The quality of surface water and groundwater in the eastern Haouz and Tassaout area, Morocco (original) (raw)
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Environmental Earth Sciences, 2014
The present study has analyzed the origin of recharge and groundwater salinity in the Haouz alluvial plain, located in Central Morocco. Stable isotopic data (18 O, 2 H) indicate that the recharge of the alluvial aquifer is dominated by high-altitude meteoric water originating from the High-Atlas Mountains that border the plain to the south. Tritium globally indicates the presence of recent groundwater, as well as mixing between old and recent groundwater. Alluvial groundwater salinity varies from east to west. This variability is mainly induced by enrichment in chloride and sulfate salt contents. Strontium content reveals that sulfate could be related, respectively, to the influence of the Senonian carbonate deposits containing gypsum. Dissolution of halite is revealed by the plot of 18 O vs Cl, where the most saline samples do not show any changes in 18 O. Br/Cl ratio varies in a wide range, probably due to an orographic effect. The nitrate distribution was analyzed using indicator-geostatistical techniques resulting in probability maps. Nitrate contamination is shown to occur particularly in the eastern part of the Haouz plain. In this paper, some aspects of groundwater resources management are addressed. Different management actions are identified with regard to the current water resources status and to the land and water uses. In this framework controlling groundwater abstraction, optimizing irrigation and enhancing mountain-front recharge constitute the major key management actions that should be carried out.
The Rharb hydrogeological basin, of which our study area is part, is one of the main sources of drinking water and irrigation for a large part of northern Morocco. The groundwater of the Rharb basin is characterized by its poor quality, which may be related to its high mineralization. In order to characterize these features, we have applied an approach that relies on the compilation of hydrochemical parameters, hydrogeological drilling, and geophysical data (VES and well logs). The main objective of this work is to highlight some of the features in the geometry of the quaternary deposits and identify the origin of the groundwater mineralization as well as study its spatial variability. The obtained results showed that the geometry of the Amirian bedrock is mainly constituted by two depressions separated by NW-SE and NE-SW trending faults. The main chemical facies of the groundwater are a mixture of calcium and magnesium sulfate chloride facies and chloride-sodium facies. The origin of this mineralization is related to reverse ion exchange processes, halite and gypsum dissolution, in addition to the processes of evaporation-crystallization and water-rock interaction under geological conditions that favor residence time. Such results open up new perspectives for the sustainable management of this important hydrogeological groundwater area.
Water
Located in the southeastern region of Morocco, the Zagora area mainly relies on groundwater as a source of water supply. However, this groundwater is often of concern, due to the limited recharge and unfavorable geological conditions for the development of the aquifer. Despite this, private wells in the Zagora ditch reveal relatively rich water resources. Geochemical and isotopic studies were conducted in the area to understand the origin of the groundwater and its salinity, aiding in informed water management strategies to assist in better planning and regulation of well construction, as well as in mitigating the impacts of high salinity on local water supply and agricultural systems. The results show that the water quality varies, with some wells having conductivity values in excess of 5 mS/cm. Most groundwater samples have high salinity and low pH due to the CO2 dissolved in groundwater. Geochemical analysis indicated two chemical facies: chloride–sulfate calcic/magnesic and bica...
