Origins and processes of groundwater salinisation in Barka coastal aquifer, Sultanate of Oman

Askri, Brahim; Ahmed, Abdelkader T.; Bouhlila, Rachida

doi:10.1016/j.pce.2022.103116

“…These three categories of correlation coefficients were bolded in the correlation matrix table. The high and the very high positive correlations of Na + , Cl -, Mg 2+ , and K + with EC and TDS reveal that the observed high salinity is mainly controlled by these major ions which are most likely to originate from the same sources (Kura et al, 2014), such as the occurrence of SWI (Kim et al, 2003) and the dissolution of salts (Askri et al, 2022;Gebeyehu et al, 2022). The very high correlation between Na + and Cl -(r=0.99) emphasizes the effects of chemical weathering, secondary salt leaching, and SWI (Abu-alnaeem et al, 2019;Prasanna et al, 2010;Srinivasamoorthy et al, 2011).…”

Section: Correlation Of Hydrochemical Parametersmentioning

confidence: 94%

“…The very high correlation between Ca 2+ and SO4 2− (r=0.92) may indicate that the source for these two ions is gypsum (CaSO4. 2H2O) or anhydrite (CaSO4) dissolution (Abu-alnaeem et al, 2019;Askri et al, 2022;Dobrzyński, 2007). However, the high correlation of Mg 2+ with Ca 2+ (r = 0.74), Na + (r = 0.84) and Cl -(r=0.85) strongly suggests the same sources for these elements, primarily SWI and carbonate dissolution (Abu-alnaeem et al, 2019).…”

Section: Correlation Of Hydrochemical Parametersmentioning

confidence: 99%

A geochemical approach in assessing seawater intrusion by integrating geospatial techniques: a case study of Ghiss-Nekor coastal aquifer, Central Rif of Morocco

BOURJILA

¹

,

Dimane

²

,

GHALIT³

et al. 2022

Preprint

2

0

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For effective coastal aquifers management, it is strongly required to effectively analyze seawater intrusion (SWI). This study used an integrated approach of hydrogeochemical, statistical, geological, and geospatial techniques to assess the extent of SWI in the Ghiss-Nekor aquifer by evaluating the physicochemical parameters of 52 groundwater samples. Two main groundwater facies were identified, Na-Cl (38%) and Ca-Mg-Cl-SO4 (62%). The correlation matrix and a principal component analysis (PCA) depicted that the high salinization in the study area is influenced by both geogenic and anthropogenic factors, including a potential mixing with seawater. A single indicator or a small number of techniques were insufficient to evaluate SWI owing to the multiple causes of salinization in the study area. As a result, we coupled various geochemical indicators with geospatial methods to assess this complicated phenomenon. Accordingly, several ionic ratios (Cl/HCO3, SO4/Cl, Na/Cl, and Mg/Mg+Ca) and SWI indices (GQIswi and SMI) were overlaid to generate the final map that highlights the regions prone to SWI. Most of the SWI spots were discovered within two kilometers or less from the coast. The saline water detected far from the coast was interpreted as the encroachment of seawater from the Souani area being trapped where the clay-marly substratum is deep. These results support the application of geospatial tools to manage groundwater resources in water-stressed areas with complex aquifer systems, by combining various ionic ratios and indices. These findings will assist decision-makers in the Al Hoceima region in developing suitable groundwater management plans and strategies.

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“…These three categories of correlation coefficients were bolded in the correlation matrix table. The high and the very high positive correlations of Na + , Cl -, Mg 2+ , and K + with EC and TDS reveal that the observed high salinity is mainly controlled by these major ions which are most likely to originate from the same sources (Kura et al 2014), such as the occurrence of SWI (Kim et al 2003) and the dissolution of salts (Askri et al 2022;Gebeyehu et al 2022). The very high correlation between Na + and Cl -(r=0.99) emphasizes the effects of chemical weathering, secondary salt leaching, and SWI (Prasanna et al 2010;Srinivasamoorthy et al 2011;Abu-alnaeem et al 2019).…”

Section: Correlation Of Hydrochemical Parametersmentioning

confidence: 95%

An integrated seawater intrusion assessment in the Moroccan Ghiss-Nekor coastal aquifer using hydrogeochemical and geospatial techniques

