Journal of African Earth Sciences xxx (xxxx) xxx Please cite this article as: Safa Kamal, Journal of African Earth Sciences, https://doi.org/10.1016/j.jafrearsci.2020.104077 Available online 24 November 2020 1464-343X/© 2020 Elsevier Ltd. All rights reserved. Hydrochemical and isotopic assessment for characterizing groundwater quality and recharge processes under a semi arid area: Case of the Haouz plain aquifer (Central Morocco) Safa Kamal a, * , Salma Sefani a , Nour-Eddine Laftouhi a , Abdennabi El Mandour a, b , Jalal Moustadraf c , Mohammed Elgettaf d , Mahjoub Himi e, f , Albert Casas f a Cadi Ayyad University, GEOSCIENCES Laboratory, Faculty of Sciences Semlalia, BP 2390, Marrakesh, Morocco b Director of Mohammed VI Museum for the Civilization of Water in Morocco, Ministry of Habous and Islamic Affairs, Marrakesh, Morocco c Sultan Moulay Slimane University, Equipe G´ eosciences, Environnement et D´ eveloppement Durable, Polydisciplinary Faculty of Khouribga, BP 145 25000, Khouribga, Morocco d Mohammed First University, LCM2E Laboratory G´ eo-Environnement et Sant´ e Team, Multidisciplinary Faculty of Nador, BP 300 Selouane, 26702, Nador, Morocco e Mohammed First University, G2E Laboratory, ENSAH, BP 3, Ajdir Al Hoceima, Morocco f Barcelona University, Facultat de Ciencies de la Terra, MPGA, 02028, Barcelona, Spain A R T I C L E INFO Keywords: Plio-quaternary aquifer Central Haouz Piezometry Hydrochemistry Groundwater quality δ 18 δD ABSTRACT The Haouz plain aquifer is one of the most important aquifers in Morocco. It is supporting so many activities tightly connected to the local and national socioeconomic development (agriculture, tourism, industry). The recurrent drought the region has been experiencing, had led to a major mobilization of groundwater to meet human needs and socioeconomic objectives. A hydrogeochemical, isotopic and statistical study based on feld data was conducted to understand the functioning of the aquifer, to characterize the processes controlling the groundwater’s chemistry, as well as identify areas presenting water salinity anomalies. The objective of this study is to develop a conceptual model of functioning of the Haouz aquifer, leading to a better comprehension of the spatial evolution of mineralization regarding the geological frame and the current context of exploitation to evaluate groundwater suitability for domestic and agricultural use. The Plio-Quaternary aquifer water-table contours map showed a fow direction from the High Atlas Mountains, in the south (recharge zone) towards the Tensift bed river in the northwest part of the region. Physico-chemical analysis showed that electrical conductivity are essentially controlled by the chloride and sodium ions and varies over a wide range from 326 to 6800 μS/cm. Regarding irrigation, poor groundwater quality was defned specially near Tensift River in the north of the study area. Stable isotopes contents of water, range respectively from 8.35 to 5.26‰ for δ 18 O and from 54.4 to 32.4‰ for δD. The recharge altitude of the aquifer was estimated between 860 and 2110 m, following an altitudinal gradient of 0.25% per 100 m. 1. Introduction Given its geographical situation, Morocco is dominated by a semi- arid to arid climate, except in its northern part and mountainous areas. In this context, groundwater plays a strategic role and constitutes a privileged support for the socioeconomic development. The water demand is increasing year after year to cover water for domestic, agri- cultural, recreational and industrial needs. Pressures on water resource made it very fragile, nowadays it faces many problems, in particular, pollution and salinization constituting a real and sensitive risk of deterioration of water quality, as well as the development of pumping beyond the authorized limits. Water resources constraints at the local and national scales are similar in other regions of the world with similar climatic characteristics, such as El Eulma region Algeria (Belkhiri and Mouni, 2012), Sfax region in Tunisia (Trabelsi et al., 2005), southern region of Portugal (Stigter et al., 2005), Almeria region in Spain (San- chez Martos and Calaforra, 1999). At the national level, water issues, especially groundwater saliniza- tion, has become the center of interests of scientifc researchers and managers. It has been raised by several studies across the country. * Corresponding author. E-mail address: safakamal26@gmail.com (S. Kamal). Contents lists available at ScienceDirect Journal of African Earth Sciences journal homepage: www.elsevier.com/locate/jafrearsci https://doi.org/10.1016/j.jafrearsci.2020.104077 Received 7 June 2018; Received in revised form 26 July 2020; Accepted 17 November 2020