Accessibility of fresh water, the nature's gift wheels the foremost part of the world economy. The sufficient supplies of water are essential for agriculture, human intake, industry as well as regeneration. The Oued Righ region is located in Algeria's South-East, specifically in the North-East of the Sahara, on the Northern edge of the Grand Erg Oriental and the Southern border of the Aures massif. This area appears as a lower Sahara synclinal basin and is part of a broad North-South trending ditch.

It is famous for its date palms, the development of the date culture in this region is attributed not only to the population’s efforts, but above all to the particular climatic conditions, the favorable soil characteristics and the existence of significant groundwater. The aim of this study is to understand the results obtained from using different approaches of water   hydrodynamics in   the Complex Terminal aquifer. The aquifer’s hydrodynamic characterization was carried out using hydrodynamic parameters and piezometry. As a result, the transmissivity and permeability obtained data using traditional Cooper-Jacob method showed that the flow capacities of the aquifer environment and the productivities of the structures are important in the studied zone where, the highest value of transmissivity equal 2.36× 10^2-m²/s is found in the central part of the study area in El-Meghair. The establishment of piezometric maps reveals a flow direction oriented toward the chott.

Thorough sedimentological and palaeontological analyses of four expanded Upper Cretaceous sections in northern Tademait had allowed us to address and reconsider the stratigraphical framework of the so-called ‘Continental Intercalary’ and ‘Hamada series’ in this remote Saharan area. These four sections (i.e., Meguidene, Gara Samani, Oued El Mezaourou-Gour Louazouaza, and El Menia) document Upper Cretaceous strata overlying post-Palaeozoic substrata and ranging from the clastic Gara Samani Formation (of supposed early Cenomanian age), through the El Golea Clays (lower–middle Cenomanian), the Gour Louazouaza Formation (lowermost upper Cenomanian, with the Oued El Mezaourou Limestone Member ranging from the Neolobites vibrayeanus to the Vascoceras gamai ammonite zones of the uppermost Cenomanian, and the Marls of Gara Mta El Mar Member of the Choffaticeras sinaiticum ammonite Zone in the lower, but not lowermost, Turonian), to the Ain El-Hadjaj Formation (of alleged Campanian age). Most efforts have concentrated on the ‘mid’-Cretaceous deposits that yield vertebrates and diversified ammonite and macrofossil assemblages. In spite of these improved correlations, further bio-chronostratigraphical data are needed in order to constrain the stratigraphical gap within the Gour Louazouaza Formation at the Cenomanian–Turonian boundary (C/TB) better. The succession studied can be correlated with other similar-aged sections in North Africa and illustrates the development of braided fluvial and aeolian dune-interdune environments followed by a ramp depositional system in response to the early Late Cretaceous second-order sea level rise along the southern margin of the Tethys.

The Maastrichtian-Thanetian Ncham Member of the Aurès Basin in northeastern Algeria contains variably lenticular microfossils, which are defined as Laffitteina genera. It is a large benthic foraminifera, studied from three stratigraphic sections. The systematic study of Laffitteina led identification of nine species, four of which, Laffitteina marsicana, L. aff. mengaudi, L. monodi and L. erki were recorded for the first time in the study area. Various species of Laffitteina were used as index fossils to recognize the K/Pg transition in the Aurès Basin. The last occurrence of L. oztuerki marks the end of the Maastrichtian, which was found in association with Omphalocyclus macroporus (Lamarck) in the upper Maastrichtian. The first occurrence of L. erki marks the Thanetian age, while the Danian and Selandian deposits are missing in the field after a general emersion in the early Paleocene, despite the absence of a visible non unconformity. It could therefore be proposed that the K/Pg transition may occurs in the last 10 m of the Ncham Member. Concerning the paleoenvironment, Laffitteina is considered as a resistant foraminifera and thrives in meso-to eutrophic environments (lagoon). Microfacies data from the Upper Cretaceous-Lower Paleogene limestones of the Aurès Basin suggests a carbonate platform with shallowing-up sequential organization, mainly controlled by fluctuations in sea-level.

