycle of flood and drought in the Nile River region, and exploited a tremendous source of renewable energy, but had a controversial environmental impact.
A dam was completed at Aswan, 500 miles south of Cairo, in 1902. The first Aswan dam provided valuable irrigation during droughts but could not hold back the annual flood of the mighty Nile River. In the 1950s, Egyptian leader Gamal Abdel Nasser envisioned building a new dam across the Nile, one large enough to end flooding and bring electric power to every corner of Egypt. He won United States and British financial backing, but in July 1956 both nations canceled the offer after learning of a secret Egyptian arms agreement with the USSR. In response, Nasser nationalized the British and French-owned Suez Canal, intending to use tolls to pay for his High Dam project. This act precipitated the Suez Canal Crisis, in which Israel, Britain, and France attacked Egypt in a joint military operation. The Suez Canal was occupied, but Soviet, U.S., and U.N. forced Israel, Britain, and France to withdraw, and the Suez Canal was left in Egyptian hands in 1957.
Soviet loans and proceeds from Suez Canal tolls allowed Nasser to begin work on the Aswan High Dam in 1960. Some 57 million cubic yards of earth and rock were used to build the dam, which has a mass 16 times that of the Great Pyramid at Giza. On July 21, 1970, the ambitious project was completed. President Nasser died of a heart attack in September 1970, before the dam was formally dedicated in 1971.
The giant reservoir created by the dam–300 miles long and 10 miles wide–was named Lake Nasser in his honor. The formation of Lake Nasser required the resettlement of 90,000 Egyptian peasants and Sudanese Nubian nomads, as well as the costly relocation of the ancient Egyptian temple complex of Abu Simbel, built in the 13th century B.C.
The Aswan High Dam brought the Nile’s devastating floods to an end, reclaimed more than 100,000 acres of desert land for cultivation, and made additional crops possible on some 800,000 other acres. The dam’s 12 giant Soviet-built turbines produce as much as 10 billion kilowatt-hours annually, providing a tremendous boost to the Egyptian economy and introducing 20th-century life into many villages. The water stored in Lake Nasser, several trillion cubic feet, is shared by Egypt and the Sudan and was crucial during the African drought years of 1984 to 1988.
Despite its successes, the Aswan High Dam has produced several negative side effects. Most costly is the gradual decrease in the fertility of agricultural lands in the Nile delta, which used to benefit from the millions of tons of silt deposited annually by the Nile floods. Another detriment to humans has been the spread of the disease schistosomiasis by snails that live in the irrigation system created by the dam. The reduction of waterborne nutrients flowing into the Mediterranean is suspected to be the cause of a decline in anchovy populations in the eastern Mediterranean. The end of flooding has sharply reduced the number of fish in the Nile, many of which were migratory. Lake Nasser, however, has been stocked with fish, and many species, including perch, thrive there.
Aswan High Dam is a rock-fill dam located at the northern border between Egypt and Sudan.
The dam is fed by the River Nile and the reservoir forms Lake Nasser.
Construction for the project began in 1960 and was completed in 1968. It was officially inaugurated in 1971.
The total investment for constructing the dam reached $1bn.
With a reservoir capacity of 132km³, the Aswan High Dam provides water for around 33,600km² of irrigation land. It serves the irrigation needs of both Egypt and Sudan, controls flooding, generates power, and helps in improving navigation across the Nile.
Egypt and Sudan reached an agreement in 1959 that saw the allocation of 18.5 cubic kilometres of water to Sudan.
History of the Aswan High Dam“Institute Hydroproject of Russia, in collaboration with various engineers from Egypt, designed the Aswan High rock-fill dam.”The Aswan Low Dam was constructed in 1898 under the direction of Sir William Willcocks. The dam was completed in 1902 and was raised twice between 1907 and 1912, followed by a further two between 1929 and 1933 to further alleviate the Nile from flooding.
However, the Aswan Low Dam was not adequate to control the annual flooding, which gave rise to the idea of constructing a higher dam in 1952, with funding from the World Bank being sought in 1954.
The US and the UK had previously tried to fund part of the project but it did not materialise. The US withdrew the funding, followed by the UK and the World Bank. The Soviet Union finally provided the required funds in 1958. Construction of Aswan High Dam began in 1960.
Purpose and benefits of the North African projectThe dam was constructed to regulate the flow of the river, which serves the whole of Egypt.
Flooding of the Nile occurs annually, with almost half of the water being drained into the sea wastefully. The dam controls floods by regulating the flow of river and supplies water for irrigation throughout the year, which almost doubles the agricultural yield.
The dam also improved navigation across the Nile, benefiting the tourism and fishing industries. Water from the dam is used to feed 12 power turbines, which provides half of Egypt’s power demands. The reservoir also helps supply water during droughts.
Details of the rock-fill dam projectAswan High Dam measures 111m in height, 3,830m in length, and has a base width of 980m. The spillway has a discharge capacity of 11,000m³ a second.
“The dam was constructed with the aim of regulating the flow of the River Nile, which serves as a lifeline to almost all of Egypt.”An array of rocks, cement, and metals creates the reservoir of the dam measuring 550km in length and 35km in width. With its surface area of 5,250 square kilometres, elevation of 183m, and depth of 185m, the reservoir has a storage capacity of 132 cubic kilometres.
The dam consists of 180 sluice gates to regulate the flow of water to achieve flood control. It also has 12 Francis turbines, with an installed capacity of 2,100MW to supply electricity for industrial and household use.
The dam’s construction required some 44 million cubic metres of building materials and a workforce of about 34,000 people.
Controversies surrounding Aswan High DamRelated projectNile River Barrage, Naga Hammadi, EgyptThe barrage is of crucial importance to the development of the Nile Valley water supply infrastructure.
Aswan High Dam had been controversial right from its inception. The project was hit by financial controversies before its implementation when the US, the UK, and the World Bank backed out from their decision of partially funding the project.
It created tension between various countries and contributed to the Cold War, when Egypt decided to fund the project by nationalising the Suez Canal. The project came through after the then Soviet Union funded part of the project.
The dam also witnessed various oppositions due to environmental issues. The River Nile was the main source of providing silts required for irrigation along the course of the river. Issues concerning aquatic life were also raised.
The dam’s site also submerged certain historical sites and caused the relocation of about 100,000 inhabitants.
Key players involved with the African damIn collaboration with various engineers from Egypt, the Institute Hydroproject of Russia designed the Aswan High rock-fill dam. Out of the 34,000 people involved during the construction process, 25,000 were Egyptian engineers. The construction project involved Osman Ahmed Osman.
he Aswan Dam, located in Aswan, Egypt, tames the Nile River and utilizes the power of the river for a variety of social and economic causes. There are actually two dams on the Nile River at Aswan, the Aswan High Dam and the Aswan Low Dam, both of which work together to prevent the annual large floods from the Nile. Prior to the building of the Aswan Dam, the Nile flooded every winter, potentially destroying any crops that were planted in the fertile Nile Valley. For the purpose of this article the two Aswan Dams will be counted as a single dam, due to the fact that their effects are virtually inseparable.Contents1 Description2 History3 Environmental and cultural issues4 Notes5 References6 External links7 CreditsDescription
Aswan High Dam (NASA satellite photo)The Aswan Dam is a rock fill dam, a type of dam that relies on compacted dirt for its stability. Unlike a traditional cement dam, a rock fill dam relies on the friction between small particles of stone and dirt to maintain its stability. Rock fill dams also need to be placed in a solid bedrock of rock for stability.
