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Ben Said M.,University Mohamed Khider of Biskra | Ben Said M.,Center for Scientific and Technical Research on Arid Regions | Ouamane A.,University Mohamed Khider of Biskra
Labyrinth and Piano Key Weirs - Proceedings of the International Conference on Labyrinth and Piano Key Weirs, PKW 2011 | Year: 2011

The spillway represents a fundamental importance for the safety of dams; however, its cost represents a significant part of the global cost of dam. The labyrinth weir represents an effective alternative for the control of floods with a low realization cost. It is characterized by length crest longer than that of a rectilinear weir for a same width of influence; this allows to increase the discharge significantly. The labyrinth weir is conceived using several geometrical simple and repetitive forms. The two concepts, simplicity and repetition, makes the conception and construction easy and economic. However, the variety of forms of the labyrinth and the complexity of the flow did not allow the determination of an optimal shape for this type of weir. This paper is interested in the study of optimization of the labyrinth weir by an experimental way. The study showed that the flow on the labyrinth weir is dependent of various geometrical parameters which characterize this particular type of weir. © 2011 Taylor & Francis Group, London.


Noui A.,University Mohamed Khider of Biskra | Noui A.,Center for Scientific and Technical Research on Arid Regions | Ouamane A.,University Mohamed Khider of Biskra
Labyrinth and Piano Key Weirs - Proceedings of the International Conference on Labyrinth and Piano Key Weirs, PKW 2011 | Year: 2011

Labyrinth weirs are adequate solution in dam rehabilitation projects when the storage and\or discharge capacity has to be increased. Piano key weirs (PKW) are particularly interesting due to their structure as well as their upstream and downstream flow conditions. PKW have a different geometrical shape than the classic labyrinth weirs. The keys are rectangular shaped with inclined key bottoms allowing the use of overhangs. Two different types of PKW were defined: Type A shows two overhangs, one upstream and one downstream. Type B does not have the downstream overhangs. Physical modelling tests have showed that the efficiency of Type B is higher than of Type A. The study reveals that flow on the PKW is influenced by different geometrical parameters. The dimensional analysis allowed the development of relations between discharge capacity and the shape of the PKW. © 2011 Taylor & Francis Group, London.


Bougherira N.,Center for Scientific and Technical Research on Arid Regions | Rezek A.,Center for Scientific and Technical Research on Arid Regions | Drouiche A.,Center for Scientific and Technical Research on Arid Regions | Hamzaoui W.,Center for Scientific and Technical Research on Arid Regions | And 2 more authors.
Journal of Materials and Environmental Science | Year: 2011

The region of El-Ghrous, has known an important agricultural rise which required the extensive use of inputs, where the risk to cause pollution of ground water in the region (Mio-Pliocene and Lower Eocene). These two layers are collected from boreholes of which there are 40 holes at the lower of the Eocene and 13 at the Mio-Pliocene. Chemical analysis conducted in the laboratory of CRSTRA ( November 2010), showed that the water was particularly rich in SO4 2-, Ca2+, Na+, K+, Mg2+ and HCO3 -. In detail, we note that the sulfates are high concentrations reaching values ranging from 1.43 g.l-1 to 3.14 g.l-1 in the water of the Mio-Pliocene and 0.16 g.l-1 to 2.24 g.l-1 in the water from the lower Eocene, which gives the water a calcium sulfate facies sometimes to sodium sulfate. The measured conductivity is still high for the waters of the Mio-Pliocene with 5.62 mS/cm; however we notice relatively drop for the waters of the lower Eocene (2.55mS/cm). These concentrations determined, led to the calculation of the SAR. The latter combined with the conductivity to determine the suitability of ground water for irrigation.


Drouiche A.,Center for Scientific and Technical Research on Arid Regions | Harrat N.,Center for Scientific and Technical Research on Arid Regions | Zahi F.,Center for Scientific and Technical Research on Arid Regions | Boucham N.,Center for Scientific and Technical Research on Arid Regions | And 2 more authors.
Journal of Materials and Environmental Science | Year: 2011

The Aquifer System of the Sahara shared by Algeria, Libya and Tunisia contains huge reserves of water, characterizing by a lower renewable resources. It consists of two aquifer levels, the Continental Intercalary and the Terminal Complex. The reserves are estimated at 30.109 m3 (SASS, 2003). The last thirty years have shown an increase in exploitation of these aquifers, with an annual throughput of 0.6 109 m3 in 1970 to a rate of 2.5 109 m3 in 2005, indicating overexploitation. The Biskra region belongs to this group of aquifers. It has in recent years, a large hydro-agricultural development with a growing population, resulting in a considerable increase of water demand. For the setting up of a monitoring system for exploitation of water resources in the Saharan zone, the ANRH services in collaboration with CRSTRA have established a monitoring network to monitor changes in groundwater piezometric level of Terminal Complex. This includes 23 piezometers located in different exploited aquifer system. The piezometric mapping shows a drawdown of about 20 m in lower Eocene in the localities of Tolga and Doucen. This drawdown differs from an area to another in the Mio-Pliocene aquifer system, and it is 30 m between Ourellal and Sidi Okba and about 6 m in Zribet El Oued.

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