The Coniacian-Santonian series in the Aures Mountains of northeastern Algeria is characterized by marly-dominated sedimentation processes. This study aims to comprehensively investigate this series by combining lithostratigraphic and biostratigraphic data. The unique paleogeographic position of the Aures basin supports the co-occurrence of diverse paleontological contents in the Upper Cretaceous sediments. The methodology employed in this study includes a detailed bio-lithostratigraphic analysis to subdivide the Coniacian-Santonian series into two distinct sets. The first set comprises alternating marl-limestone units that exhibit a high fossil concentration from the Coniacian age, while the second set mainly consists of marly sediments corresponding to the Santonian age. The results obtained from this study highlight the geographical distribution of litho-biostratigraphic characteristics and reveal the presence of two formations. The lower formation is characterized by carbonated marls intercalated with limestone banks, containing fossils of Peroniceras (Tissotia tissoto) from the Coniacian age. Meanwhile, the upper formation is predominantly marly and indicates the Santonian age by displaying fossils of Palcenticeras polypsis. Furthermore, a biostratigraphic analysis focused on foraminifers allows for the subdivision of the Coniacian-Santonian series in the Aures Mountains into three distinct biozones. The first biozone corresponds to the lower Coniacian age and is identified by the presence of Dicarinella primitiva. The second biozone represents the middle to upper coniacian age and contains Dicarinella concavata fossils. Finally, the third biozone, belonging to the Santonian age, is marked by the occurrence of Dicarinella asymetrica. The boundary between the Coniacian and Santonian series in the Aures Mountains is characterized by the first appearance of Dicarinella asymetrica and Palcenticeras polypsis species. This multidisciplinary study provides valuable insights into the litho-biostratigraphic characteristics and geographical distribution of the Coniacian-Santonian series in the Aures Mountains. The findings make a significant contribution to a better understanding of sedimentary processes and the paleontological content within this region during the Upper Cretaceous period.

The systematic study of bivalves collected from the Cenomanian-Turonian succession of the Bellezma-Batna Mountains (northeastern Algeria) led identification of nine species belonging to eight genera, three of which, Nicaisolopha nicaisei (Coquand), Pterotrigonia (Scabrotrigonia) scabra (Lamarck), and Agelasina plenodonta Riedel, were recorded for the first time from the study area. Particular attention was paid to the rudist fauna, including Vaccinites praegiganteus (Toucas), Vaccinites rousseli (Douvillé), and Sauvagesia nicaisei (Coquand), occurring in very large numbers within composite biostromes (5 to 10 m-thick) composed of both hippuritids and radiolitids. A distribution map of Cenomanian-Turonian bivalves is established based on data from Algeria and other localities.

The map shows that the most bivalve genera are widely distributed and some of them are probably cosmopolitan. They are present in northern Africa, Middle East, south and northern Europe, western Africa, and South America, with some taxa are also known from the south-eastern coast of Africa (Madagascar and South Africa) and India.

The middle Cenomanian deposits of the southern part of the Bellezma-Batna Mountains, northeastern Algeria, have been investigated to evaluate the response of Foraminifera to variations of paleo-bathymetry, oxygen, and salinity. The Djebel Azeb section, with a thickness of 40 m, is composed of a clay-marl mass interspersed with lumachellic limestone layers. It makes up the middle part of the ‘’Marnes de Smail’’ Formation. The Turrilites acutus Subzone of the upper part of the Acanthoceras rhotomagense Zone corresponds to the Aspidiscus cristatus Total Range Zone, and the Rotalipora cushmani Zone was recognized based on the study of ammonites, scleractinian and planktic foraminifera in this section. The statistical analysis of the foraminifera yielded only one assemblage of planktic foraminifera with globular chambers and trochospiral test belonging to the Cenomanian–Turonian; no association is typically restricted to the middle Cenomanian. The benthic foraminifera are poorly represented, belonging to the orders Textulariina, Lituolina, Trochamminina, Verneuilinina, Loftusiina, Orbitolinina, Miliolina, and Rotaliina. These foraminifera assemblages indicate that the bottom-water conditions during the middle Cenomanian were characterized by periodic changes in the oxygen and salinity. All planktic foraminifera species are opportunists related to poorly oxygenated, eutrophic conditions interspersed by a short interval of well-oxygenated environment with Planolites. The maximum abundance of Whiteinella and Muricohedbergella and the minimum amount of Planoheterohelix species within the Cenomanian of Djebel Azeb reflect dwindling palaeosalinity during this time, except for a slight increase in the middle of the section.

