Résumé: A methodology was developed and applied to the Tindouf basin (south-western Algeria) to understand the hydrogeology of a complex aquifer system with a limited number of data, to identify the favorable areas for the design and building of new wells, and to know whether there is still current recharge of these aquifers. The principal components analysis (PCA), diagram of deuterium versus oxygen-18, and equilibrium diagrams Mg/Na and Ca/Na were the techniques used to combine different datasets in order to identify chemical and isotopic groups, which were in turn used to define the groundwater flow paths. In addition, on the basis of thermodynamic equilibrium, it is possible to define the chemical evolution of the Tindouf basin aquifer. The results of this study are consistent with the generally accepted hydrogeological conceptual model. The combination of the different methods made possible to define and and to characterise the main groundwater flow paths from their sources to the discharge zones. These flow paths are defined by water categories, which are represented by salinity and groundwater origin. This approach can be used to analyze aquifers characterized by a lack of data and can also be useful for studying other complex groundwater basins.

Résumé: In this paper, multiple linear regression (MLR) and radial basis function neural network (RBF-NN) are applied to predict nitrate (NO 3−) concentration with and without reservoir volume (WV) as predictor using monthly data for ten years in three water reservoirs located in the upper Cheliff basin (NW of Algeria). The datasets were divided into training (80%) and testing (20%) sets and two different scenarios were compared. The results revealed that RBF-NN was more efficient (MAE = 0.192 and SI = 0.061) compared with the MLR model to predict NO3− in all reservoirs. RBF-NN provided the best accuracy in the testing period with a high R2 of 0.957 in reservoir II, and low MSE and PBias of 0.048 mg/l and 2.98% in the training period in reservoir III, respectively. Overall, the best results were generated by M(iii) in scenario B.

Résumé: Seawater intrusion represents a high risk for the water supply, the agriculture and industry activities in the lower Seybouse region of North-Eastern Algeria. In order to analyze this risk, a three-dimensional model was developed using the MODFLOW and MT3DMS codes to predict seawater intrusion in the coastal aquifer. The application of this model indicates that the groundwater withdrawals result in a continuous decrease of the water level and in an increase of chloride concentration. Moreover, the salt front could progress by 300 to 2500 m in the land. These results show the necessity of adequate measures for the protection of the aquifer. Numerical predictions for 2045, considering an increase of groundwater withdrawals by 20%, show a fairly significant decrease in water levels, up to -6 m with respect to the mean sea level, and an increase of Cl- concentrations up to about 10 km inland.

Résumé: The Bouchegouf Plain is an industrial and mainly agricultural region. The results of analyses revealed high concentrations of physicochemical and bacteriological parameters in surface and underground waters. The objective of this research is to study the impact of the various discharges on water and the environment. Physicochemical and bacteriological analysis methods are used to characterize the surface and groundwaters. The synthesis of geological, hydrogeological and physicochemical data made it possible to develop models of underground flows and to delimit the perimeters of protection of the wells. The results showed a significant threat to the environment (Mellah and Seybouse streams) and to the waters of the alluvial aquifer. Indeed, the high concentrations of physicochemical and bacteriological parameters, in particular at the point of discharge of the yeast plant, can have harmful effects on fauna, flora and human health (waterborne diseases). Simulations of groundwater flows and pollutant transfer showed that groundwater is strongly affected by the drainage of the Seybouse wadi. Road traffic can also be the source of accidental pollution.

Résumé: The water quality index is one of the prominent general indicators to assess and classify surface water quality, which plays a critical role in river water resources practices. This research constructs a hybrid artificial intelligence model namely sequential minimal optimization-support vector machine (SMO-SVM) along with random forest (RF) as a benchmark model for predicting water quality values at the Wadi Saf-Saf river basin in Algeria. The fifteen input water quality datasets such as biochemical oxygen demand (BOD), oxygen saturation (OS), the potential for hydrogen (pH), chemical oxygen demand (COD), chloride (Cl−), dissolved oxygen (DO), electrical conductivity (EC), total dissolved solids (TDS), nitrate-nitrogen (NO3-N), nitrite-nitrogen (NO2-N), phosphate (PO43−), ammonium (NH4+), temperature (T), turbidity (NTU), and suspended solids (SS) were employed for constructing the predictive models …

