Irrigation And Risk Of Saline Pollution. Example: Groundwater Of Annaba Plain (North East Of Algeria)

In the Annaba plain (Northeast of Algeria), the anthropogenic activities have imposed serious unfavorable impacts on hydraulic, hydrochemical and biological balances that influence the socio-economic future of this area. A hydrochemical analysis was performed in 29 wells distributed over the whole of the plain region during the period of high water (December 2013) to assess the quality of groundwater for its suitability for irrigation. Several parameters were analyzed such as pH, TDS, Ca +2, Mg +2, Na+ , K+ , HCO3 - , Cl- and SO4 - . Analysis of results suggests that groundwater in the study area has the same qualities; however the observed degradation reflects a change in the water quality, and the SAR values vary from 0.08 to 16 with an average of 1.3. The US salinity laboratory, Wilcox, and percentage Na+ it suggest that the majority of groundwater samples are not good for irrigation

Hydrogeological Setting of a Karstic Aquifer in a Semi-Arid Region: A Case from Cheria Plain, Eastern Algeria

The Cheria basin is formed primarily by succession of three aquifers; from the more important one to the less important. The first one is the Maestrichtian permeable limestone aquifer which exists on the border. The second is Eocene fissured karstic limestone aquifer that constitutes a great potential of water in the study area. Its thickness is varied from 10 to 200 m. The third is mio-plio-quaternary alluvial aquifer which has no hydraulic interest due to the drought of the latest decade, The basin is affected by several tectonic phases and neotectonic movements. Compared with subsurface karstic phenomena (karstified fractures), these data allow us to propose a diagram of the preferential directions evolution of the karstifications (orientations N40 and N140 principally). There are four significant groups obtained from the rose diagram, these groups have been classified according to their order of importance: the first group is 130°–140°E; the second group is 100°–110°E; the third group is 40°–50°E; and the fourth group is 0°E

GEOPHYSICAL, GEOTECHNICAL, AND SPELEOLOGIC ASSESSMENT FOR KARST-SINKHOLE COLLAPSE GENESIS IN CHERIA PLATEAU (NE ALGERIA)

International audienceSeveral sinkhole collapses were occurred in the many sites in urban areas and/or their rural periphery; in NE Algeria, in the last few years. The abrupt collapse causes damages to properties, infra-structures, and even lives. The most spectacular oneoccurred in February 2009 inside the Cheria city, Northwest of Tebessa department, with a diameter of more than a hundred meters. This abrupt collapse is due to a sudden rupture of the roof of a large underground karst cavity. It caused panic-stricken among the population living near the crater. In order to investigate the origin of this phenomenon, we combine several geophysical and geotechnical methods, such as Ground Penetrating Radar, Electrical Resistivity Tomography, Standard Penetration Test, Mechanical Drill Core, Cave Survey Photogrammetry, etc. It appears that each method may provide specific information. Their comparison allows to precise the results itself, the limits and the application field of each. Consequently a number of open karst voids and disturbed areas were detected in the study area. The results show that sinkholes originate from two different processes: a brutal collapse of karst voids located at shallow depth, by agravitational effect especially building surcharge on top of limestone. And progressive piping and erosion of the thick gravel cover, especially after storms making large depressions. The drawdown of the aquifer following intense pumping could have accelerated these processes. The extension plans of the study area could be established with this methodical acquaintance of the underground conditions of the karst cavities such as: occurrence, depth, geometry and dimensions