Aswan Low Dam
Encyclopedia
The Aswan Low Dam or Old Aswan Dam is a gravity masonry
buttress dam
on the Nile River in Aswan
, Egypt
. The dam was built at the former first cataract
of the Nile, and is located about 1000 km up-river and 690 km (direct distance) south-southeast of Cairo
. Constructed between 1899 and 1902, it was intended to reduce flooding and to support population growth in the lower Nile. The dam provided inadequate flood protection and was raised twice, between 1907–1912 and 1929–1933. The alterations did not suffice and it was nearly over-topped in 1946 which led to the construction of the Aswan High Dam
6 kilometres (4 mi) upstream.
i 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. After his field work convinced him of the impracticality of this scheme, and fearing the Caliph's anger, he feigned madness
. He was kept under house arrest
from 1011 until al-Hakim's death in 1021, during which time he wrote his influential Book of Optics
.
. The project was designed by Sir William Willcocks
and involved several eminent engineers of the time, including Sir Benjamin Baker and Sir John Aird
, whose firm, John Aird & Co.
, was the main contractor.
The Old Aswan Dam was designed as a gravity-buttress
dam; the buttress sections accommodate numerous gates, which were opened yearly to pass the flood and its nutrient-rich sediments, but without retaining any yearly storage. The dam was constructed of rubble masonry
and faced with red ashlar
granite. When constructed, the Old Aswan Dam was the largest masonry dam in the world. The design also included a navigation lock
of similar construction on the western bank, which allowed shipping to pass upstream as far as the second cataract, before a portage
overland was required. At the time of its construction, nothing of such scale had ever been attempted. Despite initial limitations imposed on its height, due to concern for the Philae Temple
, the initial construction was soon found to be inadequate for development needs, and the height of the dam was raised in two phases, 5 meters between 1907–1912 and 9 meters between 1929–1933, and generation of electricity was added. With its final raising, the dam is 1,950 m in length, with a crest level 36 m above the original riverbed; the dam provides the main route for traffic between the city and the airport. With the construction of the High Dam upstream, the Old Dam's ability to pass the flood's sediments was lost, as was the serviceability provided by the locks. The previous Old Dam reservoir level was also lowered and now provides control of tailwater
for the High Dam.
s for a combined capacity of 322 MW and is located west of the dam. Aswan II contains 4 x 67.5 MW generators for an installed capacity of 270 MW and is located at the toe of the dam.
Masonry dam
Masonry dams are dams made out of masonry; mainly stone and brick. They are either the gravity or the arch type.The largest masonry dam of the world is Nagarjunasagar Dam in India....
buttress dam
Buttress dam
A buttress dam or hollow dam is a dam with a solid, water-tight upstream side that is supported at intervals on the downstream side by a series of buttresses or supports. The dam wall may be flat or curved. Most buttress dams are made of reinforced concrete and are heavy, pushing the dam into the...
on the Nile River in Aswan
Aswan
Aswan , formerly spelled Assuan, is a city in the south of Egypt, the capital of the Aswan Governorate.It stands on the east bank of the Nile at the first cataract and is a busy market and tourist centre...
, Egypt
Egypt
Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...
. The dam was built at the former first cataract
Cataracts of the Nile
The cataracts of the Nile are shallow lengths of the Nile between Aswan and Khartoum where the surface of the water is broken by many small boulders and stones protruding out of the river bed, as well as many rocky islets. Aswan is also the Southern boundary of Upper Egypt...
of the Nile, and is located about 1000 km up-river and 690 km (direct distance) south-southeast of Cairo
Cairo
Cairo , is the capital of Egypt and the largest city in the Arab world and Africa, and the 16th largest metropolitan area in the world. Nicknamed "The City of a Thousand Minarets" for its preponderance of Islamic architecture, Cairo has long been a centre of the region's political and cultural life...
. Constructed between 1899 and 1902, it was intended to reduce flooding and to support population growth in the lower Nile. The dam provided inadequate flood protection and was raised twice, between 1907–1912 and 1929–1933. The alterations did not suffice and it was nearly over-topped in 1946 which led to the construction of the Aswan High Dam
Aswan Dam
The Aswan Dam is an embankment dam situated across the Nile River in Aswan, Egypt. Since the 1950s, the name commonly refers to the High Dam, which is larger and newer than the Aswan Low Dam, which was first completed in 1902...
6 kilometres (4 mi) upstream.
Background
The earliest recorded attempt to build a dam near Aswan was in the 11th century, when the IraqIraq
Iraq ; officially the Republic of Iraq is a country in Western Asia spanning most of the northwestern end of the Zagros mountain range, the eastern part of the Syrian Desert and the northern part of the Arabian Desert....
i 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
Al-Hakim bi-Amr Allah
Abu ‘Ali Mansur Tāriqu l-Ḥākim, called Al-Hakim bi Amr al-Lāh , was the sixth Fatimid caliph and 16th Ismaili imam .- History :...
, to regulate the flooding of the Nile
Flooding of the Nile
has been an important natal cycle in Egypt since ancient times. It is celebrated by Egyptians as an annual holiday for two weeks starting August 15, known as Wafaa El-Nil. It is also celebrated in the Coptic Church by ceremonially throwing a martyr's relic into the river, hence the name, Esba`...
, a task requiring an early attempt at an Aswan Dam. After his field work convinced him of the impracticality of this scheme, and fearing the Caliph's anger, he feigned madness
Feigned madness
Feigned madness a term used in popular culture to describe the assumption of a mental disorder for purposes of evasion or deceit, or to divert suspicion, perhaps in advance of an act of revenge.-To avoid responsibility:...