Environmental Science and Pollution Research, 2021
The coastal aquifer of the Essaouira syncline (Morocco) was studied to identify the main processes at the origin of the salinization of groundwater. In fact, a multicriteria analysis approach on hydrochemical data and physicochemical parameters of the Plio-Quaternary aquifer was used to understand their spatiotemporal variation and their origins. Currently, integrated water resources management has become paramount to both local, regional, national and international. This management is favored by extreme hydrological events (droughts or oods) which can have direct in uences on human, economic and political aspects. Appropriate management of a resource requires its evaluation. The statistical study by Kohonen's self-organized classi cation (SOM) of hydrochemical data for the years 1995 and 2009 is used to process 47 samples distributed over the entire study area; it showed an evolution of the values of the parameters. Physico-chemical as a function of time and space with an increase in the values of the parameters, from the center of the study area towards the southwest. Introduction Groundwater remains the main water resources for drinking water consumption, agricultural exploitation, and for industrial and tourist use by inhabitants of towns and rural areas in coastal areas with arid climates and semi-arid. Several factors are involved in the degradation of electrical conductivity and consequently the quality of groundwater, these factors can be of natural origin (leaching, evaporation, dissolution, marine aerosols) or of anthropogenic origin (marine intrusion, over-fertilization, water drainage, wastewater spreading, automobile emissions), and sometimes the combination of anthropogenic and natural origins (Andreasen and Fleck 1997, Oulaaross 2009). Generally in nature, the groundwater in a relation with the surface water in ltrated and percolated in the unsaturated zone to reach the aquifer they contain (saturated zone), the effective in ltration rate to in uence the piezometric evolution and consequently the evolution of the water quality of the reservoir. Indeed, a large effective in ltration causes an increase in the piezometric level, an increase in its ow and leads to the dilution of its mineralization (Urish and Frohlich1990;Sherif et al. 2006 ; Attwa and Zamzam 2020). On the contrary, a weak or absent effective in ltration combined with intensive pumping causes a lowering of the water table and a mineral overconcentration of the groundwater (Chafouq et al. 2018). These waters are often threatened by contamination by pollutants of different origins which can be biological, chemical or physical. The Essaouira basin has seen, like other regions of Morocco, a signi cant decrease in water supplies in quantity and quality. This situation has resulted in the reduction of agricultural productivity and the degradation of several ecosystems. However, this basin has an aquifer system formed by a set of aquifers of unequal size. These aquifers can offer a natural regulating capacity which makes them valuable in ensuring a safe regular supply. The reserve also makes it possible to meet seasonal needs through temporary overexploitation to the extent that recovery is possible (Chamchati et al., 2013). The diffuse pollution generated by marine waters is ampli ed by point sources of pollution mainly represented by human and agro-industrial activities. As a result, the salt contents recorded in certain places greatly exceed the standard of drinking water or even irrigation (Bahir et al. 2001). This situation risks ultimately jeopardizing the sustainability of agricultural activity as a whole, harms public health and compromises the self-puri cation power of groundwater. These waters circulate slowly through the subsoil, so much so that pollution from human activities can persist over long periods that can range from a few years to several decades or even longer for certain speci c aquifers. In other words, in coastal areas, groundwater resources require special attention to minimize saltwater intrusions, either locally, or on a regional scale. The extent of salt water intrusion depends on the geometry, structure and properties of the aquifer, the stresses applied to the aquifer (pumping, etc.) and the ow of fresh water and salty exchanging with the surrounding environment(Karroum etal., 2017). This situation is all the more critical as the groundwater in this study area (Essaouira coastal area) constitutes the only water resources available to local populations (Ouzerbane et al. 2014 ;Bahir et al. 2019). This study will take place in the context of regional planning. It will make it possible to prepare, con rm or supplement the orientations and choices necessary for a harmonious development of the region taking into account, as far as possible, all the needs and the corresponding constraints. Geographical And Geological Location The Essaouira basin is a coastal area located in the center-west of Morocco. It belongs to the Moroccan Atlantic margin and covers approximately an area of 20,000 km² of the eastern Mesozoic passive margin of the central Atlantic Ocean. The basin is limited to the north by the Tensiftriver, to the south by the western High Atlas, to the east by the plains of Imi-N-Tanoute and Chichaoua and to the west by the Atlantic Ocean. It is a plateau, slightly raised to the South and to the North, gently sloping down towards the Atlantic Ocean then suddenly lowering to give rise to the coastal zone with dune relief. The study area known