The traditional elements of a rock fill dam, stone and clay, are the main material elements of the Aswan Dam. The towering edifice extends 111 meters from the ground, to hold back an astonishing 5.97 trillion cubic feet of water. The water that is held back by the Aswan Dam forms the Lake Nasser, a major source for water in the area. The water that is held back by the dam rushes into the reservoir at a maximum of 11,000 m³ of water per second. To allow for the possibility that heavy rainfall could push the maximum flow of the dam, a series of emergency spillways have been built around the dam to safely process an additional 5,000 m³ per second.
Most of the water that enters into Lake Nasser is slated for agricultural causes, as the area experiences very little annual rainfall. The water from the reservoir is applied to crops on the field through an extensive irrigation system, a system that allows two crops a year to be produced. This is a significant change from traditional farming methods that rely on natural precipitation. When utilizing natural precipitation as the sole source of agricultural water, only one crop a year can be produced. When using artificial irrigation, the crop yield of the area can be doubled, which enhances the economy of the region. Approximately 8 million feddans (a unit of measurement roughly equivalent to an acre) receive water from Lake Nasser for irrigation purposes. The agricultural yield of the dam is about an 83 percent efficiency, which while not high on first glance, is considerably higher than many other dams built around the world for the same purposes.One flaw in the system of water distribution, however, is the flow of water down the series of branch canals. Many feel that the water flow down the branch canals is not equally distributed.[1]
The irrigation aims of the Aswan Dam are often complicated by the chemical composition of the water flowing down the Nile River. The water that reaches the dam has a saline composition of approximately 0.25 kg/m3, a composition commonly referred to as "sweet water." The levels of salt in the Nile water have allowed for another industry to develop around the Aswan dam: That of salt exportation. Through a series of extraction methods, the Egyptian government has been able to export a large amount of salt to the world markets. In 1995, the levels of salt exportation from Egypt were higher than the levels of salt imported, an unusual occurrence for the Egyptian economy. At this time, over 27 million tons of salt are exported from Egypt, much of which derives from the Aswan Dam.
A closeup view of the Soviet-Egyptian friendship monumentThe Nile River has been a focus of engineering interest since the later nineteenth century. It had long been thought that a dam in the area would prove highly beneficial for the neighboring communities and agricultural lands. To this end, British engineers began work on the first Aswan Dam in 1899. Construction continued for three years, but the final product proved to be inadequate for the strong currents of the Nile. In response to the failures of the original dam, the height of the Aswan Dam was raised in 1907, and again in 1929. The two lengthy attempts to raise the height of the dam still proved insufficient to contain the river's flow. The dam nearly overflowed in 1946, prompting the authorities to reconsider the future of the old dam. Rather than simply add to the height of the dam, as had been attempted in the past, the Egyptian authorities decided to built a second dam farther down the river. Construction on the second dam began after the Egyptian Revolution of 1952, when Gamal Abdel Nasser gained political control of the country. The second dam was originally intended to be a joint effort between Egypt, the United States, and Great Britain, but the foreign backers pulled the funding before construction began.
Without the promised funding from the United States and Great Britain, Egypt was left unable to fully fund the ambitious building project. Recognizing the need for monetary funds, the Soviet Union offered to provide some of the needed funding to gain a foothold in Africa during the Cold War. Most historians agree that the Soviet funding of the Aswan Dam was related more towards an attempt to gain a long term foothold in the area, rather than an attempt to gain economically. For the construction, the Soviet Union provided technicians and large machinery, as well as funds. Construction on the second dam lasted for twenty years, from 1950 to 1970. In an unexpected construction method, the reservoir was allowed to fill with water before construction was officially completed. However, in light of the endemic dryness in the region, the attempt to gather as much water as possible can be easily understood.Environmental and cultural issues
A wall commemorating the completion of Aswan High DamThe main benefit of the Aswan Dam is its ability to control the annual flooding of the Nile River. Because of its ability to prevent the annual floods, the dam has helped the agricultural industries in the area. The dam has also provided much needed water for irrigation, as well as producing electricity from the hydroelectric output of the river. The dams helped Egypt to reach its highest ever level of electric production, granting many small villages the luxury of using electricity for the first time.
Despite the benefits of the Aswan Dam, blocking the flow of the Nile River has caused a few environmental concerns that need to be weighed against the economic benefits. First, the creation of Lake Nasser flooded a large part of Nubia, forcing 90,000 people to lose their homes and their homeland. During the initial floodings, it was found that Lake Nasser destroyed many rich archaeological sites, which could have benefited the study of the cultures and history of the area.
Another set of environmental issues revolves around the agricultural lands that the dam was expected to benefit. Instead of feeling the full benefits of the dam, some agricultural fields have become waterlogged as a result of silt deposits that build up in the reservoir. Other fields have been slowly eroded, particularly of coastline. In addition, the delta has lost much of its acclaimed fertility, due to the fact that the Nile River no longer carries nutrients all the way to the mouth of the river.
Just north of the border between Egypt and Sudan lies the Aswan High Dam, a huge rockfill dam which captures the world's longest river, the Nile River, in the world's third-largest reservoir, Lake Nasser. The dam, known as Saad el Aali in Arabic, was completed in 1970 after ten years of work.
Egypt has always depended on the water of the Nile River. The two main tributaries of the Nile River are the White Nile and the Blue Nile. The sources of the White Nile are the Sobat River and Bahr al-Jabal (the "Mountain Nile"), and the Blue Nile begins in the Ethiopian Highlands. The two tributaries converge in Khartoum, the capital of Sudan, where they form the Nile River. The Nile River has a total length of 4,160 miles (6,695 kilometers) from source to sea.
Nile FloodingBefore the building of a dam at Aswan, Egypt experienced annual floods from the Nile River that deposited four million tons of nutrient-rich sediment which enabled agricultural production. This process began millions of years before Egyptian civilization began in the Nile River valley and continued until the first dam at Aswan was built in 1889. This dam was insufficient to hold back the water of the Nile and was subsequently raised in 1912 and 1933. In 1946, the true danger was revealed when the water in the reservoir peaked near the top of the dam.
In 1952, the interim Revolutionary Council government of Egypt decided to build a High Dam at Aswan, about four miles upstream of the old dam. In 1954, Egypt requested loans from the World Bank to help pay for the cost of the dam (which eventually added up to one billion dollars). Initially, the United States agreed to loan Egypt money but then withdrew their offer for unknown reasons. Some speculate that it may have been due to Egyptian and Israeli conflict. The United Kingdom, France, and Israel had invaded Egypt in 1956, soon after Egypt nationalized the Suez Canal to help pay for the dam.
The Soviet Union offered to help and Egypt accepted. The Soviet Union's support was not unconditional, however. Along with the money, they also sent military advisers and other workers to help enhance Egyptian-Soviet ties and relations.
Building of the Aswan DamIn order to build the Aswan Dam, both people and artifacts had to be moved. Over 90,000 Nubians had to be relocated. Those who had been living in Egypt were moved about 28 miles (45 km) away, but the Sudanese Nubians were relocated 370 miles (600 km) from their homes. The government was also forced to develop one of the largest Abu Simel temples and dig for artifacts before the future lake would drown the land of the Nubians.
After years of construction (the material in the dam is the equivalent to 17 of the great pyramids at Giza), the resulting reservoir was named after the former president of Egypt, Gamal Abdel Nasser, who died in 1970. The lake holds 137 million acre-feet of water (169 billion cubic meters). About 17 percent of the lake is in Sudan and the two countries have an agreement for distribution of the water.