Résumé: Impact of organic and microbiological pollution on the quality of water in Boussellam Valley and its environment, Setif City, Northeast Algeria. Biodiversitas 23: 2621-2629. Water pollution is a major threat and a global challenge that endangers life on earth at risk because water plays a major role in daily life. Several sources of water pollutants, i.e., organic, industrial, domestic and microbial pollution, may trigger an outbreak of water-borne diseases. Boussellam Valley crosses the Quaternary formations, which dominate the extent of the plain surrounding the region of Sétif in the North-East of Algeria. It is one of the main water resources, mainly for drinking water supply and irrigation. The shallow water table composed of the geological formations containing this aquifer is very heterogeneous in texture and varies considerably from upstream to downstream of the sub-watershed. Thus, the North and East zones are marked by chloride-calcium facies, the central part by a Bicarbonate-calcium facies. At the same time, sulfate-magnesium facies characterize the West zone. This study aimed to evaluate the pollution by organic elements: nitrites, nitrates, and microbiological elements: total and fecal coliforms and streptococci and their impact on the water quality. Samples were collected during May and June 2021 from 5 stations along the valley, and 18 wells were spread out on the plain. The analysis of nitrites and nitrates was carried out by liquid chromatography. In addition, the colony counting of coliforms and streptococci was carried out according to the recommendations of the Algerian water company. The results show an increase in the concentration of nitrites, nitrates, total and fecal coliforms, and the streptococci, particularly in valley waters with very high levels that exceed the normal threshold of drinking water. This increase may be due to wastewater discharges and the intensive use of fertilizers, septic tanks, leaching of animal manure, runoff water, and rearing of domestic or wild animals. The increased levels of nitrites, nitrates, total and fecal coliforms, and the streptococci increase the risk of the vulnerability of the waters of the plain to pollution and degradation of surface waters and the environment in genera

Résumé: Algeria has established a growing urban pole, therefore urbanization and urban dynamics are increasing from year to another, and it occurs a flow of excessive urban wastewater discharges from these agglomerations. In this research, we are interested in the evaluation of the current state of wastewater, which comes from 1114 residences by household activities and human metabolism, or the mixing of domestic wastewater with water runoff. In the extreme North east of Algeria, the predominantly domestic waters of Drâa-Errich city, evacuated through collectors and without treatment they are rejected in nature, and the quality of the water at the level of the Gueridjima wadi has deteriorated and these waters currently constitute a polluted effluent which joins the waters of the El Aneb wadi to the west. A set of analyzes was carried out (period of April to May 2021) on domestic wastewater to assess their quality. Sampling and analysis carried out of surface water (02 samples from Gueridjima wadi and 02 samples from El Aneb wadi) and groundwater (01 well), covering an area of 15 km. The physic-chemical parameters measured with the WTW multiparameter are pH, temperature, electrical conductivity EC, biological demand in oxygen BOD5. In addition, the undesirable substances are Nitrates (NO3-), Nitrites (NO2-), Phosphates (PO4-), and orthophosphate. In front of this situation, the measures proposed are the systems for treating domestic wastewater sewage, seen the advantages represented by the topography of the land in the region; remains the better solution for possible reuse recovery of wastewater, in agriculture sector. This measure will certainly improve the quality in terms of production of an acceptable quality of (purified) wastewater, and reduce environmental problems

Résumé: The growing demand for fresh water and its scarcity are the major problems encountered in semi-arid cities. Two different techniques have been used to assess the main determinants of domestic water in the Sedrata City, North-East Algeria: prin- cipal component analysis (PCA) and artificial neural networks (ANNs). To create the ANNs models based on the PCA, twelve explanatory variables are initially investigated, of which nine are socio-economic parameters and three physical char- acteristics of building units. Two optimum ANNs models have been selected where correlation coefficients equal to 0.99 in training, testing and validation phases. In addition, results demonstrate that the combination of socio-economic parameters with physical characteristics of building units enhances the assessment of household water consumption.

