Contribution of Gravity Data for Structural Characterization of the Ifni Inlier, Western Anti-Atlas, Morocco: Hydrogeological Implications

The Sidi Ifni region in southwest Morocco is mainly composed of crystalline rocks with limited groundwater storage capacity. These water resources drain in particular fault zones with high fracture permeability. The main objective of this study is to describe the geological structure of the region to optimize future drilling locations. The gravity data were processed using various techniques, such as total horizontal gradient, tilt derivative, and Euler deconvolution, in conjunction with the interpretation of the geological data, to create a new structural map. This map confirms the presence of many previously identified or inferred faults and identifies significant new faults with their respective trends and depths. Analysis of this map shows that major faults are oriented NNESSW and NE-SW, while minor faults are oriented E-W, NW-SE, and NNW-SSE. The superposition of the hydrogeological data and the structural map reveals that the high groundwater flow values in the boreholes are located in the vicinity of the major faults and talwegs. The structures deduced from the filtering and interpretation of the gravity data suggest that the hydrogeological system of the Ifni Inlier is controlled by its structures. To confirm this impact, a high-resolution electrical resistivity map (7200 Hz) was used, with penetration depths ranging from 84 to 187 m. Negative boreholes, located in high resistivity ranges corresponding to sound basement formations without fault crossings, showed high resistivity values. The positive holes, located in anomalies with low linear resistivity, revealed the impact of fault crossings, which drain water and tend to decrease the resistivity values of the formations. Therefore, these new structural maps will assist in planning future hydrogeological studies in this area

Delineation of Groundwater Potential Area using an AHP, Remote Sensing, and GIS Techniques in the Ifni Basin, Western Anti-Atlas, Morocco

An assessment of potential groundwater areas in the Ifni basin, located in the western AntiAtlas range of Morocco, was conducted based on a multicriteria analytical approach that integrated a set of geomorphological and hydroclimatic factors influencing the availability of this resource. This approach involved the use of geographic information systems (GIS) and hierarchical analytical process (AHP) models. Different factors were classified and weighted according to their contribution to and impact on groundwater reserves. Their normalized weights were evaluated using a pairwise comparison matrix. Four classes of potentiality emerged: very high, high, moderate, and low, occupying 15.22%, 20.17%, 30.96%, and 33.65%, respectively, of the basin’s area. A groundwater potential map (GWPA) was validated by comparison with data from 134 existing water points using a receiver operating characteristic (ROC) curve. The AUC was calculated at 80%, indicating the good predictive accuracy of the AHP method. These results will enable water operators to select favorable sites with a high groundwater potential

Spatial Mapping of Groundwater Potentiality Applying Geometric Average and Fractal Models: A Sustainable Approach

Water scarcity affects all continents, with approximately 1.2 billion people living in areas where water is physically lacking. This scarcity is more accentuated in countries with an arid climate, and its impact becomes more threatening when the economy depends mainly on it. The Kingdom of Morocco, with its agricultural vocation, is one of them, especially in its southern regions. Therefore, mapping areas with high groundwater potential based on available geospatial data allows for optimizing the choice of a future well in such areas. Geometric average and fractal models were used to assess and delineate potential groundwater areas in the Tissent basin, Southeast Morocco. Eight factors, including topography, geology, hydrology, and hydrogeology, influencing the distribution of water resources was used. The formation permeability factor presents the most significant impact among the others, although it is directly related to most of them. The areas located in the central and downstream part of the basin are characterized by a high water potentiality due to increased geological formations’ permeability near the drainage system, which constitutes a recharge zone, and a low slope allowing a prolonged water-formation contact time favoring a gradual infiltration of the water towards the deep aquifers. The groundwater potential map has been edited and validated by comparing it with data from 52 wells scattered throughout the basin. The favorable potential sectors cover 15.81% of the basin’s total area. The moderate ones account for 21.36% while the unfavorable areas cover 62.83%. These results aim to provide policymakers and managers with a guide map for groundwater research and reduce hydrogeological investigation costs

Application of HEC-RAS/WMS and FHI models for extreme hydrological events under climate change in the Ifni River arid watershed from Morocco