Aswan Dam Benefits and ProblemsThe Aswan Dam benefits Egypt by controlling the annual floods on the Nile River and prevents the damage which used to occur along the floodplain. The Aswan High Dam provides about half of Egypt's power supply and has improved navigation along the river by keeping the water flow consistent.
There are several problems associated with the dam as well. Seepage and evaporation account for a loss of about 12-14% of the annual input into the reservoir. The sediments of the Nile River, as with all river and dam systems, has been filling the reservoir and thus decreasing its storage capacity. This has also resulted in problems downstream.
Farmers have been forced to use about a million tons of artificial fertilizer as a substitute for the nutrients which no longer fill the floodplain. Further downstream, the Nile delta is having problems due to the lack of sediment as well since there is no additional agglomeration of sediment to keep erosion of the delta at bay, so it slowly shrinks. Even the shrimp catch in the Mediterranean Sea has decreased due to the change in water flow.
Poor drainage of the newly irrigated lands has led to saturation and increased salinity. Over one-half of Egypt's farmland in now rated medium to poor soils.
The parasitic disease schistosomiasis has been associated with the stagnant water of the fields and the reservoir. Some studies indicate that the number of individuals affected has increased since the opening of the Aswan Dam.
The Nile River and now the Aswan High Dam are Egypt's lifeline. About 95% of Egypt's population live within twelve miles from the river. Were it not for the river and its sediment, the grand civilization of ancient Egypt probably would have never existed.
EgyptAfricaPower TrendsFor more about the terms or data used here, search the Glossary, learn All About Icons, or check out our FAQs. Information on plant specifics can be found here. If you use the data, please see our citation policy.
Tons CO2 MWh Energy Intensity2004: 0 10,042,000 02009: 0 7,393,700 0Future: 0 7,393,700 0Top Power Producing Plants in the RegionHighest CO2 Emitting Plants in the RegionSee MoreShow Past & FutureTons CO2 MWh Energy Intensity ABU SIMBULAfricaEgyptMuḩāfaz̧at AswānAbū Sunbul2009: 14,280 13,722 1,040 ASWANAfricaEgyptMuḩāfaz̧at AswānAswan2009: 0 4,074,000 0 ASWAN HIGH DAMAfricaEgyptMuḩāfaz̧at AswānAswan2009: 0 7,393,700 0 AWLAD EL SHEIKH (Planned)AfricaEgyptMuḩāfaz̧at Aswān2009: 0 0 0 EDFU SUGAR PLANT (Planned)AfricaEgyptMuḩāfaz̧at AswānEdfu2009: 0 0 0Similar Power Plant RatingsCO2 EmissionsEnergy OutputIntensityShow Past & FutureBlogCARMA Notes: Future DataOctober 15, 2012 - One of CARMA's rather unique features is the inclusion of data about the future. The v3.0 data contains entries for year 2004, year 2009, and the “Future”. All three points in time are displayed on any of the detail pages at (for example: Many CARMA users are interested in information about future developments in their area. Where are plants being constructed or planned? Where are existing plants being expanded? Which companies are likely to see their emissions rise the most? A proprietary, commercial database underpinning CARMA provides information that can help answer these questions.
First, a word of caution: The underlying database that provides information about future developments is only as good as the state of public information around the world; it reports what companies and plant builders have actually divulged. In some cases, the reported plans may be concrete and comprehensive. In other cases, they may be tentative and incomplete. There is no way of knowing which is which. In short, the “Future” figures in CARMA must be interpreted with caution. I want to briefly show some examples of how to (and how not to) use this information.
Let's consider individual plants. The simplest “Future” case is the construction of a new power plant. Such plants are included in CARMA with the signifier “(Planned)” appended to the plant name: We can see that this plant was not in operation in 2004 or 2009, but data are included for the “Future” period. “Future” refers to any point in time after 2009. So, a planned facility might have entered commercial operation last year – or it may not go into commercial operation for a decade or more. Information about start dates is sometimes included in CARMA's input data, but (unfortunately) cannot be released to the public due to proprietary data restrictions.
In the case of a planned plant, the “Future” data are simply a model estimate of plant performance once commercial operation begins, based on engineering specifications. The best way to search for planned plants via the website is to use the Dig Deeper tool and sort a given locale's power plants using the “Future” radio button on the right side.
In some cases, future plans include capacity expansions at an existing facility. The Taichung plant in Taiwan is a case in point. We can see that electricity generation and CO2 emissions jump up in the “Future” period compared to 2009. If a plant shows no change in data between 2009 and the Future, that is indicative of no planned capacity expansions (or retirements). If the two sets of data are different, then some planned change(s) is expected, though the date(s) of the change is uncertain. The “Future” data are, again, a model estimate of how the plant might operate after the alterations are completed.
“Future” data are also available for geographic regions and countries, though they should be treated carefully. In both cases, the figures simply report aggregated “Future” electricity production and emissions from all associated power plants. We do not know if the “Future” totals reflect plants planned for operation in the next 5 years or 20 years. Nor do we know if the reported future plans are exhaustive or a small sample of what will actually occur. Looking at the totals for Uttar Pradesh state in India, for example, we see that “Future” CO2 emissions are significantly higher than 2009 emissions. But whether this increase occurs by 2015 or 2025 – and whether actual emissions go even higher – is impossible to tell from CARMA's data alone.
Overall, CARMA's “Future” data is most helpful in revealing planned power plants that were not in operation as of 2009 (“new builds”) and a reasonable estimate of their likely electricity production and CO2 emissions. The “Future” data can also be used to identify the likely effects of capacity expansion (or retirement) at existing facilities by comparing the 2009 and “Future” data. The “Future” data are far less helpful when looking at region and company totals. In those cases, uncertainty about the timing and comprehensiveness of future plans make the totals difficult to reliably interpret. Users should be aware of these limitations and recognize that “Future” data reported by CARMA are by no means exhaustive projections or predictions.
Posted by: Kevin UmmelComments: Digg Technorati StumbleUponTags: CARMA FeaturesCARMA Notes: Corporate DataOctober 10, 2012 - As in previous releases, CARMA v3.0 includes information about the electricity production and emissions of corporate entities involved in power generation. Every plant in the CARMA database is assigned to a company. The vast majority of that information comes from a proprietary, commercial database underpinning CARMA. In some cases, corporate ownership of U.S. plants is also provided by data from the Department of Energy.
Power plant ownership is quite complicated, and there are often multiple layers of ownership between the immediate plant operator and the ultimate owner. CARMA attempts to report the ultimate owner whenever possible (i.e. the highest entity in the corporate hierarchy), relying largely on information from a private data supplier. When the parent company cannot be identified for a plant, the operating company (often a utility) is reported instead.
It must be stressed that maintaining accurate corporate information is extremely challenging. CARMA's data suppliers are the best in the business, but even they cannot guarantee accuracy, especially outside North America where corporate hierarchies are less evident. There is also the problem that many large facilities are owned by multiple entities and it is not possible to track ownership shares worldwide. For all these reasons, the company data in CARMA should be considered a reasonable “best guess” of the primary entity ultimately responsible for ownership or operation of the plant.
