Geochemical and isotopic evidence of groundwater salinization processes in the Essaouira region, north-west coast, Morocco

AbstractThe city of Essaouira is located along the north-west coast of Morocco, where groundwater is the main source of drinking, domestic and agricultural water. In recent decades, the salinity of groundwater has increased, which is why geochemical techniques and environmental isotopes have been used to determine the main sources of groundwater recharge and salinization. The hydrochemical study shows that for the years 1995, 2007, 2016 and 2019, the chemical composition of groundwater in the study area consists of HCO3–Ca–Mg, Cl–Ca–Mg, SO4–Ca and Cl–Na chemical facies. The results show that from 1995 to 2019, electrical conductivity increased and that could be explained by a decrease in annual rainfall in relation to climate change and water–rock interaction processes. Geochemical and environmental isotope data show that the main geochemical mechanisms controlling the hydrochemical evolution of groundwater in the Cenomanian–Turonian aquifer are the water–rock interaction and the cation exchange process. The diagram of δ2H = 8 * δ18O + 10 shows that the isotopic contents are close or above to the Global Meteoric Water Line, which suggests that the aquifer is recharged by precipitation of Atlantic origin. In conclusion, groundwater withdrawal should be well controlled to prevent groundwater salinization and further intrusion of seawater due to the lack of annual groundwater recharge in the Essaouira region.

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Characterization of Recharge Mechanisms and Sources of Groundwater Salinization in Ras Jbel Coastal Aquifer (Northeast Tunisia) Using Hydrogeochemical Tools, Environmental Isotopes, GIS, and Statistics

Journal of Chemistry ◽

10.1155/2017/8610894 ◽

2017 ◽

Vol 2017 ◽

pp. 1-20 ◽

Cited By ~ 3

Author(s):

Jamila Hammami Abidi ◽

Boutheina Farhat ◽

Abdallah Ben Mammou ◽

Naceur Oueslati

Keyword(s):

Coastal Aquifer ◽

Isotope Composition ◽

Exchange Process ◽

Environmental Isotopes ◽

Return Flow ◽

Groundwater Salinization ◽

Rock Interaction ◽

Ion Exchange Process ◽

Recharge Sources ◽

Groundwater Samples

Groundwater is among the most available water resources in Tunisia; it is a vital natural resource in arid and semiarid regions. Located in north-eastern Tunisia, the Metline-Ras Jbel-Raf Raf aquifer is a mio-plio-quaternary shallow coastal aquifer, where groundwater is the most important source of water supply. The major ion hydrochemistry and environmental isotope composition (δ18O, δ2H) were investigated to identify the recharge sources and processes that affect the groundwater salinization. The combination of hydrogeochemical, isotopic, statistical, and GIS approaches demonstrates that the salinity and the groundwater composition are largely controlled by the water-rock interaction particularly the dissolution of evaporate minerals and the ion exchange process, the return flow of the irrigation water, agricultural fertilizers, and finally saltwater intrusion which started before 1980 and which is partially mitigated by the artificial recharge since 1993. As for the stable isotope signatures, results showed that groundwater samples lay on and around the local meteoric water line LMWL; hence, this arrangement signifies that the recharge of the Ras Jbel aquifer is ensured by recent recharge from Mediterranean air masses.

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The Scottish Herring Trade, 1470–1600

The Scottish Historical Review ◽

10.3366/shr.2005.84.2.149 ◽

2005 ◽

Vol 84 (2) ◽

pp. 149-165 ◽

Cited By ~ 3

Author(s):

Martin Rorke

Keyword(s):

Sixteenth Century ◽

West Coast ◽

North West ◽

Capital Costs ◽

The North ◽

East And West

This paper uses customs figures to show that herring exports from the east and west coast lowlands expanded significantly in the last six decades of the sixteenth century. The paper argues that the rise was primarily due to the north-west Highland fisheries being opened up and exploited by east and west coast burghs. These ventures required greater capital supplies and more complex organisation than their local inshore fisheries and they were often interrupted by political hostilities. However, the costs were a fraction of those required to establish a deepwater buss fleet, enabling Scotland to expand production and take advantage of European demand for fish while minimising additional capital costs.

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