Résumé: Prediction of groundwater flow fluctuations is considered an important step in understanding groundwater systems at this scale and facilitating sustainable groundwater management. The objective of this study is to determine the factors that influence and control groundwater flow fluctuations in a specific geomorphologic situation, by developing a forecasting model and examining its potential for predicting groundwater flow using limited data. Models for prediction of groundwater flow are developed based on artificial neural networks (ANNs). Neural networks with different numbers of hidden layer neurons were developed using climatic and geomorphological characteristics as input variables, giving predicted groundwater flow as the output. To evaluate enhanced performance models, several regression statistical parameters are compared. As an example, relative mean square error in groundwater flow prediction by ANN and correlation coefficient are 0.015 and 97%, respectively. The results of the study clearly show that ANNs can be used to predict groundwater flow in shallow aquifers of northern Algeria with reasonable accuracy even in the case of limited data. HIGHLIGHTS Combine hydrological and climatic data to estimate groundwater flows.; Test the performance of ANN's models to understand the behavior of groundwater.; Large-scale groundwater flow modeling for better management of water resources.; Proposal of a predictive model for a global vision of the distribution of groundwater.; Determining the order of importance of indicators that can influence groundwater flows.

Résumé: This paper presents artificial neural network (ANN) techniques such as generalized regression neural networks (GRNNs), radial basis neural networks (RBFNNs) and multilayer perceptron neural networks (MLPNNs) for predicting quarterly water demand (QWD). The data set including total of 720 data records is divided into two subsets, training and testing. Various ANN models depending on the combination of antecedent values of water demand, temperature, rainfall and population are constructed and the best-fit input structure is examined. The performance of ANN models in training and testing phases are compared with the observed water demand values to select the best-fit forecasting model. For this purpose, some performance criteria such as root mean square error, coefficient of determination (R2) and accuracy factor (Af) are evaluated for different models (GRNN, RBFNN and MLPNN). The results …

Résumé: This study describes the combination of neural networks and multivariate methods to develop a proper model for the forecasting of water quality index (WQI) in the Saf-Saf River using water quality parameters. The main objectives of this work were to determine the importance of different input variables and to assess the spatial and temporal water quality variation. MLP models were trained using three different algorithms and tested, these models were compared in terms of efficiency criteria and goodness-of-fit for WQI modeling. The results show that MLP BFGS model provide the best performance with small root mean square error value (RMSE = 0.007) and high coefficient of determination value (R2 = 0.811) compared with the other types of MLP models. In the meantime, sensitivity analysis reveals that BOD 5 acts as the most contributor decreasing WQI. PCA/FA results show relatively spatial and seasonal changes in surface water quality, it generated three groups of sampling sites with similar characteristics. Group I (upstream sites), group II (midstream sites), and group III (downstream sites) correspond to a relatively low pollution, moderate pollution, and high pollution sites, respectively. Therefore, this approach can provide managers with the right tools to make decisions about the implementation of sustainable management practices

Résumé: To some extent, the sedimentary sequence with the largest groundwater reserves in northern Sahara is marked by a certain water table level, regionally known as the “Continental Intercalaire” (CI). “Continental Intercalaire” (CI) refers to “Continental Intercalary” widely distributed among three countries. Algeria, Tunisia and Libya, which have significant potential of water resources. As it is the only water resource relatively easily accessible to the inhabitants of the Sahara, it is widely developed. The physico-chemical characteristics of statistical processing in principal component analysis (PCA) and the chemical phase measurement of groundwater in the unconfined aquifer captured by “Foggaras” (traditional system irrigation composed of well system linked by a horizontal channel from their bases) and the deep drillings located in the study area were accessible. Therefore, there were some favorable conditions for comparing the chemistry of these waters with the standards of potability established by the World Health Organization. Then, the study detected the origin of excessive mineralization and the excessive content of Na, Cl, K, Mg and Ca that originated from the leaching of the clay and carbonate layers of the “Continental Intercalaire”. In addition, the enrichment in NO 2- , NO 3- and SO 42- was due to the excessive use of fertilizer in the whole region for shallower Foggaras waters, and this study also showed the dominant chemical facies of groundwater related to the significant abundance of these mineral salts in this thick aquifer horizon.

