Groundwater quality in Zagora south-east of Morocco by using physico-chemical analysis and geospatial techniques

Abstract

Groundwater in Morocco is restricted because of the semiarid to arid climatic conditions. In this area, the water resources, especially groundwater, are extremely significant. However, it is under threat from organic and inorganic pollution. Furthermore, it is considered the only source of potable water as well as having different usages in Zagora (the southeast of Morocco), making its quantitative and qualitative protection an urgent priority. The present study focused mainly on the anthropogenic impact on the natural resources and groundwater quality around Zagora city by using geospatial techniques and the Water Quality Index (WQI). This paper uses sampling data from 15 wells in the water table of Oasis Fezouata. 15 samples were collected from wells during rainy and dry seasons in two years 2020-2021 and the analysis of the groundwater quality of studied stations. The suitability of the aquifer Fezouata was investigated using drinking and irrigation water quality indices like SSP, SAR, MHs, PI, and KR. The results showed that sulfate and chloride are the dominant anions in the groundwater samples. While the mean abundance of major cations is Na+ > Mg2+ > Ca2+ > K+, the sodium ion is dominant and K+ is the least abundant. The Water Quality Index suggests that 28.55% are good quality water, (23.90%–47.55%) are poor and very poor quality water, respectively, and 40.24% are unsuitable for drinking purposes in 2020. Furthermore, the WQI of the 2021 campaign showed that only 17.48% were considered good quality water and 38.94% (43.58%) were poor or very poor quality water, respectively. However, 33.21% are unsuitable for drinking water. Based on SAR, PI, SSP, KR, and HM values, the majority of groundwater samples can be used for agricultural purposes, notably those of the upstream part of the study area. These results represent an important contribution to the evaluation of groundwater quality and may be influenced mainly by local factors, especially the wastewater treatment stations and mine discharges, which are the primary sources of deteriorating water quality.