Floods are among the most important natural disasters in the world. These phenomena are due to climate changes, which have caused natural hydrological events such as heavy rains. This study develops two methods applied to the watershed of the Ifni River, which is a hydro system located in the southwest of Morocco. The main objective of this chapter is to compare the flood risk determined using the Flood Hazard Index (FHI) method with the hydraulic model of HEC-RAS/WMS. This approach makes it possible to visualize and quantify the spatial distribution of floods in this basin. The FHI method makes it possible to map flood-prone areas throughout the basin while the HEC-RAS/WMS model allows it to map areas at risk of flooding downstream of the Ifni River basin due to the presence of a single station in this basin.ISBN för värdpublikation: 9780128221846; 9780128232651</p

The Missing Link in the Genesis of the Lower Paleozoic Copper Deposits of the Anti-Atlas (Morocco): The Late Triassic Central Atlantic Magmatic Province Event

Copper mineralization in the Lower Paleozoic sedimentary cover of the Anti-Atlas (Morocco) is continually being revised not only to improve its mining capacity, but also to determine its origin, which remains a matter of debate. As evidenced by the various models proposed, the related research is fragmented, localized, and confusing. The origin of the Anti-Atlas Lower Paleozoic copper mineralization is shared between synergistic and epigenetic processes or a superposition of the two processes. Based on new tectono-magmatic data and a reinterpretation of the ore structural arrangement, we propose a link between the last concentration of copper deposits and the Late Triassic–Early Liassic CAMP (Central Atlantic Magmatic Province) tectono-thermal event, as evidenced by the significant concentration of copper mineralization in the three NE–SW corridors affected by extensional faults, some of which are filled with dolerite CAMP magma. The heat flow generated by the mafic dykes within these reactivated corridors causes mineralized fluids to up well into the sedimentary layers, depositing material rich in juvenile or leached copper, or even a mixture of the two. In some cases, these fluids are trapped by fracture systems that accompany passive folds initiated on normal faults. In other cases, these fluids can infiltrate bedding planes, and even karst caves, formed during carbonate exhumation. Notably, extensive NE–SW faults systematically cover the early Hercynian structures, suggesting that they belong to a post-Hercynian extensional episode. During the Late Triassic, the global fragmentation of the Pangaea supercontinent was manifested by the stretching of the continental crust at the margin of northwest Africa, with the simultaneous opening of the Central Atlantic Ocean and emplacement of CAMP magmatism. This last and often overlooked tectonothermal event must be considered in the remobilization and reconcentration of copper mineralization and other mineralization in Morocco

Application of Fuzzy Logic and Fractal Modeling Approach for Groundwater Potential Mapping in Semi-Arid Akka Basin, Southeast Morocco

Groundwater potential delineation in the Akka basin, southwest Morocco, has been determined through the combination of geospatial techniques and geological data. The geometric average and expected value are two multi-criteria approaches used to integrate a set of factors–data for which the weights of each factor are assigned using the fuzzy logic function, which transforms values of factors influencing groundwater presence in a range of [0, 1]. The efficiency factors used in this study are the lineament density, node density, drainage density, distance from rivers, distance from lineament, permeability, slope, topographic witness index, plan curvature, and profile curvature. Thereafter, the groundwater potential map was generated in a GIS environment. To assess and compare the efficiency of the two models, the well data existing in the basin were used to choose the most efficient model. For that reason, the prediction area (P–A) graph, the normalized density (Nd), and its weight (We) were applied to estimate the capacity of each model to predict the target area. The analysis shows that the expected value model (Nd = 1.86 and We = 0.62) is more efficient than the geometric average model (Nd = 0.96 and We = −0.04). The results of the expected value model can be used in the future planning and management of water resources in the Akka basin

Application of Analytical Hierarchy Process and Geophysical Method for Groundwater Potential Mapping in the Tata Basin, Morocco

Ensuring water availability for agriculture and drinking water supply in semi-arid mountainous regions requires control of factors influencing groundwater availability. In most cases, the population draws its water needs from the alluvial aquifers close to villages that are already limited and influenced by current climatic change. In addition, the establishment of deep wells in the hard rock aquifers depletes the aquifer. Hence, understanding the factors influencing water availability is an urgent requirement. The use of geographic information system (GIS), and remote sensing (RS), together with decision-making methods like analytical hierarchy process (AHP) will be of good aid in this regard. In the Tata basin, located in SE Morocco, ten factors were used to explain the groundwater potentiality map (GWPM). Five categories of potential zones were determined: very low (8.67%), low (17.74%), moderate (46.77%), high (19.95%), and very high (6.87%). The efficiency of the AHP model is validated using the ROC curve (receiver operating characteristics) which revealed a good correlation between the high potential groundwater zones and the spatial distribution of high flow wells. Geophysical prospecting, using electrical resistivity profiles, has made it possible to propose new well sites. It corresponds to conductive resistivity zones that coincide with the intersection of hydrogeological lineaments