Résumé: The water quality of aquifer is conditioned by geological formations crossed by water during its flow. So water crossing calcareous rocks becomes rich in bicarbonates; also water crossing saliferous rocks becomes rich of sulphates or chlorides. This affirmation can be applied to water of the karst aquifer of Taoura. The recharge of this aquifer comes from rainfall or by water of different draining zones of the watershed cross-border of Medjerda-Mellegue in south part of the city of Souk Ahras. The geological studies showed that the outcrop formations in the syncline contain groundwater in low level, which make the aquifer captive. This last is exploited by several wells (T1, T3, T7, D3, D5). The observation of stratigraphic logs shows a lithological heterogeneity of the aquifer, which is going to explain the variation of its hydrochemical composition. Samples and analysis carried out showed that groundwater of this aquifer is rich in calcium and bicarbonate; however some wells are characterized by the domination of chlorides and sulphates; these anions are accompanied by sodium or by calcium. So, the impact of geological rocks crossed by water is important on the characterization of groundwater quality. Also, the risks of pollution in unconfined parts of the aquifer are quasi unavoidable, and they are confirmed by concentration of nitrates >50 mg/l.

Résumé: Increasing water demand in the Bouteldja region has led to a systematic use of all the resources available in the region, including on its borders. However, the development of anthropogenic activities and population expansion in the Bouteldja region pose a risk to groundwater, which constitutes almost half of the resources mobilized. On the basis of the analytical results obtained for series of samplings (2006- 2013), carried out on the main measurement-networks (wells, drilling and piezometers), we have tried to identify the main factors that influence the evolution-of the physico-chemical parameters quality of water and to understand the degree of vulnerability of aquifer reservoirs. From these analytical data have been developed temporal evolution diagrams, spatial distribution maps, hydrochemical maps, and Principal Component Analysis PCA to illustrate the physicochemical evolution of water in Bouteldja region.

Résumé: La plaine de Collo, à vocation agricole, d’où la nécessité d’irriguer pour faire face aux aléas des changements climatiques particulièrement durant la saison estivale. La plaine est limitée au nord par la mer Méditerranée, ce qui l’expose à une éventuelle intrusion marine. Le but de notre travail est d’utiliser les résultats issus de la combinaison de plusieurs méthodes pour mettre en évidence une éventuelle relation entre la mer-nappe dans cette région. La plaine de Collo a une forme quadrilatérale allongée, d'une longueur de 8 Km et d'une largeur de 5 Km le long de la mer, avec une superficie d’environ 18 Km². Elle est parcourue par les Oueds Guebli et Cherka, qui se versent dans la mer. A partir de mesures réalisées sur le terrain (piézométrie et paramètres physiques) et des analyses faites au laboratoire, nous avons réalisé notre travail. La carte piézométrique se rapportant au mois de mai 2016, montre des écoulements multidirectionnels : -un premier écoulement, de direction nord-sud, de la mer vers le continent dans la zone nord, -le second, localisé au centre de la plaine et mettant en évidence un pompage au niveau des puits situées non loin des Oueds. La présence de ces écoulements, nous amène à rechercher la mise en évidence d’une probable intrusion marine. Pour répondre à cette question, nous avons utilisé le calcul du delta ionique, les rapports caractéristiques et la méthode GALDIT. Les résultats obtenus indiquent une absence de l’intrusion marine. Cependant le calcul du delta ionique montre une présence des bicarbonates, leur présence est liée aux animaux marins à coquille calcaire comme les coquillages. La carte de vulnérabilité issue de la méthode GALDIT, montre que la zone nord est sujette à une probable intrusion marine.