BOURJILA

¹

,

Dimane

²

,

GHALIT³

et al. 2023

Preprint

0

View full text Add to dashboard Cite

Effective management of coastal aquifers requires a thorough understanding of seawater intrusion (SWI). The Ghiss-Nekor aquifer is one such area where the extent of SWI is unclear. This study aimed to map the extent of SWI using the hydrogeochemical approach combined to geospatial techniques. Accordingly, we coupled various geochemical indicators, including four ionic ratios (Cl/HCO3, SO4/Cl, Na/Cl, and Mg/Mg+Ca) and two SWI indices (GQIswi and SMI), with geospatial methods to generate a map highlighting the regions most prone to SWI. As a result, approximately 20% of the study area was impacted by SWI, with 70% of SWI spots found within 2 km of the shoreline. A saline water detected up to 5 km from the coast was interpreted, through the use of the aquifer's stratigraphic model, as being caused by the intrusion of seawater from the Souani area that is trapped in a deep clay-marly substratum. These promising findings highlight the effectiveness of the applied hydrogeochemical approach and offer crucial information regarding the extent of SWI. This information will aid decision-makers in the Al Hoceima region in creating efficient groundwater management plans to tackle the effects of climate change, especially the shortage of water resources caused by declining levels of precipitation.

show abstract

“…and the dissolution of salts(Askri et al, 2022;Gebeyehu et al, 2022). The very high correlation between Na + and Cl − (r = 0.99) emphasizes the effects of chemical weathering, secondary salt leaching, andSWI(Abu-alnaeem et al, 2019; Prasanna et al, 2010; Srinivasamoorthy et al, 2011).…”

mentioning

confidence: 99%

A geochemical approach in assessing seawater intrusion by integrating geospatial techniques: a case study of Ghiss-Nekor coastal aquifer, Central Rif of Morocco

BOURJILA

¹

,

Dimane

²

,

GHALIT³

et al. 2023

Preprint

View full text Add to dashboard Cite

For effective coastal aquifers management, it is strongly required to effectively analyze seawater intrusion (SWI). This study used an integrated approach of hydrogeochemical, statistical, geological, and geospatial techniques to assess the extent of SWI in the Ghiss-Nekor aquifer by evaluating the physicochemical parameters of 52 groundwater samples. Two main groundwater facies were identified, Na-Cl (38%) and Ca-Mg-Cl-SO4 (62%). The correlation matrix and a principal component analysis (PCA) depicted that the high salinization in the study area is influenced by both geogenic and anthropogenic factors, including a potential mixing with seawater. A single indicator or a small number of techniques were insufficient to evaluate SWI owing to the multiple causes of salinization in the study area. As a result, we coupled various geochemical indicators with geospatial methods to assess this complicated phenomenon. Accordingly, several ionic ratios (Cl/HCO3, SO4/Cl, Na/Cl, and Mg/Mg+Ca) and SWI indices (GQIswi and SMI) were overlaid to generate the final map that highlights the regions prone to SWI. Most of the SWI spots were discovered within two kilometers or less from the coast. The saline water detected far from the coast was interpreted as the encroachment of seawater from the Souani area being trapped where the clay-marly substratum is deep. These results support the application of geospatial tools to manage groundwater resources in water-stressed areas with complex aquifer systems, by combining various ionic ratios and indices. These findings will assist decision-makers in the Al Hoceima region in developing suitable groundwater management plans and strategies.

show abstract

Origins and processes of groundwater salinisation in Barka coastal aquifer, Sultanate of Oman

Cited by 12 publications

References 39 publications

A geochemical approach in assessing seawater intrusion by integrating geospatial techniques: a case study of Ghiss-Nekor coastal aquifer, Central Rif of Morocco

A geochemical approach in assessing seawater intrusion by integrating geospatial techniques: a case study of Ghiss-Nekor coastal aquifer, Central Rif of Morocco

An integrated seawater intrusion assessment in the Moroccan Ghiss-Nekor coastal aquifer using hydrogeochemical and geospatial techniques

A geochemical approach in assessing seawater intrusion by integrating geospatial techniques: a case study of Ghiss-Nekor coastal aquifer, Central Rif of Morocco

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