Groundwater quality evaluation based on water quality indices (WQI) using GIS: Maadher plain of Hodna, Northern Algeria
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Date
2022
Journal Title
Journal ISSN
Volume Title
Publisher
UNIVERSITE MSILA
Abstract
In a semi-arid region of Maadher, central Hodna (Algeria), groundwater is the main source for agricultural and domestic
purposes. Anthropogenic activities and the presence of climate change’s efects have a signifcant impact on the region’s
groundwater quality. This study’s goals were to use water quality indices to evaluate the groundwater’s quality and its suitability for drinking and irrigation, as well as to identify contaminated wells using a geographic information system (GIS)
and the spatial interpolation techniques of ordinary kriging and inverse distance weighting (IDW). The results reveal that
all water samples exceeded the World Health Organization’s standards for nitrate ions and had alarming concentrations of
calcium, chlorine, and sulfate (WHO). According to Piper’s diagram, the groundwater hydrochemical facies is composed
of the elements sulfate–chloride-nitrate-calcium (SO4
2−-Cl—NO3
−-Ca2+ water type). The majority of samples fall into the
poor water category, slightly more than 10% fall into the very poor water category, and less than 10% fall into the good
to the excellent quality category, per the water quality indices, which classify samples in a similar manner. According to
irrigation water indices, every sample is suitable for irrigation. Depending on the direction of groundwater fow, the spatial
distributions of Ca2+, Na+, Mg2+, SO4
2−, and Cl− show that their concentrations are high north of the area and relatively
low south of Maadher village (Fig. 3). Nitrate concentrations are high in the majority of samples, particularly those close
to the Bousaada wadi. In most samples, particularly those close to the Bousaada wadi, nitrate levels are high. Various water
quality models were described, and GIS spatial distribution maps were created using standard kriging and inverse distance
weighting (IDW) techniques through selected semi-variograms predicted against measurements. To determine the origin of
mineralization and the chemical processes that take place in the aquifer—which include the precipitation and dissolution of
dolomite, calcite, aragonite, gypsum, anhydrite, and halite—the groundwater saturation index was calculated.
Description
Keywords
Groundwater quality · Water quality indices · Kriging method · Inverse distance Weighting (IDW) method · Saturation index · Maadher