Site Visit Djeffara

The Djeffara Basin is located in  south-eastern Tunisia and covers a surface of about 15,000 Km2. It is limited by the Skhira region (N), El Hamma faults, Matmatas and Daher Mountains (W, S-W), and by the Libyan border (S; Trabelsi et al., 2012).

The area is characterized by arid to semi-arid climate (influenced by hot air masses coming from the desert and by humid masses coming from the Mediterranean Sea), with rare and irregular precipitations (Trabelsi et al., 2009).

The region is currently experiencing a rapid demographic growth, and the associated increase in agricultural, tourism and industrial activities (Trabelsi et al., 2012).

Gabes FIeld Trip Nov2013 017

Oasis

During a field trip with Dr. Trabelsi and ENIS’ students of the hydrogeology course I had the opportunity to visit some oasis that used to represent an important centre for agricultural production (and a famous tourist attraction). These areas are now suffering the effect of excessive and uncontrolled groundwater abstraction that resulted in a significant decrease of the piezometric level, an increase in groundwater salinity and sea water intrusion near to the coast.

To adapt to the drawdown of the water table (and the consequent disappearance of several springs) farmers had to start digging new wells in order to obtain water for irrigation.

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Oasis detail

Being the Djeffara partially fed by the Continental Intercalaire (CI) aquifer, most of the pumped groundwater (as well as those from artesian wells) has quite high natural temperature  and can be used for irrigation only after being cooled in atmospheric Gabes FIeld Trip Nov2013 044or vertical

Gabes FIeld Trip Nov2013 028cooling systems.

References

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