. He was kept under house arrest
House arrest
In justice and law, house arrest is a measure by which a person is confined by the authorities to his or her residence. Travel is usually restricted, if allowed at all...
from 1011 until al-Hakim's death in 1021, during which time he wrote his influential Book of Optics
Book of Optics
The Book of Optics ; ; Latin: De Aspectibus or Opticae Thesaurus: Alhazeni Arabis; Italian: Deli Aspecti) is a seven-volume treatise on optics and other fields of study composed by the medieval Muslim scholar Alhazen .-See also:* Science in medieval Islam...
.
Construction
Following their 1882 invasion and occupation of Egypt, the British began construction of the first dam across the Nile in 1898. Construction lasted until 1902, and it was opened on 10 December 1902, by HRH the Duke of Connaught and StrathearnDuke of Connaught and Strathearn
The title Duke of Connaught and Strathearn was granted by Queen Victoria of the United Kingdom of Great Britain and Ireland to her third son, Prince Arthur....
. The project was designed by Sir William Willcocks
William Willcocks
Sir William Willcocks KCMG was a British civil engineer. He is remembered as a renowned irrigation engineer, having proposed the first Aswan Dam and undertaken major projects of irrigation in South Africa and Turkey.A graduate of the Thomason College of Civil Engineering, Roorkee 1872 batch...
and involved several eminent engineers of the time, including Sir Benjamin Baker and Sir John Aird
John Aird (engineer)
Sir John Aird, 1st Baronet was a notable English civil engineering contractor of the late 19th and early 20th centuries. He is the Great Grandfather of Ollie Parkes...
, whose firm, John Aird & Co.
John Aird & Co.
John Aird & Co. was once a leading British civil engineering business based in London.-Early history:The company was founded in 1848 by John Aird with the objective of laying mains for gas and water companies in London....
, was the main contractor.
The Old Aswan Dam was designed as a gravity-buttress
Buttress dam
A buttress dam or hollow dam is a dam with a solid, water-tight upstream side that is supported at intervals on the downstream side by a series of buttresses or supports. The dam wall may be flat or curved. Most buttress dams are made of reinforced concrete and are heavy, pushing the dam into the...
dam; the buttress sections accommodate numerous gates, which were opened yearly to pass the flood and its nutrient-rich sediments, but without retaining any yearly storage. The dam was constructed of rubble masonry
Masonry
Masonry is the building of structures from individual units laid in and bound together by mortar; the term masonry can also refer to the units themselves. The common materials of masonry construction are brick, stone, marble, granite, travertine, limestone; concrete block, glass block, stucco, and...
and faced with red ashlar
Ashlar
Ashlar is prepared stone work of any type of stone. Masonry using such stones laid in parallel courses is known as ashlar masonry, whereas masonry using irregularly shaped stones is known as rubble masonry. Ashlar blocks are rectangular cuboid blocks that are masonry sculpted to have square edges...
granite. When constructed, the Old Aswan Dam was the largest masonry dam in the world. The design also included a navigation lock
Lock (water transport)
A lock is a device for raising and lowering boats between stretches of water of different levels on river and canal waterways. The distinguishing feature of a lock is a fixed chamber in which the water level can be varied; whereas in a caisson lock, a boat lift, or on a canal inclined plane, it is...
of similar construction on the western bank, which allowed shipping to pass upstream as far as the second cataract, before a portage
Portage
Portage or portaging refers to the practice of carrying watercraft or cargo over land to avoid river obstacles, or between two bodies of water. A place where this carrying occurs is also called a portage; a person doing the carrying is called a porter.The English word portage is derived from the...
overland was required. At the time of its construction, nothing of such scale had ever been attempted. Despite initial limitations imposed on its height, due to concern for the Philae Temple
Philae
Philae is an island in the Nile River and the previous site of an Ancient Egyptian temple complex in southern Egypt...
, the initial construction was soon found to be inadequate for development needs, and the height of the dam was raised in two phases, 5 meters between 1907–1912 and 9 meters between 1929–1933, and generation of electricity was added. With its final raising, the dam is 1,950 m in length, with a crest level 36 m above the original riverbed; the dam provides the main route for traffic between the city and the airport. With the construction of the High Dam upstream, the Old Dam's ability to pass the flood's sediments was lost, as was the serviceability provided by the locks. The previous Old Dam reservoir level was also lowered and now provides control of tailwater
Tailwater
Tailwater refers to waters located immediately downstream from a hydraulic structure, such as a dam , bridge or culvert. Tailwater can refer to a type of fishery...
for the High Dam.
Power plants
The Aswan Low Dam supports two hydroelectric power plants, Aswan I (1960) and Aswan II (1985–1986). Aswan I contains 7 X 46 MW generators with Kaplan turbineKaplan turbine
The Kaplan turbine is a propeller-type water turbine which has adjustable blades. It was developed in 1913 by the Austrian professor Viktor Kaplan, who combined automatically adjusted propeller blades with automatically adjusted wicket gates to achieve efficiency over a wide range of flow and...
s for a combined capacity of 322 MW and is located west of the dam. Aswan II contains 4 x 67.5 MW generators for an installed capacity of 270 MW and is located at the toe of the dam.
Further reading
- Sidney Peel, The Binding of the Nile and the new Soudan, Oxford 1904. Discusses 'Assouan' Dam and Nile River development.
- The Assuan Dam, Journal of the Royal African Society, Vol. 12, No. 46, January, 1913
- Hanbury Brown, Irrigation; its principles and practice as a branch of engineering, Third Edition, London. 1920