For example, the generating units at the Scherer Plant in Juliette, Georgia (the largest CO2 emitter in the U.S.) are jointly owned to varying degrees by seven different corporate entities. Based on this information, one could reasonably consider Oglethorpe Power Corporation to be the primary owner. On the other hand, the plant is actually operated on a day-to-day basis by Georgia Power (also part owner), which is, in turn, a subsidiary of Southern Company – as is Gulf Power, also part owner of the plant. CARMA's data suppliers, and hence the CARMA database, report the parent company as Southern Company. I use this example to illustrate the potential complexity of ownership arrangements and dispense the necessary “grain of salt”. To be fair, this is an especially complex case.
Although electricity and emissions data are available for multiple points in time (e.g. 2004, 2009, and the “Future”), the company assigned to each plant is based upon the most recent information available. For example, the CARMA v3.0 release in July, 2012 uses corporate ownership data thought to be current as of March, 2012. Notice that this makes company totals for earlier points in time (e.g. 2004 and 2009) possibly subject to error, since ownership could have been different at that time. The 2004 company totals for Southern Company, for example, are the aggregate 2004 electricity production and emissions of plants that Southern Company is currently listed as owning (not the plants they actually owned as of 2004). In general, the 2009 company totals are more likely to be accurate than 2004, especially in developing country power markets where changes are occurring rapidly.
CARMA also assigns a “Parent Country” to each company in the database. At present, this is based solely on an analysis of where the plurality of the company's associated generating capacity is located. In the vast majority of cases, this yields an accurate result. If you come across exceptions, please contact me so I can rectify for future releases.
Finally, it is worth reiterating that CARMA's company totals simply reflect emissions from associated power plants. Occasionally, one will find companies that have both power plants and other business activities. For example, major oil and gas companies like BP often own generators, and their operation is reflected as best as possible in CARMA's company totals. But these figures do not reflect the full extent of CO2 or other greenhouse gas emissions from BP's wider activities (drilling, refineries, pipelines, etc.).
Posted by: Kevin UmmelComments: Digg Technorati StumbleUponTags: CARMA FeaturesCARMA Notes: Geographic DataOctober 8, 2012 - CARMA v3.0 greatly improves both and scope and quality of geographic information provided for individual power plants.
Basic information like country, state/province, and city comes from a proprietary, commercial database of global power plants. Similar data is provided for U.S. facilities by the Department of Energy (DoE). This raw data is processed with an algorithm that cleans and standardizes the data and conducts a “fuzzy string” match against the open-source GeoNames place names database. The algorithm attempts to extract maximum geographic information; in some cases, it is able to add information not found in the raw data. I believe this makes CARMA v3.0 probably the most extensive public geocoding of global power plants to date.
CARMA's geocoding algorithm attempts to return the continent, country, state/province, county/district, city, and postal code for each plant. Data coverage is universal for continent and country and nearly so (>95%) for state/province. A further 80% of plants have been assigned a city, 40% a county/district (i.e. secondary region), and ~16% a unique postal code.
CARMA users are often interested in pin-pointing the location of facilities, usually for the purposes of modeling pollutant dispersal or making high-quality maps. This requires specific geographic coordinates. Coordinate data from the DoE and EPA are used to provide high-resolution coordinates for all plants in the U.S. Outside the U.S., the same datasets that disclose emissions or power generation sometimes report coordinates, too. In addition, many large facilities have been manually geocoded using public sources (usually Wikipedia). All told, 12% of facilities responsible for about about 40% of current electricity and emissions are assigned high-resolution coordinates.
When high-resolution coordinates are not available, CARMA v3.0 provides the coordinates for the associated city center, as given by GeoNames. An additional 70% of plants are assigned these approximate coordinates. Comparison of approximate and precise coordinates for plants with both suggest that the approximate coordinates have an average spatial error of about 7 km. When downloading a .csv file from, a variable called “crd” is included to indicate if the given coordinates are approximate (crd=1) or precise (crd=2).
The CARMA website reports aggregate totals for the geographic entities previously mentioned, as well as counties, congressional districts, and metro areas for the U.S. The definition of a “metro area” has changed in v3.0 and now reflect the borders of “combined statistical areas”, as determined by the OMB. For users of CARMA's API, it is important to note that all regions in CARMA v3.0 (excluding congressional districts and metro areas) now have unique, permanent identifiers that match those used by GeoNames. For example, the Australian state of New South Wales has region_id=2155400 (specified in the URL), which matches that used by the GeoNames API. This allows the two databases to be easily linked, if desired.
The regional totals provided in CARMA v3.0 are simply the aggregate electricity production and emissions of all geocoded facilities within the borders of the region in question. The one exception is cities. The city totals (for example, Madrid) are the aggregate of all plants with precise or approximate coordinates within 100 km (~60 miles) of the city center. CARMA v3.0 provides such totals for capital cities and those with population greater than 50,000 – more than 13,000 cities worldwide. It's also worth noting that CARMA's algorithms attempt to ensure accurate country totals for electricity generation and, for most countries, CO2 emissions. National totals from the DoE and International Energy Agency are used. There may be discrepancies in some cases. If you notice any, please let me know.Posted by: Kevin UmmelComments: Digg Technorati StumbleUponTags: CARMA FeaturesCARMA Notes: Data AccuracyOctober 4, 2012 - Although CARMA incorporates all known major public disclosure databases, the majority of the site's data is necessarily estimated using statistical models. This will hopefully change in the future as governments and companies become more open about the source of global warming pollution, but for now estimates are unavoidable. So, how accurate are CARMA's model estimates?
This question is addressed in detail in a technical paper describing the CARMA methodology and results. Here I want to share some of the main findings and highlight important caveats related to use of the data.
As detailed elsewhere, CARMA's models are fit to a high-resolution dataset of U.S. plant performance. The models then predict the electricity production and CO2 emissions of plants outside the U.S. for which publicly disclosed data is not available. As part of the CARMA technical paper, an analysis was undertaken to estimate the likely accuracy of the model output. Overall, the models do a better job of predicting the carbon intensity of a given plant (kg CO2 per MWh) and have more difficulty accuracy predicting total electricity generation. For example, it is estimated that, for CO2-emitting plants with estimated values, CARMA reports CO2 intensity that is within 20% of the true value about 60% of the time. But for electricity generation, the reported value is within 20% of the true value only about 40% of the time.
Why is predicting the amount of electricity generated by a given plant in a given year so difficult? The short answer is that utilization of many plants jumps around from year to year (i.e. high inter-annual variability) for reasons that cannot be easily observed or modeled. For example, the CARMA technical paper analyzes how annual generation changed between 2009 and 2010 for ~5,000 U.S. power plants that showed no change in engineering characteristics. Nearly 50% of the plants saw annual generation change at least 20% between 2009 and 2010 and about 30% saw a change of at least 40%. Remember, the variables that CARMA's models are able to use have not changed for these plants – but generation is still jumping around from year-to-year. This variability makes it fundamentally difficult to detect clear patterns or “rules” that the models can use to precisely predict performance when public data is not available.
When we consider these difficulties, the CARMA models are actually performing reasonably well. For example, an “ideal” model, given the range of variables available to CARMA and accounting for inter-annual variability, would likely predict annual generation to within 20% of the true value in about 55% of cases. The evidence suggests that the CARMA v3.0 models currently achieve that level of accuracy for slightly more than 40% of plants. And whereas an ideal model could be expected to be within 40% of the true value for about 70% of plants, CARMA does so in more than 60% of cases. Overall, that's pretty decent model performance.
It's also clear that accuracy depends on the type of power plant in question. In general, larger plants are easier to predict than smaller ones. And coal power plants – owing to their predominant and more consistent use as base-load electricity providers – exhibit greater model accuracy than other fuel types. Conversely, smaller and/or gas- or oil-based units are likely to see higher prediction errors. Hydroelectric power plants are a mixed bag since performance in any given year is highly dependent on local weather conditions that are not observed by CARMA's models.