In the western part of the Aurès Basin (northeastern Algeria), the Red Marls of El Kantara Formation records a mixed microfaunal association of non-marine-brackish ostracoda, marine foraminifera, lacustrine charophytes, and subaerial Microcodiums. Based on the recovered biotic component, it is considered that the Red Marls of El-Kantara Formation date from the upper Paleocene (Thanetian). Seven species of brackish water (Neocyprideis raoi) and non-marine ostracoda (Frambocythere tumiensis anjarensis, Paracypretta jonesi, Paracypretta verruculosa, Limnocythere deccanensis, Darwinula torpedo and Zonocypris spirula), have been discovered for the first time in Algeria and on the south Tethyan margin. Paleoenvironmentally, the overall biotic assemblage recovered indicates the presence of a freshwater palustrine/lacustrine depositional system connected to a low energy stream/river. This indicates that marginal marine conditions were prevalent in northeastern Algeria’s far inland regions. Paleobiogeographically, the seven known ostracod species have limited distributions that are until now common only with India. However, this disproved the theory that these species are endemic to the Indian Subcontinent, which is confirmed by their association with cosmopolitan charophytes.

This study aims to analyze the chemical composition of Lioua’s groundwater in order to determine the geological processes influencing the composition and origin of its chemical elements. Therefore, chemometrics techniques, such as multivariate statistical analysis (MSA) and time series methods (TSM) are used. Indeed, MSA includes a component analysis (PCA) and a cluster analysis (CA), while autocorrelation analysis (AA), supplemented by a simple spectral density analysis (SDA), is used for the TMS. PCA displays three main factors explaining a total variance (TV) of 85.01 %. Factors 1, 2, and 3 are 68.72%, 11.96%, and 8.89 % of TV, respectively. In the CA, total dissolved solids (TDS) and electrical conductivity (EC) controlled three groups. The elements SO₄²⁻, K⁺, and Ca²⁺ are closely related to TDS, the elements Na⁺, Cl⁻, and Mg²⁺ are closely related to CE, while HCO³⁻ and NO³⁻ indicate the dissociation of other chemical elements. AA shows a linear interrelationship of EC, Mg²⁺, Na⁺, K⁺, Cl⁻, and SO₄²⁻. However, NO₃⁻ and HCO₃⁻ indicate uncorrelated characteristics with other parameters. For SDA, the correlograms of Mg²⁺, Na⁺, K⁺, Cl⁻, and SO₄²⁻ have a similar trend with EC. Nonetheless, pH, Ca²⁺, HCO₃⁻ and NO₃⁻ exhibit multiple peaks related to the presence of several distinct cyclic mechanisms. Using these techniques, the authors were able to draw the following conclusion: the geochemical processes impacting the chemical composition are (i) dissolution of evaporated mineral deposits, (ii) water–rock interaction, and (iii) evaporation process. In addition, the groundwater exhibits two bipolar characteristics, one recorded with negative and positive charges on pH and Ca⁺ and another recorded only with negative charges on HCO₃⁻ and NO₃⁻. On the other hand, SO₄²⁻, K⁺, Ca²⁺, and TDS are the major predominant elements in the groundwater’s chemical composition. Chloride presence mainly increases the electrical conductivity of water. The lithological factor is dominant in the overall mineralization of the Plio Quaternary surface aquifer waters. The origins of HCO₃⁻ and NO₃⁻ are as follows: HCO₃⁻ has a carbonate origin, whereas NO₃^– has an anthropogenic origin. The salinity was affected by Mg²⁺, SO₄²⁻, Cl⁻, Na⁺, K⁺, and EC. Ca²⁺, HCO₃⁻, and NO₃⁻ result from human activity such as the usage of fertilizers, the carbonate facies outcrops, and domestic sewage.

