Oued Fodda dam

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Oued Fodda dam
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Tributaries: Oued Fodda
Drain: Oued Fodda
Oued Fodda dam (Algeria)
Oued Fodda dam
Coordinates 36 ° 2 '44 "  N , 1 ° 36' 42"  E Coordinates: 36 ° 2 '44 "  N , 1 ° 36' 42"  E
Data on the structure
Construction time: 1926 to 1932
Height of the barrier structure : 100 m
Crown length: 182 m
Base width: 65 m
Data on the reservoir
Altitude (at congestion destination ) 370.5 m
Water surface 7 km²dep1
Total storage space : 228 million m³

The Oued Fodda dam ( French Barrage Oued Fodda ) is in Algeria in the area of ​​the municipality of El Karimia , Chlef province . It dams the Oued Fodda , a tributary of the Cheliff , into a reservoir. The dam was formerly known as Barrage Steeg , after the former governor general of Algeria Théodore Steeg . The place Oued Fodda is about 17 km north of the dam.

The dam was built from 1926 to 1932, first by Dufour Constructions Générales, then by Campenon Bernard . The damming took place in 1932. The dam is used for irrigation, drinking water supply and electricity generation.

Barrier structure

The barrier structure is a concrete gravity dam with a height of 100 (or 101) m and a crown length of 182 m. The volume of the structure is 320,000 or 300,000 m³. The width of the dam is 65 m at the base.

The dam wall has both a bottom outlet and a flood relief . A maximum of 100 m³ / s could be discharged via the bottom outlet.

Reservoir

With the normal storage target of 370.5 m (maximum 374 m at high water), the reservoir extends over an area of ​​around 7 km² and originally held 228 million m³ of water. The annual inflow into the reservoir was around 85 million m³. This figure is the mean of the mean annual inflow of 113 million m³ in the years 1945–1975 and the inflow of 51 million m³ in the years 1976–1998 and therefore hides the decrease in precipitation during this period. The annual inflow also fluctuates strongly over the years: in the years 1943–1993 the minimum was 10 million m³ and the maximum was 234 million m³.

power plant

The Oued Fodda power plant has an installed capacity of 7 or 15.6 MW . The power plant was completed in 1942.

Barrage des Portes de Fer

About five kilometers downstream ( ) there is a weir system built between 1936 and 1940 ( French Barrage des Portes de Fer , weir of the iron gates , also in the singular: Barrage de Porte de Fer ), which is a small reservoir with an original volume of 300,000 m³ accumulated. The weir was the starting point for around 44 km long pressurized water pipes of various diameters to Oued Fodda in the valley floor and to the surrounding fields for the irrigation of 18,000 hectares of land. World icon

For the pressure water pipeline, a factory was built in Oued Fogga, in which the prestressed concrete pipes designed by Eugène Freyssinet were manufactured. With the technology that was completely new at the time and had hardly been tested, the pipes could also cross trenches without additional supports.

Next to the weir there is a road bridge over the river which, like the immovable parts of the weir, was built from prestressed concrete according to the plans of Freyssinet. Prefabricated 19 m long double-T girders made of prestressed concrete were used for the bridge.

Recent problems

The gravity dam survived the earthquakes of 1954 and 1980 unscathed. But a number of other events have left their mark, such as the War of Independence from 1954 to 1962 and the Civil War at the end of the last century with damage to irrigation systems and inadequate maintenance and repair of technical systems, which increased the population by 6.1 million in 1926 40.4 million inhabitants in January 2016 with the even greater increase in water demand and noticeable climatic changes.

The decline in forest cover, largely caused by human activities, led to an increase in the sediments washed out by the streams and thus to premature sedimentation of the reservoirs. In the catchment area of ​​the Oued Fodda there is only greatly reduced or no vegetation at all, but at the same time there is little political interest in afforestation. As a result, the volume of the reservoir had already decreased in 1996 from an initial 228 million m³ to 115.2 million m³, i.e. only 49.4% of the original volume.

The bottom of the reservoir is covered by a 40 m high layer of sediment, a bottom drain is no longer possible. The sediments should have been flushed out by regularly opening the bottom outlet. The fact that this did not happen may be due to the widespread inadequate maintenance and repair or the fact that the reservoir is often insufficiently full, where the little water may not have been wasted on flushing. Between 1999 and 2009 the levels fluctuated between a high of 34% in 2001 and a minimum of 4% in 2007 and 2008.

It cannot be determined how long the water pipes of the Barrage des Portes de fer were in operation. From 2013 a new line was built to Oued Fodda.

See also

Individual evidence

  1. ↑ a b c d e Oued Fodda. Agence Nationale des Barrages et Transferts (ANBT), accessed on July 13, 2015 (French).
  2. ↑ a b c d e f g BARRAGE DE L'OUED FODDA. popodoran.canalblog.com, accessed July 13, 2015 (French).
  3. ↑ a b List of African dams. FAO , accessed July 16, 2016 .
  4. ↑ Bouzid Touati: Les barrages et la politique hydraulique en Algérie: état, diagnostic et perspectives d'un aménagement durable. Dissertation University Mentouri, Constantine, 2010, p. 79 ( digital version, PDF 25.2 MB!)
  5. ↑ Bouzid Touati: Les barrages et la politique hydraulique en Algérie. P. 58
  6. ^ Parc de production hydroélectrique. www.mem-algeria.org, accessed on July 13, 2015 (English).
  7. ↑ Les énergies renouvelables: Expérience, Initiatives politiques et Perspectives Algériennes. (PDF 7.7 MB, p. 68) era.dz, accessed on July 13, 2015 (French).
  8. ^ J. Olivier-Martin: précontrainte et préfabrication industrial - Les Tuyaux. In: L'Ingénieur – Constructeur, Revue technique mensuelle n ° 134, March – April 1969; Special edition on Freyssinet and prestressed concrete ( digitalisat PDF; 17.6 MB), p. 66 (69 in PDF)
  9. ↑ Les conduites d'eau de l'Oued Fodda, Algérie 1936 on the website of the Association Eugène Freyssinet
  10. ↑ Leonardo Fernández Troyano: Bridge Engineering. A global perspective. Colegio de Ingenieros de Caminos, Canales y Puentes, Thomas Telford 2003, ISBN 0-7277-3215-3 , p. 414
  11. ^ David Fernández-Ordóñez: Eugène Freyssinet: “I was born a builder” . In: Manfred Curbach (Ed.): 28th Dresden Bridge Construction Symposium ; 12./13. March 2018 . Technical University of Dresden, Dresden 2018, ISBN 978-3-86780-544-5 , p. 101–126 (In PDF: pp. 103–128) ( tu-dresden.de [PDF; 23.6 MB ]). (English)
  12. ↑ Der Große Brockhaus, 15th edition, Leipzig 1928
  13. ^ Démographie des Office National des Statistiques
  14. ↑ Bouzid Touati: Les barrages et la politique hydraulique en Algérie. P. 44
  15. ↑ Bouzid Touati: Les barrages et la politique hydraulique en Algérie. P. 205
  16. ↑ Bouzid Touati: Les barrages et la politique hydraulique en Algérie. P. 204: Les raisons avancées sont l'absence quasi-totale de maintenance et d'entretien
  17. ↑ Bouzid Touati: Les barrages et la politique hydraulique en Algérie. P. 164
  18. ↑ On Google Earth in the recording from July 2013 and the one from 2016.