On the plus side, CARMA's estimates can be fairly interpreted as reasonable long-term performance metrics. CARMA's models show no evidence of systematic bias, so while estimates for any particular year may exhibit significant error, the long-term performance of most plants is likely consistent with the model predictions. This is especially true of larger plants. Measures of typical, long-term performance for larger facilities (existing and planned) are, perhaps, the most relevant information for many real-world applications of CARMA. In addition, prediction of CO2 intensity – an equally useful metric for many CARMA users - is shown to be quite feasible and exhibits relatively low error.
Posted by: Kevin UmmelComments: Digg Technorati StumbleUponTags: CARMA FeaturesCARMA Notes: MethodologyOctober 2, 2012 - Perhaps the most common question from CARMA users is: “Where do the figures on the site come from?” There is a brief answer to this question in the site's FAQ section. A detailed CARMA v3.0 technical paper provides a complete answer to that question. This blog post aims to provide something in-between: sufficient detail for the average user, but not too much.
In an ideal world, the electricity generation, CO2 emissions, location, and ownership of the world's power plants would be regularly published by the appropriate national authorities. Of course, this is not the case. In fact, for the vast majority of countries it is difficult (if not impossible) to find any comprehensive, public information about state of power generators, never mind their environmental impact.
At present, only about 10% of the world's CO2-emitting power plants regularly disclose CO2 emissions through public databases. These plants are limited to the United States, European Union, Canada, India, and South Africa. Collectively, these databases disclose the specific source of about 35% of global power sector CO2 emissions. A database maintained by the International Atomic Energy Agency also discloses the electricity production of nuclear power plants worldwide. Some databases, like in the U.S., India, and South Africa, report both electricity generation and emissions. Others report only emissions. Some have corporate data, some do not. Some report the location of plants, some do not. Some are exhaustive (covering all facilities in their jurisdiction), some are not. Outside of these sources, information about plant-specific performance is fragmented, privately-held, or non-existent. In short, it's kind of a mess.
CARMA's basic task is to consolidate the public data that is made available and come up with reasonable estimates for the rest. A private, commercial database maintained by Platts, Inc. provides valuable information about the location, engineering, fuel type, and ownership of effectively all of the world's generating units (though it reveals nothing about actual generation or emissions). This database provides a basis for knowing which plants are reported publicly and which are undisclosed and in need of estimates. It also provides variables that can be used to predict the performance of a given plant.
Electricity generation and emissions for undisclosed plants are estimated using statistical models. The U.S. Department of Energy and Environmental Protection Agency publish detailed information about almost all power plants in the U.S. It is possible to process this data to determine what is happening at individual units in particular months. From this data, CARMA constructs a large, detailed dataset of unit-level, monthly performance at U.S. facilities (electricity generation, CO2 emissions, fuel type and consumption, etc.). This dataset is used to fit statistical models that predict how much electricity or CO2 a plant is likely to produce given its size, age, the various technologies and fuels in use, the nature of the electricity grid, etc. The resulting models are then applied to the global database provided by Platts, Inc. to derive estimated performance for power plants that lack publicly disclosed data.
Obviously, there are limitations to this approach. For example, it assumes that the experience and performance of U.S. power plants is similar to those in any other country (controlling, of course, for the various fuel and engineering characteristics that can be observed). The biggest challenge, though, is that utilization rates for plants across time are highly variable. This makes it difficult to accurately estimate the emissions of a given plant in a given year. While CARMA will always have difficulty precisely predicting the performance of a given plant in a given year, it does do a a few things well:
First, and most obviously, it consolidates the high-quality information that is available. This is not a trivial task given that each national disclosure database has its own particular format, standards, and (annoying) idiosyncrasies. And the national databases alone do not provide all the desired data points, which means they must be painstakingly matched against the Platts, Inc. database (and others) to extract the full suite of required information.
Second, even when disclosed data is unavailable, CARMA's statistical models do a decent job of estimating the amount of CO2 a given plant emits for each MWh of electricity produced (called “Intensity” on the site and given units of kgCO2/MWh). In some ways, the carbon intensity is the most important metric, since it allows us to identify those power plants that are the greatest relative threat in terms of climate change.
Third, even if CARMA's models cannot precisely estimate total electricity generation or emissions for a given plant and year, the model output is likely to be indicative of the long-term performance of a plant. In other words, CARMA's models still do a reasonable job of identifying a plant's typical or average emissions over a longer period, even if the performance for any given year is over- or under-estimated.
Ultimately, CARMA is a mix of the ideal (disclosed data) and the imperfect (estimated data). The hope is that, over time, better disclosure efforts will tip the balance in favor of the former. Users interested in the U.S. will be happy to know that CARMA's U.S. power plant data come from the DoE and EPA and can be considered high-quality. For facilities outside the U.S., it is possible to check the disclosure status of a given plant by downloading the associated .csv file from the site and finding the “dis” variable in the output. This variable indicates one of the following situations:
dis=0: No data disclosed
dis=1: Electricity generation disclosed
dis=2: CO2 emissions disclosed
dis=3: Electricity generation and CO2 emissions disclosedPosted by: Kevin UmmelComments: Digg Technorati StumbleUponTags: CARMA FeaturesBlog Archive
The Aswan Dam, or more specifically since the 1960s, the Aswan High Dam, is the world's largest embankment dam built across the Nile in Aswan, Egypt, between 1960 and 1970. Its significance largely eclipsed the previous Aswan Low Dam initially completed in 1902 downstream. Based on the success of the Low Dam, then at its maximum utilization, construction of the High Dam became a key objective of the government following the Egyptian Revolution of 1952; with its ability to better control flooding, provide increased water storage for irrigation and generate hydroelectricity the dam was seen as pivotal to Egypt's planned industrialization. Like the earlier implementation, the High Dam has had a significant effect on the economy and culture of Egypt.
Before the High Dam was built, even with the old dam in place, the annual flooding of the Nile during late summer had continued to pass largely unimpeded down the valley from its East African drainage basin. These floods brought high water with natural nutrients and minerals that annually enriched the fertile soil along its floodplain and delta; this predictability had made the Nile valley ideal for farming since ancient times. However, this natural flooding varied, since high-water years could destroy the whole crop, while low-water years could create widespread drought and associated famine. Both these events had continued to occur periodically. As Egypt's population grew and technology increased, both a desire and the ability developed to completely control the flooding, and thus both protect and support farmland and its economically important cotton crop. With the greatly increased reservoir storage provided by the High Aswan Dam, the floods could be controlled and the water could be stored for later release over multiple years.
