al-Wahda reservoir
| Al Wahda | |||||||||
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| Coordinates | 34 ° 35 '54 " N , 5 ° 11' 51" W | ||||||||
| Data on the structure | |||||||||
| Construction time: | 1988-1996 | ||||||||
| Height above foundation level : | 88 m | ||||||||
| Height above the river bed : | 166 m | ||||||||
| Crown length: | 2 600 m | ||||||||
| Crown width: | 50 m | ||||||||
| Base width: | 300 m | ||||||||
| Power plant output: | 240 MW | ||||||||
| Operator: | Ministry of Energy, Mines, Water and Environment, Morocco | ||||||||
| Data on the reservoir | |||||||||
| Water surface | 123 km² | ||||||||
| Reservoir length | 15 km | ||||||||
| Reservoir width | 1-6 km | ||||||||
| Storage space | 3000 million m³ | ||||||||
| Catchment area | 6th 200 km² | ||||||||
| Design flood : | 13 000 m³ / s | ||||||||
| Particularities: |
Largest reservoir in Morocco |
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The al-Wahda reservoir ( Arabic سد الوحدة Sadd al-Waḥda = "dam of unity") is located in the southern foothills of the Rif mountain rangeor on the eastern edge of the Gharb plain in the regions of Fès-Meknès (approx. 98%) and Tanger-Tétouan-Al Hoceïma (approx . 2%) in northern Morocco ; it lies north of the Sebou river plain.
history
Construction began in 1988 on the recommendation of the Supreme Council for Water Management and Climate Research; Trial operation started in 1996 and in March 1997 the project was officially inaugurated by King Hassan II .
Dimensions
The gravity dam, consisting of approx. 28 million m³ of tamped earth with a concrete cover of 720,000 m³, is about 88 m high and 2600 m long; at its base it is about 300 m wide from the discharge side to the wall side of the reservoir and about 50 m wide at the flattened dam crest, which is provided with a road and ends with a wall on the reservoir side. The overflow channel for flood relief leads with a width of 100 m over the top of the wall, the length of the channel is 650 m. This makes the al-Wahda reservoir - in front of the Al-Massira reservoir - the largest in the Kingdom of Morocco.
Functions
irrigation
The dam is used for irrigation and energy generation and is operated by the Ministry of Water Management and Climate Research in Rabat. The reservoir is fed by the Ouerrha river and, thanks to its ideal, natural location and nature, allows almost complete control over the water masses of the river.
This made it possible to irrigate large agricultural areas that were previously rarely used: over 100,000 hectares of fallow land in the Gharb were converted into productive arable land, as well as 15,000 hectares in the downstream valley of the lower Ouerrha River. Thanks to this project, agricultural production in Morocco has increased significantly: the yield of industrially grown agricultural products such as grain or field crops rose by 1.13 million tons per year from 1996 to 2006 after the dam was put into operation. Fruit and vegetable production could be increased by 465,000 tons and the annual rice harvest increased by 27,000 tons. At the same time, the dairy farmers were able to increase their earnings by 173 million liters per year. With the increase in yields, there was also a considerable improvement in the income situation of the farmers - the net profit per unit of production quadrupled on average.
Power generation
In addition to the production and storage of water for agriculture, the dam is also used to generate energy: the al-Wahda power plant with its three 80 MW Francis turbines contributes a nominal 22% of the total installed hydro-electric power plant capacity in Morocco and has been feeding in on average since 1996 feeds around 400 million kWh per year into the national power grid, which corresponds to 16% of the total output of all Moroccan hydropower plants. The power plant is mainly used to cope with peaks in demand, with a running time of 2,000 to 3,000 hours over the whole year.
Protection against floods
A positive side effect of the dam is the reduction of the damage that has so far been caused by flooding in the Gharb plain by the Oued Ouerrha. The reservoir has large flood reserves that can hold back sudden rains. In the course of a winter, up to 1000 million cubic meters of water pass through the overflow channel of the reservoir - through skillful level management and controlled discharge of the high water, the flooding in the Gharb plain could be reduced by 90%.
Drinking water supply
In addition, the dam supplies up to 600 million m³ of water per year to the city and region of Casablanca , which is used there as drinking water and for industry, and to the region in the south of Rabat , where it is mainly used for agricultural irrigation .