Hydrochemical Differentiation of Salinisation Process of the Water in Endoreic Semi-Arid Basin: Case of Rémila Basin, Algeria

Houha Belgacem; Kherici Nacer; Kachi Slimane; Valles Vincent

Hydrochemical Differentiation of Salinisation Process of the Water in Endoreic Semi-Arid Basin: Case of Rémila Basin, Algeria

2008

Houha Belgacem | Kherici Nacer | Kachi Slimane | Valles Vincent

The aim of this study is to determine and treat a hierarchical basis of the variousmechanisms responsible for the space variation of the water quality in a endoreic semi-arid basin. Thewater chemistry showed a large variability in space and time. The total dissolved solid (TDS) in waterincreases from upstream to downstream due to the effect of the arid climate, but also due to the waterrockinteractions and the anthropic polution of surface water. The water chemistry changesprogressively from bicarbonate calcic upstream to sulphated and chlorinated calcic in the median zoneto chlorinate sodic in the Sebkha. Thermodynamic modelling showed the major role of evaporation inthe evolution of the water chemistry. The result indicated calcite precipitation then gypsumprecipitation as well as cations exchanges reactions. Statistical approach allowed to arrange processesthat responsible for the hydrochemical variability according to their important. The increase of watersalinity is due mainly to the aridity process. The differentiation between salty surface water (Sebkha)and deeper water (Chott) is the second process. The combined of the geochemical and statisticalmethods allowed to identify the main variability sources of the water composition and to classify themin this complex system.

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