The Aswan Dam was designed by the Moscow-based Hydroproject Institute.[2]Contents1 Construction history1.1 Aswan Low Dam, 1898–19021.2 Aswan High Dam prelude, 1954–19591.3 Construction and filling, 1960–19762 Specifications3 Irrigation scheme4 Effects4.1 Drought protection, agricultural production and employment4.2 Electricity production4.3 Resettlement and Compensations4.4 Archaeological sites4.5 Loss of sediments4.6 Waterlogging and increase in soil salinity4.7 Health4.8 Other effects5 See also6 References7 External linksConstruction historyThe earliest recorded attempt to build a dam near Aswan was in the 11th century, when the Arab polymath and engineer Ibn al-Haytham (known as Alhazen in the West) was summoned to Egypt by the Fatimid Caliph, Al-Hakim bi-Amr Allah, to regulate the flooding of the Nile, a task requiring an early attempt at an Aswan Dam.[3] His field work convinced him of the impracticality of this scheme.[4]
Aswan Low Dam, 1898–1902Main article: Aswan Low DamThe British began construction of the first dam across the Nile in 1898. Construction lasted until 1902 and the dam was opened on 10 December 1902. The project was designed by Sir William Willcocks and involved several eminent engineers, including Sir Benjamin Baker and Sir John Aird, whose firm, John Aird & Co., was the main contractor.[5][6]
Aswan High Dam prelude, 1954–1959In 1952, the Greek-Egyptian engineer Adrian Daninos began to develop the plan of the new Aswan Dam. Although the Low Dam was almost overtopped in 1946, the government of King Farouk showed no interest in Daninos's plans. Instead the Nile Valley Plan by the British hydrologist Harold Edwin Hurst was favored, which proposed to store water in Sudan and Ethiopia, where evaporation is much lower. The Egyptian position changed completely after the overthrow of the monarchy, led by the Free Officers Movement including Gamal Abdel Nasser. The Free Officers were convinced that the Nile Waters had to be stored in Egypt for political reasons, and within two months, the plan of Daninos was accepted.[7] Initially, both the United States and the USSR were interested in helping development of the dam. Complications ensued due to their rivalry during the Cold War, as well as growing intra-Arab tensions.
In 1955, Nasser was claiming to be the leader of Arab nationalism, in opposition to the traditional monarchies, especially the Hashemite Kingdom of Iraq following its signing of the 1955 Baghdad Pact. At that time the U.S. feared that communism would spread to the Middle East, and it saw Nasser as a natural leader of an anticommunist procapitalist Arab League. America and Britain offered to help finance construction of the High Dam, with a loan of $270 million, in return for Nasser's leadership in resolving the Arab-Israeli conflict. While opposed to communism, capitalism, and imperialism, Nasser identified as a tactical neutralist, and sought to work with both the U.S. and the USSR for Egyptian and Arab benefit.[8] After the UN criticized a raid by Israel against Egyptian forces in Gaza in 1955, Nasser realized that he could not portray himself as the leader of pan-Arab nationalism if he could not defend his country militarily against Israel. In addition to his development plans, he looked to quickly modernize his military, and he turned first to the U.S. for aid.Egyptian President Nasser and Soviet leader Nikita Khrushchev at the ceremony to divert the Nile during the construction of the Aswan High Dam on 14 May 1964. At this occasion Khrushchev called it "the eighth wonder of the world".American Secretary of State John Foster Dulles and President Dwight Eisenhower told Nasser that the U.S. would supply him with weapons only if they were used for defensive purposes and if he accepted American military personnel for supervision and training. Nasser did not accept these conditions, and consulted the USSR for support.
Although Dulles believed that Nasser was only bluffing and that the USSR would not aid Nasser, he was wrong: the USSR promised Nasser a quantity of arms in exchange for a deferred payment of Egyptian grain and cotton. On 27 September 1955, Nasser announced an arms deal, with Czechoslovakia acting as a middleman for the Soviet support.[9] Instead of attacking Nasser for turning to the Soviets, Dulles sought to improve relations with him. In December 1955, the U.S. and Britain pledged $56 and $14 million, respectively, toward construction of the High Aswan Dam.[10]Gamal Abdel Nasser observing the construction of the dam, 1963Though the Czech arms deal created an incentive for the US to invest at Aswan, Great Britain cited the deal as a reason for repeal its promise of dam funds. Dulles was angered more by Nasser's diplomatic recognition of China, which was in direct conflict with Dulles's policy of containment of communism.[11]
Several other factors contributed to the US deciding to withdraw its offer of funding for the dam. Dulles believed that the USSR would not fulfill its commitment of military aid. He was also irritated by Nasser's neutrality and attempts to play both sides of the Cold War. At the time, other Western allies in the Middle East, including Turkey and Iraq, were resentful that Egypt, a persistently neutral country, was being offered so much aid.[12]
In June 1956, the Soviets offered Nasser $1.12 billion at 2% interest for the construction of the dam. On 19 July the U.S. State Department announced that American financial assistance for the High Dam was "not feasible in present circumstances."[10]
On 26 July 1956, with wide Egyptian acclaim, Nasser announced the nationalization of the Suez Canal that included fair compensation for the former owners. Nasser planned on the revenues generated by the canal to help fund construction of the High Dam. When the Suez War broke out, the United Kingdom, France, and Israel seized the canal and the Sinai. But pressure from the U.S. and the USSR at the United Nations and elsewhere forced them to withdraw.
In 1958, the USSR proceeded to provide support for the High Dam project.A view from the vantage point in the middle of High Dam towards the monument of Arab-Soviet Friendship (Lotus Flower) by architects Piotr Pavlov, Juri Omeltchenko and sculptor Nikolay VechkanovIn the 1950s, archaeologists began raising concerns that several major historical sites, including the famous temple of Abu Simbel were about to be submerged by waters collected behind the dam. A rescue operation began in 1960 under UNESCO (for details see below under Effects).
Construction and filling, 1960–1976
A central pylon of the monument to Arab-Soviet Friendship. The memorial commemorates the completion of the Aswan High Dam. The coat of arms of the Soviet Union is on the left and the coat of arms of Egypt is on the right.The Soviets also provided technicians and heavy machinery. The enormous rock and clay dam was designed by the Soviet Hydroproject Institute along with some Egyptian engineers. 25,000 Egyptian engineers and workers contributed to the construction of the dams.
On the Egyptian side, the project was led by Osman Ahmed Osman's Arab Contractors. The relatively young Osman underoffer his only competitor by one-half.[13]
1960: Start of construction on 9 January[14]1964: First dam construction stage completed, reservoir started filling1970: The High Dam, as-Sad al-'Aali, completed on 21 July[15]1976: Reservoir reached capacity.SpecificationsThe Aswan High Dam is 4,000 metres (13,000 ft) long, 980 m (3,220 ft) wide at the base, 40 m (130 ft) wide at the crest and 111 m (364 ft) tall. It contains 43,000,000 cubic metres (56,000,000 cu yd) of material. At maximum, 11,000 cubic metres per second (390,000 cu ft/s) of water can pass through the dam. There are further emergency spillways for an extra 5,000 cubic metres per second (180,000 cu ft/s), and the Toshka Canal links the reservoir to the Toshka Depression. The reservoir, named Lake Nasser, is 550 km (340 mi) long and 35 km (22 mi) at its widest, with a surface area of 5,250 square kilometres (2,030 sq mi). It holds 132 cubic kilometres (1.73×1011 cu yd) of water.A panorama of the Aswan DamIrrigation schemeSee also: Water resources management in modern Egypt
Green irrigated land along the Nile amidst the desert
Water balances
Main irrigation systems (schematically)Due to the absence of appreciable rainfall, Egypt's agriculture depends entirely on irrigation. With irrigation, two crops per year can be produced, except for sugar cane which has a growing period of almost one year.
The high dam at Aswan releases, on average, 55 cubic kilometres (45,000,000 acre⋅ft) water per year, of which some 46 cubic kilometres (37,000,000 acre⋅ft) are diverted into the irrigation canals.
