Geochemical and multivariate statistical study to assess the salinisation origin of the Remila plain groundwater, Khenchela Algeria
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Date
2021-03-31
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
JOURNAL OF WATER AND LAND DEVELOPMENT
Abstract
Abstract: The aquifer system of the Remila plain (Khenchela, Algeria), covering 250 km
2
, is one of the semiarid
regions where groundwater is heavily exploited for urban supply and irrigation. An integrated hydrochemical and
statistical analysis was performed on 70 water samples to identify the main processes and the origin of salinisation of
our waters. Chemical analyses indicate salinity values (TDS) ranging from 568 to 1586 mg·dm
–3
with an average of 869
mg·dm
–3
, with sulphate being the dominant ions, especially in the north and northeastern parts of the region. The
identified chemical facies are SO
4
-Cl-Ca in the northeastern part, SO
4
-Cl-Ca-Mg present in most waters, and HCO
3
-
Ca-Mg in the southeastern part.
We applied the statistical approach to group the waters into three categories using Principal Component Analysis
(PCA) and Hierarchical Clustering Analysis (HCA); 1) saline waters (23%) (TDS > 1000 mg·dm
–3
and SO
4
2–
dominance), 2) moderately saline waters (51%) with HCO
3
–
dominance, 3) moderately saline waters (26%) with
a mixed facies. The binary ion diagrams used suggest that the main hydrochemical processes are: evaporites dissolution
and/or precipitation, accompanied by an exchange and/or reverse exchange of ions. Additionally, another process was
detected in the northeastern part of the area; the saline intrusion of Sabkha waters, favoured by intensive aquifer
exploitation.