as the synclinal Essaouira is part of the coastal area of the basin. It is bounded to the north by Qsob river, to the south by Tidziriver, to the east by the reliefs of Haha North and by the diapir of Tidzi and to the west by the Atlantic Ocean. It is not very rugged and is characterized by a relief of low hills with altitudes between 0 and 800 meters, modeled by a low density hydrographic network which ows into the Atlantic Ocean (Fig. 1). Geologically, the formations outcropping in the synclinal zone of Essaouira are generally Quaternary and Plio-Quaternary in age (Fig. 2). Going from the South to the North of the study area, the stratigraphic series extends from the Triassic to the Quaternary (Ouzerbane2015 ;Ouzerbane et al. 2019 ; Cohen et al. 2020). The Triassic formations outcrop in the southeastern part of the study area at the level of the Tidzi region in a NE-SW direction forming the Tidzidiapir over a large area while in the extreme south of the area. study these formations outcrop over a smaller area along the Aghbalou river. These formations are mainly known by saliferous red clays, doleritic basalts and reddish sandstone pelites(Suter1958). The Jurassic outcrops are formed mainly by limestones and gypsiferous marl-limestones dating from the Upper Jurassic of the Jbelhadid located north of the
E3S Web of Conferences
The coastal aquifer of Chtouka, with an area of 1250 km2, is located south of Agadir city in the Massa basin. The Chtouka aquifer is made up of a complex of heterogeneous formations mainly represented by alluvium and Plio-Quaternary lacustrine limestones which rest on the marls and sandy marls of the Miocene, which constitutes the substratum of this aquifer. The groundwater of the Chtouka aquifer is mainly used for agricultural and drinking water supply of Biougra, Ait Amira centers, and the rural communes of the plain. The average water withdrawals from the groundwater during the period of 2000-2015 are estimated at 85 Mm3/year, of which 90% corresponds to withdrawals by agricultural pumping. These withdrawals generated 58 Mm3/year which has led to a depletion of the groundwater reserves. The aquifer reservoir is mainly supplied by the infiltration of rainwater and partly by the irrigation water percolation by gravity which covers only 2% of the irrigation perimeter with a surface ...
The characteristics of Essaouira basin water resources are a semi-arid climate, which is severely impacted by the climate (quantity and quality). Considering the importance of the Essaouira aquifer in the groundwater supply of the region, a study was conducted in order to comprehend this aquifer groundwater evolution. The Essaouira aquifer is a coastal aquifers located on the Atlantic coastline, southern (Morocco), corresponding to a sedimentary basin with an area of near 200 km2.A water sampling from twenty wells, drillings and sources belonging to the Plio-quaternary and Tu-ronian aquifers was realized (what was realized). Samples examined from the ground for electric conductivity and temperature, determined waters belonging to the Plio-quaternary and Turonian aquifers present very variable electric conductivities from 900 μs/cm to 3880 μs/cm. In spite of this variability, they form the same family and are characterized by sodium-chloride facies. There exists, however, a good correlation between the electric conductivity and chloride and sodium contents. Therefore the lower electric conductivities are situated in the North quarter immediately in the south of the Wadi Ouazzi.
Environmental Earth Sciences, 2015
Under the arid climate in the southern sub-Saharan catchments of Morocco, groundwater is the only permanent water supply. Usually, the groundwater is scarce because of the low recharge. However, the mining activities in Oumjrane area (Eastern Anti-Atlas Mountains) reveal that water resources are relatively abundant in the fissured Ordovician aquifer. To understand this phenomenon, geochemical and isotopic investigations were carried out in the region. The results show that the quality of water is variable in superficial and deep aquifers. The specific conductivities range from 0.44 to 10 mS/cm. Most groundwater samples from the deep aquifer indicate high salinity, low pH, and CO 2 anomalies. Geochemical analyses show that groundwater concentrations are mainly controlled by (i) evaporite dissolution (halite and gypsum), (ii) cation exchange with clay minerals, (iii) silicate hydrolysis, and (iv) dedolomitisation. Carbonate precipitation takes place in the groundwater issuing from the mine sector. The discharge is estimated at 386 T/year downstream of the Bounhass mine. Moreover, stable isotope (d 2 H and d 18 O) and chemical analyses reveal a clear difference between the alluvial and deep aquifers. They also show a local recharge for the alluvial aquifer from Saghro inliers. Low isotope ratios are found in the Ordovician formation aquifer, indicating a deep water circulation. These waters could originate from the High Atlas and/or Saghro Mountains and flow through fissures and fault networks. Connections to regional faults and veins may play a role in it, as well as the proximity of the major contact with the High Atlas. Keywords Geochemistry Á Salinity Á Stable isotopes Á Arid environment Á Eastern Anti-Atlas Á Morocco Article impact statement This is the first study of groundwater in the mining area of Oumjrane. The main focus is to understand the origin of the abundant groundwater resources, under an arid environment, and the hydrochemical processes that occur within the aquifers.
