The qanat of Algerian Sahara: an evolutionary hydraulic system
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This article discusses for the first time a study on the connection and interconnection of qanats located in the Algerian Sahara. During the missions in the oases of Touat and Gourara in 2009, 2010 and 2011, we have been impressed by the complexity of the network of water distribution. The seguias of differents sections take all the senses. Connections are made between qanats to ensure water supply to each owner. In this study, we identified nine models for connecting qanats.
KeywordsQanat Seguia Network Distribution Connection
The oases of Touat and Gourara located in hyper-arid regions of the Algerian Sahara. They are known by the rarity of rainfall and the absence of surface water. To live in these areas, farmers exploit the water of the basement. They dug subterranean galleries (qanats) for collecting the water from the aquifer of Intercalary Continental. The water flows by gravity to the gardens. This ingenious technique is called foggara that resembles of qanat of Iran (Goblot 1963, 1979; Abouei 2006) and Khettara of Morocco (Lighhtfoot 1996; Ben Brahim 2003). This hydraulic system was developed in the southwestern Iranian plate since 3,000 years. Then it spread across 35 countries in the world (Hofman 2007; Adin 2006).
The qanat is an immense hydraulic apparatus consists of three parts: capture, transport and distribution. The capture and transport of water are delivered through a network of underground tunnels equipped with a multitude of ventilation wells of the gallery. As for the distribution of water is ensured by a complex network of seguias and kasriates.
During the years, social organization is established around the qanat. Water is the real property or each owner can sell, buy or rent its share of water. This has created changes in the distribution network of interconnections and connections between qanats. In this study, we are interested in types of connections between qanats oases of Touat and Gourara during 10 centuries of service.
Study site and data used
In 2001, NAWR has inventoried 907 operational qanats. In 2012, this number was revised downwards. According to the information, we obtained from the ksourienne population and owners of qanats despite some rehabilitated of qanats, the number does not exceed 880 service qanats.
Results and discussion
During our missions in 2009, 2010 and 2011 in the oasis of Touat and Gourara, we were impressed by the ingenuity and technical progress in the transfer and interconnections between the qanats. Distribution does not stop just seguias, but it is a real branched network of several kilometers seguias different dimensions. The water flows in all directions to reach madjens and guemouns from a kaseria or more kasriates. Owners who hold shares in several qanats water. Thus, they create of seguias to drain water to the gardens. We found in the oases of Touat and Gourara qanats which are connected upstream or downstream of the kasria by one or two seguias. The connection of qanats is made in two ways: kasria irrigation channel or irrigation channel. They create a real complex network forming a tangle of seguias. It is a scalable network in time. The shareholders of a qanat can buy, sell or lease their shares of water. There is a real hydraulic scholarship. Each transaction of purchase or sale is a change at seguias. The entire process (ente or purchase) will be followed by a companion measures and updating the flow of water sold or purchased parts. All the team of Kial el Ma and Chouhouds participate in this event. The qanats system consists of two parts: collection and distribution system is a collective living.
At the upstream of the kasria.
Downstream of the kasria.
Composed of two parts: collection and distribution, qanats are a dynamic hydraulic system. It is scalable in time and depending on the application. The upstream portion consisting essentially of a drainage gallery whose extension never stops in time. The downstream portion composed of a network of seguias that multiply over time. This dynamic is created by the shareholders of the transactions qanats. In an arid environment such as hyper Touat and Gourara, the value of water is greater than that of the earth; water is bought, sold and rented. The qanat is considered a hydraulic scholarship. There are owners who have shares in several qanats at once. To route the waters of these qanats in the garden, these qanats are connected by seguias. New models have been shown to consist of two types of connection: upstream and downstream of the kasria.
I thank the National Agency for Water Resources me have facilitated access to data. I thank the people of the oasis Timimoun, Adrar and In Salah for their help during our stays.
Plural of Chahad. This is the witness
The person responsible for calculating of rates
Plural of kasria—Small triangular basin equipped with a diverter comb
The person who is responsible for measurement of discharge
Houses of farmers
Copper plate equipped with openings of different diameters. This flowmeter is the qanat
National Agency for Water Resources
Plural of seguia: channel earth
Register of Kial El Ma
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