Al Wahda Dam (Morocco)

From Wikipedia, the free encyclopedia
  (Redirected from Al Wahda Dam, Morocco)
Jump to: navigation, search
For the dam in Jordan, see Al-Wehda Dam.
Al Wahda Dam
Al Wahda Dam (Morocco).jpg
The dam (on the left) and reservoir as seen from space
Al Wahda Dam (Morocco) is located in Morocco
Al Wahda Dam (Morocco)
Location of Al Wahda Dam
Official name Barrage Al Wahda
Location M´Jaara, Ouezzane Province, Morocco
Coordinates 34°35′54″N 5°11′51″W / 34.59833°N 5.19750°W / 34.59833; -5.19750Coordinates: 34°35′54″N 5°11′51″W / 34.59833°N 5.19750°W / 34.59833; -5.19750
Construction began 1991
Opening date 1997
Dam and spillways
Impounds Ouergha River
Height 88 m (289 ft)
Length 2,600 m (8,500 ft)
Dam volume 28,000,000 m3 (990,000,000 cu ft)
Spillway type Service, controlled chute
Spillway capacity 13,000 m3/s (460,000 cu ft/s)
Reservoir
Creates Al Wahda Reservoir
Total capacity 3,800,000,000 m3 (3,100,000 acre·ft)
Catchment area 6,200 km2 (2,400 sq mi)
Surface area 123 km2 (47 sq mi)
Power station
Commission date 1997-1998
Turbines 3 x 80 MW Francis-type
Installed capacity 240 MW
Annual generation 400 GWh

Al Wahda Dam, formerly known as M'Jaara Dam, is an embankment dam on the Ouergha River near M´Jaara in Ouezzane Province, Morocco. It was constructed for flood control, irrigation, water supply and hydroelectric power production. It is the second largest dam in Africa and the largest in Morocco.[1] It was described by Land Ocean Interactions in the Coastal Zone (LOICZ) as "the second most important dam in Africa after the High Aswan dam."[2]

Background[edit]

In 1988, the Board of Water and Climate considered the dam and eventually it was recommended for development.[3] Construction began in 1991, the dam began to create its reservoir in 1996 and was inaugurated on March 20, 1997 by King Hassan II.[4] A total of 14,000,000 m3 (490,000,000 cu ft) of material were excavated during construction.[5]

Specifications[edit]

The dam is an earthen embankment type made of 28,000,000 m3 (990,000,000 cu ft) of material and 720,000 m3 (25,000,000 cu ft) of concrete. It is 88 m (289 ft) tall at its highest point and the main portion of the dam is 1,600 m (5,200 ft) long. Directly to the north and adjacent to the spillway is a saddle dam that is 1,000 m (3,300 ft) long and 30 m (98 ft) high. The dam's spillway, in its center is controlled by six floodgates and has a discharge capacity in excess of 13,000 m3/s (460,000 cu ft/s).[4]

The power plant, at the dam's toe and adjacent to the spillway is supplied with water via a 10.8 m (35 ft) diameter and 247 m (810 ft) long pipe which in turn transfers the water into three penstocks. Each of which is 5.7 m (19 ft) in diameter 60 m (200 ft) in length. This scheme provides 62 m (203 ft) of hydraulic head and up to 450 m3/s (16,000 cu ft/s) to the Francis turbines.[4] Each turbine powers an 80 MW generator for a total installed capacity of 240 MW.[6]

Positive and negative impacts[edit]

The dam has had a positive impact downstream by supplying water for drinking and irrigation. In addition, it has helped reduce floods in the Gharb region along the Ouergha and Sebou Rivers by 90%. It provides water for the potential irrigation of over 110,000 ha (270,000 acres).[3] Electricity produced by the dam's hydroelectric power station also alleviates the burning of 140,000 metric tons of fossil fuels a year along with serving peak energy demand. The dam's reservoir though has a high rate of siltation and it is estimated to lose 60,000,000 m3 (2.1×109 cu ft) of storage each year. The silt trapped in the reservoir also doesn't reach the coastal estuary which increases erosion along the coast.[1]

References[edit]

  1. ^ a b "Lake Al Wahda Morocco". Atlas of Our Changing Environment. Retrieved 17 October 2010. 
  2. ^ R. Arthurton, M. Le Tissier, M. Snoussi, J. Kitheka, Y. Shaghude, A. Kane, G. Flöser and H. Kremer (2008). "Global Change Assessment and Synthesis of River Catchment - Coastal Sea Interactions and Human Dimensions in Africa". LOICZ. p. 10. Retrieved 17 October 2010. 
  3. ^ a b Boumehdi, Hadj Ahmed (December 9, 2007). "The management plan's Water Ouergha had a decisive contribution to the region" (in French). Maghress. Retrieved 17 October 2010. 
  4. ^ a b c Boumehdi, Ahmed (March 12, 2003). "Grands équipements : le barrage Al Wahda". Maghress. Retrieved 17 October 2010. 
  5. ^ "Al Wahda M'Jaara Dam". Structurae. Retrieved 17 October 2010. 
  6. ^ "Hydroelectric Power Plants in Morocco". IndustCards. Archived from the original on 29 September 2010. Retrieved 17 October 2010.