In order to evaluate and project the quality of groundwater utilized for irrigation in the Sahara aquifer in Algeria, this research employed irrigation water quality indices (IWQIs), artificial neural network (ANN) models, and Gradient Boosting Regression (GBR), alongside multivariate statistical analysis and a geographic information system (GIS), to assess and forecast the quality of groundwater used for irrigation in the Sahara aquifer in Algeria. Twenty-seven groundwater samples were examined using conventional analytical methods. The obtained physicochemical parameters for the collected groundwater samples showed that Ca²⁺ > Mg²⁺ > Na⁺ > K⁺, and Cl⁻ > SO₄²⁻ > HCO₃⁻ > NO₃⁻, owing to the predominance of limestone, sandstone, and clay minerals under the effects of human activity, ion dissolution, rock weathering, and exchange processes, which indicate a Ca-Cl water type. For evaluating the quality of irrigation water, the IWQIs values such as irrigation water quality index (IWQI), sodium adsorption ratio (SAR), Kelly index (KI), sodium percentage (Na%), permeability index (PI), and magnesium hazard (MH) showed mean values of 47.17, 1.88, 0.25, 19.96, 41.18, and 27.87, respectively. For instance, the IWQI values revealed that 33% of samples were severely restricted for irrigation, while 67% of samples varied from moderate to high restriction for irrigation, indicating that crops that are moderately to highly hypersensitive to salt should be watered in soft soils without any compressed layers. Two-machine learning models were applied, i.e., the ANN and GBR for IWQI, and the ANN model, which surpassed the GBR model. The findings showed that ANN-2F had the highest correlation between IWQI and exceptional features, making it the most accurate prediction model. For example, this model has two qualities that are critical for the IWQI prediction. The outputs’ R² values for the training and validation sets are 0.973 (RMSE = 2.492) and 0.958 (RMSE = 2.175), respectively. Finally, the application of physicochemical parameters and water quality indices supported by GIS methods, machine learning, and multivariate modeling is a useful and practical strategy for evaluating the quality and development of groundwater.

Accessibility of fresh water, the nature's gift wheels the foremost part of the world economy. The sufficient supplies of water are essential for agriculture, human intake, industry as well as regeneration. The Oued Righ region is located in Algeria's South-East, specifically in the North-East of the Sahara, on the Northern edge of the Grand Erg Oriental and the Southern border of the Aures massif. This area appears as a lower Sahara synclinal basin and is part of a broad North-South trending ditch.

It is famous for its date palms, the development of the date culture in this region is attributed not only to the population’s efforts, but above all to the particular climatic conditions, the favorable soil characteristics and the existence of significant groundwater. The aim of this study is to understand the results obtained from using different approaches of water   hydrodynamics in   the Complex Terminal aquifer. The aquifer’s hydrodynamic characterization was carried out using hydrodynamic parameters and piezometry. As a result, the transmissivity and permeability obtained data using traditional Cooper-Jacob method showed that the flow capacities of the aquifer environment and the productivities of the structures are important in the studied zone where, the highest value of transmissivity equal 2.36× 10^2-m²/s is found in the central part of the study area in El-Meghair. The establishment of piezometric maps reveals a flow direction oriented toward the chott.

Purpose. The neritic aquifer that extends between Hammam Bradaa and El Fedjoudj, despite its faulted and in places karstified structure, due toits capacity and lateral extension represent a strategic resource for the region. Its waters are used for drinking water supply in the neighboring towns: Heliopolis, Guelaat Bousbaa, Nechmaya and El Fedjoudj, as well as in part of the Annaba wilaya. These neritic limestones outcrop at Djebel Debagh and Bouzitoune.

Methods. In order to better study the potential of this aquifer, it is essential to identify its geometry and structure by ana lyzing the geological data, mechanical drilling data and geophysical data analysis through an electrical survey campaign. Findings. The main results indicate that the study area has identified two important aquifer formations: a formation in the Mio-Plio-Quaternary alluvium consisting of clays, marls, gravel and sand; the second is a deep carbonate aquifer composed of fissured and karstified neritic limestone of the Cretaceous age of variable depth ranging within 50 and 350 m.