In the Nile valley and delta, almost 336,000 square kilometres (130,000 sq mi) benefit from these waters producing on average 1.8 crops per year. The annual crop consumptive use of water is about 38 cubic kilometres (31,000,000 acre⋅ft). Hence, the overall irrigation efficiency is 38/46 = 0.82 or 82%. This is a relatively-high irrigation efficiency. The field irrigation efficiencies are much less, but the losses are reused downstream. This continuous reuse accounts for the high overall efficiency.
The following table shows that the equal distribution of irrigation water over the branch canals taking off from the one main irrigation canal, the Mansuriya Canal near Giza, leaves much to be desired:[16]
Branch canal Water delivery in m3/feddan *Kafret Nasser 4,700Beni Magdul 3,500El Mansuria 3,300El Hammami upstream 2,800El Hammami downstream 1,800El Shimi 1,200* Period 1 March to 31 July. 1 feddan is 0.42 ha or about 1 acre.* Data from the Egyptian Water Use Management Project (EWUP)[17]The salt concentration of the water in the Aswan reservoir is about 0.25 kilograms per cubic metre (0.42 lb/cu yd), a very low salinity level. At an annual inflow of 55 cubic kilometres (45,000,000 acre⋅ft), the annual salt influx reaches 14 million tons. The average salt concentration of the drainage water evacuated into the sea and the coastal lakes is 2.7 kilograms per cubic metre (4.6 lb/cu yd).[18] At an annual discharge of 10 cubic kilometres (2.4 cu mi) (not counting the 2 kilograms per cubic metre [3.4 lb/cu yd] of salt intrusion from the sea and the lakes, see figure "Water balances"), the annual salt export reaches 27 million ton. In 1995, the output of salt was higher than the influx, and Egypt's agricultural lands were desalinizing. Part of this could be due to the large number of subsurface drainage projects executed in the last decades to control the water table and soil salinity.[19]
Drainage through subsurface drains and drainage channels is essential to prevent a deterioration of crop yields from waterlogging and soil salinization caused by irrigation. By 2003, more than 20,000 square kilometres (7,700 sq mi) have been equipped with a subsurface drainage system and approximately 7.2 square kilometres (2.8 sq mi) of water is drained annually from areas with these systems. The total investment cost in agricultural drainage over 27 years from 1973 to 2002 was about $3.1 billion covering the cost of design, construction, maintenance, research and training. During this period 11 large-scale projects were implemented with financial support from World Bank and other donors.[20]
EffectsThe High Dam has resulted in protection from floods and droughts, an increase in agricultural production and employment, electricity production, and improved navigation that also benefits tourism. Conversely, the dam flooded a large area, causing the relocation of over 100,000 people. Many archaeological sites were submerged while others were relocated. The dam is blamed for coastline erosion, soil salinity, and health problems.
The assessment of the costs and benefits of the dam remains controversial decades after its completion. According to one estimate, the annual economic benefit of the High Dam immediately after its completion was E£255 million, $587 million using the exchange rate in 1970 of $2.30 per E£1): £140 million from agricultural production, £100 million from hydroelectric generation, £10 million from flood protection, and £5 million from improved navigation. At the time of its construction, total cost, including unspecified "subsidiary projects" and the extension of electric power lines, amounted to £450 million. Not taking into account the negative environmental and social effects of the dam, its costs are thus estimated to have been recovered within only two years.[21] One observer notes: "The impacts of the Aswan High Dam (...) have been overwhelmingly positive. Although the Dam has contributed to some environmental problems, these have proved to be significantly less severe than was generally expected, or currently believed by many people."[22] Another observer disagreed and he recommended that the dam should be torn down. Tearing it down would cost only a fraction of the funds required for "continually combating the dam's consequential damage" and 500,000 hectares of fertile land could be reclaimed from the layers of mud on the bed of the drained reservoir.[23]
Periodic floods and droughts have affected Egypt since ancient times. The dam mitigated the effects of floods, such as those in 1964, 1973, and 1988. Navigation along the river has been improved, both upstream and downstream of the dam. Sailing along the Nile is a favorite tourism activity, which is mainly done during the winter when the natural flow of the Nile would have been too low to allow navigation of cruise ships.[clarification needed] A new fishing industry has been created around Lake Nasser, though it is struggling due to its distance from any significant markets. The annual production was about 35 000 tons in the mid-1990s. Factories for the fishing industry and packaging have been set up near the Lake.[24]
Drought protection, agricultural production and employment
The Egyptian countryside benefited from the Aswan High Dam through improved irrigation as well as electrification, as shown here in Al Bayadiyah, south of Luxor.The dams also protected Egypt from the droughts in 1972–73 and 1983–87 that devastated East and West Africa. The High Dam allowed Egypt to reclaim about 2.0 million feddan (840,000 hectares) in the Nile Delta and along the Nile Valley, increasing the country's irrigated area by a third. The increase was brought about both by irrigating what used to be desert and by bringing under cultivation of 385,000 ha that were previously used as flood retention basins.[25] About half a million families were settled on these new lands. In particular the area under rice and sugar cane cultivation increased. In addition, about 1 million feddan (420,000 hectares), mostly in Upper Egypt, were converted from flood irrigation with only one crop per year to perennial irrigation allowing two or more crops per year. On other previously irrigated land, yields increased because water could be made available at critical low-flow periods. For example, wheat yields in Egypt tripled between 1952 and 1991 and better availability of water contributed to this increase. Most of the 32 km3 of freshwater, or almost 40 percent of the average flow of the Nile that were previously lost to the sea every year could be put to beneficial use. While about 10 km3 of the water saved is lost due to evaporation in Lake Nasser, the amount of water available for irrigation still increased by 22 km3.[24] Other estimates put evaporation from Lake Nasser at between 10 and 16 cubic km per year.[26]
Electricity production
Power plant of the Aswan High Dam, with the dam itself in the background.The dam powers twelve generators each rated at 175 megawatts (235,000 hp), with a total of 2.1 gigawatts (2,800,000 hp). Power generation began in 1967. When the High Dam first reached peak output it produced around half of Egypt's production of electric power (about 15 percent by 1998), and it gave most Egyptian villages the use of electricity for the first time. The High Dam has also improved the efficiency and the extension of the Old Aswan Hydropower stations by regulating upstream flows.[24]
Resettlement and Compensations
A picture of the old Wadi Halfa town that was flooded by Lake Nasser.Lake Nasser flooded much of lower Nubia and 100,000 to 120,000 people were resettled in Sudan and Egypt.[27]View of New Wadi Halfa, a settlement created on the shore of Lake Nasser to house part of the resettled population from the Old Wadi Halfa town.In Sudan, 50,000 to 70,000 Sudanese Nubians were moved from the old town of Wadi Halfa and its surrounding villages. Some were moved to a newly created settlement on the shore of Lake Nasser called New Wadi Halfa, and some were resettled approximately 700 kilometres south to the semi-arid Butana plain near the town of Khashm el-Girba up the Atbara River. The climate there had a regular rainy season as opposed to their previous desert habitat in which virtually no rain fell. The government developed an irrigation project, called the New Halfa Agricultural Development Scheme to grow cotton, grains, sugar cane and other crops. The Nubians were resettled in twenty five planned villages that included schools, medical facilities, and other services, including piped water and some electrification.
