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Toshka Lakes

Toshka Lakes (Arabic: بحيرات توشكى, Egyptian Arabic pronunciation: [boħeˈɾæːt ˈtoʃkæ]) is the name given to recently formed endorheic lakes in the Sahara Desert of Egypt.[2] Their presence is caused by periodic overflow from Lake Nasser.

Toshka Lakes
The Toshka lakes and Lake Nasser in 2021
Location of Toshka Lakes in Egypt.
Location of Toshka Lakes in Egypt.
Toshka Lakes
LocationNew Valley Governorate
Coordinates23°06′N 30°54′E / 23.1°N 30.9°E / 23.1; 30.9
TypeEndorheic lake
Primary inflowsNile-Lake Nasser via Sadat Canal
Basin countriesEgypt
Surface area1,450 km2 (560 sq mi) (2000)
307 km2 (119 sq mi) (Lowest, 2012)[1]
Water volume25.26 km3 (10 cu mi) (2000)[1]
Location of the Toshka Lakes and Lake Nasser in Egypt.
Photograph of the Toshka Lakes taken Dec. 2002 from the International Space Station looking NE. Lake Nasser is the very long lake that lies east of the lakes. Wadi Toshka is the large bay in Lake Nasser directly east of the Toshka lakes. The Western Desert of Egypt can be seen west of Lake Nasser

The presence of the depression helped establish the Toshka New Valley Project, made possible by the Sheikh Zayed Canal, which starts from the Mubarak pump station to raise water from the creek of Lake Nasser to the canal, and whose aim is to develop the southern valley area.[3]

Etymology

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There are two opinions regarding the origin of the name "Toshka". The first is that that the word "toshka" is made up of two syllables: "toshi" or "tosho", and "ki", "ke", or "ka". "Toshi" is the name of the stump plant, a type of medicinal herb that grows in the valley, and "ki" means "the place", "the house", or "the homeland" in the Nubian dialect or the region. Toshka in its entirety then means "the home of the Ghubeira plant."[4]

The second opinion is, which is more widely accepted, is the lakes are named after a Nubian village (Old Nubian: ⲧⲱϣⲕⲉⲁ[5]) which existed in the region until it was flooded after the construction of the Aswan High Dam.[4] The word "toshka" consists of two syllables.[5]

In the past, the Toshka region included two villages, one east of the Nile, "Toshka East" and the other west of the Nile, "Toshka West." The residents used Nile boats to move between the two villages. The two new ones have the same name "Toshka East" and "Toshka West".[6] A new city was built in remembrance of the village.[7]

History

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Battle of Toski

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See also: Mahdist War and Battle of Toski

In the year 1889, a famous battle took place in the Toshka region between the British campaign and the army of the Mahdist State. Madhist revolutionaries marched from Sudan under the leadership of Abd al-Rahman al-Nujumi, proclaiming that they were ridding the Nile Valley of the corruption of the Turkish and British rulers, spread the Madhist faith to Egypt,[8] and to free Ahmed Orabi from prison.[6]

Aswan High Dam

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See also: Aswan Dam

The Aswan High Dam, constructed in Egypt in 1964–1968, created Lake Nasser. It was designed with a maximum water level of 183 metres (600 ft) above sea level. As a precaution against any unexpected rise in Lake Nasser's water level, a spillway and channel were built in 1978. The channel has the potential to divert water from the reservoir to the Toshka basin, which is located outside the Nile basin. This design relieves dam pressure and protects downstream areas from massive flooding. The canal was made through a spillway channel that was dug starting from Khor Toshka branching from Lake Nasser and passing through the Toshka Valley in the Western Desert until it connects to the depression.

Formation

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In 1998, Ethiopia experienced mass flash floods and river floods.[9] Excess water coming from in Ethiopia's highlands put strain on the river Nile and put the flood control plan of the Aswan High Dam to the test. For the first time, the massive reservoir reached its highest level of 183 meters above sea level in September.[10] Excess water started being released from Lake Nasser by overflow into a hollow at the south end of the Eocene limestone plateau. During September and October, the basin received between 32 and 98 million cubic meters of water per day.[11]

Astronauts on the ISS began noticing the first, easternmost lake growing in November 1998.[12] By late 1999, three additional lakes formed successively westward, and the westernmost lake started forming sometime between September 2000 and March 2001. These lakes are not yet named individually.

 
Landsat mosaic of Toshka Lakes (April 2003). False-color image, with bands 7-4-2 assigned to R-G-B.

It was estimated that in total, the Toshka Lakes cover approximately 1300 square kilometers (502 mi2). The levels of the lakes as of 2006 are lower than in 2001, and areas of wetlands and sand dunes have formed between the former and present shorelines. A minor lake downstream of the three larger lakes has completely dried out. The levels of the lakes vary between 175 metres (574 ft) for the one closest to Lake Nasser to 144 metres (472 ft) for the one furthest downstream.