Hydrogeochemical mechanisms and recharge mode of the aquifers under semiarid climate from Morocco
Applied Water Science
Comprehensive investigations of groundwater were performed in the Ouazzi Wadi area, north part of Essaouira basin, Western Morocco. In the present investigation, hydrogeochemical data together with environmental stable (18 O, 2 H, 13 C) and radioactive (3 H and 14 C) were used to get an insight into the processes controlling groundwater mineralization and their recharge modes. Hydrogeochemical approach revealed that the observed groundwater mineralization is linked to (1) dissolution phenomenon of evaporitics minerals (halite, gypsum, and anhydrite) and of carbonates minerals (dolomite), (2) cations exchange processes, and (3) marine effect. Groundwater quality for drinking purpose has been evaluated and compared to WHO standards; the obtained result shows that the consumption of groundwater in the study area requires a treatment before use as drinking water. As for irrigation purpose, using USSL and Wilcox diagram, groundwater remains suitable for plants supporting high salinity. Data inferred from isotopic approach indicated that (1) the groundwater samples are of a meteoric origin and the recharge of the aquifer is assured by direct infiltration of precipitations without notable evaporation, (2) the recharge of aquifers is assured at the Sebt Kourimat region, near the samples 7, 8, and 9, where the high tritium contents are observed, (3) the age evaluations using radioisotope techniques vary between actual age and Pleistocene.
Mapping of groundwater quality in the Turonian aquifer of Oum Er-Rabia Basin, Morocco: a case study
Environmental Geology, 2006
This study takes the groundwater of the Moroccan limestone aquifer of Oum Er-Rabia as an example of statistical and cartographical approaches in water resources management. Statistical analyses based on frequency distribution and PCA methods revealed the homogeneity of waters with the existence of abnormal points and have helped to assess correlations between the studied variables. The mapping approach illustrated that waters are influenced by the lithology of the surrounding rocks and are of Ca-Mg-HCO 3 , Ca-Mg-Cl-SO 4 , and mixed types according to the Piper classification. The quality of water is of high to medium, north of the basin, but it is of medium to bad, NE and south, due to excessive contents of chloride, sulfate and nitrate. According to the US Salinity Laboratory classification, water used for irrigation in the eastern and the southern parts of the basin should take into consideration the drainage conditions, the nature of plants and the addition of gypsum doses.
Assessement of the Physico-Chemical Quality of Groundwater in the Sidi Yahya Region, Gharb, Morocco
2019
Groundwater is the most important natural resource which cannot be optimally used and sustained unless its quality is properly assessed. The aim of this work is to study the physico-chemical quality of groundwater in the water table of the Sidi Yahya region (Gharb, Morocco). We have carried out a qualitative study of the water in different sites of the irrigated perimeter of Sidi Yahya. In fact several measurements (pH and groundwater depth) and laboratory analysis (ionic balance) were conducted to determine the physico-chemical characteristics of water. We prospected 33 wells distributed into 6 zones: A, B, C, D, E, and F. Data were statistically analyzed using the analysis of variance (ANOVA). The results showed that the depth of water table varied between 6 and 96 m and that 51.5% of the wells were highly to extremely saline, thus inadequate for irrigation. The studied zones do not have the same salinity level. In fact, the B and F zones represent a significantly higher salinity ...