Originality. The originality of the study is in the fact that the studied area is characterized by the presence of thick, frac tured and karstified carbonate formations, which are intensively tectonized and have significant aquifer potential.

Practical implications. The correlation of geological data with geophysical data made it possible to conclude that the stu died area is a sedimentary basin bounded by faults predominantly oriented to the south-west and north-east, forming a highly fractured unit consisting of horsts and grabens. The significant water potential reservoir is formed essentially by carbonate geological formations, highly fractured with the presence of karst forms represented by resistant horizons.

Most Middle Eastern and North African regions are characterized by an arid and semi-arid climate. As such, the drinking water supply and management have become a challenging task for local and regional authorities. The Mio-Plio Quaternary aquifer of the Barika area is the only drinking and irrigation water reservoir in the region. The objective of this paper is to identify the origin and evolution process of the groundwater mineralization of this aquifer using major elements as indicators. To achieve this objective water samples were collected, from several boreholes drilled in the aquifer, in June 2018 and March 2019, and subsequently analyzed. The results obtained in terms of Gibbs plot, Piper, chemical correlation, and statistical analysis of chemical data identified the origins of groundwater mineralization. The dissolution of evaporated minerals, precipitation of carbonates, evapotranspiration, and ion exchange reactions have been identified as the primary processes of mineralization. The results of the physicochemical analysis showed that these waters consisted mainly of chloride, calcium sulfate, and magnesium facies types with a slight change of facies in some boreholes during the two sampling periods. This is due to the interactions with the-aquifer geology and to the water scarcity caused by climate change.

Recently, the Guelma region, located northeast of Algeria, has been facing an unusual water shortage. To bypass this situation, a geophysical study using gravity and resistivity has been initiated to enhance the understanding of the geology and hydrogeology of the deep structures of the study area. In order to accomplish this, a residual gravity anomaly map has been constructed by removing from the Bouguer anomaly map a regional gravity gradient using the upward continuation technique. For the purpose of validating the Vertical Electrical Sounding(VES) interpretation, two soundings were conducted near boreholes with known lithology. The Hammam Bradaa deep aquifer of the Guelma region is composed of limestones that belong to the Constantine neritic domain. The Constantine neritic domain is covered by thrust nappes and outcrops in some places of the study area as tectonic windows. The exact geometry such as depth and lateral extent of the aquifer are not well known. Since limestones are characterized by high densities and resistivities relative to the host rock, the combining of gravity and VES was able to accurately map their extension among the other lithologies composing the geological section. Multiscale edge detection of gravity data known as "worms" made it possible to highlight the principal lineaments across the study area which may contribute to the recharge of the Hammam Bradaa aquifer. The 3D Gravity inversion enabled the mapping of the spatial configuration of limestones that are characterized by positive gravity contrast relative to the host rocks. A vertical density slice extracted from the 3D gravity inversion, running from north to south, reveals a significant thickness of limestone beneath Hammam Bradaa which suggests a strong potential for groundwater resources. The geo-electric section, constructed from the interpretation of VES data and calibrated with well lithology, enabled the mapping of the depth to the top of limestone beneath conductive alluvium and marls.

The Bellezma Mounts, located in the northeast of Algeria, present cases of hydrothermalism with temperatures ranging between 30° C and 63° C. For the evaluation of the thermal potential of this dissymmetrical mountains chains (often rectified in the South, where Cretaceous and Jurassic limestones emerge), we used a multidisciplinary approach, notably geology, geophysics, hydrogeology, hydrochemistry and the isotopic tool. Hydrogeological investigations have shown that these carbonate formations can offer an important aquifer potential. From the hydrochemical point of view, the warm waters of the Bellezma mounts are characterized by the presence of three different chemical facies: the sulfated-sodium, the bicarbonate-calcium and the chloride-calcium. Evaporite terrigenous origin is attributed to sodium, chlorides and sulphates of these waters. The thermal waters circulation in this region, at great depths in the crystallophyllian formations and the carbonate ones, in contact with terrigenous salt formations, could be responsible of the salinity characterizing these waters, in some places. Geothermometry has shown that these thermal waters acquire a high temperature in their original tanks coming from a depth ranging from 1100 to 2600 m through a fault system that affects the basement. The use of the isotopic tool has shown that the thermal waters of this region are ancient and that their recharge is weak or non-existent.