Decline

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By the late 2000s, the Toshka region experienced an increase in agricultural activity, with farmers using water from Lake Toshka and pumps from Lake Nasser for agricultural purposes. The region saw some economic growth as a result of the increased agricultural activity, and a new city was built to support the Toshka Agricultural Project located northeast of the Sheikh Zayed Canal. The city of New Toshka was established by Presidential Decree No. 199 of 2000 and its location modified by Presidential Decree No. 268 of 2006 with the aim of creating an integrated urban community.[13][7]

By 2006, Lake Toshka's water levels began to decline rapidly, exposing large areas of dry land. The amount of stored water had been reduced by 50%. By June 2012, water filled only the lowest parts of the main western and eastern basins, covering a surface area of 307 square kilometers, an 80% decrease compared to 2002. The central basin is almost completely devoid of water and the rest of the lakes had mostly dried up due to low flow in the river. By 2017 and 2018, the lakes were nearly completely dry, leaving only small remnants of water in the western basins.[14]

Sudan Floods

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The 2019 summer rainfall in Sudan and South Sudan was significant enough to raise the water level in Lake Nasser, which allowed the eastern Toshka basin to start refilling. This was followed by the record-breaking floods that occurred in Sudan in 2020. These floods led to the highest water level ever recorded in Lake Nasser. The following year, in 2021, another flood occurred in Sudan. Then, due to the 2022 Sudanese floods, Lake Nasser approached record levels once again, causing the Toshka Lakes to fill rapidly.[15]

The filling of the Toshka Lakes in 2022 resulted in the highest water levels ever recorded in the area, and it also indicated the formation of new lakes in depressions located to the north and south of the eastern basin. The area covered by the original lakes increased substantially above the levels seen in 2001, gaining 3 more lakes on the eastern side. This increase in water levels has had a significant impact on the agricultural areas in the region, which have grown considerably due to the abundance of water. As a result, the Toshka agriculture project has benefited greatly from the increased water supply, and the region's economy has improved due to growth in the agricultural industry.[15]

Geography

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The new lake system is endorheic, meaning the waters never flow out to the sea. The Nile-sourced water creates the lakes and helps to recharge the underlying aquifer; however, desert temperatures cause very high levels of evaporation. Although the new lakes already contain an impressive number of fish, these high evaporation levels will make the waters increasingly saline over time, reducing fish stocks and harming the newly established flora and fauna.

The Toshka Hollow lies within the seismically active Nubian Swell. The Egyptian government is developing the surrounding region, also known as the "New Valley Project". The plan is to extend the waterway to the Kharga oasis. Use of Nile resources is governed by the Nile Basin Initiative; however, the Toshka project does not breach the agreement as water is diverted from Lake Nasser only after heavy water flows upstream have raised lake levels above 178 metres (584 ft).

See also

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References

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  1. ^ a b "Toshka Lakes, Southern Egypt". earthobservatory.nasa.gov. 2012-07-16. Archived from the original on 2023-03-03. Retrieved 2023-03-03.
  2. ^ El-Shabrawy, Gamal M; Henri J. Dumont (2009). "The Toshka Lakes". The Nile. Monographiae Biologicae. Vol. 89. pp. 157–162. doi:10.1007/978-1-4020-9726-3_8. ISBN 978-1-4020-9725-6.
  3. ^ "مشروعى توشكى ونرعة السلام وقضية المياه وحق مصر التاريخى". atef.helals.net (in Arabic). Archived from the original on 2017-04-14. Retrieved 2023-03-01.
  4. ^ a b Fathi Al-Turkmani, Gouda (1999). "The Geomorphology of the Toshka Region and Development Potential". Egyptian Geographical Society (1999 ed.).
  5. ^ a b Pierce, Richard Holton. "Nubian Toponyms in Medieval Nubian Sources". Dotawo: A Journal of Nubian Studies. 4. doi:10.5070/D64110024.
  6. ^ a b Salih Al-Nimr, Huda (2006). "The South Valley Development Project (Tushka) between objectives and achievements". Institute of National Planning (in Egyptian Arabic) (2006 ed.).
  7. ^ a b "Home - New Toshka City". New Urban Communities Authority. Archived from the original on 12 March 2023. Retrieved 3 March 2023.
  8. ^ Churchill, Winston Spencer (1899). The River War. Vol. 1. Longmans. pp. 140–141.
  9. ^ Extreme hydrology and climate variability: monitoring, modelling, adaptation, and mitigation. Assefa M. Melesse, Wossenu Abtew, Gabriel Senay (First ed.). Amsterdam, Netherlands. 2019. ISBN 978-0-12-815999-6. OCLC 1107667172.{{cite book}}: CS1 maint: location missing publisher (link) CS1 maint: others (link)
  10. ^ "Rain-fed Nile swamps Egypt's dam and villages - Sudan | ReliefWeb". reliefweb.int. 25 September 1998. Retrieved 2023-03-03.
  11. ^ "The Lakes Form | EROS". eros.usgs.gov. Archived from the original on 2023-03-03. Retrieved 2023-03-03.
  12. ^ "New Lakes in the Egyptian Desert". earthobservatory.nasa.gov. 2000-12-02. Archived from the original on 2023-03-03. Retrieved 2023-03-03.
  13. ^ "تعديل موقع مدينة توشكى الجديدة". منشورات قانونية (in Arabic). 2018-11-12. Archived from the original on 2020-10-19. Retrieved 2023-03-01.
  14. ^ "Two Decades of Change at Toshka Lakes". The Earth Observatory. NASA Goddard Space Flight Center. Retrieved 27 July 2024.
  15. ^ a b "Two Decades of Change at Toshka Lakes". earthobservatory.nasa.gov. 2022-01-18. Archived from the original on 2023-03-03. Retrieved 2023-03-03.

Further reading

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