In Egypt, the majority of the 50,000 Nubians were moved three to ten kilometers from the Nile near Kom Ombo, 45 kilometers downstream from Aswan in what was called "New Nubia". Housing and facilities were built for 47 village units whose relationship to each other approximated that in Old Nubia. Irrigated land was provided to grow mainly sugar cane.[28][29]
In 2019–20, Egypt started to compensate the Nubians who lost their homes following the dam impoundment.[30]
Archaeological sites
The statue of Ramses the Great at the Great Temple of Abu Simbel is reassembled after having been moved in 1967 to save it from being flooded.22 monuments and architectural complexes that were threatened by flooding from Lake Nasser, including the Abu Simbel temples, were preserved by moving them to the shores of the lake under the UNESCO Nubia Campaign.[31] Also moved were Philae, Kalabsha and Amada.[24]
These monuments were granted to countries that helped with the works:
The Debod temple to MadridThe Temple of Dendur to the Metropolitan Museum of Art of New YorkThe Temple of Taffeh to the Rijksmuseum van Oudheden of LeidenThe Temple of Ellesyia to the Museo Egizio of TurinThese items were removed to the garden area of the Sudan National Museum of Khartoum:[32]
The temple of Ramses II at AkshaThe temple of Hatshepsut at BuhenThe temple of Khnum at KummaThe tomb of the Nubian prince Djehuti-hotep at DebeiraThe temples of Dedwen and Sesostris III at SemnaThe granite columns from the Faras CathedralA part of the paintings of the Faras Cathedral; the other part is in the National Museum of Warsaw.The Temple of Ptah at Gerf Hussein had its free-standing section reconstructed at New Kalabsha, alongside the Temple of Kalabsha, Beit el-Wali, and the Kiosk of Qertassi.
The remaining archaeological sites, including the Buhen fort or the cemetery of Fadrus have been flooded by Lake Nasser.
Loss of sediments
Lake Nasser behind the Aswan dam displaced more than 100,000 people and traps significant amounts of sediment.Before the construction of the High Dam, the Nile deposited sediments of various particle size – consisting of fine sand, silt and clay – on fields in Upper Egypt through its annual flood, contributing to soil fertility. However, the nutrient value of the sediment has often been overestimated. 88 percent of the sediment was carried to the sea before the construction of the High Dam. The nutrient value added to the land by the sediment was only 6,000 tons of potash, 7,000 tons of phosphorus pentoxide and 17,000 tons of nitrogen. These amounts are insignificant compared to what is needed to reach the yields achieved today in Egypt's irrigation.[33] Also, the annual spread of sediment due to the Nile floods occurred along the banks of the Nile. Areas far from the river which never received the Nile floods before are now being irrigated.[34]
A more serious issue of trapping of sediment by the dam is that it has increased coastline erosion surrounding the Nile Delta. The coastline erodes an estimated 125–175 m (410–574 ft) per year.[35]
Waterlogging and increase in soil salinityBefore the construction of the High Dam, groundwater levels in the Nile Valley fluctuated 8–9 m per year with the water level of the Nile. During summer when evaporation was highest, the groundwater level was too deep to allow salts dissolved in the water to be pulled to the surface through capillary action. With the disappearance of the annual flood and heavy year-round irrigation, groundwater levels remained high with little fluctuation leading to waterlogging. Soil salinity also increased because the distance between the surface and the groundwater table was small enough (1–2 m depending on soil conditions and temperature) to allow water to be pulled up by evaporation so that the relatively small concentrations of salt in the groundwater accumulated on the soil surface over the years. Since most of the farmland did not have proper subsurface drainage to lower the groundwater table, salinization gradually affected crop yields.[25] Drainage through sub-surface drains and drainage channels is essential to prevent a deterioration of crop yields from soil salinization and waterlogging. By 2003, more than 2 million hectares have been equipped with a subsurface drainage system at a cost from 1973 to 2002 of about $3.1 billion.[36]
Skin vesicles: a symptom of schistosomiasis. A more common symptom is blood in the urine.Contrary to many predictions made prior to the Aswan High Dam construction and publications that followed, that the prevalence of schistosomiasis (bilharzia) would increase, it did not.[37] This assumption did not take into account the extent of perennial irrigation that was already present throughout Egypt decades before the high dam closure. By the 1950s only a small proportion of Upper Egypt had not been converted from basin (low transmission) to perennial (high transmission) irrigation. Expansion of perennial irrigation systems in Egypt did not depend on the high dam. In fact, within 15 years of the high dam closure there was solid evidence that biharzia was declining in Upper Egypt. S. haematobium has since disappeared altogether.[38] Suggested reasons for this include improvements in irrigation practice. In the Nile Delta, schistosomiasis had been highly endemic, with prevalence in the villages 50% or higher for almost a century before. This was a consequence of the conversion of the Delta to perennial irrigation to grow long staple cotton by the British. This has changed. Large scale treatment programmes in the 1990s using single dose oral medication contributed greatly to reducing the prevalence and severity of S. mansoni in the Delta.
Other effectsSediment deposited in the reservoir is lowering the water storage capacity of Lake Nasser. The reservoir storage capacity is 162 km3, including 31 km3 dead storage at the bottom of the lake below 147 m above sea level, 90 km3 live storage, and 41 km3 of storage for high flood waters above 175m above sea level. The annual sediment load of the Nile is about 134 million tons. This means that the dead storage volume would be filled up after 300–500 years if the sediment accumulated at the same rate throughout the area of the lake. Obviously sediment accumulates much faster at the upper reaches of the lake, where sedimentation has already affected the live storage zone.[33]
Before the construction of the High Dam, the 50,000 km of irrigation and drainage canals in Egypt had to be dredged regularly to remove sediments. After construction of the dam, aquatic weeds grew much faster in the clearer water, helped by fertilizer residues. The total length of the infested waterways was about 27,000 km in the mid-1990s. Weeds have been gradually brought under control by manual, mechanical and biological methods.[24]The catch of sardines in the Mediterranean off the Egyptian coast declined after the Aswan Dam was completed, but the exact reasons for the decline are still disputed.Mediterranean fishing and brackish water lake fishery declined after the dam was finished because nutrients that flowed down the Nile to the Mediterranean were trapped behind the dam. For example, the sardine catch off the Egyptian coast declined from 18,000 tons in 1962 to a mere 460 tons in 1968, but then gradually recovered to 8,590 tons in 1992. A scientific article in the mid-1990s noted that "the mismatch between low primary productivity and relatively high levels of fish production in the region still presents a puzzle to scientists."[39]
A concern before the construction of the High Dam had been the potential drop in river-bed level downstream of the Dam as the result of erosion caused by the flow of sediment-free water. Estimates by various national and international experts put this drop at between 2 and 10 meters. However, the actual drop has been measured at 0.3–0.7 meters, much less than expected.[24]
The red-brick construction industry, which consisted of hundreds of factories that used Nile sediment deposits along the river, has also been negatively affected. Deprived of sediment, they started using the older alluvium of otherwise arable land taking out of production up to 120 square kilometers annually, with an estimated 1,000 square kilometers destroyed by 1984 when the government prohibited, "with only modest success," further excavation.[40] According to one source, bricks are now being made from new techniques which use a sand-clay mixture and it has been argued that the mud-based brick industry would have suffered even if the dam had not been built.[34]
Because of the lower turofferity of the water sunlight penetrates deeper in the Nile water. Because of this and the increased presence of nutrients from fertilizers in the water, more algae grow in the Nile. This in turn increases the costs of drinking water treatment. Apparently few experts had expected that water quality in the Nile would actually decrease because of the High Dam.[25]
See alsoflag Egypt portalicon Water portalicon Renewable energy portalEnergy in EgyptEgyptian Public WorksList of conventional hydroelectric power stationsList of largest damsList of power stations in EgyptWater politics in the Nile Basin

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