Characterization and Productivity of Alluvial Aquifers in Sustainability Oasis Areas: A Case Study of the Tata Watershed (Southeast Morocco)

Groundwater from alluvial aquifers is a critical source of water supply for rural agriculture, particularly in semi-arid and arid regions. Effective management of these aquifers requires an understanding of the factors that influence their water resources. In this study, we present a case study of the Tata watershed in southeastern Morocco, where the economy is heavily dependent on agriculture and relies exclusively on groundwater. We demonstrate the importance of integrating geological, hydrogeological, and geophysical methods to characterize the aquifer and evaluate groundwater productivity. Analysis of 64 data wells tapping into the aquifer revealed significant disparities in flow yields, ranging from 0.05 to 15.50 L per second. The highest yields were found between depths of 12 and 43 m, which correspond to the alluvium and the altered and fractured part of its substrate. The maximum alluvial thickness of 57 m was determined using geo-electrical prospecting. A piezometric map was created to define the recharge zones, which correspond to the lateral contributions of the bordering Georgian limestones, and infiltration of both rain and surface water along the Tata wadi. Since 1987, there has been a continuous drop in groundwater level, which can be attributed to the increase in irrigated areas following financial incentives provided by the Moroccan government to the agricultural sector. A proposal has been made for the construction of a recharge dam to enable the recharge of the alluvial aquifer. This development is expected to serve a dual purpose by mitigating the deleterious impacts of flooding and facilitating the gradual water infiltration of the alluvial aquifer. This case study provides insights into the hydrodynamics of the aquifer and establishes a simplified model of its functioning. These findings have important implications for the management of alluvial aquifers in similar regions

Mineral prospectivity mapping: a potential technique for sustainable mineral exploration and mining activities – a case study using the copper deposits of the Tagmout basin, Morocco

Mineral prospectivity mapping (MPM) based on the principle of geometric mean was applied to stream sediment geochemical, fault density, and aeromagnetic data from Tagmout basin, Morocco to determine new areas for optimizing copper exploration. The application of a fuzzy operator using stream sediment data, factor analysis, and fault density map, allowed weights to be assigned to these parameters so that the MPM function can process them to indicate the most favorable zones of copper mineralization. The model's accuracy as evaluated using a normalized density index (Nd with value 1.22) shows the reliability of the method. The potential copper concentration areas represent 8.22% of the entire basin of which 30% are concentrated in the western portion of the basin and other significant areas are in the southwest and northeast portions. The results indicate that MPM is a powerful technique for planning exploration programs that aim for sustainable mining activities

Spatial Mapping of Groundwater Potentiality Applying Geometric Average and Fractal Models: A Sustainable Approach

Water scarcity affects all continents, with approximately 1.2 billion people living in areas where water is physically lacking. This scarcity is more accentuated in countries with an arid climate, and its impact becomes more threatening when the economy depends mainly on it. The Kingdom of Morocco, with its agricultural vocation, is one of them, especially in its southern regions. Therefore, mapping areas with high groundwater potential based on available geospatial data allows for optimizing the choice of a future well in such areas. Geometric average and fractal models were used to assess and delineate potential groundwater areas in the Tissent basin, Southeast Morocco. Eight factors, including topography, geology, hydrology, and hydrogeology, influencing the distribution of water resources was used. The formation permeability factor presents the most significant impact among the others, although it is directly related to most of them. The areas located in the central and downstream part of the basin are characterized by a high water potentiality due to increased geological formations’ permeability near the drainage system, which constitutes a recharge zone, and a low slope allowing a prolonged water-formation contact time favoring a gradual infiltration of the water towards the deep aquifers. The groundwater potential map has been edited and validated by comparing it with data from 52 wells scattered throughout the basin. The favorable potential sectors cover 15.81% of the basin’s total area. The moderate ones account for 21.36% while the unfavorable areas cover 62.83%. These results aim to provide policymakers and managers with a guide map for groundwater research and reduce hydrogeological investigation costs