Résumé: Many regions are facing formidable freshwater management challenges. Allocation of limited water resources, environmental quality and policies for sustainable water use are issues of increasing concern. Over the last decade, an integrated approach to water development has emerged which places water supply projects in the context of demand-side issues, as well as issues of water quality and ecosystem preservation. This paper investigates the water supply and demand situation in the Kebir-West River Basin, North-Eastern Algeria, and formulates a demand oriented water management approach in the all use sector in response to the increasing water penury due to population growth and local land irrigation expansion. This approach requires institutional reinforcement, water pricing reform and agricultural sector adjustment based on economic irrigation methods can reduce water demand by 30%. It is also the paper proposed to use a water evaluation and planning model (WEAP) for reviews the results of measures proposed for the Kebir-West River Basin management and concludes that with the growing water demand and climate change impact, the water authority can't continue to supply the water without trying to actually influence the demand. Demand management has to come into force as an important part of integrated river basin management, so as to ensure the sustainable development of the Kebir-West River Basin.

Résumé: The potentiometer area in the Annaba basin, covering an area of 264 km2, has declined considerably since 1995. The analysis of the chronological hydrographs (1991–2009) of the piezometric observations shows that this decline is related to about twenty years (20 years) drought that began in 1991. To synthesize hydrological data and study regional changes in aquifer interactions caused by changes in discharge, and determine the contamination of aquifers by salty intrusion in coastal areas, and making forecasts by the year 2023, a multi-layered transient model as well as a solute transport model has been developed. The groundwater flow was modelled using the finite difference method with a horizontal dimension of 500× 500 m for the cells. The model consists of two layers, the first corresponding to the alluvial phreatic aquifer and the second to the deep confined aquifer, and is calibrated against the steady state groundwater heads recorded before 1996. Model verification was done by history matching over the period 1991–2009. Under steady-state conditions, the correspondence between simulated and observed water levels is generally good (average difference of 0.4 m). For the deep aquifer, the simulated time--series hydrographs closely match the recorded hydrographs for most of the observation wells. For the alluvial aquifer, the recorded hydrographs cover only a short time period, but they are reproduced. The model indicates that groundwater pumping induced a decrease in natural discharge, a downward leakage in most of the basin and a continual water-level decline. The model has also been applied to the analysis of recharge.

Résumé: Water resources management in semi-arid Mediterranean countries with scarce water resources is a complex challenge. It requires new concepts and techniques if management should be based on sound scientific findings in order to optimize and conserve the precious water resources. In regards to integrated water resources management (IWRM), no systematic comprehensive multidisciplinary works have been developed so far and even they seem to have shortcomings. Therefore, many scholars explicitly have called for additional work to substantiate this aspect. In this research, a relation between groundwater abstraction and socioeconomic variables in the Annaba coastal aquifer has been developed based on a cause–effect relationship tackling the life cycle of water resources management. The driver-pressure-state-impact-response (DPSIR), EEA, was selected as a well-established framework to develop the possible socio-economic variables (Lallahem and Hani 2016).

Résumé: The current understanding of the causes of land-use change is dominated by simplifications, which in turn, underline many environment-development policies that led to unsustainable situation in Gaza City. Therefore, this research aims at establishing an integrated land-use management framework for Gaza city based on cause-effect relationship within sustainability context. It also aims at establishing a prediction model for the relationship between the most influential socio-economic, environmental and institutional indicators that had shaped the current land-use status of the city for the period 1967-2003. The methodology presented in this research work, offers opportunities to simulate the future demand of the different land-uses based upon actual land-use conditions and other determinant factors. The determinant variables of land-use changes have been identified and prioritized using statistical analysis and Artificial Neural Network (ANN). The results were compared with other statistical techniques and expert opinions. ANN prediction model helped in drawing scenarios for future development. Combinations of socio- economic, environmental and institutional variables in addition to the actual land use for the last four years are used as a basis of land-use change explanations and modeling. These pathways indicate that land-use policies and projections for the future must not only capture the population indicators as the only drivers for land-use change but also account for the specific human resource development indicators and urban- environmental conditions. This recognition requires moving beyond some of the simplifications that persist in much of the current understanding of the causes of land-use change and its driving forces. The analysis of the local expert’s opinions provide evidence support the conclusion that the simple answers found in population growth, poverty and infrastructure rarely provide an adequate explanations of land-use changes. Rather, social responses follow from changing economic conditions, mediated by institutional factors are the real causes for land-use changes in Gaza.