The Mexa and Bougous dams were built to control river floods and supply crop-irrigation and drinking water. This study aimed to characterize the hydrogeochemical state in the region containing the dams, which influences the quality of the waters and thus their suitability for agricultural use, given the extent of the river networks that naturally transport sediments and pollutants into the reservoirs via streams. Thus, some physicochemical and organic parameters, including electrical conductivity, calcium, magnesium, sodium, potassium, chloride, bicarbonate, sulfate, biological oxygen demand, nitrite, ammonium, and phosphate, were used as benchmarks to examine the stiffness of the water pollution. Sampling was carried out during May and September of 2011 and 2012. The obtained results showed that, according to the Stiff diagram, the dominant hydrogeochemical facies is calcium bicarbonate in waters that do not have calcium levels in excess of 3 meq/l and bicarbonate levels in excess of 2.4 meq/l. The organic pollution index disclosed that the waters have evolved from a moderate to a high degree of organic pollution due to the accumulation of pollutants and nutrients from waste disposal and fertilizers. The samples fell into the C2-S1 class in the Richards diagram; this implies that the waters are suitable for plants that are salt tolerant, but that the use of these waters can cause problems for clay soils. However, in the long term, irrigation with the dam waters may pose difficulties for agriculture due to the resulting increase in the electrical conductivity of the soil. This study concludes that water salinity and alkalinity affect crop suitability, meaning that the temporal monitoring of water quality is needed to avoid adverse consequences for crop production.

The region of Tadjenanet is in eastern Algeria in the high plains, characterized by a varied age detritus Mio-Plio-Quaternary. Some geological formations can be an important source of groundwater (alluvial sand, shell limestone, gravel). Its location in semi-arid area involves evaporation pronounced even tilt the balance in a chronic deficit, excluding periods characterized by rainfall events. Agriculture in the study area is the first socio-economic activity and the largest consumer of water resources. It is therefore necessary to consider for effective water management. Indeed, the combination of hydrogeological and hydro chemical geological mapping, geophysics, harvested from field data and their interpretations can be an excellent tool for deciding the suitability of water for irrigation. The analysis of the physicochemical data shows an increase in the concentration of nitrates reaching 200 mg · l–1, as well as the analysis by the Richards SAR parameter shows that most groundwater samples are generally suitable for agricultural purposes with 33%, belong characterizing poor quality. Indeed, the groundwater in the region generally requires prior treatment before consumption and use depending on the type of crop. The assessment of the quality of the water in the region and its consequences on the soil and the types of crops has enabled the authorities concerned to manage the water supply adequately to preserve and protect this vital source for the future from any risk of contamination.

Purpose. Several natural and anthropogenic factors control the hydro-geochemical behavior of groundwater. These factors influence on the quality, even the suitability of this resource for drinking. The main purpose of our study is the application of multivariate statistical methods to compile the mechanisms of mineralization acquisition in confined aquifers. Methods. The adopted method measures the chemical evolution of Ca+2, Mg+2, Na+, K+, HCO-3, Cl-, SO4-2, NO-3, NO-2, NH+4, and PO4-3 using an atomic-absorption spectrometer. The content of nitrogen and dissolved oxygen is measured using a spectrophotometer. Temperature (T°), electrical conductivity (EC), pH and dissolved oxygen are determined using a multi-parameter system. Findings. The main results show that 28 water samples from the Mio-Plio-Quaternary aquifer of the Gadaïne-Ain Yaghout plain have chemical facies of chloride, sulfate-calcium and chloride-magnesium types. Originality. The originality of the study is in the demonstration that water acquires its carbonate mineralization at the supply limits. Whereas it acquires its chloride, sodium and sulfate mineralization in contact with terrigenous saliferous formations, as well as in its interaction with the salt chotts formations. The results show a significant variation in the concentrations of chemical elements, in some cases exceeding drinkability standards. Mineralization is mainly caused by the dissolution of evaporitic minerals such as gypsum, halite and epsomite.

Practical implications. The practical implications of this study could be resumed in terms of the convenience of multiva-riate statistical evaluation of complex physical-chemical databases in identifying pollution sources and understanding temporal variations for effective groundwater quality management in semiarid regions.

The landslide studied is located on RN 77 at PK 23+100 in the municipality of Texenna, 25 km southeast of the wilaya of Jijel. The faults observed in the study area are the result of the combination of several factors: the slope of the slope, the lithology of the soil and the strong pluviometry. The project studied consists in the design and analysis of the stability and reinforcement by backfill reinforced with geotextiles. A visual survey was carried out to clarify the probable causes of the impairments, followed by a geological and geotechnical reconnaissance campaign to determine the lithological nature and the physical and mechanical properties of the different formations that make up the soil. The study continued with a backfill reinforced with geotextiles. The analysis of stability and reinforcement was carried out using the finite element method and Plaxis 2D software. According to the results obtained, which give satisfactory values for the coefficient of safety for different combinations of loads, the choice of installing the geotextile wall at the foot of the road is a technical and economic solution aimed at ensuring stability and restoring the collapsed part of the roadway Keywords: Stability; Reinforced embankment; Coefficient of safety.

The Mexa and Bougous dams were built to control river floods and supply crop-irrigation and drinking water. This study aimed to characterize the hydrogeochemical state in the region containing the dams, which influences the quality of the waters and thus their suitability for agricultural use, given the extent of the river networks that naturally transport sediments and pollutants into the reservoirs via streams. Thus, some physicochemical and organic parameters, including electrical conductivity, calcium, magnesium, sodium, potassium, chloride, bicarbonate, sulfate, biological oxygen demand, nitrite, ammonium, and phosphate, were used as benchmarks to examine the stiffness of the water pollution. Sampling was carried out during May and September of 2011 and 2012. The obtained results showed that, according to the Stiff diagram, the dominant hydrogeochemical facies is calcium bicarbonate in waters that do not have calcium levels in excess of 3 meq/l and bicarbonate levels in excess of 2.4 meq/l. The organic pollution index disclosed that the waters have evolved from a moderate to a high degree of organic pollution due to the accumulation of pollutants and nutrients from waste disposal and fertilizers. The samples fell into the C2-S1 class in the Richards diagram; this implies that the waters are suitable for plants that are salt tolerant, but that the use of these waters can cause problems for clay soils. However, in the long term, irrigation with the dam waters may pose difficulties for agriculture due to the resulting increase in the electrical conductivity of the soil. This study concludes that water salinity and alkalinity affect crop suitability, meaning that the temporal monitoring of water quality is needed to avoid adverse consequences for crop production.

In this study, a new approach integrating a groundwater vulnerability method and a numerical model for predicting groundwater resource sustainability under actual and future conditions of exploitation (2010–2030) is proposed in the semi-arid region of the Tebessa-Morsott alluvial aquifer (northeastern Algeria). The groundwater vulnerability method-based DRASTIC model was used to evaluate and delineate the vulnerable areas using a GIS technique. The MODFLOW code, on the other hand, was used to calculate the dynamics of groundwater level under actual and future conditions of exploitation considering two scenarios. The results of the application of the DRASTIC method to the reference year conditions (year 2010) showed that the high and average vulnerability classes covered a wide zone of the study area, about 97%. These results were validated based on the nitrate concentration values (R² = 0.955). However, the results for predicting future groundwater vulnerability showed that groundwater vulnerability variation over time (period 2010–2030) was closely related to groundwater depth variation caused by the pumping rate, since the decreases in the piezometric level produce a worsening of groundwater vulnerability. To achieve better groundwater management, an experimental site for artificial recharge supplemented by hydro-chemical monitoring of the groundwater could be an effective remediation strategy.